Colon, or colorectal, cancer is cancer that starts in the large intestine (colon) or the rectum (end of the colon).

Other types of cancer can affect the colon, such as lymphoma, carcinoid tumors, melanoma, and sarcomas. These are rare. In this article, use of the term "colon cancer" refers to colon carcinoma only.

Colorectal cancer; Cancer - colon; Rectal cancer; Cancer - rectum; Adenocarcinoma - colon; Colon - adenocarcinoma

According to the American Cancer Society, colorectal cancer is one of the leading causes of cancer-related deaths in the United States. However, early diagnosis often leads to a complete cure.

Almost all colon cancer starts in glands in the lining of the colon and rectum. When doctors talk about colorectal cancer, this is usually what they are talking about.

There is no single cause of colon cancer. Nearly all colon cancers begin as noncancerous (benign) polyps, which slowly develop into cancer.

You have a higher risk for colon cancer if you:

• Are older than 60
• Are African American of eastern European descent
• Eat a diet high in red or processed meats
• Have cancer elsewhere in the body
• Have colorectal polyps
• Have inflammatory bowel disease (Crohn's disease or ulcerative colitis)
• Have a family history of colon cancer
• Have a personal history of breast cancer

Certain genetic syndromes also increase the risk of developing colon cancer. Two of the most common are:

• Familial adenomatous polyposis (FAP)
• Hereditary nonpolyposis colorectal cancer (HNPCC), also known as Lynch syndrome

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 have found that the risk does not drop if you switch to a high-fiber diet, so this link is not yet clear.

Smoking cigarettes and drinking alcohol are other risk factors for colorectal cancer.

Images

The large intestine

Stages of cancer

Sigmoid colon cancer, X-ray

Large intestine

Structure of the colon

Rectal cancer, X-ray

Spleen metastasis - CT scan

Colon culture

Barium enema

Review Date: 12/28/2010
Reviewed By: Yi-Bin Chen, MD, Leukemia/Bone Marrow Transplant Program, Massachusetts General Hospital. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc.

A.D.A.M., Inc. is accredited by URAC, also known as the American Accreditation HealthCare Commission (www.urac.org)