Adults aged 50 to 75 should be screened for colorectal cancer using one of three methods that are deemed equally effective in new recommendations from the U.S. Preventive Services Task Force (USPSTF). Several screening methods have now been shown to save lives, the panel of independent experts concluded: annual high-sensitivity fecal occult blood testing; sigmoidoscopy every 5 years with fecal occult testing between exams; or colonoscopy every 10 years. The recommendations appeared online October 6 in the Annals of Internal Medicine.
 
In addition, the panel advised against routine screening for adults aged 76 to 85, saying that the potential benefits were small compared to the risks. For similar reasons, adults older than age 85 were urged to forgo screening. This was the first time the USPSTF has identified an upper age limit for colorectal cancer screening, but the group recently advised against routine screening for prostate cancer in men over age 74.

The Task Force concluded that there was insufficient evidence to assess the benefits and harms of computed tomographic (CT) colonography - also known as virtual colonoscopy - and of fecal DNA testing as screening methods.

Current levels of screening for colorectal cancer in the United States lag behind those of other effective cancer screening tests. In its previous (2002) recommendations, the Task Force endorsed colorectal cancer screening but said there was insufficient evidence to recommend one method over another.

The new report discusses the risks and benefits of the tests. While colonoscopy is considered the gold standard in screening, it is imperfect and may miss some polyps and colorectal cancer, the authors note. And because colonoscopy is an invasive procedure, it has a greater risk of complications than sigmoidoscopy or fecal occult blood testing, which are less invasive. Regardless of the screening method used, a patient who receives a positive test result requires a follow-up colonoscopy.