Prevention Is Key. Colon cancer is one of the most preventable types of cancer. Research shows that colon cancer screening saves lives. Because a colonoscopy allows the gastroenterologist direct visual examination of the inside of the entire colon and the ability to immediately remove precancerous polyps, a colonoscopy is considered the “gold standard” screening method. It is a screening and prevention method in one. In most cases, polyp removal is the only treatment required. However, if cancer is detected, the patient can receive treatment at an early stage when it is most likely to be successful.