Colon cancer refers to a malignant tumor that grows in the large intestine (colon). Since rectal cancer is a malignant tumor that grows in the rectum, doctors often refer to them jointly, as "colorectal cancer."

Most colon cancers arise from a benign (non-cancerous) polyp that, over a period of many years, develops into a cancer.

Colorectal cancer is the most common, non-smoking related cancer in women and men today, and it is the second deadliest cancer after lung cancer.

The American Cancer Society estimates that around 150,000 new cases will be diagnosed in the United States in 2005 and that nearly 60,000 deaths will occur due to this disease. Equal numbers of men and women develop colorectal cancer each year.

However, the disease is treatable: the five-year survival rate is as high as 90 percent if the disease is caught early.