Prevent Colon Cancer with a Colonoscopy Starting at Age 45. It used to be 50. Now, anyone approaching their 45th birthday should talk to their primary care provider to schedule a possibly lifesaving colonoscopy. A colonoscopy is an exam that can stop colorectal cancer, which is among the most common – and deadly – forms of the disease. Carolyn Cegielski, DO, at South Central Gastroenterology, explains the importance of colonoscopies. To schedule a screening, visit https://scrmc.com/services/gastroenterology-direct-access/