Isn't it time to stop talking about colonoscopy quality and start doing something about it?

Colonoscopy is central to one of the great success stories of the war on cancer. Although colorectal cancer (CRC) is still the second leading cause of cancer death in the United States, both the incidence and mortality has been declining by 2–3% per year for the last 15 years. This decline has been largely attributed to increasing rates of CRC screening. Although guidelines list other screening options (stool tests/imaging/flexible sigmoidoscopy) colonoscopy has become the dominant CRC screening test in the US while fecal testing has declined slowly, and flexible sigmoidoscopy has declined markedly over the last decade [1]. Colonoscopy is widely viewed in the US as the single best test for both detection and removal of pre-cancerous lesions. The efficacy of colonoscopic polypectomy was initially highlighted by the National Polyp Study (NPS), which estimated a 76–90% reduction in incidence of colorectal cancer after polyp removal [2]. Subsequent studies [3], which often have not shown as robust a CRC risk reduction as the NPS, have highlighted the importance of the quality of colonoscopy as a critical element in its efficacy. There is compelling evidence that colonoscopy quality is highly variable [4] and guidelines for a high-quality colonoscopy have been published [5], but in the end, quality needs to be assessed by whether a test accomplishes its primary goal. In the case of colonoscopy, directly measuring whether a colonoscopy has prevented a CRC is not feasible in the short term. Instead, more measurable surrogates of quality such as cecal intubation rates, withdrawal times, and particularly adenoma detection rates (ADR) have been used as quality measures. Kaminski et al. found that ADR appeared to be an acceptable surrogate for real colonoscopy quality as it was an independent predictor of the risk of interval colorectal cancer [6]. Numerous studies have demonstrated marked (twofold to sixfold) variability in ADRs among endoscopists working in the same endoscopy unit [4]. Although some of this variability might be due to patient factors such as age, gender, or adequacy of bowel preparation, individual endoscopists appear to be the single most predictive factor in adenoma detection [7], implying that the efficacy of colonoscopy is highly dependent on the individual skill of the endoscopist. To compound matters, Brenner [8] and Lakoff [9] presented data from Germany and Canada that showed that while colonoscopy does decrease the rate of distal CRCs by approximately 67–79%, it was not at all protective for proximal colon cancers, suggesting that there is a substantial need for improvement in colonoscopy quality by all endoscopists. The variability in colonoscopy quality among providers and the dubious utility of colonoscopy in preventing rightsided colon cancers have called into question the overall efficacy of colonoscopy as it is used today and would seem to be a clear mandate for endoscopists and professional organizations to critically examine colonoscopist performance and address areas in need of improvement. Is it possible to identify provider characteristics that are predictive of quality procedures? If so, can we incorporate these findings into endoscopic training, continuing medical education and ultimately ongoing quality assurance programs? Any such efforts are dependent, in part, on an understanding of the relationships between endoscopist characteristics and quality outcomes and there is growing literature examining one aspect of this relationship—the S. G. Patel D. J. Ahnen (&) Department of Medicine, Division of Gastroenterology, Denver VA Medical Center and University of Colorado School of Medicine, Denver, CO, USA e-mail: dennis.ahnen@ucdenver.edu