A colonoscopy isn't something you get just for giggles. Beyond the obvious unpleasantness, there's the small but real risk of complications that in rare cases can lead to hospitalization or even death. That's why the American Cancer Society and other groups recommend that people screened for colorectal cancer using a colonoscopy wait a decade in between tests if no polyps or other signs of potential cancer are found. Polyps are slow-growing, and the benefits of being screened more frequently than that don't seem to outweigh the risks. A new study, however, suggests that a significant percentage of Medicare patients are having screening colonoscopies more frequently than that, for no apparent medical reason. Researchers at the University of Texas Medical Branch found that among 24,071 Medicare enrollees who had a negative screening colonoscopy between 2001 and 2003, almost 24% were re-examined within seven years "with no clear indication for the early repeated examination."