AGA experts highlight benefits and limits of colorectal cancer screening tests

As new colorectal cancer screening guidance draws attention to the growing number of testing options, the American Gastroenterological Association urges patients and primary care providers to understand how those options compare. AGA experts emphasize that screening saves lives - and that the type of test matters. 

1. Colonoscopy remains the strongest screening option. AGA recommends colonoscopy because it is the only test that both detects colorectal cancer early and helps prevent it by allowing doctors to remove precancerous polyps during the same procedure. 

2. Stool tests are a reasonable alternative when colonoscopy is not available or feasible. Patients who choose stool-based screening should understand that abnormal results must be followed by a colonoscopy, and that testing must be repeated at recommended intervals. 

3. Blood tests should be approached with caution. AGA cautions that blood-based tests are less effective than colonoscopy or stool tests at detecting colorectal cancer and cannot identify precancerous polyps that should be removed before cancer develops. 

Health care providers seeking more information about colorectal cancer screening options should review the AGA clinical practice update titled Current Role of Blood Tests for Colorectal Cancer Screening.