The colon and rectum are part of the digestive system . The rectum is the last 6 to 8 inches of the large intestine. After food is digested in the stomach and small intestine, it moves into the colon, where any remaining water is absorbed into the body. Solid waste, called feces, is left in the colon.
Feces move through the colon and rectum and leave the body through the anus.
The colon and rectum are made up of many types of cells. Normally the body only produces new cells as they are needed. If cells keep dividing when new cells are not needed a mass of tissue forms. This mass of extra tissue, called a growth or a tumor , can be benign or malignant . Benign tumors are not cancer .