One of the most common types of cancer, colon cancer, also known as colorectal cancer, is the growth of malignant cells in the colon or rectum. Tumors in the colon are slow-growing, but may eventually become large enough to obstruct the digestive tract. Colon cancer may spread to the liver, lymph nodes, or other parts of the body, and symptoms may not appear until the cancer is quite advanced. However, if detected and treated early, the outlook is optimistic.

Symptoms of Colon Cancer

• Often there are no symptoms of colon cancer in early stages.

• Change in bowel habits (constipation, diarrhea, or extremely narrow stools) lasting for more than 10 days.

• Bloody or black, tarry stools.

• Pain or tenderness in the lower abdomen.

• Bloating, cramps, gas pains, and a protracted feeling of fullness.

• Loss of appetite and loss of weight.

• Fatigue, paleness (pallor), and heart palpitations due to anemia that often occurs in conjunction with colon cancer.

• Inability to pass stools (a sign of intestinal obstruction, an emergency situation).

What Causes Colon Cancer?

• A diet high in animal fats (especially from red meat) and low in fiber is associated with a higher incidence of colon cancer.

• A personal or family history of colon polyps or ulcerative colitis increases the likelihood of colon cancer. A family history of colon, breast, or endometrial cancer is also a risk factor.

• The risk of colon cancer increases after age 40.

Prevention of Colon Cancer

• Eat a diet low in animal fat and high in fiber.

• Get regular checkups if you have a personal or family history of colon or digestive tract disease.

• The American Cancer Society recommends that people over 40 have an annual digital rectal exam (half of all colon cancers occur in the rectum).

• Starting at age 50, individuals also should have an annual stool sample test for hidden bleeding and a colonoscopy or sigmoidoscopy (in which a lighted viewing tube is used to examine the rectum and colon).

Diagnosis of Colon Cancer

• Blood and stool samples are taken.

• A digital rectal exam (in which the doctor examines the rectum with a gloved finger) is performed.

• Sigmoidoscopy or colonoscopy is used to view the bowel, during which a biopsy may be taken to determine whether the tumor is benign or malignant.

• A barium enema may be necessary. The barium creates a sharp image of the colon during x-ray.

• Colon cancer should always be suspected (and proper tests conducted) in older men and in postmenopausal women with iron deficiency anemia.

How To Treat Colon Cancer

• Surgery is necessary to remove the tumor. If the cancer is detected early, the surgery may be limited to a bowel resection, in which the cancerous part of the colon is removed and the healthy parts are rejoined. Nearby lymph nodes are also removed.

• If the tumor is blocking the colon, the cancerous part of the colon is removed, and the end of the remaining upper portion of the colon is brought through an opening created in the abdominal wall for waste to pass through, into a bag. This procedure (colostomy) may be temporary, to allow the colon to heal after the operation, or permanent, when cancer is extensive (about 15 percent of cases).

• Radiation therapy may be used before surgery to reduce the size of the tumor or after surgery to destroy remaining cancer cells; chemotherapy may be used to halt the spread of the cancer.

When To Call A Doctor

• Call a doctor if you experience rectal bleeding or if you have changes in your bowel movements that persist for three weeks or more.

• Make an appointment with a doctor if you have a personal or family history of colon disease.

• Emergency: Get immediate medical attention if you experience a total inability to pass stools.

For more information on colon cancer and related digestive disorders, click on this link -- Johns Hopkins Health Alerts: Digestive Disorders

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