Colon cancer, also known as colorectal or large bowel cancer, is the third most common form of cancer in the United States and the second leading cause of cancer-related deaths in the Western world, according to the American Cancer Society (ACS).

Nationally, there were 112,000 cases of colon cancer and 41,000 cases of rectal cancer in 2007, the organization estimated. Combined, the two diseases would result in approximately 52,000 deaths. Worldwide, the disease accounts for 655,000 deaths per year, according to the World Health Organization.

What Is Colorectal Cancer?

To understand what colorectal cancer is, it helps to first know how the digestive, or gastrointestinal, system works. Food is swallowed and processed in the stomach; it then passes through the small intestine to reach the large intestine, also known as the colon. The first part of the colon absorbs water and nutrients and sets aside waste matter, which then moves to the rectum, the last section of the digestive system.

The colon has four sections, and both the colon and the rectum have several layers of tissues, the first of which is where cancer begins. The stage of the cancer depends on the number of layers the cancer reaches.

Most colorectal cancers begin as a noncancerous polyp that may take several years to develop. Found early enough, polyps can be removed before they become cancerous.

Common Risk Factors

According to the ACS, the following factors may increase an individual's risk for colon cancer.

  • Age. The risk of colorectal cancer increases after age 50.
  • History of colorectal cancer. Even if it has been removed, you have a greater chance of the cancer returning if you've had it before.
  • Bowel disease. Those afflicted with ulcerative colitis and Crohn's disease are at higher risk for colorectal cancer.
  • Family history. Those with close family members who had the disease are more likely to get it.
  • Ethnic background and race. Jews of Eastern European descent have the highest colorectal cancer risk of any ethnic group in the world. In the United States, African Americans have the highest number of cases and highest number of deaths from colorectal cancers.
  • Diet. Too much red meat and fatty meat can increase your colorectal cancer risk.
  • Smoking. Smokers are 30 to 40 percent more likely to die of colorectal cancer.
  • Diabetes. Diabetics have a 30 percent increased chance of getting colorectal cancer.

Preventing Colon Cancer

Experts say colon cancer is often highly preventable and detectable. To reduce your risk, follow these guidelines.

  • Get screened. Beginning at age 50, everyone should be screened for colon cancer, according to the ACS. These tests may include fecal occult blood tests (FOBT), fecal immunochemical test (FIT), flexible sigmoidoscopy, and colonoscopy. If you have a family history of colon cancer or other risk factors, you should begin screening earlier and/or be screened more often.
  • Keep your body healthy. Eat plenty of fruit and vegetables daily, and be sure to get at least the recommended 30 minutes of physical activity five or more days per week.
  • Vitamins. Multivitamins with folic acid as well as calcium and vitamin D may help to lower your cancer risk.

Colon Cancer Treatment

Though colorectal cancers are treated primarily through surgery, they may also be treated with radiation and chemotherapy, depending on the stage of the cancer. Stage I colon cancer, the earliest and least severe kind, has a 93 percent survival rate, while Stage IV, the most serious, has a survival rate of 8 percent.

The death rate from colorectal cancers has been going down in the last 15 years, thanks in large part to patients' early screenings and polyp removals.