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Polyp Detection Rate Correlates Strongly with Adenoma Detection Rate in Trainee Endoscopists



The adenoma detection rate (ADR) is a widely accepted quality benchmark for screening colonoscopy but can be burdensome to calculate. Previous studies have shown good correlation between polyp detection rate (PDR) and ADR, but this has not been validated in trainees. Additionally, the correlation between PDR and detection rates for sessile serrated polyps (SSPDR) and advanced neoplasia (ANDR) is not well studied.


We investigated the relationship between PDR and ADR, SSPDR, and ANDR in trainees.


We examined 1600 outpatient colonoscopies performed by 24 trainees at a VA hospital from 2014 to 2017. Variables collected included patient demographics, year of fellowship, colonoscopy indication, and endoscopic and histologic findings. We calculated the overall ratios of PDR to ADR, SSPDR, and ANDR to assess the correlation between measured and calculated ADR, SSPDR, and ANDR, which is equivalent to the correlation between PDR and measured ADR, SSPDR, and ANDR.


The overall PDR, ADR, SSPDR, and ANDR were 72%, 52%, 2%, and 14%. PDR (48%) was highest in the left colon, while ADR (32%) and ANDR (7%) were highest in the right colon (p < 0.001 for all). The overall ADR/PDR, SSPDR/PDR, and ANDR/PDR ratios were 0.73, 0.03, and 0.20. Correlation between PDR and ADR was highly positive overall (r = 0.87, p < 0.0001) and stronger in the right (r = 0.91) and transverse (r = 0.94) colon than the left colon (r = 0.80). Correlation between PDR and overall SSPDR and ANDR were not statistically significant.


PDR can serve as a surrogate measure of ADR to monitor colonoscopy quality in gastroenterology fellowship.

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Peter S. Liang is supported by Grant K08CA230162 from the National Cancer Institute.

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SN: study design, data collection and interpretation, drafted and approved manuscript; AKS: study design, data collection and interpretation, approved manuscript; JP: study design, data collection, approved manuscript; PSL: study design, data collection and interpretation, drafted and approved manuscript.

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Correspondence to Peter S. Liang.

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Ng, S., Sreenivasan, A.K., Pecoriello, J. et al. Polyp Detection Rate Correlates Strongly with Adenoma Detection Rate in Trainee Endoscopists. Dig Dis Sci 65, 2229–2233 (2020).

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  • Colorectal cancer screening
  • Quality metric
  • Quality improvement
  • Gastroenterology fellow