Colon cancer - one of the most common forms of cancer

Colon cancer is one of the most common forms of cancer in the U.S., affecting about 130,000 Americans each year, according to the National Cancer Institute. Colon cancer is more common than rectal cancer, and more dangerous: About half of colon cancer patients eventually die from the disease because it often isn't detected until the later stages. Due to increased testing, death rates from colorectal cancer have dropped by 25 percent in women and 13 percent in men over the past 20 years. Fortunately, colon cancer is also one of the most curable forms of cancer. When detected early, more than 90 percent of patients can be cured.

What is colon cancer?

As the name suggests, colorectal cancer is cancer of the colon or rectum, which together form the 6-foot-long tube in the digestive tract called the large intestine. This disease begins as a polyp - or fleshy tumor, shaped like a mushroom or a dome-like button - on the inside lining of the colon. Colon polyps start out as benign tumors but in time may become malignant. The larger the polyp, the more likely it is to contain cancer cells. Although they're very common among older people, it is not clear what causes polyps in most cases.

There now is strong medical evidence that there are abnormal genes for colon polyps and cancer that can be passed from parent to child. The genes within each cell are the hereditary structures that tell the cell what it should do. When these controlling genes are absent there is a tendency to grow polyps. The cells in the polyp eventually become uncontrolled and turn into a cancer. Colon cancer also can develop with other conditions, such as ulcerative colitis, a chronic inflammation in the colon.

Who is at risk for developing colon cancer?

Cancer of the colon is most common after age 50, but on rare occasions, the disease strikes younger people. For unknown reasons, the tumors that develop in young people are often especially fast-growing and likely to spread. Relatives of a person who has had colon cancer at a young age are at a slightly increased risk.

Certain genes also increase the risk of developing numerous polyps in the colon and increase the risk of developing colon cancer at a younger age. Inherited types of colon cancer also exist. Family members of people who develop numerous polyps or colon cancer at an early age can have genetic testing performed.

How can I lower my risk for developing colon cancer?

Doctors believe the best way to lower your risk of colon cancer is to reduce red meat intake, exercise regularly, stop smoking and control your weight. Annual stool testing and other screening methods are also critically important.

Folic acid, and calcium also can lower the risk of colon cancer. Most studies show that as dietary or supplemental intake increases, the risk of both polyps and colon cancer decreases.