The large intestine, which is part of the digestive system, is divided into two sections:
The rectum, which consists of the last several inches of the large intestine, and the colon, which is the first four to five feet. The colon is responsible for removing water and nutrients from digested food and turning it into stool, which is then passed to the rectum and eventually leaves the body through the anus.
Cancer that starts in either the colon or rectum can be referred to as colorectal cancer, or they also can be referred to as colon or rectal cancer separately, depending on where the cancer originates. Colorectal cancers are usually treated based on where the cancer actually starts (i.e., the rectum or colon). It is estimated that there will be 39,000 new cases of rectal cancer diagnosed this year.
Treatment for rectal cancer can consist of one or more of the following:
- Surgery
- The most common treatment for rectal cancer is surgery, which can be performed by one of four methods: a colonoscopy, which uses a flexible tube that is inserted in the rectum to remove small polyps or tumors; a local excision, which is a procedure that removes the tumor and surrounding areas if the rectal cancer is only on the inside surface of the rectum and has not yet spread to the rectum wall; a resection, which is a surgery that takes occurs when the cancer has spread to the rectum wall; and, a pelvic extenteration, which occurs when the rectal cancer has spread to other nearby organs that also need to be removed. In women, this could include the bladder, cervix, colon, ovaries or vagina. For men, the prostate may be removed in addition to the colon and bladder.
- Radiation Therapy
- Radiation therapy, the use of high energy rays to destroy cancer cells, can be given before or after surgery to help prevent the rectal cancer from recurring. Sometimes it is also given in combination with chemotherapy. Additionally, radiation can be used to help to alleviate pain and other symptoms associated with rectal cancer that has spread to other parts of the body.
- Chemotherapy
- Chemotherapies such as 5-fluorouracil, capecitabine, irinotecan, leucovorin and oxaliplatin are commonly used to treat rectal cancer. These drugs can be used alone, in combination with one another, and/or in combination with radiation therapy.
- Monoclonal Antibodies/Targeted Therapy
- Rectal cancer also can be treated with a specially designed treatment called a monoclonal antibody, which also referred to as a targeted therapy. Monoclonal antibodies are designed to bind to specific proteins that are found on the surface of rectal cancer cells in order to kill and destroy them. Avastin, Erbitux and Vectibix are three monoclonal antibodies that can be used in combination with chemotherapy or after chemotherapy has stopped working to treat rectal cancer.
