High adenoma detection rate during colonoscopy associated with lower incidence of colorectal cancer

Clinical Question

Does a gastroenterologist’s adenoma detection rate make a difference in the subsequent incidence of colorectal cancer?
Bottom Line

There is a consistent, linear, inverse relationship between higher adenoma detection rates and a lower rate of colorectal cancer (CRC) and CRC death. I’ll be asking my gastroenterologist about his detection rate before my next colonoscopy! (LOE = 2b)


Corley DA, Jensen CD, Marks AR, et al. Adenoma detection rate and risk of colorectal cancer and death. N Engl J Med 2014;370(14):1298-1306.

Study Design: Cohort (retrospective) Funding: Foundation
Setting: Outpatient (specialty) Allocation: Unknown


The adenoma detection rate has been proposed as a quality measure, with professional societies recommending a rate of at least 15% for female patients and 25% for male patients. But is this a valid quality measure? These researchers at Kaiser Permanente identified all patients who received colonoscopy between 1998 and 2010 and who had at least 6 months of follow-up. Patients were followed up for 10 years, or until a diagnosis of CRC, or until they left the insurance plan. The population had a median age of 64 years, 52% were women, and 57.4% of the colonoscopies were diagnostic (ie, in a symptomatic patient). Gastroenterologists had to perform 300 or more total colonoscopies (75 or more screening colonoscopies) during the study period to be included, and colonoscopies included screening, surveillance, and diagnostic procedures. The detection rate was defined as the percentage of examinations that found at least one adenoma or adenocarcinoma. There were a total of 264,972 colonoscopies eligible for analysis of interval cancers (cancers diagnosed within 6 months of the index colonoscopy were excluded). They detected 712 interval cancers, 60% of which were proximal, and there was a median interval of 39 months from index colonoscopy to diagnosis of cancer. Adenoma detection rates varied widely among the 136 physicians, from 10% to 60% for male patients and 4% to 46% for female patients. The researchers defined quintiles of adenoma detection rates from 16.6% to 38.9%.They found that the risk of an interval CRC, an advanced stage CRC, and a fatal CRC all declined with increasing adenoma detection rates. For example, compared with the lowest quintile, patients of physicians in the highest quintile had hazard ratios of 0.52 for interval CRC (95% CI, 0.39-0.69) and 0.38 for fatal CRC (0.22 – 0.65).

Mark H. Ebell, MD, MS
Associate Professor
University of Georgia
Athens, GA


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