Endoscopist Adenoma Per Colonoscopy Detection Rates and Risk for Post Colonoscopy Colorectal Cancer: Data From New Hampshire Colonoscopy Registry.

BACKGROUND AND AIMS: Adenomas per colonoscopy (APC) may be a better measure of colonoscopy quality than adenoma detection rate (ADR) since it credits endoscopists for each detected adenoma. There are few data examining the association between APC and post colonoscopy colorectal cancer (PCCRC) incidence. We used data from the New Hampshire Colonoscopy Registry (NHCR) to examine APC and PCCRC risk.

METHODS: We included NHCR patients with an index exam and at least one follow up event, either a colonoscopy or a CRC diagnosis. Our outcome was PCCRC defined as any CRC diagnosed > 6 months after an index exam. The exposure variable was endoscopist specific APC quintiles of 0.25, 0.40, 50 and 0.70. Cox regression was used to model the hazard of PCCRC on APC, controlling for age, sex, year of index exam, index findings, bowel preparation and having more than 1 surveillance exam.

RESULTS: In 32,535 patients, a lower hazard for PCCRC (n=178) was observed for higher APCs as compared to APCs <0.25 (Reference) (0.25-<0.40:HR=0.35, 95% CI: 0.22-0.56;0.40-<0.50: HR=0.31, 95% CI: 0.20-0.49; 0.50-<0.70: HR=0.20, 95% CI: 0.11-0.36; and ≥0.70: HR=0.19, 95% CI: 0.09-0.37). When examining endoscopists with an ADR of at least 25%, an APC < 0.50 was associated with a significantly higher hazard than an APC > 0.50 (HR=1.65; 95% CI: 1.06-2.56). A large proportion of endoscopists, 1/5th (32/152; 21.1%), had an ADR >25 but an APC <0.50.

DISCUSSION: Our novel data demonstrating lower PCCRC risk in exams performed by endoscopists with higher APCs suggest that APC could be a useful quality measure. Quality improvement programs may identify important deficiencies in endoscopist detection performance by measuring APC for endoscopists with ADR > 25%.