A single colon cancer screening procedure, performed one time in midlife, may provide meaningful protection against colorectal cancer for more than two decades, according to one of the longest and largest randomized screening trials ever conducted.
The study, published May 12, 2026, in Annals of Internal Medicine, enrolled 100,210 adults between the ages of 50 and 64 in Norway and followed them for 23 years. Men who received a single flexible sigmoidoscopy were 28 percent less likely to develop colorectal cancer and 37 percent less likely to die from it compared to men who received no screening — sustained effects measured more than two decades after that one appointment.
