Colon cancer, or colorectal cancer, is the third most common cancer diagnosed in men and women in the United States. Most colon cancers begin as small clumps of cells called polyps that grow on the inner lining of the colon or rectum. Not all polyps are cancerous.

Symptoms can include changes in bowel habits (constipation or diarrhea), rectal bleeding and persistent abdominal pain or cramping. Because symptoms are not always present, regular screening for colon cancer is critical. Doctors can remove any detected polyps before becoming cancerous.