INTRODUCTION — Colorectal cancer (cancer of the large portion of the bowel [colon] or rectum) is a common, preventable disease. Approximately one-third of people who develop it die of the disease, making it the second leading cause of cancer death. However, screening tests now make it possible to detect existing cancers at an early, treatable stage and even to prevent the development of colorectal cancer.
There is general agreement by experts that all adults should undergo screening beginning at age 50, or earlier for people who are at high risk for colorectal cancer. Several different tests are currently available, and new tests are being developed; all of these have advantages and disadvantages. The optimal screening test depends upon a person's preferences and their risk of colon cancer. It is important to review each test's effectiveness, safety, convenience, and costs.
EFFECTIVENESS OF SCREENING — Most colorectal cancers develop gradually over many years. They begin as small, benign tumors called adenomatous polyps. These polyps grow, develop precancerous changes, eventually become cancerous, and later spread and become incurable. This progression takes at least 10 years in most people.
The screening tests described below all work by detecting pre-cancers at the polyp stage before they become cancerous or by detecting cancers themselves while they are still curable. Regular screening for and removal of polyps can reduce a person's risk of developing colorectal cancer by up to 90 percent. In addition, early detection of cancers that are already present in the colon often allows for successful treatment.
WHO SHOULD BE SCREENED? — Several factors increase an individual's risk of developing colorectal cancer. The presence of these factors will determine the age at which screening should begin, the frequency of screening, and the screening tests that are most appropriate.
Small increases in risk — Several characteristics increase the risk of colorectal cancer two to several fold. While each is of some importance individually, risk can be substantially increased if several are present together. Family history of colorectal cancer — The occurrence of colorectal cancer in a family member increases the risk of getting the cancer, especially if it is a first degree relative (a parent, brother or sister, or child), several family members are affected, or if the cancers have occurred at an early age (eg, before age 55 years). Prior colorectal cancer or polyps — People who have previously had colorectal cancer have an increased risk of developing a new colorectal cancer. People who have had adenomatous polyps before the age of 60 years are also at increased risk for colorectal cancer. (See "Patient information: Colon polyps"). Increasing age — Although the average person has a 5 percent lifetime risk of developing colorectal cancer, 90 percent of these cancers occur in people older than 50 years of age. Risk increases throughout life. Race — Black Americans have a higher risk of dying from colorectal cancer than white Americans. This risk is also high in native Alaskans and low in American Indians. Lifestyle factors — Several lifestyle factors have been linked to the risk of colorectal cancer. Factors that appear to increase risk include: A diet high in fat and red meat and low in fiber A sedentary lifestyle Cigarette smoking
Factors that may decrease risk include: Folic acid supplements Calcium supplements Aspirin, ibuprofen, and related drugs (the evidence for these is not yet strong enough to recommend taking them for this purpose)
Large increase in risk — Some conditions are associated with very high rates of colorectal cancer. Familial adenomatous polyposis — Familial adenomatous polyposis (FAP) is an uncommon inherited condition associated with an increased risk of colorectal cancer. Nearly 100 percent of people with this condition will develop colorectal cancer during their lifetime, and most of these cancers occur before the age of 50 years. FAP causes hundreds of polyps to develop throughout the colon. Hereditary nonpolyposis colon cancer — Hereditary nonpolyposis colon cancer (HNPCC) is another inherited condition associated with an increased risk of colorectal cancer. It is slightly more common than FAP, but is still uncommon. About 70 percent of people with HNPCC will experience colorectal cancer by the age of 65. Cancer also tends to occur at younger ages and in the part of the colon on the right side of the body (the ascending colon).
HNPCC is suspected in those with a strong family history of colon cancer; several family members from different generations may have been affected, some of whom developed the cancer relatively early in life. Persons with HNPCC are also at risk for other types of cancer, including endometrial (uterine), stomach, bladder, renal (kidney) and ovarian cancer. Inflammatory bowel disease — The risk of colorectal cancer is increased in people with Crohn's disease of the colon or ulcerative colitis. The risk increases as the amount of inflamed colon increases and as the duration of disease increases; pancolitis (inflammation of the entire colon) and colitis of 10 years' duration or longer are associated with the greatest risk for colorectal cancer. Risk is not increased in irritable bowel disease.
SCREENING TESTS — Four tests are currently recommended for colorectal cancer screening: the fecal occult blood test, sigmoidoscopy, barium enema, and colonoscopy.
Fecal occult blood test — Colorectal cancers (and, more rarely, polyps) often bleed, releasing microscopic amounts of blood into the stool. The blood is frequently not visible to the naked eye, requiring specialized tests for detection. The fecal occult blood test can be used to detect blood in the stool. Procedure — This simple test is performed by putting small amounts of stool on chemically coated cards. Usually, two samples from three consecutive stools are applied to the cards at home and returned to the clinician. The sample on the card is then treated with a solution that changes color when blood is present.
Some simple dietary restrictions for two days prior to testing can improve the accuracy of the test. These include: Eliminate red meat, turnips, and horseradishes Avoid drugs that may irritate the stomach lining (such as aspirin, ibuprofen-like drugs) Do not take vitamin C Eat high-fiber foods Effectiveness — The fecal occult blood test, when performed once every year, has been shown to reduce the risk of dying from colorectal cancer by up to one-third [1]. Risks and disadvantages — Because polyps seldom bleed, the fecal occult blood test is less likely to detect polyps than other screening tests (see below). In addition, only 2 to 5 percent of people with a positive test actually have colorectal cancer; thus, for every patient with cancer, 50 patients are unnecessarily distressed and undergo tests that eventually reveal no cancer. Following the dietary restrictions above reduces the chance of a false-positive test. Additional testing — If a fecal occult blood test has a positive result, the entire colon should be examined, usually with colonoscopy.
Sigmoidoscopy — Sigmoidoscopy allows direct viewing of the lining of the rectum and the lower part of the colon (the descending colon, show figure 1). This area accounts for about one-half of the total area of the rectum and colon, where half of the cancers occur. (See "Patient information: Flexible sigmoidoscopy"). Procedure — Sigmoidoscopy requires that the patient prepare by cleaning out the bowel. This usually involves consuming a clear liquid diet, laxatives, and using an enema shortly before the examination. During the procedure, a thin, lighted tube is advanced into the rectum and the left side of the colon to check for polyps and cancer. Biopsies (small samples of tissue) can be removed during sigmoidoscopy. Sigmoidoscopy may be performed in a doctor's office. The procedure may cause mild cramping; most people do not need sedative drugs and are able to return to work or other activities the same day. Effectiveness — Physicians who perform sigmoidoscopy can identify polyps and cancers in the descending colon and rectum with a high degree of accuracy. Studies suggest that sigmoidoscopy, performed as infrequently as every 5 to 10 years, reduces death from cancers in the lower half of the colon and rectum (the area directly examined) by 66 percent [2]. Risks and disadvantages — The risks of sigmoidoscopy are small. The procedure can create a small tear in the intestinal wall in about 2 per every 10,000 people; death from this complication is rare. A major disadvantage of sigmoidoscopy is that it cannot detect polyps or cancers located in the right side of the colon. Additional testing — Certain changes in the left-sided colon increase the likelihood of polyps or cancer in the remaining part of the colon. Thus, if sigmoidoscopy reveals suspicious findings in the left-sided colon, such as many small polyps or polyps with certain microscopic features, colonoscopy may be recommended to view the entire length of the colon.
Fecal occult blood test and sigmoidoscopy — Combined screening with a fecal occult blood test and sigmoidoscopy is a common practice and may be more effective than screening with either test alone [3].
Colonoscopy — Colonoscopy allows direct viewing of the lining of the rectum and the entire colon (show figure 1). (See "Patient information: Colonoscopy"). Procedure — During colonoscopy, a thin, lighted tube is used to directly view the lining of the rectum and the entire colon. This test can therefore detect polyps and cancers that are beyond the reach of the sigmoidoscope. People are usually given a mild sedative drug during the procedure. Effectiveness — Colonoscopy detects most small polyps and almost all large polyps and cancers [4]. Polyps and some cancers can be removed during this procedure. Risks and disadvantages — The risks of colonoscopy are greater than those of other screening tests. Colonoscopy leads to serious bleeding or a tear of the intestinal wall in about 1 in 1,000 people. Because the procedure requires sedation, most people must be accompanied home after the procedure and are unable to return to work or other activities on the same day.
Barium enema test — A barium enema test provides a detailed x-ray picture of the rectum and the entire colon (show figure 1). A double-contrast barium enema is usually recommended. Procedure — During a barium enema test, liquid barium is used to coat the inside of the colon. The barium outlines the profile of the colon on x-rays and can reveal structural abnormalities such as polyps and cancers. Preparation for a barium enema entails cleansing the colon with a saline laxative. Some people experience mild cramping during the procedure, but sedative drugs are usually not necessary, and most people can return to work or other activities on the same day. Effectiveness — The barium enema test detects about one-half of large polyps and about 40 percent of all polyps in the colon and rectum [5]. Most experts feel that screening with barium enema reduces the risk of dying from colorectal cancer, but this has not been definitively proven. Risks and disadvantages — The barium enema test is relatively safe compared with other screening tests for colorectal cancer. Additional testing — If a barium enema test reveals an abnormality, a colonoscopy may be recommended.
New tests — Several new screening tests for colorectal cancer are being developed and evaluated. These tests include improved fecal occult blood tests, fecal tests for genetic abnormalities linked to colorectal cancer, and a type of computed tomography (CT) scan called a virtual colonoscopy. These tests are still being studied, and they are not yet recommended for routine screening.
Virtual colonoscopy, in particular, is being performed more commonly. The major advantages of virtual colonoscopy compared with optical colonoscopy are that the procedure is safe, and there is no need for sedation. However, if a worrisome polyp is found on virtual colonoscopy, a traditional colonoscopy will be needed for confirmation and biopsy. Additionally, the accuracy of virtual colonoscopy depends upon how it is performed; the test that is currently available may not be accurate enough for use as a screening test.
SCREENING PLANS — The screening plan that is recommended depends upon a person's risk of colorectal cancer.
Average risk of colorectal cancer — People with an average risk of colorectal cancer should begin screening at age 50. The tests differ in features (effectiveness in preventing cancer, comfort, safety, cost, and convenience). No single screening test has been identified as the best test. The available options should be discussed with a clinician to develop a screening plan that can be followed.
Some clinicians recommend a fecal occult blood test once per year and a sigmoidoscopy once every five years; a combination of these screening tests may also be recommended. Alternative screening plans include a barium enema test once every five years or colonoscopy once every 10 years. If the results of one or more of these tests is abnormal, more frequent examinations with colonoscopy may be recommended.
Increased risk of colorectal cancer — Screening plans for people with an increased risk may entail screening at a younger age, more frequent screening, and the use of more sensitive screening tests (like colonoscopy). The optimal screening plan depends upon the reason for increased risk.
Family history of colorectal cancer
- People who have one first-degree relative (parent, brother, sister, or child) who has experienced colorectal cancer or adenomatous polyps at a young age (before the age of 60 years), or two first-degree relatives diagnosed at any age, should begin screening earlier, typically at age 40, or 10 years younger than the earliest diagnosis in their family, whichever comes first, and screening should be repeated every five years.
- People who have one first-degree relative (parent, brother, sister, or child) who has experienced colorectal cancer or adenomatous polyps at age 60 or later, or two or more second degree relatives (grandparent, aunt, uncle) with colorectal cancer should begin screening at age 40, and screening should be repeated as for average risk people.
- People with a second-degree relative (grandparent, aunt, or uncle) or third-degree relative (great-grandparent or cousin) with colorectal cancer are considered to have an average risk of colorectal cancer (See "Average risk of colorectal cancer" above).
Familial adenomatous polyposis — People with a family history of familial adenomatous polyposis (FAP) should consider genetic counseling and genetic testing to determine if they carry the affected gene. People who carry the gene or do not know if they carry the gene should begin screening with sigmoidoscopy once every year, beginning at puberty. If this screening reveals many polyps, plans for colectomy (surgical removal of the colon) should be considered; this surgery is the only way to prevent colorectal cancer in people with FAP.
Hereditary nonpolyposis colon cancer — People with a family history of hereditary nonpolyposis colon cancer (HNPCC) should consider genetic counseling and genetic testing to determine if they carry the affected gene. People who carry the gene or who do not know if they carry the gene should be screened with colonoscopy or barium enema because HNPCC is associated with cancers of the right-sided colon. This screening should be done once every one to two years between age 20 and 30 years, and once every year after age 40. Because polyps can progress more rapidly to cancer in people with HNPCC, more frequent screening may also be recommended.
Inflammatory bowel disease — In people with ulcerative colitis or Crohn's disease of the colon, the optimal screening plan depends upon the amount of colon affected and the duration of the disease. Screening usually entails colonoscopy once every one to two years beginning after eight years of pancolitis (inflammation of the entire colon) or after 15 years of colitis of the left-sided colon. (See "Patient information: Crohn's disease" and see "Patient information: Ulcerative colitis").
WHERE TO GET MORE INFORMATION — Your healthcare provider is the best source of information for questions and concerns related to your medical problem. Because no two patients are exactly alike and recommendations can vary from one person to another, it is important to seek guidance from a provider who is familiar with your individual situation.
This discussion will be updated as needed every four months on our web site (www.patients.uptodate.com). Additional topics as well as selected discussions written for healthcare professionals are also available for those who would like more detailed information.
A number of web sites have information about medical problems and treatments, although it can be difficult to know which sites are reputable. Information provided by the National Institutes of Health, national medical societies and some other well-established organizations are often reliable sources of information, although the frequency with which they are updated is variable. National Cancer Institute
1-800-4-CANCER
(www.nci.nih.gov)
People Living With Cancer: The official patient information
website of the American Society of Clinical Oncology
(www.plwc.org/portal/site/PLWC)
National Comprehensive Cancer Network
(www.nccn.org/patients/patient_gls.asp)
American Cancer Society
1-800-ACS-2345
(www.cancer.org)
National Library of Medicine
(www.nlm.nih.gov/medlineplus/healthtopics.html)
The American Gastroenterological Association
(www.gastro.org)
The American College of Gastroenterology
(www.acg.gi.org)
[1-5]
Use of UpToDate is subject to the Subscription and License Agreement. REFERENCES 1. Mandel, JS, Bond, JH, Church, TR, et al. Reducing mortality from colorectal cancer by screening for fecal occult blood. Minnesota Colon Cancer Control Study. N Engl J Med 1993; 328:1365.
2. Selby, JV, Friedman, GD, Quesenberry, CP Jr, Weiss, NS. A case-control study of screening sigmoidoscopy and mortality from colorectal cancer. N Engl J Med 1992; 326:653.
3. Winawer, SJ, Flehinger, BJ, Schottenfeld, D, Miller, DG. Screening for colorectal cancer with fecal occult blood testing and sigmoidoscopy. J Natl Cancer Inst 1993; 85:1311.
4. Rex, DK, Cutler, CS, Lemmel, GT, et al. Colonoscopic miss rates of adenomas determined by back-to-back colonoscopies. Gastroenterology 1997; 112:24.
5. Winawer, SJ, Stewart, ET, Zauber, AG, et al. A comparison of colonoscopy and double-contrast barium enema for surveillance after polypectomy. National Polyp Study Work Group. N Engl J Med 2000; 342:1766.
Friday, October 12, 2007
Screening for colon cancer
INTRODUCTION — Colorectal cancer (cancer of the large portion of the bowel [colon] or rectum) is a common, preventable disease. Approximately one-third of people who develop it die of the disease, making it the second leading cause of cancer death. However, screening tests now make it possible to detect existing cancers at an early, treatable stage and even to prevent the development of colorectal cancer.
There is general agreement by experts that all adults should undergo screening beginning at age 50, or earlier for people who are at high risk for colorectal cancer. Several different tests are currently available, and new tests are being developed; all of these have advantages and disadvantages. The optimal screening test depends upon a person's preferences and their risk of colon cancer. It is important to review each test's effectiveness, safety, convenience, and costs.
EFFECTIVENESS OF SCREENING — Most colorectal cancers develop gradually over many years. They begin as small, benign tumors called adenomatous polyps. These polyps grow, develop precancerous changes, eventually become cancerous, and later spread and become incurable. This progression takes at least 10 years in most people.
The screening tests described below all work by detecting pre-cancers at the polyp stage before they become cancerous or by detecting cancers themselves while they are still curable. Regular screening for and removal of polyps can reduce a person's risk of developing colorectal cancer by up to 90 percent. In addition, early detection of cancers that are already present in the colon often allows for successful treatment.
WHO SHOULD BE SCREENED? — Several factors increase an individual's risk of developing colorectal cancer. The presence of these factors will determine the age at which screening should begin, the frequency of screening, and the screening tests that are most appropriate.
Small increases in risk — Several characteristics increase the risk of colorectal cancer two to several fold. While each is of some importance individually, risk can be substantially increased if several are present together. Family history of colorectal cancer — The occurrence of colorectal cancer in a family member increases the risk of getting the cancer, especially if it is a first degree relative (a parent, brother or sister, or child), several family members are affected, or if the cancers have occurred at an early age (eg, before age 55 years). Prior colorectal cancer or polyps — People who have previously had colorectal cancer have an increased risk of developing a new colorectal cancer. People who have had adenomatous polyps before the age of 60 years are also at increased risk for colorectal cancer. (See "Patient information: Colon polyps"). Increasing age — Although the average person has a 5 percent lifetime risk of developing colorectal cancer, 90 percent of these cancers occur in people older than 50 years of age. Risk increases throughout life. Race — Black Americans have a higher risk of dying from colorectal cancer than white Americans. This risk is also high in native Alaskans and low in American Indians. Lifestyle factors — Several lifestyle factors have been linked to the risk of colorectal cancer. Factors that appear to increase risk include: A diet high in fat and red meat and low in fiber A sedentary lifestyle Cigarette smoking
Factors that may decrease risk include: Folic acid supplements Calcium supplements Aspirin, ibuprofen, and related drugs (the evidence for these is not yet strong enough to recommend taking them for this purpose)
Large increase in risk — Some conditions are associated with very high rates of colorectal cancer. Familial adenomatous polyposis — Familial adenomatous polyposis (FAP) is an uncommon inherited condition associated with an increased risk of colorectal cancer. Nearly 100 percent of people with this condition will develop colorectal cancer during their lifetime, and most of these cancers occur before the age of 50 years. FAP causes hundreds of polyps to develop throughout the colon. Hereditary nonpolyposis colon cancer — Hereditary nonpolyposis colon cancer (HNPCC) is another inherited condition associated with an increased risk of colorectal cancer. It is slightly more common than FAP, but is still uncommon. About 70 percent of people with HNPCC will experience colorectal cancer by the age of 65. Cancer also tends to occur at younger ages and in the part of the colon on the right side of the body (the ascending colon).
HNPCC is suspected in those with a strong family history of colon cancer; several family members from different generations may have been affected, some of whom developed the cancer relatively early in life. Persons with HNPCC are also at risk for other types of cancer, including endometrial (uterine), stomach, bladder, renal (kidney) and ovarian cancer. Inflammatory bowel disease — The risk of colorectal cancer is increased in people with Crohn's disease of the colon or ulcerative colitis. The risk increases as the amount of inflamed colon increases and as the duration of disease increases; pancolitis (inflammation of the entire colon) and colitis of 10 years' duration or longer are associated with the greatest risk for colorectal cancer. Risk is not increased in irritable bowel disease.
SCREENING TESTS — Four tests are currently recommended for colorectal cancer screening: the fecal occult blood test, sigmoidoscopy, barium enema, and colonoscopy.
Fecal occult blood test — Colorectal cancers (and, more rarely, polyps) often bleed, releasing microscopic amounts of blood into the stool. The blood is frequently not visible to the naked eye, requiring specialized tests for detection. The fecal occult blood test can be used to detect blood in the stool. Procedure — This simple test is performed by putting small amounts of stool on chemically coated cards. Usually, two samples from three consecutive stools are applied to the cards at home and returned to the clinician. The sample on the card is then treated with a solution that changes color when blood is present.
Some simple dietary restrictions for two days prior to testing can improve the accuracy of the test. These include: Eliminate red meat, turnips, and horseradishes Avoid drugs that may irritate the stomach lining (such as aspirin, ibuprofen-like drugs) Do not take vitamin C Eat high-fiber foods Effectiveness — The fecal occult blood test, when performed once every year, has been shown to reduce the risk of dying from colorectal cancer by up to one-third [1]. Risks and disadvantages — Because polyps seldom bleed, the fecal occult blood test is less likely to detect polyps than other screening tests (see below). In addition, only 2 to 5 percent of people with a positive test actually have colorectal cancer; thus, for every patient with cancer, 50 patients are unnecessarily distressed and undergo tests that eventually reveal no cancer. Following the dietary restrictions above reduces the chance of a false-positive test. Additional testing — If a fecal occult blood test has a positive result, the entire colon should be examined, usually with colonoscopy.
Sigmoidoscopy — Sigmoidoscopy allows direct viewing of the lining of the rectum and the lower part of the colon (the descending colon, show figure 1). This area accounts for about one-half of the total area of the rectum and colon, where half of the cancers occur. (See "Patient information: Flexible sigmoidoscopy"). Procedure — Sigmoidoscopy requires that the patient prepare by cleaning out the bowel. This usually involves consuming a clear liquid diet, laxatives, and using an enema shortly before the examination. During the procedure, a thin, lighted tube is advanced into the rectum and the left side of the colon to check for polyps and cancer. Biopsies (small samples of tissue) can be removed during sigmoidoscopy. Sigmoidoscopy may be performed in a doctor's office. The procedure may cause mild cramping; most people do not need sedative drugs and are able to return to work or other activities the same day. Effectiveness — Physicians who perform sigmoidoscopy can identify polyps and cancers in the descending colon and rectum with a high degree of accuracy. Studies suggest that sigmoidoscopy, performed as infrequently as every 5 to 10 years, reduces death from cancers in the lower half of the colon and rectum (the area directly examined) by 66 percent [2]. Risks and disadvantages — The risks of sigmoidoscopy are small. The procedure can create a small tear in the intestinal wall in about 2 per every 10,000 people; death from this complication is rare. A major disadvantage of sigmoidoscopy is that it cannot detect polyps or cancers located in the right side of the colon. Additional testing — Certain changes in the left-sided colon increase the likelihood of polyps or cancer in the remaining part of the colon. Thus, if sigmoidoscopy reveals suspicious findings in the left-sided colon, such as many small polyps or polyps with certain microscopic features, colonoscopy may be recommended to view the entire length of the colon.
Fecal occult blood test and sigmoidoscopy — Combined screening with a fecal occult blood test and sigmoidoscopy is a common practice and may be more effective than screening with either test alone [3].
Colonoscopy — Colonoscopy allows direct viewing of the lining of the rectum and the entire colon (show figure 1). (See "Patient information: Colonoscopy"). Procedure — During colonoscopy, a thin, lighted tube is used to directly view the lining of the rectum and the entire colon. This test can therefore detect polyps and cancers that are beyond the reach of the sigmoidoscope. People are usually given a mild sedative drug during the procedure. Effectiveness — Colonoscopy detects most small polyps and almost all large polyps and cancers [4]. Polyps and some cancers can be removed during this procedure. Risks and disadvantages — The risks of colonoscopy are greater than those of other screening tests. Colonoscopy leads to serious bleeding or a tear of the intestinal wall in about 1 in 1,000 people. Because the procedure requires sedation, most people must be accompanied home after the procedure and are unable to return to work or other activities on the same day.
Barium enema test — A barium enema test provides a detailed x-ray picture of the rectum and the entire colon (show figure 1). A double-contrast barium enema is usually recommended. Procedure — During a barium enema test, liquid barium is used to coat the inside of the colon. The barium outlines the profile of the colon on x-rays and can reveal structural abnormalities such as polyps and cancers. Preparation for a barium enema entails cleansing the colon with a saline laxative. Some people experience mild cramping during the procedure, but sedative drugs are usually not necessary, and most people can return to work or other activities on the same day. Effectiveness — The barium enema test detects about one-half of large polyps and about 40 percent of all polyps in the colon and rectum [5]. Most experts feel that screening with barium enema reduces the risk of dying from colorectal cancer, but this has not been definitively proven. Risks and disadvantages — The barium enema test is relatively safe compared with other screening tests for colorectal cancer. Additional testing — If a barium enema test reveals an abnormality, a colonoscopy may be recommended.
New tests — Several new screening tests for colorectal cancer are being developed and evaluated. These tests include improved fecal occult blood tests, fecal tests for genetic abnormalities linked to colorectal cancer, and a type of computed tomography (CT) scan called a virtual colonoscopy. These tests are still being studied, and they are not yet recommended for routine screening.
Virtual colonoscopy, in particular, is being performed more commonly. The major advantages of virtual colonoscopy compared with optical colonoscopy are that the procedure is safe, and there is no need for sedation. However, if a worrisome polyp is found on virtual colonoscopy, a traditional colonoscopy will be needed for confirmation and biopsy. Additionally, the accuracy of virtual colonoscopy depends upon how it is performed; the test that is currently available may not be accurate enough for use as a screening test.
SCREENING PLANS — The screening plan that is recommended depends upon a person's risk of colorectal cancer.
Average risk of colorectal cancer — People with an average risk of colorectal cancer should begin screening at age 50. The tests differ in features (effectiveness in preventing cancer, comfort, safety, cost, and convenience). No single screening test has been identified as the best test. The available options should be discussed with a clinician to develop a screening plan that can be followed.
Some clinicians recommend a fecal occult blood test once per year and a sigmoidoscopy once every five years; a combination of these screening tests may also be recommended. Alternative screening plans include a barium enema test once every five years or colonoscopy once every 10 years. If the results of one or more of these tests is abnormal, more frequent examinations with colonoscopy may be recommended.
Increased risk of colorectal cancer — Screening plans for people with an increased risk may entail screening at a younger age, more frequent screening, and the use of more sensitive screening tests (like colonoscopy). The optimal screening plan depends upon the reason for increased risk.
Family history of colorectal cancer
- People who have one first-degree relative (parent, brother, sister, or child) who has experienced colorectal cancer or adenomatous polyps at a young age (before the age of 60 years), or two first-degree relatives diagnosed at any age, should begin screening earlier, typically at age 40, or 10 years younger than the earliest diagnosis in their family, whichever comes first, and screening should be repeated every five years.
- People who have one first-degree relative (parent, brother, sister, or child) who has experienced colorectal cancer or adenomatous polyps at age 60 or later, or two or more second degree relatives (grandparent, aunt, uncle) with colorectal cancer should begin screening at age 40, and screening should be repeated as for average risk people.
- People with a second-degree relative (grandparent, aunt, or uncle) or third-degree relative (great-grandparent or cousin) with colorectal cancer are considered to have an average risk of colorectal cancer (See "Average risk of colorectal cancer" above).
Familial adenomatous polyposis — People with a family history of familial adenomatous polyposis (FAP) should consider genetic counseling and genetic testing to determine if they carry the affected gene. People who carry the gene or do not know if they carry the gene should begin screening with sigmoidoscopy once every year, beginning at puberty. If this screening reveals many polyps, plans for colectomy (surgical removal of the colon) should be considered; this surgery is the only way to prevent colorectal cancer in people with FAP.
Hereditary nonpolyposis colon cancer — People with a family history of hereditary nonpolyposis colon cancer (HNPCC) should consider genetic counseling and genetic testing to determine if they carry the affected gene. People who carry the gene or who do not know if they carry the gene should be screened with colonoscopy or barium enema because HNPCC is associated with cancers of the right-sided colon. This screening should be done once every one to two years between age 20 and 30 years, and once every year after age 40. Because polyps can progress more rapidly to cancer in people with HNPCC, more frequent screening may also be recommended.
Inflammatory bowel disease — In people with ulcerative colitis or Crohn's disease of the colon, the optimal screening plan depends upon the amount of colon affected and the duration of the disease. Screening usually entails colonoscopy once every one to two years beginning after eight years of pancolitis (inflammation of the entire colon) or after 15 years of colitis of the left-sided colon. (See "Patient information: Crohn's disease" and see "Patient information: Ulcerative colitis").
WHERE TO GET MORE INFORMATION — Your healthcare provider is the best source of information for questions and concerns related to your medical problem. Because no two patients are exactly alike and recommendations can vary from one person to another, it is important to seek guidance from a provider who is familiar with your individual situation.
This discussion will be updated as needed every four months on our web site (www.patients.uptodate.com). Additional topics as well as selected discussions written for healthcare professionals are also available for those who would like more detailed information.
A number of web sites have information about medical problems and treatments, although it can be difficult to know which sites are reputable. Information provided by the National Institutes of Health, national medical societies and some other well-established organizations are often reliable sources of information, although the frequency with which they are updated is variable. National Cancer Institute
1-800-4-CANCER
(www.nci.nih.gov)
People Living With Cancer: The official patient information
website of the American Society of Clinical Oncology
(www.plwc.org/portal/site/PLWC)
National Comprehensive Cancer Network
(www.nccn.org/patients/patient_gls.asp)
American Cancer Society
1-800-ACS-2345
(www.cancer.org)
National Library of Medicine
(www.nlm.nih.gov/medlineplus/healthtopics.html)
The American Gastroenterological Association
(www.gastro.org)
The American College of Gastroenterology
(www.acg.gi.org)
[1-5]
Use of UpToDate is subject to the Subscription and License Agreement. REFERENCES 1. Mandel, JS, Bond, JH, Church, TR, et al. Reducing mortality from colorectal cancer by screening for fecal occult blood. Minnesota Colon Cancer Control Study. N Engl J Med 1993; 328:1365.
2. Selby, JV, Friedman, GD, Quesenberry, CP Jr, Weiss, NS. A case-control study of screening sigmoidoscopy and mortality from colorectal cancer. N Engl J Med 1992; 326:653.
3. Winawer, SJ, Flehinger, BJ, Schottenfeld, D, Miller, DG. Screening for colorectal cancer with fecal occult blood testing and sigmoidoscopy. J Natl Cancer Inst 1993; 85:1311.
4. Rex, DK, Cutler, CS, Lemmel, GT, et al. Colonoscopic miss rates of adenomas determined by back-to-back colonoscopies. Gastroenterology 1997; 112:24.
5. Winawer, SJ, Stewart, ET, Zauber, AG, et al. A comparison of colonoscopy and double-contrast barium enema for surveillance after polypectomy. National Polyp Study Work Group. N Engl J Med 2000; 342:1766.
There is general agreement by experts that all adults should undergo screening beginning at age 50, or earlier for people who are at high risk for colorectal cancer. Several different tests are currently available, and new tests are being developed; all of these have advantages and disadvantages. The optimal screening test depends upon a person's preferences and their risk of colon cancer. It is important to review each test's effectiveness, safety, convenience, and costs.
EFFECTIVENESS OF SCREENING — Most colorectal cancers develop gradually over many years. They begin as small, benign tumors called adenomatous polyps. These polyps grow, develop precancerous changes, eventually become cancerous, and later spread and become incurable. This progression takes at least 10 years in most people.
The screening tests described below all work by detecting pre-cancers at the polyp stage before they become cancerous or by detecting cancers themselves while they are still curable. Regular screening for and removal of polyps can reduce a person's risk of developing colorectal cancer by up to 90 percent. In addition, early detection of cancers that are already present in the colon often allows for successful treatment.
WHO SHOULD BE SCREENED? — Several factors increase an individual's risk of developing colorectal cancer. The presence of these factors will determine the age at which screening should begin, the frequency of screening, and the screening tests that are most appropriate.
Small increases in risk — Several characteristics increase the risk of colorectal cancer two to several fold. While each is of some importance individually, risk can be substantially increased if several are present together. Family history of colorectal cancer — The occurrence of colorectal cancer in a family member increases the risk of getting the cancer, especially if it is a first degree relative (a parent, brother or sister, or child), several family members are affected, or if the cancers have occurred at an early age (eg, before age 55 years). Prior colorectal cancer or polyps — People who have previously had colorectal cancer have an increased risk of developing a new colorectal cancer. People who have had adenomatous polyps before the age of 60 years are also at increased risk for colorectal cancer. (See "Patient information: Colon polyps"). Increasing age — Although the average person has a 5 percent lifetime risk of developing colorectal cancer, 90 percent of these cancers occur in people older than 50 years of age. Risk increases throughout life. Race — Black Americans have a higher risk of dying from colorectal cancer than white Americans. This risk is also high in native Alaskans and low in American Indians. Lifestyle factors — Several lifestyle factors have been linked to the risk of colorectal cancer. Factors that appear to increase risk include: A diet high in fat and red meat and low in fiber A sedentary lifestyle Cigarette smoking
Factors that may decrease risk include: Folic acid supplements Calcium supplements Aspirin, ibuprofen, and related drugs (the evidence for these is not yet strong enough to recommend taking them for this purpose)
Large increase in risk — Some conditions are associated with very high rates of colorectal cancer. Familial adenomatous polyposis — Familial adenomatous polyposis (FAP) is an uncommon inherited condition associated with an increased risk of colorectal cancer. Nearly 100 percent of people with this condition will develop colorectal cancer during their lifetime, and most of these cancers occur before the age of 50 years. FAP causes hundreds of polyps to develop throughout the colon. Hereditary nonpolyposis colon cancer — Hereditary nonpolyposis colon cancer (HNPCC) is another inherited condition associated with an increased risk of colorectal cancer. It is slightly more common than FAP, but is still uncommon. About 70 percent of people with HNPCC will experience colorectal cancer by the age of 65. Cancer also tends to occur at younger ages and in the part of the colon on the right side of the body (the ascending colon).
HNPCC is suspected in those with a strong family history of colon cancer; several family members from different generations may have been affected, some of whom developed the cancer relatively early in life. Persons with HNPCC are also at risk for other types of cancer, including endometrial (uterine), stomach, bladder, renal (kidney) and ovarian cancer. Inflammatory bowel disease — The risk of colorectal cancer is increased in people with Crohn's disease of the colon or ulcerative colitis. The risk increases as the amount of inflamed colon increases and as the duration of disease increases; pancolitis (inflammation of the entire colon) and colitis of 10 years' duration or longer are associated with the greatest risk for colorectal cancer. Risk is not increased in irritable bowel disease.
SCREENING TESTS — Four tests are currently recommended for colorectal cancer screening: the fecal occult blood test, sigmoidoscopy, barium enema, and colonoscopy.
Fecal occult blood test — Colorectal cancers (and, more rarely, polyps) often bleed, releasing microscopic amounts of blood into the stool. The blood is frequently not visible to the naked eye, requiring specialized tests for detection. The fecal occult blood test can be used to detect blood in the stool. Procedure — This simple test is performed by putting small amounts of stool on chemically coated cards. Usually, two samples from three consecutive stools are applied to the cards at home and returned to the clinician. The sample on the card is then treated with a solution that changes color when blood is present.
Some simple dietary restrictions for two days prior to testing can improve the accuracy of the test. These include: Eliminate red meat, turnips, and horseradishes Avoid drugs that may irritate the stomach lining (such as aspirin, ibuprofen-like drugs) Do not take vitamin C Eat high-fiber foods Effectiveness — The fecal occult blood test, when performed once every year, has been shown to reduce the risk of dying from colorectal cancer by up to one-third [1]. Risks and disadvantages — Because polyps seldom bleed, the fecal occult blood test is less likely to detect polyps than other screening tests (see below). In addition, only 2 to 5 percent of people with a positive test actually have colorectal cancer; thus, for every patient with cancer, 50 patients are unnecessarily distressed and undergo tests that eventually reveal no cancer. Following the dietary restrictions above reduces the chance of a false-positive test. Additional testing — If a fecal occult blood test has a positive result, the entire colon should be examined, usually with colonoscopy.
Sigmoidoscopy — Sigmoidoscopy allows direct viewing of the lining of the rectum and the lower part of the colon (the descending colon, show figure 1). This area accounts for about one-half of the total area of the rectum and colon, where half of the cancers occur. (See "Patient information: Flexible sigmoidoscopy"). Procedure — Sigmoidoscopy requires that the patient prepare by cleaning out the bowel. This usually involves consuming a clear liquid diet, laxatives, and using an enema shortly before the examination. During the procedure, a thin, lighted tube is advanced into the rectum and the left side of the colon to check for polyps and cancer. Biopsies (small samples of tissue) can be removed during sigmoidoscopy. Sigmoidoscopy may be performed in a doctor's office. The procedure may cause mild cramping; most people do not need sedative drugs and are able to return to work or other activities the same day. Effectiveness — Physicians who perform sigmoidoscopy can identify polyps and cancers in the descending colon and rectum with a high degree of accuracy. Studies suggest that sigmoidoscopy, performed as infrequently as every 5 to 10 years, reduces death from cancers in the lower half of the colon and rectum (the area directly examined) by 66 percent [2]. Risks and disadvantages — The risks of sigmoidoscopy are small. The procedure can create a small tear in the intestinal wall in about 2 per every 10,000 people; death from this complication is rare. A major disadvantage of sigmoidoscopy is that it cannot detect polyps or cancers located in the right side of the colon. Additional testing — Certain changes in the left-sided colon increase the likelihood of polyps or cancer in the remaining part of the colon. Thus, if sigmoidoscopy reveals suspicious findings in the left-sided colon, such as many small polyps or polyps with certain microscopic features, colonoscopy may be recommended to view the entire length of the colon.
Fecal occult blood test and sigmoidoscopy — Combined screening with a fecal occult blood test and sigmoidoscopy is a common practice and may be more effective than screening with either test alone [3].
Colonoscopy — Colonoscopy allows direct viewing of the lining of the rectum and the entire colon (show figure 1). (See "Patient information: Colonoscopy"). Procedure — During colonoscopy, a thin, lighted tube is used to directly view the lining of the rectum and the entire colon. This test can therefore detect polyps and cancers that are beyond the reach of the sigmoidoscope. People are usually given a mild sedative drug during the procedure. Effectiveness — Colonoscopy detects most small polyps and almost all large polyps and cancers [4]. Polyps and some cancers can be removed during this procedure. Risks and disadvantages — The risks of colonoscopy are greater than those of other screening tests. Colonoscopy leads to serious bleeding or a tear of the intestinal wall in about 1 in 1,000 people. Because the procedure requires sedation, most people must be accompanied home after the procedure and are unable to return to work or other activities on the same day.
Barium enema test — A barium enema test provides a detailed x-ray picture of the rectum and the entire colon (show figure 1). A double-contrast barium enema is usually recommended. Procedure — During a barium enema test, liquid barium is used to coat the inside of the colon. The barium outlines the profile of the colon on x-rays and can reveal structural abnormalities such as polyps and cancers. Preparation for a barium enema entails cleansing the colon with a saline laxative. Some people experience mild cramping during the procedure, but sedative drugs are usually not necessary, and most people can return to work or other activities on the same day. Effectiveness — The barium enema test detects about one-half of large polyps and about 40 percent of all polyps in the colon and rectum [5]. Most experts feel that screening with barium enema reduces the risk of dying from colorectal cancer, but this has not been definitively proven. Risks and disadvantages — The barium enema test is relatively safe compared with other screening tests for colorectal cancer. Additional testing — If a barium enema test reveals an abnormality, a colonoscopy may be recommended.
New tests — Several new screening tests for colorectal cancer are being developed and evaluated. These tests include improved fecal occult blood tests, fecal tests for genetic abnormalities linked to colorectal cancer, and a type of computed tomography (CT) scan called a virtual colonoscopy. These tests are still being studied, and they are not yet recommended for routine screening.
Virtual colonoscopy, in particular, is being performed more commonly. The major advantages of virtual colonoscopy compared with optical colonoscopy are that the procedure is safe, and there is no need for sedation. However, if a worrisome polyp is found on virtual colonoscopy, a traditional colonoscopy will be needed for confirmation and biopsy. Additionally, the accuracy of virtual colonoscopy depends upon how it is performed; the test that is currently available may not be accurate enough for use as a screening test.
SCREENING PLANS — The screening plan that is recommended depends upon a person's risk of colorectal cancer.
Average risk of colorectal cancer — People with an average risk of colorectal cancer should begin screening at age 50. The tests differ in features (effectiveness in preventing cancer, comfort, safety, cost, and convenience). No single screening test has been identified as the best test. The available options should be discussed with a clinician to develop a screening plan that can be followed.
Some clinicians recommend a fecal occult blood test once per year and a sigmoidoscopy once every five years; a combination of these screening tests may also be recommended. Alternative screening plans include a barium enema test once every five years or colonoscopy once every 10 years. If the results of one or more of these tests is abnormal, more frequent examinations with colonoscopy may be recommended.
Increased risk of colorectal cancer — Screening plans for people with an increased risk may entail screening at a younger age, more frequent screening, and the use of more sensitive screening tests (like colonoscopy). The optimal screening plan depends upon the reason for increased risk.
Family history of colorectal cancer
- People who have one first-degree relative (parent, brother, sister, or child) who has experienced colorectal cancer or adenomatous polyps at a young age (before the age of 60 years), or two first-degree relatives diagnosed at any age, should begin screening earlier, typically at age 40, or 10 years younger than the earliest diagnosis in their family, whichever comes first, and screening should be repeated every five years.
- People who have one first-degree relative (parent, brother, sister, or child) who has experienced colorectal cancer or adenomatous polyps at age 60 or later, or two or more second degree relatives (grandparent, aunt, uncle) with colorectal cancer should begin screening at age 40, and screening should be repeated as for average risk people.
- People with a second-degree relative (grandparent, aunt, or uncle) or third-degree relative (great-grandparent or cousin) with colorectal cancer are considered to have an average risk of colorectal cancer (See "Average risk of colorectal cancer" above).
Familial adenomatous polyposis — People with a family history of familial adenomatous polyposis (FAP) should consider genetic counseling and genetic testing to determine if they carry the affected gene. People who carry the gene or do not know if they carry the gene should begin screening with sigmoidoscopy once every year, beginning at puberty. If this screening reveals many polyps, plans for colectomy (surgical removal of the colon) should be considered; this surgery is the only way to prevent colorectal cancer in people with FAP.
Hereditary nonpolyposis colon cancer — People with a family history of hereditary nonpolyposis colon cancer (HNPCC) should consider genetic counseling and genetic testing to determine if they carry the affected gene. People who carry the gene or who do not know if they carry the gene should be screened with colonoscopy or barium enema because HNPCC is associated with cancers of the right-sided colon. This screening should be done once every one to two years between age 20 and 30 years, and once every year after age 40. Because polyps can progress more rapidly to cancer in people with HNPCC, more frequent screening may also be recommended.
Inflammatory bowel disease — In people with ulcerative colitis or Crohn's disease of the colon, the optimal screening plan depends upon the amount of colon affected and the duration of the disease. Screening usually entails colonoscopy once every one to two years beginning after eight years of pancolitis (inflammation of the entire colon) or after 15 years of colitis of the left-sided colon. (See "Patient information: Crohn's disease" and see "Patient information: Ulcerative colitis").
WHERE TO GET MORE INFORMATION — Your healthcare provider is the best source of information for questions and concerns related to your medical problem. Because no two patients are exactly alike and recommendations can vary from one person to another, it is important to seek guidance from a provider who is familiar with your individual situation.
This discussion will be updated as needed every four months on our web site (www.patients.uptodate.com). Additional topics as well as selected discussions written for healthcare professionals are also available for those who would like more detailed information.
A number of web sites have information about medical problems and treatments, although it can be difficult to know which sites are reputable. Information provided by the National Institutes of Health, national medical societies and some other well-established organizations are often reliable sources of information, although the frequency with which they are updated is variable. National Cancer Institute
1-800-4-CANCER
(www.nci.nih.gov)
People Living With Cancer: The official patient information
website of the American Society of Clinical Oncology
(www.plwc.org/portal/site/PLWC)
National Comprehensive Cancer Network
(www.nccn.org/patients/patient_gls.asp)
American Cancer Society
1-800-ACS-2345
(www.cancer.org)
National Library of Medicine
(www.nlm.nih.gov/medlineplus/healthtopics.html)
The American Gastroenterological Association
(www.gastro.org)
The American College of Gastroenterology
(www.acg.gi.org)
[1-5]
Use of UpToDate is subject to the Subscription and License Agreement. REFERENCES 1. Mandel, JS, Bond, JH, Church, TR, et al. Reducing mortality from colorectal cancer by screening for fecal occult blood. Minnesota Colon Cancer Control Study. N Engl J Med 1993; 328:1365.
2. Selby, JV, Friedman, GD, Quesenberry, CP Jr, Weiss, NS. A case-control study of screening sigmoidoscopy and mortality from colorectal cancer. N Engl J Med 1992; 326:653.
3. Winawer, SJ, Flehinger, BJ, Schottenfeld, D, Miller, DG. Screening for colorectal cancer with fecal occult blood testing and sigmoidoscopy. J Natl Cancer Inst 1993; 85:1311.
4. Rex, DK, Cutler, CS, Lemmel, GT, et al. Colonoscopic miss rates of adenomas determined by back-to-back colonoscopies. Gastroenterology 1997; 112:24.
5. Winawer, SJ, Stewart, ET, Zauber, AG, et al. A comparison of colonoscopy and double-contrast barium enema for surveillance after polypectomy. National Polyp Study Work Group. N Engl J Med 2000; 342:1766.
Flexible sigmoidoscopy
INTRODUCTION — A flexible sigmoidoscopy is an examination of the lower (distal) part of the gastrointestinal tract, called the colon or large intestine (show figure 1). It is performed by an endoscopist, a doctor or other health professional with special training in endoscopic procedures. There are several reasons that flexible signmoidoscopy may be recommended, with one of the most common reasons being the need to screen for colon cancer in people older than 50 years.
Colonoscopy allows the physician to examine the entire large intestine, and is preferred over flexible sigmoidoscopy if the entire colon needs to be examined. (See "Patient information: Colonoscopy").
REASONS FOR FLEXIBLE SIGMOIDOSCOPY — The most common reasons for flexible sigmoidoscopy are the following: As a screening test to detect colon polyps or colon cancer in people over age fifty Blood in the stool or rectal bleeding (sigmoidoscopy may be recommended to evaluate bleeding) Persistent diarrhea After radiation treatment to the pelvis when a patient has lower gastrointestinal symptoms Evaluation of the colon in conjunction with a barium enema For the medical management of colitis (inflammation of the colon)
PREPARATION — Your doctor will provide you with specific Instructions on how to prepare for the examination. The instructions are designed to maximize your safety during and after the examination, minimize possible complications, and provide the endoscopist with the best look at your colon.
It is important for you to read the instructions ahead of time and follow them carefully. Call your doctor or the endoscopy unit if you have questions.
Bowel cleaning — The lower part of the colon must be cleaned to permit the endoscopist to see the inside lining of the colon. Specific instruction will be provided, although preparation usually involves consuming a clear liquid diet, laxatives, and use of an enemas shortly before the examination.
Medications — Some medications, such as aspirin products and iron preparations, should be stopped one to two weeks before the examination. Aspirin increases the risk of bleeding after the test, while iron coats the colon, making it difficult to see the lining. People who take a blood thinning medication such as warfarin (Coumadin®) should consult with their clinician regarding the need to stop taking this medication temporarily.
Most medications for high blood pressure, heart disease, lung disease, and seizure disorders are safe during sigmoidoscopy and can be taken the day of the examination.
Medications for diabetes may need to be decreased before the test; patients should talk with their diabetes clinician.
WHAT TO EXPECT — Prior to the sigmoidoscopy, a nurse will ask questions to ensure the patient understands the procedure and the reason it is planned A doctor will review the procedure, including possible complications, and will ask the patient to sign a consent form.
The procedure — Flexible sigmoidoscopy usually takes between five and fifteen minutes. It is performed while the patient lies on their left side with the legs curled up against the chest. The sigmoidoscope, which is approximately the size of one finger, is inserted into the anus and advanced through the rectum, sigmoid colon, and descending colon. The sigmoidoscope has a lens and a light source that permits the endoscopist to look into the scope or at a television monitor.
The endoscope allows the endoscopist to take biopsies (small pieces of tissue) and to introduce or withdraw fluid or air. Biopsies do not hurt because the lining of the colon does not sense pain. However, some patients will feel cramping as air is introduced through the scope and as the scope is passed through segments of the colon. The air is needed to permit the endoscopist to advance the scope and see the lining of the colon. It is common to feel embarrassed about releasing air through their rectum, although this is recommended to decrease discomfort. Let the endoscopist know if there is discomfort since air can also be removed through the scope. Because the procedure is brief and discomfort is mild, pain medications or sedation are not routinely used.
COMPLICATIONS — Flexible sigmoidoscopy is a safe procedure and complications are rare. Bleeding can occur from biopsies or the removal of polyps, but this is usually minimal and stops quickly or can be controlled. The scope can cause a tear or hole in the tissue being examined. This is a serious problem that does not occur commonly.
The following symptoms should be reported immediately: Severe abdominal pain (not just gas cramps) A firm, distended abdomen Vomiting Fever Bleeding greater than a few tablespoons
AFTER FLEXIBLE SIGMOIDOSCOPY — Although patients worry about discomforts of the examination, most people tolerate it very well and feel fine afterwards. Most patients are able to return to normal activities, including eating, after the examination
Patients should contact their doctor about the results of the test and if there are any questions. The endoscopy team will let the patient know when all the results will be available and if further treatment is necessary.
WHERE TO GET MORE INFORMATION — Your healthcare provider is the best source of information for questions and concerns related to your medical problem. Because no two patients are exactly alike and recommendations can vary from one person to another, it is important to seek guidance from a provider who is familiar with your individual situation.
This discussion will be updated as needed every four months on our web site (www.patients.uptodate.com). Additional topics as well as selected discussions written for healthcare professionals are also available for those who would like more detailed information.
A number of web sites have information about medical problems and treatments, although it can be difficult to know which sites are reputable. Information provided by the National Institutes of Health, national medical societies and some other well-established organizations are often reliable sources of information, although the frequency with which they are updated is variable. National Library of Medicine
(www.nlm.nih.gov/medlineplus/healthtopics.html)
The American Society of Gastrointestinal Endoscopy:
(www.askasge.org)
National Digestive Disease Information Clearinghouse
(http://digestive.niddk.nih.gov/ddiseases/pubs/sigmoidoscopy/index.htm)
[1-3]
Use of UpToDate is subject to the Subscription and License Agreement. REFERENCES 1. Doria-Rose, VP, Levin, TR, Selby, JV, et al. The incidence of colorectal cancer following a negative screening sigmoidoscopy: Implications for screening interval. Gastroenterology 2004; 127:714.
2. Fletcher, RH. Screening sigmoidoscopy-- how often and how good?. JAMA 2003; 290:106.
3. Levin, TR, Conell, C, Shapiro, JA, et al. Complications of screening flexible sigmoidoscopy. Gastroenterology 2002; 123:1786.
Colonoscopy allows the physician to examine the entire large intestine, and is preferred over flexible sigmoidoscopy if the entire colon needs to be examined. (See "Patient information: Colonoscopy").
REASONS FOR FLEXIBLE SIGMOIDOSCOPY — The most common reasons for flexible sigmoidoscopy are the following: As a screening test to detect colon polyps or colon cancer in people over age fifty Blood in the stool or rectal bleeding (sigmoidoscopy may be recommended to evaluate bleeding) Persistent diarrhea After radiation treatment to the pelvis when a patient has lower gastrointestinal symptoms Evaluation of the colon in conjunction with a barium enema For the medical management of colitis (inflammation of the colon)
PREPARATION — Your doctor will provide you with specific Instructions on how to prepare for the examination. The instructions are designed to maximize your safety during and after the examination, minimize possible complications, and provide the endoscopist with the best look at your colon.
It is important for you to read the instructions ahead of time and follow them carefully. Call your doctor or the endoscopy unit if you have questions.
Bowel cleaning — The lower part of the colon must be cleaned to permit the endoscopist to see the inside lining of the colon. Specific instruction will be provided, although preparation usually involves consuming a clear liquid diet, laxatives, and use of an enemas shortly before the examination.
Medications — Some medications, such as aspirin products and iron preparations, should be stopped one to two weeks before the examination. Aspirin increases the risk of bleeding after the test, while iron coats the colon, making it difficult to see the lining. People who take a blood thinning medication such as warfarin (Coumadin®) should consult with their clinician regarding the need to stop taking this medication temporarily.
Most medications for high blood pressure, heart disease, lung disease, and seizure disorders are safe during sigmoidoscopy and can be taken the day of the examination.
Medications for diabetes may need to be decreased before the test; patients should talk with their diabetes clinician.
WHAT TO EXPECT — Prior to the sigmoidoscopy, a nurse will ask questions to ensure the patient understands the procedure and the reason it is planned A doctor will review the procedure, including possible complications, and will ask the patient to sign a consent form.
The procedure — Flexible sigmoidoscopy usually takes between five and fifteen minutes. It is performed while the patient lies on their left side with the legs curled up against the chest. The sigmoidoscope, which is approximately the size of one finger, is inserted into the anus and advanced through the rectum, sigmoid colon, and descending colon. The sigmoidoscope has a lens and a light source that permits the endoscopist to look into the scope or at a television monitor.
The endoscope allows the endoscopist to take biopsies (small pieces of tissue) and to introduce or withdraw fluid or air. Biopsies do not hurt because the lining of the colon does not sense pain. However, some patients will feel cramping as air is introduced through the scope and as the scope is passed through segments of the colon. The air is needed to permit the endoscopist to advance the scope and see the lining of the colon. It is common to feel embarrassed about releasing air through their rectum, although this is recommended to decrease discomfort. Let the endoscopist know if there is discomfort since air can also be removed through the scope. Because the procedure is brief and discomfort is mild, pain medications or sedation are not routinely used.
COMPLICATIONS — Flexible sigmoidoscopy is a safe procedure and complications are rare. Bleeding can occur from biopsies or the removal of polyps, but this is usually minimal and stops quickly or can be controlled. The scope can cause a tear or hole in the tissue being examined. This is a serious problem that does not occur commonly.
The following symptoms should be reported immediately: Severe abdominal pain (not just gas cramps) A firm, distended abdomen Vomiting Fever Bleeding greater than a few tablespoons
AFTER FLEXIBLE SIGMOIDOSCOPY — Although patients worry about discomforts of the examination, most people tolerate it very well and feel fine afterwards. Most patients are able to return to normal activities, including eating, after the examination
Patients should contact their doctor about the results of the test and if there are any questions. The endoscopy team will let the patient know when all the results will be available and if further treatment is necessary.
WHERE TO GET MORE INFORMATION — Your healthcare provider is the best source of information for questions and concerns related to your medical problem. Because no two patients are exactly alike and recommendations can vary from one person to another, it is important to seek guidance from a provider who is familiar with your individual situation.
This discussion will be updated as needed every four months on our web site (www.patients.uptodate.com). Additional topics as well as selected discussions written for healthcare professionals are also available for those who would like more detailed information.
A number of web sites have information about medical problems and treatments, although it can be difficult to know which sites are reputable. Information provided by the National Institutes of Health, national medical societies and some other well-established organizations are often reliable sources of information, although the frequency with which they are updated is variable. National Library of Medicine
(www.nlm.nih.gov/medlineplus/healthtopics.html)
The American Society of Gastrointestinal Endoscopy:
(www.askasge.org)
National Digestive Disease Information Clearinghouse
(http://digestive.niddk.nih.gov/ddiseases/pubs/sigmoidoscopy/index.htm)
[1-3]
Use of UpToDate is subject to the Subscription and License Agreement. REFERENCES 1. Doria-Rose, VP, Levin, TR, Selby, JV, et al. The incidence of colorectal cancer following a negative screening sigmoidoscopy: Implications for screening interval. Gastroenterology 2004; 127:714.
2. Fletcher, RH. Screening sigmoidoscopy-- how often and how good?. JAMA 2003; 290:106.
3. Levin, TR, Conell, C, Shapiro, JA, et al. Complications of screening flexible sigmoidoscopy. Gastroenterology 2002; 123:1786.
Flexible sigmoidoscopy
INTRODUCTION — A flexible sigmoidoscopy is an examination of the lower (distal) part of the gastrointestinal tract, called the colon or large intestine (show figure 1). It is performed by an endoscopist, a doctor or other health professional with special training in endoscopic procedures. There are several reasons that flexible signmoidoscopy may be recommended, with one of the most common reasons being the need to screen for colon cancer in people older than 50 years.
Colonoscopy allows the physician to examine the entire large intestine, and is preferred over flexible sigmoidoscopy if the entire colon needs to be examined. (See "Patient information: Colonoscopy").
REASONS FOR FLEXIBLE SIGMOIDOSCOPY — The most common reasons for flexible sigmoidoscopy are the following: As a screening test to detect colon polyps or colon cancer in people over age fifty Blood in the stool or rectal bleeding (sigmoidoscopy may be recommended to evaluate bleeding) Persistent diarrhea After radiation treatment to the pelvis when a patient has lower gastrointestinal symptoms Evaluation of the colon in conjunction with a barium enema For the medical management of colitis (inflammation of the colon)
PREPARATION — Your doctor will provide you with specific Instructions on how to prepare for the examination. The instructions are designed to maximize your safety during and after the examination, minimize possible complications, and provide the endoscopist with the best look at your colon.
It is important for you to read the instructions ahead of time and follow them carefully. Call your doctor or the endoscopy unit if you have questions.
Bowel cleaning — The lower part of the colon must be cleaned to permit the endoscopist to see the inside lining of the colon. Specific instruction will be provided, although preparation usually involves consuming a clear liquid diet, laxatives, and use of an enemas shortly before the examination.
Medications — Some medications, such as aspirin products and iron preparations, should be stopped one to two weeks before the examination. Aspirin increases the risk of bleeding after the test, while iron coats the colon, making it difficult to see the lining. People who take a blood thinning medication such as warfarin (Coumadin®) should consult with their clinician regarding the need to stop taking this medication temporarily.
Most medications for high blood pressure, heart disease, lung disease, and seizure disorders are safe during sigmoidoscopy and can be taken the day of the examination.
Medications for diabetes may need to be decreased before the test; patients should talk with their diabetes clinician.
WHAT TO EXPECT — Prior to the sigmoidoscopy, a nurse will ask questions to ensure the patient understands the procedure and the reason it is planned A doctor will review the procedure, including possible complications, and will ask the patient to sign a consent form.
The procedure — Flexible sigmoidoscopy usually takes between five and fifteen minutes. It is performed while the patient lies on their left side with the legs curled up against the chest. The sigmoidoscope, which is approximately the size of one finger, is inserted into the anus and advanced through the rectum, sigmoid colon, and descending colon. The sigmoidoscope has a lens and a light source that permits the endoscopist to look into the scope or at a television monitor.
The endoscope allows the endoscopist to take biopsies (small pieces of tissue) and to introduce or withdraw fluid or air. Biopsies do not hurt because the lining of the colon does not sense pain. However, some patients will feel cramping as air is introduced through the scope and as the scope is passed through segments of the colon. The air is needed to permit the endoscopist to advance the scope and see the lining of the colon. It is common to feel embarrassed about releasing air through their rectum, although this is recommended to decrease discomfort. Let the endoscopist know if there is discomfort since air can also be removed through the scope. Because the procedure is brief and discomfort is mild, pain medications or sedation are not routinely used.
COMPLICATIONS — Flexible sigmoidoscopy is a safe procedure and complications are rare. Bleeding can occur from biopsies or the removal of polyps, but this is usually minimal and stops quickly or can be controlled. The scope can cause a tear or hole in the tissue being examined. This is a serious problem that does not occur commonly.
The following symptoms should be reported immediately: Severe abdominal pain (not just gas cramps) A firm, distended abdomen Vomiting Fever Bleeding greater than a few tablespoons
AFTER FLEXIBLE SIGMOIDOSCOPY — Although patients worry about discomforts of the examination, most people tolerate it very well and feel fine afterwards. Most patients are able to return to normal activities, including eating, after the examination
Patients should contact their doctor about the results of the test and if there are any questions. The endoscopy team will let the patient know when all the results will be available and if further treatment is necessary.
WHERE TO GET MORE INFORMATION — Your healthcare provider is the best source of information for questions and concerns related to your medical problem. Because no two patients are exactly alike and recommendations can vary from one person to another, it is important to seek guidance from a provider who is familiar with your individual situation.
This discussion will be updated as needed every four months on our web site (www.patients.uptodate.com). Additional topics as well as selected discussions written for healthcare professionals are also available for those who would like more detailed information.
A number of web sites have information about medical problems and treatments, although it can be difficult to know which sites are reputable. Information provided by the National Institutes of Health, national medical societies and some other well-established organizations are often reliable sources of information, although the frequency with which they are updated is variable. National Library of Medicine
(www.nlm.nih.gov/medlineplus/healthtopics.html)
The American Society of Gastrointestinal Endoscopy:
(www.askasge.org)
National Digestive Disease Information Clearinghouse
(http://digestive.niddk.nih.gov/ddiseases/pubs/sigmoidoscopy/index.htm)
[1-3]
Use of UpToDate is subject to the Subscription and License Agreement. REFERENCES 1. Doria-Rose, VP, Levin, TR, Selby, JV, et al. The incidence of colorectal cancer following a negative screening sigmoidoscopy: Implications for screening interval. Gastroenterology 2004; 127:714.
2. Fletcher, RH. Screening sigmoidoscopy-- how often and how good?. JAMA 2003; 290:106.
3. Levin, TR, Conell, C, Shapiro, JA, et al. Complications of screening flexible sigmoidoscopy. Gastroenterology 2002; 123:1786.
Colonoscopy allows the physician to examine the entire large intestine, and is preferred over flexible sigmoidoscopy if the entire colon needs to be examined. (See "Patient information: Colonoscopy").
REASONS FOR FLEXIBLE SIGMOIDOSCOPY — The most common reasons for flexible sigmoidoscopy are the following: As a screening test to detect colon polyps or colon cancer in people over age fifty Blood in the stool or rectal bleeding (sigmoidoscopy may be recommended to evaluate bleeding) Persistent diarrhea After radiation treatment to the pelvis when a patient has lower gastrointestinal symptoms Evaluation of the colon in conjunction with a barium enema For the medical management of colitis (inflammation of the colon)
PREPARATION — Your doctor will provide you with specific Instructions on how to prepare for the examination. The instructions are designed to maximize your safety during and after the examination, minimize possible complications, and provide the endoscopist with the best look at your colon.
It is important for you to read the instructions ahead of time and follow them carefully. Call your doctor or the endoscopy unit if you have questions.
Bowel cleaning — The lower part of the colon must be cleaned to permit the endoscopist to see the inside lining of the colon. Specific instruction will be provided, although preparation usually involves consuming a clear liquid diet, laxatives, and use of an enemas shortly before the examination.
Medications — Some medications, such as aspirin products and iron preparations, should be stopped one to two weeks before the examination. Aspirin increases the risk of bleeding after the test, while iron coats the colon, making it difficult to see the lining. People who take a blood thinning medication such as warfarin (Coumadin®) should consult with their clinician regarding the need to stop taking this medication temporarily.
Most medications for high blood pressure, heart disease, lung disease, and seizure disorders are safe during sigmoidoscopy and can be taken the day of the examination.
Medications for diabetes may need to be decreased before the test; patients should talk with their diabetes clinician.
WHAT TO EXPECT — Prior to the sigmoidoscopy, a nurse will ask questions to ensure the patient understands the procedure and the reason it is planned A doctor will review the procedure, including possible complications, and will ask the patient to sign a consent form.
The procedure — Flexible sigmoidoscopy usually takes between five and fifteen minutes. It is performed while the patient lies on their left side with the legs curled up against the chest. The sigmoidoscope, which is approximately the size of one finger, is inserted into the anus and advanced through the rectum, sigmoid colon, and descending colon. The sigmoidoscope has a lens and a light source that permits the endoscopist to look into the scope or at a television monitor.
The endoscope allows the endoscopist to take biopsies (small pieces of tissue) and to introduce or withdraw fluid or air. Biopsies do not hurt because the lining of the colon does not sense pain. However, some patients will feel cramping as air is introduced through the scope and as the scope is passed through segments of the colon. The air is needed to permit the endoscopist to advance the scope and see the lining of the colon. It is common to feel embarrassed about releasing air through their rectum, although this is recommended to decrease discomfort. Let the endoscopist know if there is discomfort since air can also be removed through the scope. Because the procedure is brief and discomfort is mild, pain medications or sedation are not routinely used.
COMPLICATIONS — Flexible sigmoidoscopy is a safe procedure and complications are rare. Bleeding can occur from biopsies or the removal of polyps, but this is usually minimal and stops quickly or can be controlled. The scope can cause a tear or hole in the tissue being examined. This is a serious problem that does not occur commonly.
The following symptoms should be reported immediately: Severe abdominal pain (not just gas cramps) A firm, distended abdomen Vomiting Fever Bleeding greater than a few tablespoons
AFTER FLEXIBLE SIGMOIDOSCOPY — Although patients worry about discomforts of the examination, most people tolerate it very well and feel fine afterwards. Most patients are able to return to normal activities, including eating, after the examination
Patients should contact their doctor about the results of the test and if there are any questions. The endoscopy team will let the patient know when all the results will be available and if further treatment is necessary.
WHERE TO GET MORE INFORMATION — Your healthcare provider is the best source of information for questions and concerns related to your medical problem. Because no two patients are exactly alike and recommendations can vary from one person to another, it is important to seek guidance from a provider who is familiar with your individual situation.
This discussion will be updated as needed every four months on our web site (www.patients.uptodate.com). Additional topics as well as selected discussions written for healthcare professionals are also available for those who would like more detailed information.
A number of web sites have information about medical problems and treatments, although it can be difficult to know which sites are reputable. Information provided by the National Institutes of Health, national medical societies and some other well-established organizations are often reliable sources of information, although the frequency with which they are updated is variable. National Library of Medicine
(www.nlm.nih.gov/medlineplus/healthtopics.html)
The American Society of Gastrointestinal Endoscopy:
(www.askasge.org)
National Digestive Disease Information Clearinghouse
(http://digestive.niddk.nih.gov/ddiseases/pubs/sigmoidoscopy/index.htm)
[1-3]
Use of UpToDate is subject to the Subscription and License Agreement. REFERENCES 1. Doria-Rose, VP, Levin, TR, Selby, JV, et al. The incidence of colorectal cancer following a negative screening sigmoidoscopy: Implications for screening interval. Gastroenterology 2004; 127:714.
2. Fletcher, RH. Screening sigmoidoscopy-- how often and how good?. JAMA 2003; 290:106.
3. Levin, TR, Conell, C, Shapiro, JA, et al. Complications of screening flexible sigmoidoscopy. Gastroenterology 2002; 123:1786.
Colonoscopy
INTRODUCTION — Patients who require colonoscopy may have some questions and concerns about the procedure. This handout will provide information about colonoscopy and answers to questions that patients often ask.
Colonoscopy is a safe procedure that provides information other tests may not be able to give. A colonoscopy is an examination of the lower part of the gastrointestinal tract, which is called the colon or large intestine (bowel). It is performed by an endoscopist, a physician with special training in endoscopy procedures. The colonoscope is inserted into the anus and advanced through the entire colon (to the cecum) and possibly a short distance into the small intestine. The procedure generally between twenty minutes and one hour.
REASONS FOR COLONOSCOPY — The most common reasons for colonoscopy are to evaluate the following: As a screening exam for anyone over age 50 Blood in the stool or rectal bleeding Dark/black stools Persistent diarrhea Iron deficiency anemia (a decrease in blood count due to loss of iron) Significant, unexplained weight loss, accompanied by gastrointestinal symptoms A family history of colon cancer To follow up an abnormal barium enema A history of previous colon polyps or colon cancer Surveillance in people with ulcerative colitis For the medical management of chronic inflammatory bowel disease Chronic, unexplained abdominal pain.
PREPARATION — The endoscopy unit will provide specific instructions about how to prepare for the examination. The instructions are designed to maximize safety during and after the examination, minimize possible complications, and allow the endoscopist to fully view the colon.
It is important to read the instructions ahead of time and follow them carefully; patients who have questions should speak with their healthcare provider or the endoscopy unit.
The inside lining of the colon must be cleaned of stool to permit the endoscopist to complete a thorough examination. This is accomplished by restricting what is eaten and by using purgatives. What to eat — As a general rule, patients should not eat any solid food for at least one day before the examination. Only clear liquids (such as juices without pulp, bouillon, ginger ale) or clear gelatin (flavored is fine, but without added fruit) are recommended. The doctor's office or endoscopy unit will supply a list of fluids that are allowed. Purgatives — There are two methods commonly used to empty the bowel of stool. The first involves drinking a gallon of an undigestible solution (Go-Lytely®, and others) that causes temporary diarrhea. It comes in several flavors, which, unfortunately, only partially mask a somewhat unpleasant taste. Refrigerating the solution may make it more palatable. Drinking such a large volume of cold solution may cause a patient to feel chilled, but the sensation is temporary. Do not add flavoring to the solution. Many patients say that drinking the purgative solution is the most unpleasant part of the examination.
The second method involves drinking a solution called Fleets® Phosphosoda, along with several cups of liquid. This preparation is easier to consume than the purgative described above. However, the solution contains a large amount of phosphorus, which may be a problem for people with heart or kidney conditions. Medications — Some medications, such as aspirin and iron preparations, should be discontinued for one to two weeks before the examination. Aspirin and pain killers such as Motrin (which contains ibuprofen) slightly increase the risk of bleeding. Patients who take a blood thinning medication should consult with their doctor as to when they should stop taking it. Patients should also ask about medications for diabetes, heart or lung disease, high blood pressure, or seizure disorders. Some medications should not be stopped, and many of them can be taken the examination. Patients who take antibiotics before dental procedures should ask if they will be needed before colonoscopy. Transportation home — Patients need to arrange for someone to escort them safely home after the examination. Although patients will be awake by the time of discharge, the sedative medications cause changes in reflexes and judgment that cause a person to feel well but can interfere with the ability to make decisions, similar to the effect of alcohol.
WHAT TO EXPECT — Prior to the endoscopy, a nurse will ask questions to ensure the patient understands the procedure and the reason it is planned. The nurse will ask questions to ensure the patient has prepared properly for the procedure. A doctor will also review the procedure, including possible complications, and will ask patients to sign a consent form.
The nurse will start an intravenous line (insert a needle into a vein in the hand or arm) to administer medications. The intravenous line insertion feels like a pin prick, similar to having blood drawn. The vital signs (blood pressure, heart rate, and blood oxygen level) will be monitored before, during, and after the examination. The monitoring is not painful. Some patients will be given oxygen during the examination.
THE PROCEDURE — The colonoscopy will be performed while the patient lies on their left side. Medications will be administered through the intravenous line. Most endoscopy units use a combination of a sedative (to help patients relax), and a narcotic (to prevent discomfort). Many people sleep during the examination while others are very relaxed, comfortable, and generally not aware of the examination.
The colonoscope is a flexible tube, approximately the size of the index finger. It has a lens and a light source that allows the endoscopist to look into the scope or at a TV monitor. The image on the TV monitor is magnified many times so the endoscopist can see small changes in tissue.
The endoscope contains channels that allow the endoscopist to obtain biopsies (small pieces of tissue), remove polyps and to introduce or withdraw fluid or air. Polyps are extra growths of tissue that can range in size from the tip of a pen to several inches (doctors measure them in millimeters and centimeters). Most polyps are benign (not cancerous) but can turn into cancers if left to grow for a very long time. As a result, they are usually removed so they can be analyzed under the microscope. This does not hurt since the lining of the colon does not sense pain.
Air is introduced through the scope to open up the colon so that the scope can be moved forward and to allow the endoscopist to see. Patients may experience a feeling of bloating or gas cramps from the air as it distends the colon. Try not to be embarrassed about releasing the air through the rectum; patients should let their physician know if they are uncomfortable
RECOVERY — After the colonoscopy, a patient will be observed until the effects of the sedative medication are gone. The most common discomfort after colonoscopy is a feeling of bloating and gas cramps. Patients may also feel groggy from the sedation medications. Patients should not return to work that day. Most patients are able to eat a regular diet after the examination. Patients should ask about when it is safe to restart aspirin or blood thinning medications.
COMPLICATIONS — Colonoscopy is a safe procedure and complications are rare, but can occur: Bleeding can occur from biopsies or the removal of polyps, but it is usually minimal and stops quickly or can be controlled. The colonoscope can cause a tear or hole in the tissue being examined, which is a serious problem, but, fortunately, very uncommon. Adverse reactions to the medications used to sedate you are possible. The endoscopy team (doctors and nurses) will ask about previous medication allergies or reactions and about health problems such as heart, lung, kidney, or liver disease. The medications can also produce irritation in the vein at the site of the intravenous line. If redness, swelling, or warmth occur, warm to hot wet towels applied to the site may relieve the discomfort. If the discomfort persists, notify the endoscopy unit.
The following symptoms should be reported immediately: Severe abdominal pain (not just gas cramps) A firm, distended abdomen Vomiting Fever Bleeding greater than a few tablespoons.
AFTER COLONOSCOPY — Although patients worry about discomforts of the examination, most people tolerate it very well and feel fine afterwards. Some fatigue after the examination is common. Patients should plan to take it easy and relax the rest of the day.
The endoscopist can describe the result of their examination before the patient leaves the endoscopy unit. If biopsies have been taken or polyps removed, the patient should call for results within one to two weeks.
WHERE TO GET MORE INFORMATION — Your healthcare provider is the best source of information for questions and concerns related to your medical problem. Because no two patients are exactly alike and recommendations can vary from one person to another, it is important to seek guidance from a provider who is familiar with your individual situation.
This discussion will be updated as needed every four months on our web site (www.patients.uptodate.com). Additional topics as well as selected discussions written for healthcare professionals are also available for those who would like more detailed information.
A number of web sites have information about medical problems and treatments, although it can be difficult to know which sites are reputable. Information provided by the National Institutes of Health, national medical societies and some other well-established organizations are often reliable sources of information, although the frequency with which they are updated is variable. National Library of Medicine
(www.nlm.nih.gov/medlineplus/healthtopics.html)
The American Society of Gastrointestinal Endoscopy
(www.askasge.org)
[1-3]
Use of UpToDate is subject to the Subscription and License Agreement. REFERENCES 1. Rex, DK, Johnson, DA, Lieberman, DA, et al. Colorectal cancer prevention 2000: screening recommendations of the American College of Gastroenterology. American College of Gastroenterology. Am J Gastroenterol 2000; 95:868.
2. Lieberman, DA, Weiss, DG, Bond, JH, et al. Use of colonoscopy to screen asymptomatic adults for colorectal cancer. Veterans Affairs Cooperative Study Group 380. N Engl J Med 2000; 343:162.
3. Singh, H, Turner, D, Xue, L, et al. Risk of developing colorectal cancer following a negative colonoscopy examination: evidence for a 10-year interval between colonoscopies. JAMA 2006; 295:2366.
Colonoscopy is a safe procedure that provides information other tests may not be able to give. A colonoscopy is an examination of the lower part of the gastrointestinal tract, which is called the colon or large intestine (bowel). It is performed by an endoscopist, a physician with special training in endoscopy procedures. The colonoscope is inserted into the anus and advanced through the entire colon (to the cecum) and possibly a short distance into the small intestine. The procedure generally between twenty minutes and one hour.
REASONS FOR COLONOSCOPY — The most common reasons for colonoscopy are to evaluate the following: As a screening exam for anyone over age 50 Blood in the stool or rectal bleeding Dark/black stools Persistent diarrhea Iron deficiency anemia (a decrease in blood count due to loss of iron) Significant, unexplained weight loss, accompanied by gastrointestinal symptoms A family history of colon cancer To follow up an abnormal barium enema A history of previous colon polyps or colon cancer Surveillance in people with ulcerative colitis For the medical management of chronic inflammatory bowel disease Chronic, unexplained abdominal pain.
PREPARATION — The endoscopy unit will provide specific instructions about how to prepare for the examination. The instructions are designed to maximize safety during and after the examination, minimize possible complications, and allow the endoscopist to fully view the colon.
It is important to read the instructions ahead of time and follow them carefully; patients who have questions should speak with their healthcare provider or the endoscopy unit.
The inside lining of the colon must be cleaned of stool to permit the endoscopist to complete a thorough examination. This is accomplished by restricting what is eaten and by using purgatives. What to eat — As a general rule, patients should not eat any solid food for at least one day before the examination. Only clear liquids (such as juices without pulp, bouillon, ginger ale) or clear gelatin (flavored is fine, but without added fruit) are recommended. The doctor's office or endoscopy unit will supply a list of fluids that are allowed. Purgatives — There are two methods commonly used to empty the bowel of stool. The first involves drinking a gallon of an undigestible solution (Go-Lytely®, and others) that causes temporary diarrhea. It comes in several flavors, which, unfortunately, only partially mask a somewhat unpleasant taste. Refrigerating the solution may make it more palatable. Drinking such a large volume of cold solution may cause a patient to feel chilled, but the sensation is temporary. Do not add flavoring to the solution. Many patients say that drinking the purgative solution is the most unpleasant part of the examination.
The second method involves drinking a solution called Fleets® Phosphosoda, along with several cups of liquid. This preparation is easier to consume than the purgative described above. However, the solution contains a large amount of phosphorus, which may be a problem for people with heart or kidney conditions. Medications — Some medications, such as aspirin and iron preparations, should be discontinued for one to two weeks before the examination. Aspirin and pain killers such as Motrin (which contains ibuprofen) slightly increase the risk of bleeding. Patients who take a blood thinning medication should consult with their doctor as to when they should stop taking it. Patients should also ask about medications for diabetes, heart or lung disease, high blood pressure, or seizure disorders. Some medications should not be stopped, and many of them can be taken the examination. Patients who take antibiotics before dental procedures should ask if they will be needed before colonoscopy. Transportation home — Patients need to arrange for someone to escort them safely home after the examination. Although patients will be awake by the time of discharge, the sedative medications cause changes in reflexes and judgment that cause a person to feel well but can interfere with the ability to make decisions, similar to the effect of alcohol.
WHAT TO EXPECT — Prior to the endoscopy, a nurse will ask questions to ensure the patient understands the procedure and the reason it is planned. The nurse will ask questions to ensure the patient has prepared properly for the procedure. A doctor will also review the procedure, including possible complications, and will ask patients to sign a consent form.
The nurse will start an intravenous line (insert a needle into a vein in the hand or arm) to administer medications. The intravenous line insertion feels like a pin prick, similar to having blood drawn. The vital signs (blood pressure, heart rate, and blood oxygen level) will be monitored before, during, and after the examination. The monitoring is not painful. Some patients will be given oxygen during the examination.
THE PROCEDURE — The colonoscopy will be performed while the patient lies on their left side. Medications will be administered through the intravenous line. Most endoscopy units use a combination of a sedative (to help patients relax), and a narcotic (to prevent discomfort). Many people sleep during the examination while others are very relaxed, comfortable, and generally not aware of the examination.
The colonoscope is a flexible tube, approximately the size of the index finger. It has a lens and a light source that allows the endoscopist to look into the scope or at a TV monitor. The image on the TV monitor is magnified many times so the endoscopist can see small changes in tissue.
The endoscope contains channels that allow the endoscopist to obtain biopsies (small pieces of tissue), remove polyps and to introduce or withdraw fluid or air. Polyps are extra growths of tissue that can range in size from the tip of a pen to several inches (doctors measure them in millimeters and centimeters). Most polyps are benign (not cancerous) but can turn into cancers if left to grow for a very long time. As a result, they are usually removed so they can be analyzed under the microscope. This does not hurt since the lining of the colon does not sense pain.
Air is introduced through the scope to open up the colon so that the scope can be moved forward and to allow the endoscopist to see. Patients may experience a feeling of bloating or gas cramps from the air as it distends the colon. Try not to be embarrassed about releasing the air through the rectum; patients should let their physician know if they are uncomfortable
RECOVERY — After the colonoscopy, a patient will be observed until the effects of the sedative medication are gone. The most common discomfort after colonoscopy is a feeling of bloating and gas cramps. Patients may also feel groggy from the sedation medications. Patients should not return to work that day. Most patients are able to eat a regular diet after the examination. Patients should ask about when it is safe to restart aspirin or blood thinning medications.
COMPLICATIONS — Colonoscopy is a safe procedure and complications are rare, but can occur: Bleeding can occur from biopsies or the removal of polyps, but it is usually minimal and stops quickly or can be controlled. The colonoscope can cause a tear or hole in the tissue being examined, which is a serious problem, but, fortunately, very uncommon. Adverse reactions to the medications used to sedate you are possible. The endoscopy team (doctors and nurses) will ask about previous medication allergies or reactions and about health problems such as heart, lung, kidney, or liver disease. The medications can also produce irritation in the vein at the site of the intravenous line. If redness, swelling, or warmth occur, warm to hot wet towels applied to the site may relieve the discomfort. If the discomfort persists, notify the endoscopy unit.
The following symptoms should be reported immediately: Severe abdominal pain (not just gas cramps) A firm, distended abdomen Vomiting Fever Bleeding greater than a few tablespoons.
AFTER COLONOSCOPY — Although patients worry about discomforts of the examination, most people tolerate it very well and feel fine afterwards. Some fatigue after the examination is common. Patients should plan to take it easy and relax the rest of the day.
The endoscopist can describe the result of their examination before the patient leaves the endoscopy unit. If biopsies have been taken or polyps removed, the patient should call for results within one to two weeks.
WHERE TO GET MORE INFORMATION — Your healthcare provider is the best source of information for questions and concerns related to your medical problem. Because no two patients are exactly alike and recommendations can vary from one person to another, it is important to seek guidance from a provider who is familiar with your individual situation.
This discussion will be updated as needed every four months on our web site (www.patients.uptodate.com). Additional topics as well as selected discussions written for healthcare professionals are also available for those who would like more detailed information.
A number of web sites have information about medical problems and treatments, although it can be difficult to know which sites are reputable. Information provided by the National Institutes of Health, national medical societies and some other well-established organizations are often reliable sources of information, although the frequency with which they are updated is variable. National Library of Medicine
(www.nlm.nih.gov/medlineplus/healthtopics.html)
The American Society of Gastrointestinal Endoscopy
(www.askasge.org)
[1-3]
Use of UpToDate is subject to the Subscription and License Agreement. REFERENCES 1. Rex, DK, Johnson, DA, Lieberman, DA, et al. Colorectal cancer prevention 2000: screening recommendations of the American College of Gastroenterology. American College of Gastroenterology. Am J Gastroenterol 2000; 95:868.
2. Lieberman, DA, Weiss, DG, Bond, JH, et al. Use of colonoscopy to screen asymptomatic adults for colorectal cancer. Veterans Affairs Cooperative Study Group 380. N Engl J Med 2000; 343:162.
3. Singh, H, Turner, D, Xue, L, et al. Risk of developing colorectal cancer following a negative colonoscopy examination: evidence for a 10-year interval between colonoscopies. JAMA 2006; 295:2366.
Colonoscopy
INTRODUCTION — Patients who require colonoscopy may have some questions and concerns about the procedure. This handout will provide information about colonoscopy and answers to questions that patients often ask.
Colonoscopy is a safe procedure that provides information other tests may not be able to give. A colonoscopy is an examination of the lower part of the gastrointestinal tract, which is called the colon or large intestine (bowel). It is performed by an endoscopist, a physician with special training in endoscopy procedures. The colonoscope is inserted into the anus and advanced through the entire colon (to the cecum) and possibly a short distance into the small intestine. The procedure generally between twenty minutes and one hour.
REASONS FOR COLONOSCOPY — The most common reasons for colonoscopy are to evaluate the following: As a screening exam for anyone over age 50 Blood in the stool or rectal bleeding Dark/black stools Persistent diarrhea Iron deficiency anemia (a decrease in blood count due to loss of iron) Significant, unexplained weight loss, accompanied by gastrointestinal symptoms A family history of colon cancer To follow up an abnormal barium enema A history of previous colon polyps or colon cancer Surveillance in people with ulcerative colitis For the medical management of chronic inflammatory bowel disease Chronic, unexplained abdominal pain.
PREPARATION — The endoscopy unit will provide specific instructions about how to prepare for the examination. The instructions are designed to maximize safety during and after the examination, minimize possible complications, and allow the endoscopist to fully view the colon.
It is important to read the instructions ahead of time and follow them carefully; patients who have questions should speak with their healthcare provider or the endoscopy unit.
The inside lining of the colon must be cleaned of stool to permit the endoscopist to complete a thorough examination. This is accomplished by restricting what is eaten and by using purgatives. What to eat — As a general rule, patients should not eat any solid food for at least one day before the examination. Only clear liquids (such as juices without pulp, bouillon, ginger ale) or clear gelatin (flavored is fine, but without added fruit) are recommended. The doctor's office or endoscopy unit will supply a list of fluids that are allowed. Purgatives — There are two methods commonly used to empty the bowel of stool. The first involves drinking a gallon of an undigestible solution (Go-Lytely®, and others) that causes temporary diarrhea. It comes in several flavors, which, unfortunately, only partially mask a somewhat unpleasant taste. Refrigerating the solution may make it more palatable. Drinking such a large volume of cold solution may cause a patient to feel chilled, but the sensation is temporary. Do not add flavoring to the solution. Many patients say that drinking the purgative solution is the most unpleasant part of the examination.
The second method involves drinking a solution called Fleets® Phosphosoda, along with several cups of liquid. This preparation is easier to consume than the purgative described above. However, the solution contains a large amount of phosphorus, which may be a problem for people with heart or kidney conditions. Medications — Some medications, such as aspirin and iron preparations, should be discontinued for one to two weeks before the examination. Aspirin and pain killers such as Motrin (which contains ibuprofen) slightly increase the risk of bleeding. Patients who take a blood thinning medication should consult with their doctor as to when they should stop taking it. Patients should also ask about medications for diabetes, heart or lung disease, high blood pressure, or seizure disorders. Some medications should not be stopped, and many of them can be taken the examination. Patients who take antibiotics before dental procedures should ask if they will be needed before colonoscopy. Transportation home — Patients need to arrange for someone to escort them safely home after the examination. Although patients will be awake by the time of discharge, the sedative medications cause changes in reflexes and judgment that cause a person to feel well but can interfere with the ability to make decisions, similar to the effect of alcohol.
WHAT TO EXPECT — Prior to the endoscopy, a nurse will ask questions to ensure the patient understands the procedure and the reason it is planned. The nurse will ask questions to ensure the patient has prepared properly for the procedure. A doctor will also review the procedure, including possible complications, and will ask patients to sign a consent form.
The nurse will start an intravenous line (insert a needle into a vein in the hand or arm) to administer medications. The intravenous line insertion feels like a pin prick, similar to having blood drawn. The vital signs (blood pressure, heart rate, and blood oxygen level) will be monitored before, during, and after the examination. The monitoring is not painful. Some patients will be given oxygen during the examination.
THE PROCEDURE — The colonoscopy will be performed while the patient lies on their left side. Medications will be administered through the intravenous line. Most endoscopy units use a combination of a sedative (to help patients relax), and a narcotic (to prevent discomfort). Many people sleep during the examination while others are very relaxed, comfortable, and generally not aware of the examination.
The colonoscope is a flexible tube, approximately the size of the index finger. It has a lens and a light source that allows the endoscopist to look into the scope or at a TV monitor. The image on the TV monitor is magnified many times so the endoscopist can see small changes in tissue.
The endoscope contains channels that allow the endoscopist to obtain biopsies (small pieces of tissue), remove polyps and to introduce or withdraw fluid or air. Polyps are extra growths of tissue that can range in size from the tip of a pen to several inches (doctors measure them in millimeters and centimeters). Most polyps are benign (not cancerous) but can turn into cancers if left to grow for a very long time. As a result, they are usually removed so they can be analyzed under the microscope. This does not hurt since the lining of the colon does not sense pain.
Air is introduced through the scope to open up the colon so that the scope can be moved forward and to allow the endoscopist to see. Patients may experience a feeling of bloating or gas cramps from the air as it distends the colon. Try not to be embarrassed about releasing the air through the rectum; patients should let their physician know if they are uncomfortable
RECOVERY — After the colonoscopy, a patient will be observed until the effects of the sedative medication are gone. The most common discomfort after colonoscopy is a feeling of bloating and gas cramps. Patients may also feel groggy from the sedation medications. Patients should not return to work that day. Most patients are able to eat a regular diet after the examination. Patients should ask about when it is safe to restart aspirin or blood thinning medications.
COMPLICATIONS — Colonoscopy is a safe procedure and complications are rare, but can occur: Bleeding can occur from biopsies or the removal of polyps, but it is usually minimal and stops quickly or can be controlled. The colonoscope can cause a tear or hole in the tissue being examined, which is a serious problem, but, fortunately, very uncommon. Adverse reactions to the medications used to sedate you are possible. The endoscopy team (doctors and nurses) will ask about previous medication allergies or reactions and about health problems such as heart, lung, kidney, or liver disease. The medications can also produce irritation in the vein at the site of the intravenous line. If redness, swelling, or warmth occur, warm to hot wet towels applied to the site may relieve the discomfort. If the discomfort persists, notify the endoscopy unit.
The following symptoms should be reported immediately: Severe abdominal pain (not just gas cramps) A firm, distended abdomen Vomiting Fever Bleeding greater than a few tablespoons.
AFTER COLONOSCOPY — Although patients worry about discomforts of the examination, most people tolerate it very well and feel fine afterwards. Some fatigue after the examination is common. Patients should plan to take it easy and relax the rest of the day.
The endoscopist can describe the result of their examination before the patient leaves the endoscopy unit. If biopsies have been taken or polyps removed, the patient should call for results within one to two weeks.
WHERE TO GET MORE INFORMATION — Your healthcare provider is the best source of information for questions and concerns related to your medical problem. Because no two patients are exactly alike and recommendations can vary from one person to another, it is important to seek guidance from a provider who is familiar with your individual situation.
This discussion will be updated as needed every four months on our web site (www.patients.uptodate.com). Additional topics as well as selected discussions written for healthcare professionals are also available for those who would like more detailed information.
A number of web sites have information about medical problems and treatments, although it can be difficult to know which sites are reputable. Information provided by the National Institutes of Health, national medical societies and some other well-established organizations are often reliable sources of information, although the frequency with which they are updated is variable. National Library of Medicine
(www.nlm.nih.gov/medlineplus/healthtopics.html)
The American Society of Gastrointestinal Endoscopy
(www.askasge.org)
[1-3]
Use of UpToDate is subject to the Subscription and License Agreement. REFERENCES 1. Rex, DK, Johnson, DA, Lieberman, DA, et al. Colorectal cancer prevention 2000: screening recommendations of the American College of Gastroenterology. American College of Gastroenterology. Am J Gastroenterol 2000; 95:868.
2. Lieberman, DA, Weiss, DG, Bond, JH, et al. Use of colonoscopy to screen asymptomatic adults for colorectal cancer. Veterans Affairs Cooperative Study Group 380. N Engl J Med 2000; 343:162.
3. Singh, H, Turner, D, Xue, L, et al. Risk of developing colorectal cancer following a negative colonoscopy examination: evidence for a 10-year interval between colonoscopies. JAMA 2006; 295:2366.
Colonoscopy is a safe procedure that provides information other tests may not be able to give. A colonoscopy is an examination of the lower part of the gastrointestinal tract, which is called the colon or large intestine (bowel). It is performed by an endoscopist, a physician with special training in endoscopy procedures. The colonoscope is inserted into the anus and advanced through the entire colon (to the cecum) and possibly a short distance into the small intestine. The procedure generally between twenty minutes and one hour.
REASONS FOR COLONOSCOPY — The most common reasons for colonoscopy are to evaluate the following: As a screening exam for anyone over age 50 Blood in the stool or rectal bleeding Dark/black stools Persistent diarrhea Iron deficiency anemia (a decrease in blood count due to loss of iron) Significant, unexplained weight loss, accompanied by gastrointestinal symptoms A family history of colon cancer To follow up an abnormal barium enema A history of previous colon polyps or colon cancer Surveillance in people with ulcerative colitis For the medical management of chronic inflammatory bowel disease Chronic, unexplained abdominal pain.
PREPARATION — The endoscopy unit will provide specific instructions about how to prepare for the examination. The instructions are designed to maximize safety during and after the examination, minimize possible complications, and allow the endoscopist to fully view the colon.
It is important to read the instructions ahead of time and follow them carefully; patients who have questions should speak with their healthcare provider or the endoscopy unit.
The inside lining of the colon must be cleaned of stool to permit the endoscopist to complete a thorough examination. This is accomplished by restricting what is eaten and by using purgatives. What to eat — As a general rule, patients should not eat any solid food for at least one day before the examination. Only clear liquids (such as juices without pulp, bouillon, ginger ale) or clear gelatin (flavored is fine, but without added fruit) are recommended. The doctor's office or endoscopy unit will supply a list of fluids that are allowed. Purgatives — There are two methods commonly used to empty the bowel of stool. The first involves drinking a gallon of an undigestible solution (Go-Lytely®, and others) that causes temporary diarrhea. It comes in several flavors, which, unfortunately, only partially mask a somewhat unpleasant taste. Refrigerating the solution may make it more palatable. Drinking such a large volume of cold solution may cause a patient to feel chilled, but the sensation is temporary. Do not add flavoring to the solution. Many patients say that drinking the purgative solution is the most unpleasant part of the examination.
The second method involves drinking a solution called Fleets® Phosphosoda, along with several cups of liquid. This preparation is easier to consume than the purgative described above. However, the solution contains a large amount of phosphorus, which may be a problem for people with heart or kidney conditions. Medications — Some medications, such as aspirin and iron preparations, should be discontinued for one to two weeks before the examination. Aspirin and pain killers such as Motrin (which contains ibuprofen) slightly increase the risk of bleeding. Patients who take a blood thinning medication should consult with their doctor as to when they should stop taking it. Patients should also ask about medications for diabetes, heart or lung disease, high blood pressure, or seizure disorders. Some medications should not be stopped, and many of them can be taken the examination. Patients who take antibiotics before dental procedures should ask if they will be needed before colonoscopy. Transportation home — Patients need to arrange for someone to escort them safely home after the examination. Although patients will be awake by the time of discharge, the sedative medications cause changes in reflexes and judgment that cause a person to feel well but can interfere with the ability to make decisions, similar to the effect of alcohol.
WHAT TO EXPECT — Prior to the endoscopy, a nurse will ask questions to ensure the patient understands the procedure and the reason it is planned. The nurse will ask questions to ensure the patient has prepared properly for the procedure. A doctor will also review the procedure, including possible complications, and will ask patients to sign a consent form.
The nurse will start an intravenous line (insert a needle into a vein in the hand or arm) to administer medications. The intravenous line insertion feels like a pin prick, similar to having blood drawn. The vital signs (blood pressure, heart rate, and blood oxygen level) will be monitored before, during, and after the examination. The monitoring is not painful. Some patients will be given oxygen during the examination.
THE PROCEDURE — The colonoscopy will be performed while the patient lies on their left side. Medications will be administered through the intravenous line. Most endoscopy units use a combination of a sedative (to help patients relax), and a narcotic (to prevent discomfort). Many people sleep during the examination while others are very relaxed, comfortable, and generally not aware of the examination.
The colonoscope is a flexible tube, approximately the size of the index finger. It has a lens and a light source that allows the endoscopist to look into the scope or at a TV monitor. The image on the TV monitor is magnified many times so the endoscopist can see small changes in tissue.
The endoscope contains channels that allow the endoscopist to obtain biopsies (small pieces of tissue), remove polyps and to introduce or withdraw fluid or air. Polyps are extra growths of tissue that can range in size from the tip of a pen to several inches (doctors measure them in millimeters and centimeters). Most polyps are benign (not cancerous) but can turn into cancers if left to grow for a very long time. As a result, they are usually removed so they can be analyzed under the microscope. This does not hurt since the lining of the colon does not sense pain.
Air is introduced through the scope to open up the colon so that the scope can be moved forward and to allow the endoscopist to see. Patients may experience a feeling of bloating or gas cramps from the air as it distends the colon. Try not to be embarrassed about releasing the air through the rectum; patients should let their physician know if they are uncomfortable
RECOVERY — After the colonoscopy, a patient will be observed until the effects of the sedative medication are gone. The most common discomfort after colonoscopy is a feeling of bloating and gas cramps. Patients may also feel groggy from the sedation medications. Patients should not return to work that day. Most patients are able to eat a regular diet after the examination. Patients should ask about when it is safe to restart aspirin or blood thinning medications.
COMPLICATIONS — Colonoscopy is a safe procedure and complications are rare, but can occur: Bleeding can occur from biopsies or the removal of polyps, but it is usually minimal and stops quickly or can be controlled. The colonoscope can cause a tear or hole in the tissue being examined, which is a serious problem, but, fortunately, very uncommon. Adverse reactions to the medications used to sedate you are possible. The endoscopy team (doctors and nurses) will ask about previous medication allergies or reactions and about health problems such as heart, lung, kidney, or liver disease. The medications can also produce irritation in the vein at the site of the intravenous line. If redness, swelling, or warmth occur, warm to hot wet towels applied to the site may relieve the discomfort. If the discomfort persists, notify the endoscopy unit.
The following symptoms should be reported immediately: Severe abdominal pain (not just gas cramps) A firm, distended abdomen Vomiting Fever Bleeding greater than a few tablespoons.
AFTER COLONOSCOPY — Although patients worry about discomforts of the examination, most people tolerate it very well and feel fine afterwards. Some fatigue after the examination is common. Patients should plan to take it easy and relax the rest of the day.
The endoscopist can describe the result of their examination before the patient leaves the endoscopy unit. If biopsies have been taken or polyps removed, the patient should call for results within one to two weeks.
WHERE TO GET MORE INFORMATION — Your healthcare provider is the best source of information for questions and concerns related to your medical problem. Because no two patients are exactly alike and recommendations can vary from one person to another, it is important to seek guidance from a provider who is familiar with your individual situation.
This discussion will be updated as needed every four months on our web site (www.patients.uptodate.com). Additional topics as well as selected discussions written for healthcare professionals are also available for those who would like more detailed information.
A number of web sites have information about medical problems and treatments, although it can be difficult to know which sites are reputable. Information provided by the National Institutes of Health, national medical societies and some other well-established organizations are often reliable sources of information, although the frequency with which they are updated is variable. National Library of Medicine
(www.nlm.nih.gov/medlineplus/healthtopics.html)
The American Society of Gastrointestinal Endoscopy
(www.askasge.org)
[1-3]
Use of UpToDate is subject to the Subscription and License Agreement. REFERENCES 1. Rex, DK, Johnson, DA, Lieberman, DA, et al. Colorectal cancer prevention 2000: screening recommendations of the American College of Gastroenterology. American College of Gastroenterology. Am J Gastroenterol 2000; 95:868.
2. Lieberman, DA, Weiss, DG, Bond, JH, et al. Use of colonoscopy to screen asymptomatic adults for colorectal cancer. Veterans Affairs Cooperative Study Group 380. N Engl J Med 2000; 343:162.
3. Singh, H, Turner, D, Xue, L, et al. Risk of developing colorectal cancer following a negative colonoscopy examination: evidence for a 10-year interval between colonoscopies. JAMA 2006; 295:2366.
Colon polyps
THE SIGNIFICANCE OF POLYPS — The presence of polyps in the colon or rectum often raises questions for patients and their family. What is the significance of finding a polyp? Does this mean that I have, or will develop, colon or rectal (colorectal) cancer? Will a polyp require surgery?
Some types of polyps (called adenomas) have the potential to become cancerous while others (hyperplastic or inflammatory polyps) have virtually no chance of becoming cancerous.
When discussing colon polyps, the following points should be considered: Polyps are common (they occur in 30-50 percent of adults) Not all polyps will become cancer It takes many years for a polyp become cancerous Polyps can be completely and safely removed
The best course of action when a polyp is found depends upon the type, size, and location of the polyps and the way in which they were removed. Most people who have an adenoma removed will require a follow up examination; this allows the clinician to be sure that all adenomas have been removed.
CAUSES — Polyps are very common in men and women of all races who live in industrialized countries, which suggests that dietary and environmental factors are important in their development.
Lifestyle — Although the exact causes are not completely understood, lifestyle risk factors include the following: A high fat diet A diet high in red meat A low fiber diet Cigarette smoking Obesity
On the other hand, use of aspirin and other NSAIDs and calcium intake may protect against the development of colon cancer. (See "Patient information: Screening for colon cancer").
Aging — Colorectal cancer is uncommon before age 40. Ninety percent of cases occur after age 50, with men and women being equally affected; therefore, colon cancer screening usually begins at age 50 for both sexes. It takes approximately 10 years for a small polyp to grow and develop into cancer.
Family history and genetics — Polyps and colon cancer tend to run in families, which suggests that genetic factors are also important in their development. Research on the genetic basis of colon cancer is ongoing.
Any history of colon polyps or colon cancer in the family should be discussed with a healthcare provider, particularly if cancer developed at an early age, in close relatives, or in multiple family members. As a general rule, screening for colon cancer begins at an earlier age in people with a family history of cancer or polyps.
Rare genetic diseases can cause high rates of colorectal cancer relatively early in adult life. One disease that causes multiple colon polyps is familial adenomatous polyposis (FAP). Hereditary Non-Polyposis Colon Cancer (HNPCC) also significantly increases the risk of colon cancer, often beginning in the 20s and 30s, but does not cause a large number of polyps. Testing for these genes may be recommended for families with high rates of colorectal cancer, but is not generally recommended for other groups.
TYPES OF POLYPS — The two most common types of polyps are hyperplastic and adenomatous polyps. Other types of polyps can also be found in the colon, although these are far less common and are not discussed here.
Hyperplastic polyps — Hyperplastic polyps are usually small, located in the end-portion of the colon (the rectum and sigmoid colon), have no potential to become malignant, and are not concerning (show figure 1). It is not always possible to distinguish a hyperplastic polyp from an adenomatous polyp based upon appearance, which means that hyperplastic polyps are often removed or biopsied to allow microscopic examination.
Adenomatous polyps — Two-thirds of colon polyps are adenomas. Most of these polyps do not develop into cancer, although they have the potential to become cancerous. Adenomas are classified by their size, general appearance, and their specific features as seen under the microscope.
As a general rule, the larger the adenoma, the more likely it is to eventually become a cancer; large adenomas may already contain cancer cells. As a result, large polyps are usually biopsied (a small sample of tissue is removed) or removed completely to allow for microscopic examination.
DIAGNOSIS — Polyps usually do not cause symptoms. They are most commonly detected during a colon cancer screening examinations (such as flexible sigmoidoscopy or colonoscopy, show endoscopy 1) or during testing after a positive stool blood test. Polyps can also be detected on a barium enema x-ray, although small polyps are less often seen on x-ray and cannot be removed during the examination.
Colonoscopy is the best way to evaluate the colon because it allows the physician to see the entire lining of the colon and remove any polyps that are found. During colonoscopy, a physician inserts a very thin flexible tube with a light source and small camera into the anus. The tube is advanced through the entire length of the large intestine (colon). (See "Patient information: Colonoscopy").
The inside of the colon is a tube-like structure with a flat surface with curved folds. A polyp appears as a lump that protrudes into the inside of the colon (show endoscopy 1). The tissue covering a polyp may look the same as normal colon tissue, or, there may be tissue changes ranging from subtle color changes to ulceration and bleeding. Some polyps are flat ("sessile") and others extend out on a stalk ("pedunculated").
Colonoscopy is also the best test for the follow-up examination of polyps. New technologies are being developed that show promise for detecting polyps (including molecular genetic tests and "virtual colonoscopy" using CT or MRI technology). Further study is needed before these tests are recommended to the general public.
POLYP REMOVAL — Colorectal cancer is the second leading cause of cancer deaths in the United States, accounting for 14 percent of cancer deaths. Colorectal cancer is preventable if precancerous polyps (ie, adenomas) are detected and removed before they become malignant (cancerous). Over time, small polyps can change their structure and become cancerous. Polyps are removed when they are found on colonoscopy, which eliminates the potential for them to become malignant.
Procedure — The medical term for removing polyps is polypectomy. Most polypectomies can be performed through a colonoscope. Small polyps can be removed with an instrument that is inserted through the colonoscope and snips off small pieces of tissue (show endoscopy 2). Larger polyps are usually removed by placing a noose, or snare, around the polyp base and burning through it with electric cautery (show endoscopy 3). The cautery also helps to stop bleeding after the polyp is removed.
Polyp removal is not painful because the colon does not have the ability to feel pain. In addition, a sedative medication is given before the colonoscopy to prevent pain and induce sleep. Rarely, a polyp will be too large to remove during colonoscopy, which means that a surgical procedure will be needed at a later time.
Complications — Polypectomy is very safe, but it has a few risks and potential complications. The most common complications of polypectomy include bleeding and perforation (creating a hole in the colon). Fortunately, this occurs infrequently (one in a thousand patients having colonoscopy). Bleeding can usually be controlled during colonoscopy by cauterizing (applying heat) to the bleeding site; surgery is sometimes required for perforation.
After polyp removal — Medications that can increase bleeding, including aspirin, ibuprofen (Advil®, Motrin®), and naproxen (Aleve®), should be avoided for two weeks after polypectomy. Acetaminophen (Tylenol®) is safe to take. People who require anticoagulant medications such as warfarin (Coumadin®) should discuss how and when to resume this medication after polypectomy with their clinician.
A follow up appointment or phone call is usually scheduled after the polyp removal to discuss the results of the tissue analysis and the need for a repeat examination.
PREVENTION
Follow up examination — People with adenomatous polyps have an increased risk of developing more polyps, which are likely to be adenomatous. There is a 25 to 30 percent chance that adenomas will be present on a repeat colonoscopy done three years after initial polypectomy. Some of these polyps may have been present during the original examination, but were too small to detect. Other new polyps may also have developed.
After polyps are removed, repeat colonoscopy is recommended, usually three to five years after the initial colonoscopy. However, this time interval depends upon several factors: Characteristics of the polyps when they are analyzed under the microscope Number and size of the polyps The appearance of the colon during the colonoscopy. A bowel preparation is needed before colonoscopy to remove all traces of feces (stool). If the bowel prep was not completed, feces may remain in the colon, making it more difficult to see small to moderate size polyps. In this situation, follow up colonoscopy may be recommended sooner than three to five years later.
Persons who undergo screening (and re-screening) for colon cancer are much less likely to die from colon cancer. Thus, following screening guidelines is one of the most important measures.
Preventing colon cancer — Intensive research is underway to develop ways to prevent polyps and colon cancer with diet or with medications. A number of nutrients and medications have been identified that may reduce the risk of colon cancer. Guidelines issued by one of the major medical societies in the United States (the American College of Gastroenterology) suggest the following to prevent polyps from recurring: Eat a diet that is low in fat and high in fruits, vegetables, and fiber Maintain a normal body weight Avoid smoking and excessive alcohol use Consider taking a dietary supplementation with 3 g of calcium carbonate
(See "Patient information: Diet and health" and see "Patient information: Smoking cessation").
IMPLICATIONS FOR THE FAMILY — First-degree relatives (a parent, brother, sister, or child) of a person who has been diagnosed with an adenomatous polyp (or colorectal cancer) before the age of 60 years are at increased risk for adenomatous polyps and colorectal cancer compared to the general population. Thus, family members should be made aware if adenoma or colon cancer are diagnosed. While screening for polyps and cancer is recommended for all people at risk (typically beginning at age 50), those at increased risk should begin screening earlier, typically at age 40.
Relatives can be told the following: People who have one first-degree relative (parent, brother, sister, or child) with colorectal cancer or adenomatous polyps at a young age (before the age of 60 years), or two first-degree relatives diagnosed at any age, should begin screening earlier, typically at age 40, or 10 years younger than the earliest diagnosis in their family, whichever comes first. Screening should be repeated every five years. People who have one first-degree relative (parent, brother, sister, or child) with colorectal cancer or adenomatous polyps at age 60 or later should begin screening at age 40, and screening should be repeated similar to a person with an average risk of colon cancer. (See "Patient information: Screening for colon cancer" section on "Average risk"). People with a second-degree relative (grandparent, aunt, or uncle) or third-degree relative (great-grandparent or cousin) with colorectal cancer may be screened similar to a person with an average risk. (See "Patient information: Screening for colon cancer" section on "Average risk").
Some conditions, such as hereditary nonpolyposis colorectal cancer, familial adenomatous polyposis, and inflammatory bowel disease (eg, ulcerative colitis, Crohn's disease) significant increase the risk of colonic polyps or cancer in family members. Colon cancer screening in this group is discussed separately. (See "Patient information: Screening for colon cancer" section on "Increased risk").
WHERE TO GET MORE INFORMATION — Your healthcare provider is the best source of information for questions and concerns related to your medical problem. Because no two patients are exactly alike and recommendations can vary from one person to another, it is important to seek guidance from a provider who is familiar with your individual situation.
This discussion will be updated as needed every four months on our web site (www.patients.uptodate.com). Additional topics as well as selected discussions written for healthcare professionals are also available for those who would like more detailed information.
A number of web sites have information about medical problems and treatments, although it can be difficult to know which sites are reputable. Information provided by the National Institutes of Health, national medical societies and some other well-established organizations are often reliable sources of information, although the frequency with which they are updated is variable. National Library of Medicine
(www.nlm.nih.gov/medlineplus)
The American Gastroenterological Association
(www.gastro.org)
The American College of Gastroenterology
(www.acg.gi.org)
The American Society of Colon and Rectal Surgeon
(www.fascrs.org)
[1-3]
Use of UpToDate is subject to the Subscription and License Agreement. REFERENCES 1. Winawer, S, Fletcher, R, Rex, D, et al. Colorectal cancer screening. Gastroenterology 2003; 124:544.
2. Winawer, SJ, Zauber, AG, Ho, MN, et al. Prevention of colorectal cancer by colonoscopic polypectomy. N Engl J Med 1993; 329:1977.
3. Bond, JH. Polyp guideline: Diagnosis, treatment, and surveillance for patients with colorectal polyps. Am J Gastroenterol 2000; 95:3053.
Some types of polyps (called adenomas) have the potential to become cancerous while others (hyperplastic or inflammatory polyps) have virtually no chance of becoming cancerous.
When discussing colon polyps, the following points should be considered: Polyps are common (they occur in 30-50 percent of adults) Not all polyps will become cancer It takes many years for a polyp become cancerous Polyps can be completely and safely removed
The best course of action when a polyp is found depends upon the type, size, and location of the polyps and the way in which they were removed. Most people who have an adenoma removed will require a follow up examination; this allows the clinician to be sure that all adenomas have been removed.
CAUSES — Polyps are very common in men and women of all races who live in industrialized countries, which suggests that dietary and environmental factors are important in their development.
Lifestyle — Although the exact causes are not completely understood, lifestyle risk factors include the following: A high fat diet A diet high in red meat A low fiber diet Cigarette smoking Obesity
On the other hand, use of aspirin and other NSAIDs and calcium intake may protect against the development of colon cancer. (See "Patient information: Screening for colon cancer").
Aging — Colorectal cancer is uncommon before age 40. Ninety percent of cases occur after age 50, with men and women being equally affected; therefore, colon cancer screening usually begins at age 50 for both sexes. It takes approximately 10 years for a small polyp to grow and develop into cancer.
Family history and genetics — Polyps and colon cancer tend to run in families, which suggests that genetic factors are also important in their development. Research on the genetic basis of colon cancer is ongoing.
Any history of colon polyps or colon cancer in the family should be discussed with a healthcare provider, particularly if cancer developed at an early age, in close relatives, or in multiple family members. As a general rule, screening for colon cancer begins at an earlier age in people with a family history of cancer or polyps.
Rare genetic diseases can cause high rates of colorectal cancer relatively early in adult life. One disease that causes multiple colon polyps is familial adenomatous polyposis (FAP). Hereditary Non-Polyposis Colon Cancer (HNPCC) also significantly increases the risk of colon cancer, often beginning in the 20s and 30s, but does not cause a large number of polyps. Testing for these genes may be recommended for families with high rates of colorectal cancer, but is not generally recommended for other groups.
TYPES OF POLYPS — The two most common types of polyps are hyperplastic and adenomatous polyps. Other types of polyps can also be found in the colon, although these are far less common and are not discussed here.
Hyperplastic polyps — Hyperplastic polyps are usually small, located in the end-portion of the colon (the rectum and sigmoid colon), have no potential to become malignant, and are not concerning (show figure 1). It is not always possible to distinguish a hyperplastic polyp from an adenomatous polyp based upon appearance, which means that hyperplastic polyps are often removed or biopsied to allow microscopic examination.
Adenomatous polyps — Two-thirds of colon polyps are adenomas. Most of these polyps do not develop into cancer, although they have the potential to become cancerous. Adenomas are classified by their size, general appearance, and their specific features as seen under the microscope.
As a general rule, the larger the adenoma, the more likely it is to eventually become a cancer; large adenomas may already contain cancer cells. As a result, large polyps are usually biopsied (a small sample of tissue is removed) or removed completely to allow for microscopic examination.
DIAGNOSIS — Polyps usually do not cause symptoms. They are most commonly detected during a colon cancer screening examinations (such as flexible sigmoidoscopy or colonoscopy, show endoscopy 1) or during testing after a positive stool blood test. Polyps can also be detected on a barium enema x-ray, although small polyps are less often seen on x-ray and cannot be removed during the examination.
Colonoscopy is the best way to evaluate the colon because it allows the physician to see the entire lining of the colon and remove any polyps that are found. During colonoscopy, a physician inserts a very thin flexible tube with a light source and small camera into the anus. The tube is advanced through the entire length of the large intestine (colon). (See "Patient information: Colonoscopy").
The inside of the colon is a tube-like structure with a flat surface with curved folds. A polyp appears as a lump that protrudes into the inside of the colon (show endoscopy 1). The tissue covering a polyp may look the same as normal colon tissue, or, there may be tissue changes ranging from subtle color changes to ulceration and bleeding. Some polyps are flat ("sessile") and others extend out on a stalk ("pedunculated").
Colonoscopy is also the best test for the follow-up examination of polyps. New technologies are being developed that show promise for detecting polyps (including molecular genetic tests and "virtual colonoscopy" using CT or MRI technology). Further study is needed before these tests are recommended to the general public.
POLYP REMOVAL — Colorectal cancer is the second leading cause of cancer deaths in the United States, accounting for 14 percent of cancer deaths. Colorectal cancer is preventable if precancerous polyps (ie, adenomas) are detected and removed before they become malignant (cancerous). Over time, small polyps can change their structure and become cancerous. Polyps are removed when they are found on colonoscopy, which eliminates the potential for them to become malignant.
Procedure — The medical term for removing polyps is polypectomy. Most polypectomies can be performed through a colonoscope. Small polyps can be removed with an instrument that is inserted through the colonoscope and snips off small pieces of tissue (show endoscopy 2). Larger polyps are usually removed by placing a noose, or snare, around the polyp base and burning through it with electric cautery (show endoscopy 3). The cautery also helps to stop bleeding after the polyp is removed.
Polyp removal is not painful because the colon does not have the ability to feel pain. In addition, a sedative medication is given before the colonoscopy to prevent pain and induce sleep. Rarely, a polyp will be too large to remove during colonoscopy, which means that a surgical procedure will be needed at a later time.
Complications — Polypectomy is very safe, but it has a few risks and potential complications. The most common complications of polypectomy include bleeding and perforation (creating a hole in the colon). Fortunately, this occurs infrequently (one in a thousand patients having colonoscopy). Bleeding can usually be controlled during colonoscopy by cauterizing (applying heat) to the bleeding site; surgery is sometimes required for perforation.
After polyp removal — Medications that can increase bleeding, including aspirin, ibuprofen (Advil®, Motrin®), and naproxen (Aleve®), should be avoided for two weeks after polypectomy. Acetaminophen (Tylenol®) is safe to take. People who require anticoagulant medications such as warfarin (Coumadin®) should discuss how and when to resume this medication after polypectomy with their clinician.
A follow up appointment or phone call is usually scheduled after the polyp removal to discuss the results of the tissue analysis and the need for a repeat examination.
PREVENTION
Follow up examination — People with adenomatous polyps have an increased risk of developing more polyps, which are likely to be adenomatous. There is a 25 to 30 percent chance that adenomas will be present on a repeat colonoscopy done three years after initial polypectomy. Some of these polyps may have been present during the original examination, but were too small to detect. Other new polyps may also have developed.
After polyps are removed, repeat colonoscopy is recommended, usually three to five years after the initial colonoscopy. However, this time interval depends upon several factors: Characteristics of the polyps when they are analyzed under the microscope Number and size of the polyps The appearance of the colon during the colonoscopy. A bowel preparation is needed before colonoscopy to remove all traces of feces (stool). If the bowel prep was not completed, feces may remain in the colon, making it more difficult to see small to moderate size polyps. In this situation, follow up colonoscopy may be recommended sooner than three to five years later.
Persons who undergo screening (and re-screening) for colon cancer are much less likely to die from colon cancer. Thus, following screening guidelines is one of the most important measures.
Preventing colon cancer — Intensive research is underway to develop ways to prevent polyps and colon cancer with diet or with medications. A number of nutrients and medications have been identified that may reduce the risk of colon cancer. Guidelines issued by one of the major medical societies in the United States (the American College of Gastroenterology) suggest the following to prevent polyps from recurring: Eat a diet that is low in fat and high in fruits, vegetables, and fiber Maintain a normal body weight Avoid smoking and excessive alcohol use Consider taking a dietary supplementation with 3 g of calcium carbonate
(See "Patient information: Diet and health" and see "Patient information: Smoking cessation").
IMPLICATIONS FOR THE FAMILY — First-degree relatives (a parent, brother, sister, or child) of a person who has been diagnosed with an adenomatous polyp (or colorectal cancer) before the age of 60 years are at increased risk for adenomatous polyps and colorectal cancer compared to the general population. Thus, family members should be made aware if adenoma or colon cancer are diagnosed. While screening for polyps and cancer is recommended for all people at risk (typically beginning at age 50), those at increased risk should begin screening earlier, typically at age 40.
Relatives can be told the following: People who have one first-degree relative (parent, brother, sister, or child) with colorectal cancer or adenomatous polyps at a young age (before the age of 60 years), or two first-degree relatives diagnosed at any age, should begin screening earlier, typically at age 40, or 10 years younger than the earliest diagnosis in their family, whichever comes first. Screening should be repeated every five years. People who have one first-degree relative (parent, brother, sister, or child) with colorectal cancer or adenomatous polyps at age 60 or later should begin screening at age 40, and screening should be repeated similar to a person with an average risk of colon cancer. (See "Patient information: Screening for colon cancer" section on "Average risk"). People with a second-degree relative (grandparent, aunt, or uncle) or third-degree relative (great-grandparent or cousin) with colorectal cancer may be screened similar to a person with an average risk. (See "Patient information: Screening for colon cancer" section on "Average risk").
Some conditions, such as hereditary nonpolyposis colorectal cancer, familial adenomatous polyposis, and inflammatory bowel disease (eg, ulcerative colitis, Crohn's disease) significant increase the risk of colonic polyps or cancer in family members. Colon cancer screening in this group is discussed separately. (See "Patient information: Screening for colon cancer" section on "Increased risk").
WHERE TO GET MORE INFORMATION — Your healthcare provider is the best source of information for questions and concerns related to your medical problem. Because no two patients are exactly alike and recommendations can vary from one person to another, it is important to seek guidance from a provider who is familiar with your individual situation.
This discussion will be updated as needed every four months on our web site (www.patients.uptodate.com). Additional topics as well as selected discussions written for healthcare professionals are also available for those who would like more detailed information.
A number of web sites have information about medical problems and treatments, although it can be difficult to know which sites are reputable. Information provided by the National Institutes of Health, national medical societies and some other well-established organizations are often reliable sources of information, although the frequency with which they are updated is variable. National Library of Medicine
(www.nlm.nih.gov/medlineplus)
The American Gastroenterological Association
(www.gastro.org)
The American College of Gastroenterology
(www.acg.gi.org)
The American Society of Colon and Rectal Surgeon
(www.fascrs.org)
[1-3]
Use of UpToDate is subject to the Subscription and License Agreement. REFERENCES 1. Winawer, S, Fletcher, R, Rex, D, et al. Colorectal cancer screening. Gastroenterology 2003; 124:544.
2. Winawer, SJ, Zauber, AG, Ho, MN, et al. Prevention of colorectal cancer by colonoscopic polypectomy. N Engl J Med 1993; 329:1977.
3. Bond, JH. Polyp guideline: Diagnosis, treatment, and surveillance for patients with colorectal polyps. Am J Gastroenterol 2000; 95:3053.
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