Screening Methods

Colonoscopy is the preferred diagnostic tool for colon cancer screening. Research has proven the superiority of colonoscopy over other colon cancer screening tests. A colonoscopy allows your doctor to view the entire length of the colon to evaluate the health of your digestive tract.

Flexible sigmoidoscopy is a procedure in which a lighted tube (a sigmoidoscope) is inserted into the rectum, and the lower colon (also known as the sigmoid) is examined. Since this type of screening only looks at the lower colon, polyps and other abnormalities in the rest of the colon may not be discovered. If any polyps are found in a sigmoidoscopy, you may have to schedule a follow-up colonoscopy to examine the rest of the colon.

Virtual colonoscopy uses multiple computerized tomography (CT) images to create a detailed picture of the inside of the colon. While this test is less invasive than a colonoscopy, this test cannot remove any polyps in the colon. If polyps are detected, a follow-up colonoscopy may be necessary to remove them.

Fecal Occult Blood Test (FOBT) detects blood in a stool sample. Blood in the stool may be a sign of colorectal cancer, but this is not a diagnostic test. If blood in the stool is detected, a follow-up colonoscopy may need to be performed.

Double Contrast Barium Enema (DCBE) uses a series of X-rays to evaluate the entire colon and rectum. Barium, a contrast dye, is placed into the colon through an enema, and then air is also added. The barium and air help to outline the colon and rectum on the X-rays.