• Home

Home > Medical Reference > Encyclopedia (English)

Toggle: English / Spanish

Colon cancer

• Overview
• Symptoms
• Treatment
• Prevention

Alternative Names:

Colorectal cancer; Cancer - colon

Symptoms:

Many cases of colon cancer have no symptoms. The following symptoms, however, may indicate colon cancer:

• Diarrhea , constipation, or other change in bowel habits
• Blood in the stool
• Unexplained anemia
• Abdominal pain and tenderness in the lower abdomen
• Intestinal obstruction
• Weight loss with no known reason
• Narrow stools

With proper screening, colon cancer can be detected BEFORE the development of symptoms, when it is most curable.

Signs and tests:

Your doctor will perform a physical exam and press on your belly area. The physical exam rarely shows any problems, although an abdominal mass may be felt. A rectal exam may reveal a mass in patients with rectal cancer, but not colon cancer.

Imaging tests to diagnose colorectal cancer include:

• Colonoscopy
• Sigmoidoscopy

Note: Only colonoscopy can see the entire colon.

A fecal occult blood test (FOBT) may detect small amounts of blood in the stool, which could suggest colon cancer. However, this test is often negative in patients with colon cancer. For this reason, a FOBT must be done along with colonoscopy or sigmoidoscopy. It is also important to note that a positive FOBT doesn't necessarily mean you have cancer.

A complete blood count may reveal show signs of anemia with low iron levels.

If your doctor learns that you do have colorectal cancer, additional tests will be done to see if the cancer has spread. This is called staging.

• Stage 0: Very early cancer on the innermost layer of the intestine
• Stage I: Cancer is in the inner layers of the colon
• Stage II: Cancer has spread through the muscle wall of the colon
• Stage III: Cancer has spread to the lymph nodes
• Stage IV: Cancer that has spread to other organs

References:

U.S. Preventive Services Task Force. Routine Aspirin or Nonsteroidal Anti-inflammatory Drugs for the Primary Prevention of Colorectal Cancer: U.S. Preventive Services Task Force Recommendation Statement. Ann Intern Med . 2007 Mar 6;146 (5): 361-364.

American Cancer Society. Cancer Facts and Figures 2006. Atlanta, GA: American Cancer Society; 2006.

• Review Date: 3/6/2007
• Reviewed By: Updated by: A.D.A.M. Editorial Team: Greg Juhn, M.T.P.W., David R. Eltz, Kelli A. Stacy. Previously reviewed by Rita Nanda, M.D., Department of Medicine, Section of Hematology/Oncology, University of Chicago Medical Center, Chicago, IL. Review provided by VeriMed Healthcare Network. (October 31, 2006)

A.D.A.M., Inc. is accredited by URAC, also known as the American Accreditation HealthCare Commission (www.urac.org). URAC's accreditation program is the first of its kind, requiring compliance with 53 standards of quality and accountability, verified by independent audit. A.D.A.M. is among the first to achieve this important distinction for online health information and services. Learn more about A.D.A.M.'s editorial process . A.D.A.M. is also a founding member of Hi-Ethics (www.hiethics.com) and subscribes to the principles of the Health on the Net Foundation (www.hon.ch).

The information provided herein should not be used during any medical emergency or for the diagnosis or treatment of any medical condition. A licensed physician should be consulted for diagnosis and treatment of any and all medical conditions. Call 911 for all medical emergencies. Links to other sites are provided for information only -- they do not constitute endorsements of those other sites. Copyright 1997-2007 A.D.A.M., Inc. Any duplication or distribution of the information contained herein is strictly prohibited.