Cells divide in an orderly, controlled way to produce more cells when more cells are needed in the body. When cells divide in an abnormal, uncontrolled way, they can form either a benign or malignant tumor. Benign tumors are not cancerous. In the colon and rectum, a polyp is a benign tumor that may form. Because they can become cancerous, polyps should be removed.
Malignant tumors are cancerous.
Cancer cells can spread to nearby healthy cells and destroy them. The cancerous cells can also invade other parts of the body. Cancerous cells in the colon and rectum can spread to the lymph glands which are located nearby. The cancer can also spread to other parts of the body. The risk of colorectal cancer appears to increase with age, with the risk rising sharply at the ages of 50 to 55 and peaking at age 75.