Cancer of the colon, a common form of cancer, is a disease in which cancer (malignant) cells are found in the tissues of the colon. The colon is part of the body ‘s digestive system. The purpose of the digestive system is to remove nutrients (vitamins, minerals, carbohydrates, fats, proteins, and water) from the foods eaten and to store the waste until it passes out of the body. The digestive system is made up of the esophagus, stomach, and the small and large intestines. The last 6 feet of intestine is called the large bowel or colon.

Genes are markers in cells associated with hereditary traits. Abnormal genes have been found in patients with some forms of colon and rectal cancer. Tests are being developed to determine who carries these genes long before cancer appears.

Screening test (such as a rectal examination, proctoscopy, and colonoscopy) may be done regularly in patients who are at higher risk to get cancer. These test may be done in patients who are over age 50; who have a family history of cancer of the colon, rectum, or of the female organs; who have had small noncancerous growths (polyps) in the colon; or who have a history of ulcerative colitis (ulcers in the lining of the large intestines). A doctor may order these tests to look for cancer if there is a change in bowel habits or if there is any bleeding from the rectum.

The doctor may also want to look inside the rectum and lower colon with a special instrument called a sigmoidoscope or a proctosigmoidoscope. This examination, called a proctoscopy or procto examination, finds about half of all colon and rectal cancers. The test is usually done in a doctor’s office. Some pressure may be felt, but usually with no pain.

If tissue that is not normal is found, the doctor will need to cut a small piece and look at it under the microscope to see if there are any cancer cells. This is called a biopsy.Biopsies are usually done during the proctoscopy or colonoscopy, in a doctor’s office.

The prognosis (chance of recovery) and choice of treatment depend on the stage of the cancer (whether it is just in the inner lining of the colon or if it has spread to other places) and the patient’s general state of health. After treatment, a blood test (to measure amounts of carcinoembryonic antigen or CEA in the blood) and x-rays may be done to see if the cancer has come back.

There are treatments for all patients with cancer of the colon. Three kinds of treatments are available:

    * surgery (taking out the cancer)
    * radiation therapy (using high-dose x-rays or other high-energy rays to kill cancer cells)
    * chemotherapy (using drugs to kill cancer cells)

Surgery is the most common treatment of all stages of cancer of the colon. A doctor may take out the cancer from the colon using one of the following;

If the cancer is found at a very early stage, the doctor may take out the cancer without cutting into the abdomen. Instead, the doctor may put a tube through the rectum into the colon and cut the tumor out. This is called a local excision. If the cancer is found in a small bulging piece of tissue (called a polyp), the operation is called a polypectomy.

If the cancer is larger, the doctor will take out the cancer and a small amount of healthy tissue around it (bowel or colon resection). The healthy parts of the colon are then sewn together (anastomosis). The doctor will also take out lymph nodes near the intestine and look at them under the microscope to see if they contain cancer.

If the doctor is not able to sew the colon back together, he or she will make an opening (stoma) on the outside of the body for waste to pass out of the body. This is called a colostomy. Sometime, the colostomy is only needed until the colon has healed, and then it can be reversed. However, the doctor may have to take out the entire lower colon and the colostomy is permanent. If a patient has a colostomy, a special bag will need to be worn to collect body wastes. This special bag, which sticks to the skin around the stoma with a special glue, can be thrown away after it is used. This bag does not show under clothing, and most people take care of these bags themselves.

Radiation therapy is the use of x-rays or other high-energy rays to kill cancer cells and shrink tumors. Radiation may come from a machine outside the body (external radiation therapy) or from putting materials that contain radiation through thin plastic tubes (internal radiation therapy) in the intestine area. Radiation through thin plastic tubes (internal radiation therapy) in the intestine area. Radiation can be used alone or in addition to surgery and / or chemotherapy.

Chemotherapy is the use of drugs to kill cancer cells. Chemotherapy may be taken by pill, or it may be put into the body by inserting a needle into a vein. A patient may be given chemotherapy through a tube that will be left in the vein while a small pump gives the patient constant traetment over a period of weeks. Chemotherapy is called a systemic treatment because the drug enters the bloodstream, travels through the body, and can kill cancer cells outside the colon. If the cancer has spread to the liver, the patient may be given chemotherapy directly into the artery going to the liver.

If the doctor removes all the cancer that can be seen at the time of the operation, the patient may be given chemotherapy after surgery to kill any cancer cells that are left. Chemotherapy given after an operation to a person who has no cancer cells that can be seen is called adjuvant chemotherapy.

Biological treatments try to get the body to fight cancer. It uses materials made by the body or made in a laboratory to boost, direct, or restore the body’s natural defenses against disease. Biological treatment is sometimes called biological response modifier (BRM) therapy or immunotherapy.

Treatment for cancer of the colon depends on the stage of the disease and the patient’s general health.  Standard treatment may be considered because of its effectiveness in patients in past studies, or participation in a clinical trial may be considered. Not all patients are cured with standard therapy and some standard treatments may have more side effects than are desired. For these reasons, clinical trials are designed to find better ways to treat cancer patients and are based on the most up-to-date information. Clinical trials are ongoing in most parts of the country for most stages of cancer of the colon. To learn more about clinical trials, call the Cancer Information Service at 1-800-4-CANCER (1-800-422-6237); TTY at 1-800-332-8615.