When muscle contracts, tumors will form from the extra tissue. T he colon and the rectum are located in the body's digestive system, which absorbs water and nutrients from food and passes waste materials through the body. The colon and rectum compose the large intestine, where the colon is defined as the first several feet of the intestine and the rectum is the last 8 inches. The ascending colon goes up the side, the transverse colon goes across the middle, and the descending colon goes down the other side. Most of developing colon cancer is found on the cells lining the walls of the colon and rectum.
Colon cancer is a progressive disease that occurs in several stages.
In Stage 0, the cancer is very early and is found very localized in the inner lining of the colon wall. The cancer has spread within the colon, but is contained within the organ in Stage I. Stage II is characterized by the spread of cancer to areas outside of the colon into nearby tissue, but not the spread to the lymph nodes. In Stage III, the cancer has spread to the lymph nodes, but not to other body parts. Recurrent cancer returns after it has been treated, either in the colon or in another part of the body.