The Digestive System, Colon and Rectum

The Digestive System, Colon and Rectum The colon and rectum are part of the body's digestive system. When we eat food, it passes through the small intestine. Here, food is broken down and nutrients are absorbed. The small intestine is quite long - about 20 feet. The term "small" refers to the smaller diameter of the tubular system compared to the next area of the digestive tract - the large intestine.

The large intestine is made up of the colon and the rectum. The first four to five feet make up the colon, where water and nutrients continue to be absorbed. Waste products move on the rectum, or the last four to five inches of the large intestine. From here, waste leaves the body through the muscular opening, called the anus.

Colorectal Cancer Colorectal cancer commonly develops from a non-cancerous growth, called a polyp. Polyps develop in the lining of the colon or rectum. A polyp can range in size from a very small, flat lesion to a very large, protruding growth. It can take years for a polyp to turn into cancer. A certain type of polyp, called an adenomatous polyp, is more likely to become cancerous.

Once a cancer forms, the tumor cells can invade the wall of the colon or rectum. Eventually, the cancer can enter the bloodstream and lymph system, spreading beyond the colon/rectum to other areas of the body.

Colorectal cancer is the third most commonly diagnosed cancer in American men and women. This year, the American Cancer Society estimates 104,950 new cases of colon cancer and 40,340 new cases of rectal cancer will be diagnosed in the U.S. Colorectal cancer is the second leading cause of cancer death and is expected to kill 56,290 Americans in 2005.

Surgery for Colorectal Cancer The main treatment for colorectal cancer is surgery. Doctors locate and surgically remove the diseased section of the colon/rectum. The two ends of the remaining intestine are then connected. In some cases, patients may require a temporary or permanent colostomy. The end of the colon is connected to an opening (stoma) created in the abdominal wall. Waste products move through the new opening into a storage pouch attached to the stoma.

Traditonally, surgery for colorectal cancer is done through a large incision in the abdomen. However, sometimes the surgery can be performed laparoscopically, through several tiny incisions. A lighted viewing camera is inserted through one incision and tiny surgical instruments through the others. The images from the camera are displayed on a television monitor, enabling the surgeon to watch as he/she manipulates the tiny instruments inside the patient. With smaller incisions, patients have less pain and recovery time is quicker. Surgeons say laparoscopic surgery may also be performed to remove polyps that are too large, too flat or too extensive in number to remove during colonoscopy.

For information on colon cancer: American Cancer Society, http://www.cancer.org, or contact your local chapter National Cancer Institute, http://www.nci.nih.gov