Symptoms of colon cancer include:
A change in bowel habits such as diarrhea, constipation or narrowing of stool that lasts for more than a few days.
Rectal bleeding or blood in the stool.
Cramping or gnawing stomach pain.
Other conditions such as infections, hemorrhoids and inflammatory bowel disease can cause the same symptoms listed above. It's also possible to have colon cancer and have no symptoms.
Colon cancer risk factors include:
A family history of the cancer. This can include certain conditions or syndromes that result in hundreds, even thousands, of polyps developing in the colon. Over time, cancer may develop in one or more of these polyps.
A personal history of colon cancer. Even when the cancer has been removed, new cancers can develop in other areas of the colon.
A personal history of intestinal polyps. Some types of polyps don't increase the risk of cancer. Others, such as adenomatous polyps, do, especially if they're large or multiple in number.
A personal history of inflammatory bowel disease. Chronic ulcerative colitis, in which the colon is inflamed over a long period of time, can increase the risk.
Aging. About 90 percent of people with colon cancer are older than 50.
Diet. Eating foods that are high in fat, low in fiber can increase the risk.
Physical inactivity. A sedentary lifestyle is also associated with a higher risk.