Colon and Rectal Cancer

Signs and Symptoms

Cancer of the colon or rectum is a form of cancer that develops in the tissues of the large intestine. It is the third most common cancer in both men and women in the United States. Abnormal genes have been detected in patients who have some forms of colon and rectal cancer. Tests are being developed to determine who carries these genes long before cancer appears. Patients who are at a high risk of developing cancer may undergo regular screening tests to monitor their health.

Common signs and symptoms of colon cancer include:

• A change in bowel habits
• Diarrhea, constipation, or feeling that the bowel does not empty completely
• Blood, either bright red or very dark in the stool
• Stools that are narrower than usual
• General abdominal discomfort such as frequent gas pains, bloating, fullness or cramps
• Weight loss with no known reason
• Constant tiredness

Diagnosis

To help find the cause of symptoms, your doctor will evaluate your medical history. Your doctor will perform a physical exam and may recommend one or more of the following diagnostic tests:

• Sigmoidoscopy to see inside the rectum and the lower colon and remove polyps or other abnormal tissue for examination under a microscope
• Colonoscopy to see inside the rectum and the entire colon and remove polyps or other abnormal tissue for examination under a microscope
• Polypectomy to remove a polyp during a sigmoidoscopy or colonoscopy
• Biopsy to remove tissue sample for examination by a pathologist to make a diagnosis

For more information about diagnostic tests, see Colon Cancer — Prevention and Screening.

If the diagnosis is cancer, your doctor will determine the stage or extent of disease. Staging is a careful attempt to find out whether the cancer has spread and if so, to what parts of the body. More tests may be performed to help determine the stage. Knowing the stage of the disease helps your doctor plan treatment. Listed below are descriptions of the various stages of colon cancer:

• Stage 0: The cancer is very early. It is found only in the innermost lining of the rectum.
• Stage I: The cancer involves more of the inner wall of the rectum.
• Stage II: The cancer has spread outside the colon to nearby tissue, but not to the lymph nodes. (Lymph nodes are small, bean-shaped structures that are part of the body's immune system.)
• Stage III: The cancer has spread to nearby lymph nodes, but not to other parts of the body.
• Stage IV: The cancer has spread to other parts of the body. If it spreads, colorectal cancer tends to spread to the liver and lungs.
• Recurrent: Recurrent cancer means the cancer has come back after treatment. The disease may recur in the colon or in another part of the body.

Treatment

Surgery
Surgery is the most common treatment of all stages of colon cancer. A doctor may take out the cancer from the colon using a variety of methods, depending on the stage and size of a patient's tumor.

Radiation therapy
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 or external radiation therapy, or from putting materials that contain radiation through thin plastic tubes, called internal radiation therapy, in the intestine area. Radiation can be used alone or in addition to surgery and chemotherapy.

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 treatment 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, the patient may be given chemotherapy directly into the artery going to the newly infected part of the body. 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 treatment
Biological treatment tries 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 immunotherapy.