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Definition
By Mayo Clinic staffColon cancer is cancer of the large intestine (colon), the lower part of your digestive system. Rectal cancer is cancer of the last 6 inches of the colon. Together, they're often referred to as colorectal cancers. About 112,000 people are diagnosed with colon cancer annually, and about 41,000 new cases of rectal cancer are diagnosed each year, according to the American Cancer Society.
Most cases of colon cancer begin as small, noncancerous (benign) clumps of cells called adenomatous polyps. Over time some of these polyps become colon cancers.
Polyps may be small and produce few, if any, symptoms. Regular screening tests can help prevent colon cancer by identifying polyps before they become cancerous. If signs and symptoms of colon cancer do appear, they may include changes in bowel habits, blood in your stool, persistent cramping, gas or abdominal pain.
Symptoms
