How Often Should One Have a Colonoscopy?

Colonoscopy saves lives when used to detect early-stage colorectal cancer. The American Cancer Society and U.S. Preventative Services Task Force recommend regular screening for colorectal cancer beginning at age 50, for people at average risk 137. The American College of Gastroenterology further advises that African-Americans begin screening at age 45 due to increased risk 1. Colonoscopy allows visualization of the rectum and the entire length of the colon and should be repeated every 10 years. Alternative screening methods are available, including flexible sigmoidoscopy, double-contrast barium enema, CT colonography and fecal immunochemical test, or FIT.

Screening for People at Increased Risk

Certain factors increase your risk for colorectal cancer and may call for earlier or more frequent screening. People with a close relative diagnosed with colorectal cancer before age 60 should begin screening at age 40 -- or 10 years earlier than the age the relative developed cancer. Colonoscopy should be repeated every 5 years in this situation. Screening prior to age 50 may also be warranted for people who are obese or have a history of heavy smoking. Discuss a more advanced screening schedule with your doctor if you believe you are at increased risk.

Alternative Screening Methods

Although the American College of Gastroenterology recommends colonoscopy as the preferred colorectal screening test, alternative methods can be used to screen for colorectal cancer 18. These include flexible sigmoidoscopy, CT colonography and double-contrast barium enema, also known as a lower GI series. Flexible sigmoidoscopy is similar to a colonoscopy but only allows access to the lower colon. CT colonography, also called a virtual colonoscopy, provides images of the colon using computer technology. These alternative methods require more frequent screening, typically every 5 years. The FIT screening method, which detects blood in the stool, should be repeated annually.