Differences in Colonoscopy Withdrawal Times and Adenoma Detection Rates Between Senior and Junior Endoscopists: A Retrospective Observational Study

Introduction: Colonoscopy is the gold standard for detecting and preventing colorectal cancer. Two important quality indicators of colonoscopy are the adenoma detection rate (ADR), and the colonoscopy withdrawal time (CWT), a longer CWT is associated with higher ADR. Endoscopist experience is a potential factor that could influence both CWT and ADR, as more experienced endoscopists may be more efficient and thorough during the procedure. However, there is limited research comparing CWT and ADR between senior and junior endoscopists. The aim of this study is to compare CWT and ADR between senior and junior endoscopists at a single center over a 5-year period. Methods: We performed a retrospective observational study includes patients who underwent colonoscopy by either senior or junior endoscopists at a single center over a 5-year period. We categorized endoscopist experience as junior if they have less than 5 years of experience or performed fewer than 500 colonoscopies, and senior if they have more than 5 years of experience or performed more than 500 colonoscopies. Comparison of CWT and ADR between senior and junior endoscopists was done using t-tests, or chi-square tests as appropriate, as well as subgroup analyses by colonoscopy indication. All statistical tests were 2-sided with a significance level of 0.05. Data analysis was performed using STATA18. Results: A total of 22542 consecutive colonoscopies were analyzed, 10164 and 12378 performed by Junior and Senior endoscopist respectively. 55.9% were females and median age was 57 years (IQR: 50-65). The median withdrawal time (IQR) was significantly longer for junior endoscopists (13.4 [13.3-13.5] minutes) than for senior endoscopists (8.8 [8.7-8.9] minutes) in the total population (MD:4.6, P< 0.001). This difference was observed across all indications for colonoscopy, including screening (MD: 4.7, P< 0.001), surveillance (MD: 5.7, P< 0.001) and diagnostic (MD: 3.3, P< 0.001). In terms of ADR, junior endoscopists had a significantly higher ADR than senior endoscopists for the total population (38.72% vs 32.23%, P< 0.001), in both screening (42.2% vs 32.95%, P< 0.001) and surveillance (51.37% vs 41.54%, P< 0.001) indications. CWTs and ADRs per indication for diagnostic endoscopies can be found in Table 1. Conclusion: Overall, these results suggest that junior endoscopists take longer to withdraw the colonoscope but have a higher ADR than senior endoscopists, with some variation across different indications. Table 1. - Comparison of Mean Withdrawal Times and Adenoma Detection Rates Between Junior and Senior Endoscopist Number of Colonoscopies Withdrawal Time, Median (IQR) Comparison of Means ADR Junior (n=10164) Senior (n=12378) Mean Diff. (MD) t-test P-value Junior Senior Chi2 P-value Total 22542 13.4 (13.3-13.5) 8.8 (8.73-8.93) 4.56 53.53 < 0.001 38.72 32.23 < 0.001 Screening 11024 11.8 (8.7-16.2) 7.2 (5.1-10.2) 4.69 38.77 < 0.001 42.2 32.95 < 0.001 Surveillance 5243 13.4 (9.8-18.4) 7.9 (5.5-11.4) 5.75 30.97 < 0.001 51.37 41.54 < 0.001 Diagnostic 6275 10.8 (7.9-14.8) 7.5 (5.5-11) 3.34 21.69 < 0.001 22.99 22.85 0.89 Positive Stool testing 72 15.15 (12.2-22.8) 9.95 (8-14.8) 5.1 2.31 0.0118 62 36.36 0.044 IDA 698 11.2 (8.4-16.2) 7 (5.2-10.4) 4.3 9.9 < 0.001 35.02 30.67 0.23 Diarrhea 489 12.15 (9.1-15.6) 10.1 (7.1-13.8) 1.52 2.63 0.004 20.25 29.45 0.023 Abnormal imaging 287 12.9 (9.6-16.4) 8.4 (6.2-11.85) 3.71 4.32 < 0.001 25.15 25 0.98 GI bleed 1836 11.6 (8.4-16.3) 7.6 (5.6-10.8) 4.46 14.99 < 0.001 31.36 28.46 0.17 IBD 1439 10.0 (7.5-13.7) 9.3 (7.2-13.4) 1.07 3.31 0.0005 7.94 4.04 0.005