A large study has confirmed what The American College of Gastroenterology Colorectal Cancer Screening Guidelines and health experts have long recommended and stressed in public awareness campaigns: Colonoscopy reduces colorectal cancer death risk and saves lives.

In the study, ACG member and lead author Dr. Charles Kahi, compared the screening histories over about two decades and found that “colonoscopy was associated with a 61 percent reduction in colorectal cancer mortality.” Dr. Kahi and his team looked at about 25,000 patients in the Veterans Affairs (VA) health system, where colonoscopy is widely used. The VA considers colonoscopy as the main screening test for patients aged 50 and older who are at average risk for developing colon or rectal cancer.

Nearly 20,000 patients of that group were cancer-free between 2002 and 2008. About 5,000 were diagnosed with colorectal cancer during that time and died of the disease by 2010.

Those who died were significantly less likely to have had a colonoscopy, according to the study that was published in the Annals of Internal Medicine, March 13, 2013.