Rockefeller Cancer Institute. He says the earlier colonoscopy almost certainly would have prevented the cancer. The American Cancer Society recommends most men and women start undergoing colonoscopies at age 50. Those at high risk for colon cancer or experiencing symptoms such as rectal bleeding, anemia or a change in bowel habits may be advised by their doctor to receive the test earlier. One of the benefits of an academic medical center like UAMS is the physicians and staff are able to provide total comprehensive care in one location at one time.