Reducing the Risk of Colon Cancer Here are some of the preventive steps you and your doctor can take if your genetic test indicates a risk of developing an inherited cancer: Increased Surveillance Colonoscopy every one to two years beginning at age 20-25 or 5-10 years before the earliest age of a diagnosed colorectal cancer in your family, whichever comes first. Colonoscopy annually after age 40. Preventive Surgery If colon cancer (or an advanced precancerous polyp) is diagnosed in a patient with HNPCC , a full, rather than partial, colectomy is recommended. In carefully selected people, for example, those not willing or able to undergo periodic screening, preventive colectomy may be an option based on a positive genetic test result for HNPCC. Preventive Drug Therapies for Colorectal Cancer: Different drugs for the prevention of colorectal cancer are currently being researched for individuals with HNPCC. None of these drugs are currently approved by the FDA for this purpose. Increa...