The American Cancer Society believes that preventing colorectal cancer (and not just finding it early) should be a major reason for getting tested. TMC gastroenterologists screen for cancer using colonoscopy or flexible sigmoidoscopy. In both of these procedures, the physician can both screen for colon polyps and remove them. Polyps are small growths that can become cancerous over time. Removing polyps can help prevent colorectal cancer from ever starting.Listen as Richard K. Saltz, MD explains that cancers found in an early stage, while they are small and before they have spread, are more easily treated.