Colon cancer is most likely to strike older patients over the age of 50. Also called colorectal cancer, this disease is the second leading cause of cancer death in the United States, claiming the lives of almost 50,000 men and women annually. Colorectal cancer is highly treatable if caught early. However, many cases are not caught until they have progressed to advanced stages. A colonoscopy is a test where a doctor uses a camera to scan your colon for cancerous polyps. A polyp is an abnormal growth of tissue.