The American College of Gastroenterology recommends colonoscopy every 10 years for patients aged 50 or older in its update of screening guidelines last published in 2000.

That recommendation is a departure from the ACG???s endorsement of the Multisociety Task Force on Colorectal Cancer guideline, which offers clinicians a menu of treatment options instead of identifying colonoscopy as the preferred screening method. ACG leadership hopes the added emphasis will shorten discussions with patients about their course of care and increase utilization of colorectal cancer screening tests.

The updated guidelines, which appear in the March issue of The American Journal of Gastroenterology, also identify annual fecal immunochemical testing as the preferred colorectal cancer detection test; suggest that African Americans begin colonoscopy screening at age 45; and recommend "split dosing" — at least half of a prep solution is given on the day of colonoscopy, rather than all of it on the day before the exam — to improve the effectiveness and tolerability of bowel preparation.

In addition, the ACG says patients can now drink clear liquids up to two hours before sedation for colonoscopy. The College also endorses the use of virtual colonoscopy (CTC) when patients refuse colonoscopy, but warns that the virtual screening cannot match the effectiveness of the standard test: False positives are common following CTC, and it fails to detect polyps smaller than 5mm, which account for 80 percent of abnormal colorectal growths, says the ACG.

—Daniel Cook