The colon, also called the large bowel or large intestine, is the last section of the digestive tract. It is five to six feet long — the last eight to ten inches of which is called the rectum. After food is digested in the stomach and nutrients are absorbed in the small intestine, solid wastes from this process move into the colon, where they remain usually for a day or two until they are passed out of the body.

Sometimes the body’s cells fail to grow, divide and reproduce in a healthy, orderly way, thus producing too much tissue and forming a tumor. These tumors can be benign (not cancerous) or malignant (cancerous) and can spread to other parts of the body.

Colorectal cancer is the second leading cause of cancer and cancer deaths in the United States and affects men and women equally. These cancers develop in the lining of the large intestine. Tumors may also develop in the lining of the very last part of the colon, called the rectum. Fortunately, colorectal cancer is preventable and curable if detected early.

Causes

Colorectal cancer starts with polyps, or growths of the colon lining. Not all polyps become colon cancer. Polyps known as adenomas are the precursors of colorectal cancer. The risk factors for adenoma and cancer development are not all identified. High fat, low fiber diets, increasing age and gene abnormalities are the best known risk factors.

Everyone of us is at risk for colorectal cancer. The majority of people who develop colorectal cancer have no known risk factors. However, chronic inflammatory conditions of the colon (ulcerative colitis or Crohn’s disease), a family or personal history of colorectal cancer, adenomatous polyps or hereditary polyp syndromes are all associated with an increased risk.

Symptoms

Most people with colorectal cancer have no symptoms.

For this reason, it is very important to have regular colorectal cancer screening examinations. Changes in normal bowel habits, unexplained anemia (low blood count), weight loss, blood in the stool (occult or obvious) or abdominal pain are all possible cancer symptoms and should be discussed with your doctor. However, most people with polyps and cancer have no symptoms whatsoever.

Treatment

Colorectal cancer requires surgery in nearly all cases for a complete cure. Radiation and chemotherapy are sometimes used in addition to surgery. Between 80-90 percent are restored to normal health if the cancer is detected and treated in the earliest stages. The cure rate drops to 50 percent or less when diagnosed in the later stages. Thanks to modern technology, less than 5 percent of all colorectal cancer patients require a colostomy, the surgical construction of an artificial excretory opening from the colon.

Prevention

There are steps that reduce the risk of contracting the disease. One way is having benign polyps removed by an outpatient procedure called a colonoscopy. In addition to removing the polyps, the long flexible tubular instrument used in the procedure provides a more thorough bowel examination.

Though not proven, there is some evidence that diet may play a significant role in preventing colorectal cancer. As far as we know, a high fiber, low fat diet is the only dietary measure that might help prevent colorectal cancer.

Finally, you must be aware of changes in your bowel habits and make sure bowel examinations are included in routine physicals once you fall under the “high risk” category.

Although hemorrhoids cannot lead to colon cancer, they may produce symptoms similar to colon polyps or cancer. Should you experience these symptoms, you should have them examined and evaluated by a physician, preferably by a colon and rectal surgeon.