Screening for colon cancer should begin at age 50 for those at average risk and continue for as long as a person is healthy enough to benefit.  It may not be recommended after age 75.  Despite its proven effectiveness, colon cancer screening remains underutilized in older adults.

The United States Preventive Services Task Force recommends three options for colon cancer screening: 1) annual fecal occult blood testing; 2) flexible sigmoidoscopy every  five years with fecal occult blood testing every 3 years; or colonoscopy every 10 years.  Each of these methods has benefits and potential risks.  For example, fecal occult blood testing is noninvasive and inexpensive, but may not pick up early or pre-cancerous lesions and may yield false-positive test results.  Colonoscopy is very accurate in finding both cancers and pre-malignant polyps, but carries some risk, especially in older individuals, and the preparation is cumbersome for most people.

Higher-risk individuals -- those with a family history of colon cancer, polyps or inflammatory bowel disease -- should consider starting screening earlier and choose colonoscopy over the other methods because of its greater likelihood of detecting disease at an earlier stage.

A major problem with screening methods in the United States has been the failure to screen individuals who would benefit the most from early detection.  Many colon cancer deaths could be prevented every year if more people were screened. One Veterans Administration study found that colon cancer screening was done in only 47 percent of patients who would benefit from it, while as many as 41 percent of those unlikely to benefit from screening due to other illnesses were still being screened. 

It is vitally important to know your colon cancer screening status and to select the most appropriate screening option with your primary care physician.  It could be lifesaving!