Colon cancer screening
Screening for colon cancer; Colonoscopy - screening; Sigmoidoscopy - screening; Virtual colonoscopy - screening
Colon cancer screening can detect polyps and early cancers in the intestines. This type of screening can find problems that can be treated before cancer develops or spreads. Regular screenings may reduce the risk of death and pain caused by colorectal cancer.
There are several ways to screen for colon cancer.
- This method checks your bowel movements for blood.
- Polyps in the colon and smaller cancers often cause small amounts of bleeding that cannot be seen with the naked eye.
- The most common test used is the fecal occult blood test (FOBT). Newer ones are called the fecal immunochemical test (FIT) and stool DNA test (sDNA).
- This test uses a flexible small scope to look at the lower part of your colon. Because it only looks at the last one-third of the large intestine (colon), it may miss some cancers.
- A stool test and sigmoidoscopy should be used together.
- A colonoscopy is similar to a sigmoidoscopy, but the entire colon can be viewed.
- Mild sedation is usually used during a colonoscopy.
- Sometimes, CT scans are used as an alternative to a regular colonoscopy. This is called a virtual colonoscopy.
- Double-contrast barium enema is a special x-ray of the large intestine that looks at the colon and rectum
- Capsule endoscopy involves swallowing a small, pill-sized camera. It is being studied, but it is not recommended for standard screening at this time.
SCREENING FOR AVERAGE-RISK PEOPLE
There is not enough evidence to say which screening method is best. Talk to your doctor about which test is right for you.
Both men and women should have a colon cancer screening test starting at age 50. Some health care providers recommend that African Americans begin screening at age 45.
Screening options for patients with an average risk for colon cancer:
- Colonoscopy every 10 years
- Double-contrast barium enema every 5 years
- Fecal occult blood test (FOBT) every year (colonoscopy is needed if results are positive)
- Flexible sigmoidoscopy every 5 - 10 years, usually with stool testing FOBT done every 1 - 3 years
- Virtual colonoscopy every 5 years
SCREENING FOR HIGHER-RISK PEOPLE
People with certain risk factors for colon cancer may need earlier (before age 50) or more frequent testing.
More common risk factors are:
- A family history of inherited colorectal cancer syndromes, such as familial adenomatous polyposis (FAP) or hereditary nonpolyposis colorectal cancer (HNPCC)
- A strong family history of colorectal cancer or polyps. This usually means first-degree relatives (parent, sibling, or child) who developed these conditions younger than age 60.
- A personal history of colorectal cancer or polyps
- A personal history of chronic inflammatory bowel disease (for example, ulcerative colitis or Crohn's disease)
Screening for these groups of people is more likely to be done using colonoscopy.
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Levin B, Lieberman DA, McFarland B, Smith RA, Brooks D, Andrews KS, et al. Screening and surveillance for the early detection of colorectal cancer and adenomatous polyps, 2008: a joint guideline from the American Cancer Society, the U.S. Multi-Society Task Force on Colorectal Cancer, and the American College of Radiology. CA Cancer J Clin. 2008;58:130-160.
George F. Longstreth, MD, Department of Gastroenterology, Kaiser Permanente Medical Care Program, San Diego, California. Also reviewed by A.D.A.M. Health Solutions, Ebix, Inc., Editorial Team: David Zieve, MD, MHA, David R. Eltz, and Stephanie Slon.
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