The promise has been that if you endure the awkwardness and invasiveness of having a camera travel the length of your large intestine once every decade after age 45, you have the best chance of catching – and perhaps preventing – colorectal cancer.Now, a landmark study suggests the benefits of colonoscopies for cancer screening may be overestimated.The study found only meager benefits for the group of people invited to get the procedure: an 18% lower risk of getting colorectal cancer, and no significant reduction in the risk of cancer death.“And we may have oversold the message for the last 10 years or so, and we have to wind it back a little.” Other experts say that as good as this study was, it has important limitations, and these results shouldn’t deter people from getting colonoscopies.“They identify people at high risk who would benefit from colonoscopy, then the colonoscopy is done and removes polyps, for example, that prevents the individual from getting colon cancer in the first place, or it identifies colon cancer at a treatable stage.” Polyps are benign growths that can turn into cancers."