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JAMA Patient Page
December 17, 2008

Colon Cancer

JAMA. 2008;300(23):2816. doi:10.1001/jama.300.23.2816

Colorectal cancer (cancer of the colon [large intestine] or rectum) is the third most common cancer in men and women. When it is discovered in its early stages, colon cancer is treated with surgery and often cured. However, many individuals with colon cancer have no symptoms until the disease reaches an advanced stage, such as metastasizing (spreading) to other organs. Colorectal cancer is the second leading cause of cancer deaths (after lung cancer) in the United States. Testing persons without signs or symptoms of colon cancer is called screening. Screening for colon cancer is recommended for everyone older than 50 years and especially for individuals who have significant risk factors. The December 17, 2008, issue of JAMA includes an article reporting that cigarette smoking is significantly associated with the occurrence of colorectal cancer. This Patient Page is based on one previously published in the September 27, 2006, issue of JAMA.

Risk factors for colon cancer

The following conditions may put you at higher risk for colon cancer

  • Age (individuals older than 50 years)

  • Family history (you are more likely to get colorectal cancer if one of your parents, a brother, or a sister has had the disease)

  • Personal medical history (you are at increased risk for colon cancer if you have had other types of cancer, a history of colon polyps, or inflammatory diseases of the bowel)

  • Lifestyle (cigarette smoking, heavy alcohol use, inactivity, obesity, and a high-fat/low-fiber diet place you at increased risk for colon cancer)

Screening for colon cancer

Standard tests used for detecting colon cancer include

  • Fecal occult blood test (FOBT)—testing stool for small amounts of blood

  • Sigmoidoscopy (placement of a lighted tube into the rectum to examine the lower part of the colon)

  • Colonoscopy (a lighted tube with an attached camera inserted through the rectum to view the large bowel and to take tissue samples)

  • Barium enema (a type of x-ray procedure)

Genetic screening

Genetic testing can tell you whether you carry genes (the functional units of heredity) that may eventually cause colon cancer. The sooner this information is known, the sooner diagnostic testing and effective treatment can begin. If you have a strong family history of colon cancer, you should discuss with your doctor having a blood test to look for these genes. The most common genetic changes occur in 2 conditions: hereditary nonpolyposis colorectal cancer (HNPCC, now called Lynch syndrome), an inherited disorder with increased risk for several types of cancer; and familial adenomatous polyposis (FAP), an inherited disorder with many small growths inside the colon that may become cancerous.

For more information

Inform yourself

To find this and previous JAMA Patient Pages, go to the Patient Page link on JAMA's Web site at Many are available in English and Spanish. A Patient Page on colon cancer screening was published in the March 8, 2006, issue.

Sources: American Cancer Society, American College of Gastroenterology, Centers for Disease Control and Prevention, National Cancer Institute

The JAMA Patient Page is a public service of JAMA. The information and recommendations appearing on this page are appropriate in most instances, but they are not a substitute for medical diagnosis. For specific information concerning your personal medical condition, JAMA suggests that you consult your physician. This page may be photocopied noncommercially by physicians and other health care professionals to share with patients. To purchase bulk reprints, call 312/464-0776.