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Colon cancer 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 pain and death caused by colorectal cancer.


There are several ways to screen for colon cancer.

Stool test:

  • Polyps in the colon and small cancers can cause small amounts of bleeding that cannot be seen with the naked eye. But the blood can often be found in the stool.
  • This method checks your stool for blood.
  • The most common test used is the fecal occult blood test (FOBT). Two other tests are called the fecal immunochemical test (FIT) and stool DNA test (sDNA).


  • This test uses a small flexible scope to view the lower part of your colon. Only the last one-third of the large intestine (colon) is viewed. For this reason, the test may miss some cancers that are higher in the large intestine.
  • Sigmoidoscopy and a stool test should be used together.


  • A colonoscopy is similar to a sigmoidoscopy, but the entire colon can be viewed.
  • During this test, you receive medicine to make you relaxed and sleepy.
  • Sometimes, CT scans are used as an alternative to a regular colonoscopy. This is called a virtual colonoscopy.
Sigmoid colon cancer, X-ray

Other tests:

  • 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. The method is being studied, so it is not recommended for standard screening at this time.


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 people 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 to 10 years, usually with stool testing (FOBT) done every 1 to 3 years
  • Virtual colonoscopy every 5 years


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 close 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 (ulcerative colitis or Crohn disease).

Screening for these groups is more likely to be done using colonoscopy.

Talk with your provider about your risk factors and screening needs.

Alternative Names

Screening for colon cancer; Colonoscopy - screening; Sigmoidoscopy - screening; Virtual colonoscopy - screening


Itzkowitz SH, Potack J. Colonic polyps and polyposis syndromes. In: Feldman M, Friedman LS, Brandt LJ, eds.Sleisenger and Fordtran's Gastrointestinal and Liver Disease Pathophysiology/Diagnosis/Management.

Levin B, Lieberman DA, McFarland B, 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 Clinwww.ncbi.nlm.nih.gov/pubmed/18322143

National Comprehensive Cancer Network. NCCN Clinical Practice Guidelines in Oncology (NCCN Guidelines): Colorectal cancer screening. Version 1.2014. Available at: www.nccn.org/professionals/physician_gls/pdf/colorectal_screening.pdf. Accessed November 20, 2014.

Rex DK, Johnson DA, Anderson JC, Schoenfeld PS, Burke CA, Inadomi JM. American College of Gastroenterology. American College of Gastroenterology guidelines for colorectal cancer screening 2009 [corrected].Am J Gastroenterolwww.ncbi.nlm.nih.gov/pubmed/19240699

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Update Date 11/20/2014

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