Causes & Symptoms

Last year there were 102,900 new cases of colon cancer and 39,670 new cases of rectal cancer in the United States, according to the American Cancer Society. Know the signs of colorectal cancer before it's too late — colon cancer may be curable, if detected and treated early. 

What Causes Colorectal Cancer?

Almost all colon cancer starts in cells in the lining of the colon and rectum. Nearly all colon cancers begin as noncancerous (benign) polyps, which are small growths inside the colon or rectum. Colon polyps are very common, and most of them do not turn into cancer. If they are found early, usually through routine screening tests, they can be removed before they turn into cancer.

Symptoms

Colorectal cancer usually does not cause symptoms until after it has begun to spread. See your doctor if you have any of these symptoms:

• Pain in your belly.
• Blood in your stool or very dark stools.
• A change in your bowel habits, such as more frequent stools or a feeling that your bowels are not emptying completely.

You have a higher risk for colon cancer if you:

• Are older than 60.
• Are African American or of eastern European descent.
• Eat a diet high in red or processed meat.
• 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.