Colon cancer is cancer that starts in the large intestine (colon) or the rectum (end of the colon). Such cancer is sometimes referred to as "colorectal cancer."
Other types of colon cancer such as lymphoma, carcinoid tumors, melanoma, and sarcomas are rare. In this article, use of the term "colon cancer" refers to colon carcinoma and not these rare types of colon cancer.
Alternative Names
Colorectal cancer; Cancer - colon
Causes, incidence, and risk factors
According to the American Cancer Society, colorectal cancer is one of the leading causes of cancer-related deaths in the United States. (However, in almost all cases, early diagnosis can lead to a complete cure.)
There is no single cause for colon cancer. Nearly all colon cancers begin as benign polyps, which slowly develop into cancer.
You have a higher risk for colon cancer if you have:
Certain genetic syndromes also increase the risk of developing colon cancer.
What you eat may play a role in your risk of colon cancer. Colon cancer may be associated with a high-fat, low-fiber diet and red meat. However, some studies found that the risk does not drop if you switch to a high-fiber diet, so the cause of the link is not yet clear.
Symptoms
Many cases of colon cancer have no symptoms. The following symptoms, however, may indicate colon cancer:
Colonoscopy (2 images)(Doctor-Reviewed information)
A colonoscopy is an internal examination of the colon (large intestine), using an instrument called a colonoscope. The colonoscope is a small camera attached to a flexible tube. Unlike sigmoidoscopy, which examines only the lower third of the colon, colonoscopy examines the entire length of the colon. Reviewer: Jenifer K. Lehrer, MD, Department of Gastroenterology, Frankford-Torresdale Hospital, Jefferson Health System, Philadelphia, PA. Review provided by VeriMed Healthcare Network.Date: 05/08/2006
Sigmoidoscopy (3 images)(Doctor-Reviewed information)
Sigmoidoscopy is an internal examination of the lower large bowel (colon), using an instrument called a sigmoidoscope. The sigmoidoscope is a small camera attached to a flexible tube. It is inserted into the colon to examine the rectum, and the sigmoid and descending portions of the colon. Reviewer: Jenifer K. Lehrer, MD, Department of Gastroenterology, Frankford-Torresdale Hospital, Jefferson Health System, Philadelphia, PA. Review provided by VeriMed Healthcare Network.Date: 05/08/2006
Culture - colonic tissue biopsy (2 images)(Doctor-Reviewed information)
A colonic tissue culture is a laboratory test performed on a specimen of colon (large intestine) tissue to isolate and identify organisms that may be causing certain infections, such as infectious diarrhea or parasitic and viral infections involving the colon. The specimen is obtained by a colonoscopy. A colonoscopy is a procedure for viewing the interior lining of the colon using a colonoscope, a flexible fiber-optic tube about 1/2 inch thick. Reviewer: Kenneth Wener, M.D., Division of Infectious Diseases, BEth Israel Deaconess Medical Center, Boston, MA. Review provided by VeriMed Healthcare Network.Date: 02/10/2006
Colon cancer screening (3 images)(Doctor-Reviewed information) Reviewer: William Matsui, MD, Assistant Professor of Oncology, Division of HematologicMalignancies, The Sidney Kimmel Comprehensive Cancer Center at JohnsHopkins, Baltimore, MD. Review provided by VeriMed Healthcare Network.Date: 02/07/2006
Colorectal polyps (3 images)(Doctor-Reviewed information)
A colorectal polyp is a growth that sticks out of the lining of the colon or rectum. Reviewer: Jenifer K. Lehrer, MD, Department of Gastroenterology, Frankford-TorresdaleHospital, Jefferson Health System, Philadelphia, PA. Review provided by VeriMed Healthcare Network.Date: 07/25/2006