If cells keep multiplying when new cells are not needed, a mass of tissue forms. This extra tissue, called a growth or tumor, can be benign or malignant. Benign tumors are not cancer. They do not invade nearby tissue or spread to other parts of the body. Benign tumors can be removed and usually are not life threatening.
Malignant tumors are cancer.
They can invade and damage nearby tissues and organs. Sometimes cells from the tumor may break off and travel through the bloodstream or the lymphatic system and start tumors in other parts of the body. The colon and rectum form a long, muscular tube called the large intestine or large bowel. The colon is the upper 5 to 6 feet of the large intestine and the rectum is the last 6 to 8 inches. The large intestine, along with the esophagus, stomach, and the small intestine, are part of the body's digestive system.