A screening test is used to look for a disease when a person doesn't have symptoms. (When a person has symptoms, diagnostic tests are used to find out the cause of the symptoms.)
Cancer screening tests, including those for colorectal cancer, work best when they can help prevent cancer or find it early, when treatment works best.
Colorectal cancer almost always develops from precancerous polyps (abnormal growths) in the colon or rectum. Screening tests can find precancerous polyps, so that they can be removed before they turn into cancer. Screening tests can also find colorectal cancer early, when treatment works best.
Regular screening, beginning at age 50, is the key to preventing colorectal cancer. The U.S. Preventive Services Task Force (USPSTF) recommends screening for colorectal cancerExternal Web Site Icon using high-sensitivity fecal occult blood testing, sigmoidoscopy, or colonoscopy beginning at age 50 years and continuing until age 75 years.
You should begin screening for colorectal cancer soon after turning 50, then continue getting screened at regular intervals. However, you may need to be tested earlier than 50 or more often than other people if—
Speak with your doctor about when you should begin screening and how often you should be tested.