2020 年 47 巻 4 号 p. 527-530
Objective: The purpose of this study was to determine the relationship between withdrawal time (WT) and quality indicators (Polyp Detection Rate (PDR), Adenomatous polyp Detection Rate (ADR), Mean number of Polyps found per Patient (MPP), and Mean Adenomatous polyp found per Patient (MAP)) in a screening colonoscopy for medical check-up.
Methods: Endoscopic and pathological results were retrospectively reviewed for 840 colonoscopies performed by nine endoscopists at our facility between August and November 2018. ADR, PDR, MAP, and MPP were calculated and analyzed with WT at polyp identification (WT with polyp) or WT at polyp non-identification (WT without polyp).
Results: The mean WT without polyp was 6.56 minutes, the mean WT with polyp was 13.6 minutes, ADR was 23.9%, PDR was 29.3%, MAP was 0.35, MPP was 0.43, and the rate of early cancer (T1a) detection was 0.32%. Correlation analysis revealed a high correlation between WT without polyp and ADR, PDR, MAP, and MPP (R2=0.88, 0.92, 0.88 and 0.92, respectively). Regression analysis with WT without polyp as explanatory variables found each index to be significantly predictive (ADR (P=0.0101), PDR (P=0.0005), MAP (P=0.0016), and MPP (P=0.0004)). Each index was found to be significantly improved when the cutoff value was 6.5 minutes of extraction time at polyp non-identification (ADR (35% vs 13.1%, P=0.0005), PDR (43% vs 15.7%, P=0.004), MAP (0.58 vs 0.17, P=0.006), and MPP (0.73 vs 0.2, P=0.001)).
Conclusions: It was suggested that spending more than 6.5 minutes on whole colon observation may improve the rate of polyp detection.
