Screening Colonoscopy Withdrawal Time Threshold for Adequate Proximal Serrated Polyp Detection Rate
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For adequate adenoma detection rate (ADR), guidelines recommend a mean withdrawal time (MWT) of ≥ 6 min. ADR has been shown to correlate strongly with proximal serrated polyp detection rate (PSP-DR), which is another suggested quality measure for screening colonoscopy. However, the impact of directly measured withdrawal time on PSP-DR has not been rigorously studied. We examined the relationship between MWT to ADR and PSP-DR, with the aim of identifying a functional threshold withdrawal time associated with both increased ADR and PSP-DR.
This was a retrospective study of endoscopy and pathology data from average-risk screening colonoscopy examinations performed at a large system with six endoscopy laboratories. A natural language processing tool was used to determine polyp location and histology. ADR and PSP-DR were calculated for each endoscopist. MWT was calculated from colonoscopy examinations in which no polyps were resected.
In total, 31,558 colonoscopy examinations were performed, of which 10,196 were average-risk screening colonoscopy examinations with cecal intubation and adequate prep by 24 gastroenterologists. When assessing the statistical significance of increasing MWT by minute, the first significant time mark for PSP-DR was at 11 min at a rate of 14.2% (p = 0.01). There was a significant difference comparing aggregated MWT < 11 min compared to ≥ 11 min looking at the rates of adenomas [OR 1.65 (1.09–2.51)] and proximal serrated polyps [OR 1.81 (1.06–3.08)]. While ADR linearly correlated well with MWT (R = 0.76, p < 0.001), the linear relationship with PSP-DR was less robust (R = 0.42, p = 0.043).
In this large cohort of average-risk screening colonoscopy, a MWT of 11 min resulted in a statistically significant increase in both ADR and PSP-DR. Our data suggest that a longer withdrawal time may be required to meet both quality metrics.
KeywordsWithdrawal time Sessile serrated polyp Colorectal cancer screening Colonoscopy Endoscopic detection Polypectomy
V. Patel: study design, clinical content expertise, manual validation of NLP methodology/chart review, writing of manuscript and revisions, and data and statistical analysis; W. Thompson: study design, software programming/NLP code development, manual validation of NLP methodology/chart review, writing of manuscript and revisions, and data and statistical analysis; B. Lapin: data and statistical analysis; J. Goldstein: study design, writing and editing of the manuscript and revisions, and interpretation of results; E. Yen: study design, clinical content expertise, writing and editing of the manuscript and revision, and interpretation of results.
Compliance with ethical standards
Conflict of interest
The authors declare that they have no conflict of interest.
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