Colon cancer is cancer of the large intestine (colon), the lower part of your digestive system. Rectal cancer is cancer of the last 8 to 10 inches of the colon. Together, they are often referred to as colorectal cancers, and they make up the second-leading cause of cancer-related deaths in the United States. Only lung cancer claims more lives.

Most cases of colon cancer begin as small, noncancerous (benign) clumps of cells called adenomatous polyps. Over time some of these polyps become cancerous.

Polyps may be small and produce few, if any, symptoms, so it's important to get regular screening tests to help prevent colon cancer. If signs and symptoms of cancer do appear, they may include a change in bowel habits, blood in your stool, persistent cramping, gas or abdominal pain.

Despite the relatively high number of cases and deaths, there's good news about colon cancer. Screening tests, along with a few simple changes in your diet and lifestyle, can dramatically reduce your overall risk of developing colon cancer.