Introduction
Endoscopists with baseline adenoma detection rates (ADRs) ≤26% who improve their ADRs significantly reduce their patients’ risk of post-colonoscopy colorectal cancer (PCCRC)1. The recommended withdrawal time (WT) of 8–9 minutes is associated with higher ADRs; however, it includes time spent on therapeutic interventions, which may overestimate actual inspection time and limit its accuracy as a performance metric2.
Aims & Methods
We aimed to determine the corrected withdrawal time (cWT)—defined as WT minus intervention time—required for low-performing endoscopists to achieve ADR thresholds of ≥26 and ≥35.
We prospectively analyzed 1,165 the recorded videos of elective colonoscopies performed by 17 endoscopists at Montreal University Hospital Center (IRB; CER22.013/ CER25.12283). Eligible cases were consecutive adults (≥18 years) undergoing elective colonoscopy. Exclusions were complex resections, sigmoidoscopies, incomplete exams, failed recordings, and procedures by endoscopists with <10 prior cases. A research assistant was present during each procedure and documented all periprocedural metrics in real-time. Endoscopists were stratified as low (ADR ≤25%) or high performers (ADR >25%). The primary outcome was the mean cWT required for low performers to achieve an ADR ≥26%. Secondary outcomes included the cWT needed to reach ADR ≥35% and the incremental impact of each additional minute of cWT on detection metrics. Multivariable generalized estimating equation (GEE) models adjusted for patient demographics, bowel preparation, indication of colonoscopy, time of day/month, CADe use, and endoscopist effect.
Results
Low performers required a mean cWT of 10′58″ to achieve an ADR ≥26%, and 13′51″ to reach ≥35% compared to 4′01″ for high performers. Each additional minute of cWT increased ADR odds by 15.3% for low performers and 5.0% for high performers (P < .001). Similar improvements were observed across all detection metrics (Table 1). For every additional cWT minute, the odds of detecting advanced adenomas increased by 10.1%, sessile serrated lesions (SSLs) by 10.1%, and polyps by 16.5% (all P < .001). Adenoma and polyp counts increased by 7.5% and 7.9%, respectively. Absolute gains per minute were greater in low performers, with ADR increases exceeding 3% beyond 12 minutes of cWT. After adjusting for covariates, each additional cWT minute was associated with a significant increase in the odds of detection: an increase of 6.5% (P = .002) for adenomas, 9.2% (P < .001) for advanced adenomas, 11.5% (P < .001) for SSLs, and 14.9% (P < 0.01) for polyps. With each additional cWT minute, the adenoma count increased by 7.3% and the polyp count increased by 7.8% (P < .001) (results not shown).
Table 1. Mean Detection Metrics and Their Incremental Increase Per Additional Minute of Corrected Withdrawal Time, Overall and Stratified by High vs Low Performers.
| Detection rates | ADR | AADR | SSLDR | APC | PDR | PPC |
| Mean (95% CI) | 37.9%
(35.1 to 40.7) | 8.2%
(6.7 to 9.9) | 5.4%
(4.2 to 6.9) | 0.72
(0.64 to 0.79) | 64.4%
(61.5 to 67.1) | 2.18
(2.05 to 2.32) |
| Increase/additional cWT minute (P-value) | 7.2% (<.001) | 10.1% (<.001) | 10.1% (<.001) | 7.5% (<.001) | 16.5% (<.001) | 7.9% (<.001) |
| High vs low performers |
| Mean (95% CI) |
| High performers | 41.5%
(38.4 to 44.7) | 9.0%
(7.3 to 11.0) | 5.9%
(4.5 to 7.6) | 0.79
(0.71 to 0.87) | 69.0%
(66.0 to 71.9) | 2.32
(2.16 to 2.48) |
| Low performers | 19.9%
(14.7 to 26.3) | 4.1%
(1.9 to 8.2) | 3.1%
(1.3 to 6.9) | 0.34
(0.23 to 0.46) | 41.3%
(34.4 to 48.6) | 1.51
(1.25 to 1.76) |
| Increase/additional cWT minute (P-value) |
| High performers | 5.0% (<.001) | 9.5% (<.001) | 8.6% (<.001) | 6.7% (<.001) | 16.2% (<.001) | 7.9% (<.001) |
| Low performers | 15.3% (<.001) | 16.2% (.22) | 22.0% (<.001) | 11.3% (<.001) | 23.5% (.009) | 4.5% (.299) |
AADR, advanced adenoma detection rate; ADR, adenoma detection rate; APC, adenomas per colonoscopy; CI, confidence interval; PDR, polyp detection rate; PPC, polyps per colonoscopy; SSLDR, sessile serrated lesion detection rate.
Conclusion
Longer cWT enhanced detection across all metrics, particularly for low performes. These findings support personalized cWT targets based on individual performance rather than uniform WT recommendations.
References
1. Pilonis ND, Spychalski P, Kalager M, et al. Adenoma detection rates by physicians and subsequent colorectal cancer risk. JAMA 2025;333:400–407.
2. Rex DK, Anderson JC, Butterly LF, et al. Quality indicators for colonoscopy. Gastrointest Endosc 2024;100:352–381.
Disclosure
Daniel von Renteln has received research funding from ERBE Elektromedizin GmbH, Ventage, Pendopharm, Fujifilm, and Pentax, and has received consultant or speaker fees from Boston Scientific Inc., ERBE Elektromedizin GmbH, and Pendopharm. Roupen Djinbachian has received speaker fees from Fujifilm. The remaining authors declare that they have no conflict of interest.