Follow-up colonoscopy was significantly underused in the 5-year interval after a polypectomy (removal of polyps), according to the results of a study presented at the 2012 Digestive Disease Week Annual Meeting.
Cancers of the colon and rectum, sometimes referred to together as colorectal cancer, often begin with the development of an adenomatous polyp. These polyps often take 10 to 15 years to transform into cancer. Because this development phase is so long, screening and early detection can play a role in the prevention of colorectal cancer, as detection and removal of the polyps can prevent the development of the disease.
Screening procedures for colorectal cancer include the fecal occult blood test (FOBT), sigmoidoscopy, colonoscopy, and the double-contrast barium enema. The recommended interval between screening tests varies by the type of test used and the person’s risk of colorectal cancer. Some research has indicated an overuse of screening colonoscopy in average-risk individuals.
Recommendations vary, but in general, individuals who have polyps removed are recommended to undergo a follow-up colonoscopy in five years. Because there is little data to measure adherence to this recommendation, researchers used data from Medicare claims from a random sample of cancer-free patients in a single geographic area. They focused on Medicare patients without diagnosed cancer, but with a history of polyps. The sample included 12,998 patients aged 71 and older with a claim for colonoscopy with polypectomy or hot biopsy from 2001 to 2004. In addition, the researchers evaluated Medicare claims from the previous five years to obtain data about previous examinations, and to estimate a comorbidity score. They also analyzed subsequent Medicare claims through 2009 to identify patients who underwent colonoscopy within the following five years, as well as other procedures, including barium enema, fecal occult blood test and sigmoidoscopy.
The results indicated that at the end of the five-year follow-up period, only 33.5 percent of patients had received another colonoscopy and 24.2 percent underwent repeat polypectomy. The results were in startling contrast to what the researchers expected, which was an overuse of colonoscopy. Instead, they found a significant underuse of follow-up colonoscopy. They found that younger patients and those with a diagnosis of inflammatory bowel disease or carcinoma in situ were more likely to undergo the follow-up colonoscopy.
In general, patients with an identified history of polyps should come back in five years, but the researchers found that only about one-third of patients adhere to that recommendation.
 Cooper GS. Underuse of Colonoscopy for Polyp Surveillance in Medicare Beneficiaries. Presented at the 2012 Digestive Disease Week Annual Meeting; May 19-22, 2012; San Diego. Abstract #Tu1178.
 Goodwin JS, Singh A, Reddy N, Riall TS, Kuo Y-F. Overuse of screening colonoscopy in the Medicare population. Archives of Internal Medicine. Early online publication May 9, 2011.