Topic Overview

Screening tests for colorectal (colon) cancer

Screening tests for colorectal cancer look for signs of cancer before you have symptoms. Screening tests for colorectal cancer include:

• Stool tests that can be done at home. They include:
  • FIT (fecal immunochemical test). This test checks for signs of blood in small samples of stool. There are no special diets to follow. This test is done every year.
  • gFOBT (guaiac fecal occult blood test). It checks for signs of blood in small samples of stool. You will need to avoid certain foods and medicines before doing this test. This test is done every year.
• A procedure that allows your doctor to look directly at your colon. This test is usually done in your doctor's office or a medical clinic. It is done less often than stool tests but require more preparation. Getting ready may include having a liquid diet for a day or two before your appointment and following instructions to clean out your colon. This procedure includes:
  • A flexible sigmoidoscopy. It lets your doctor look at the inside of the lower part of your colon. It is done every 10 years.

For people at an average risk for colorectal cancer

Your risk for colorectal cancer gets higher as you get older. Experts say that most adults should start regular screening at age 50 and stop at age 74. Talk with your doctor about your risk and when to start and stop screening.

For people at an increased risk for colorectal cancer

Colonoscopy is the recommended screening test for people at high risk. Your doctor may recommend earlier or more frequent testing if you:

• Already have been diagnosed with colorectal cancer.
• Have a first-degree relative (parent, brother, sister, or child) with an adenomatous polyp or colorectal cancer.
• Have had adenomatous polyps removed from your colon.
• Have inflammatory bowel disease, such as ulcerative colitis or Crohn's disease.
• Have a rare inherited polyp syndrome, such as FAP or Lynch syndrome (HNPCC).