Colorectal cancer is a disease of the cells of the inner lining of the colon or rectum, which are parts of the large intestine and digestive system. The cells begin to grow out of control, first forming a cluster of cells called a polyp. Eventually some polyps become cancer, as the cells grow deeper into the wall of the colon.

The colon and rectum are parts of the digestive system. The colon absorbs water and nutrients, as it passes waste (stool, or feces) to the rectum from the body.  The colon and rectum together are also called the large intestine or large bowel.

Colon and rectal cancers are grouped together as colorectal cancer because these organs are made of the same tissues and there isn’t a clear border between them. Adenocarcinoma is the most common type of colorectal cancer, which occurs in the gland cells that line the wall of the colon or the rectum.

To learn more about colorectal cancer, please click here.