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. These include lymphoma, carcinoid tumors, melanoma, and sarcomas. These are rare. In this article, colon cancer refers to colorectal cancer only.
In the United States, colorectal cancer is one of the leading causes of deaths due to cancer. Early diagnosis can often lead to a complete cure.
Almost all colon cancers start 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 50
• Are African American or of eastern European descent
• Eat a lot of red or processed meats
• Have colorectal polyps
• Have inflammatory bowel disease (Crohn disease or ulcerative colitis)
• Have a family history of colon cancer
Some inherited diseases also increase the risk of developing colon cancer. One of the most common is called the Lynch syndrome.
What you eat may play a role in getting colon cancer. Colon cancer may be linked to a high-fat, low-fiber diet and to a high intake of red meat.
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.