Last March the Statesman published an article about colon cancer screening. This article referenced a man diagnosed with colon cancer at age 72 because he was reluctant to undergo colon cancer screening at an earlier age, believing it was not necessary. Unfortunately, he had advanced cancer, which could have been prevented with screening.

March is Colon Cancer Awareness Month and the message remains the same: colon cancer can be prevented with routine screening!

Most colon cancers begin as a benign growth called a polyp or adenoma, which usually grows slowly. Removing these polyps during screening colonoscopy prevents the polyp from progressing to cancer.

Colon cancer is common, affecting 1 in 20 Americans, and is currently the third- leading cause of cancer death in the U.S. Last year, 143,460 Americans were diagnosed with colon cancer, and 51,690 died from the disease. Ninety percent of new cases and 95 percent of deaths from colon cancer occur in people 50 or older. Colon cancer treatment costs exceed $14 billion in the United States annually.

Prevention of colon cancer with screening colonoscopy is a major medical success story, but only half of persons in the U.S. needing routine screening are being screened. The good news is that screening rates are increasing each year, largely due to increased awareness and acceptance of colonoscopy as the best screening method. Over the past 15 years, colon cancer screening has decreased the incidence of colon cancer by more than 3 percent per year, and the incidence continues to decline.

Even though the overall incidence of colon cancer is decreasing each year, right-sided colon cancers have not decreased significantly. More than half of colon cancer occurs on the right side of the colon far from the reach of a rectal examination or sigmoidoscope.

Right-sided colon cancers frequently arise from flat or sessile polyps. Common polyps protrude outward from the lining of the colon like a mushroom, making them easy to detect. Flat or sessile polyps grow like a carpet on the surface, and are more difficult to identify and remove, especially if a colonoscopy is not performed carefully, or the colon is not adequately cleaned out. Careful examination of the entire colon and removal of all polyps identified during a complete colonoscopy is currently the gold standard for colon cancer screening. The examination is usually painless, as sedation is given for patient comfort.

An important factor to consider when undergoing a colonoscopy is to choose a physician specially trained in gastroenterology who does hundreds of colonoscopies each year. A gastroenterologist is a specialist with extra training in safely and effectively performing colonoscopies. Most gastroenterologists use newer advanced techniques and are generally more adept at detecting and removing flat polyps.

Known risk factors for colon cancer include age (50 and older), family history of colon cancer or colon polyps, personal history of colon polyps, chronic inflammation of the colon (ulcerative colitis and Crohn's disease), cigarette smoking and obesity.

A colonoscopy is recommended for anyone 50 and older. Additionally, anyone with a family history of colon cancer or polyps in close relatives or anyone with symptoms that might suggest colon cancer - such as a change in bowel habits, diarrhea, constipation, blood in stool, weight loss, bloating, abdominal pain or anemia - might need earlier screening.

Remember: Colon cancer is preventable. A colonoscopy is the only test that can help prevent it. Ask your health care provider about colon cancer screening. Get the test. Get the polyp. Get the cure. Then ask your loved ones and friends to do it. You will be glad you did.

John T. Witte, M.D., FACG, is a partner at Idaho Gastroenterology Associates.