Published online Mar 21, 2016. doi: 10.3748/wjg.v22.i11.3220
Peer-review started: May 6, 2015
First decision: August 26, 2015
Revised: September 3, 2015
Accepted: November 9, 2015
Article in press: November 9, 2015
Published online: March 21, 2016
Processing time: 319 Days and 13.6 Hours
AIM: To identify whether the forceps estimation is more useful than visual estimation in the measurement of colon polyp size.
METHODS: We recorded colonoscopy video clips that included scenes visualizing the polyp and scenes using open biopsy forceps in association with the polyp, which were used for an exam. A total of 40 endoscopists from the Busan Ulsan Gyeongnam Intestinal Study Group Society (BIGS) participated in this study. Participants watched 40 pairs of video clips of the scenes for visual estimation and forceps estimation, and wrote down the estimated polyp size on the exam paper. When analyzing the results of the exam, we assessed inter-observer differences, diagnostic accuracy, and error range in the measurement of the polyp size.
RESULTS: The overall intra-class correlation coefficients (ICC) of inter-observer agreement for forceps estimation and visual estimation were 0.804 (95%CI: 0.731-0.873, P < 0.001) and 0.743 (95%CI: 0.656-0.828, P < 0.001), respectively. The ICCs of each group for forceps estimation were higher than those for visual estimation (Beginner group, 0.761 vs 0.693; Expert group, 0.887 vs 0.840, respectively). The overall diagnostic accuracy for visual estimation was 0.639 and for forceps estimation was 0.754 (P < 0.001). In the beginner group and the expert group, the diagnostic accuracy for the forceps estimation was significantly higher than that of the visual estimation (Beginner group, 0.734 vs 0.613, P < 0.001; Expert group, 0.784 vs 0.680, P < 0.001, respectively). The overall error range for visual estimation and forceps estimation were 1.48 ± 1.18 and 1.20 ± 1.10, respectively (P < 0.001). The error ranges of each group for forceps estimation were significantly smaller than those for visual estimation (Beginner group, 1.38 ± 1.08 vs 1.68 ± 1.30, P < 0.001; Expert group, 1.12 ± 1.11 vs 1.42 ± 1.11, P < 0.001, respectively).
CONCLUSION: Application of the open biopsy forceps method when measuring colon polyp size could help reduce inter-observer differences and error rates.
Core tip: Using open biopsy forceps is known to be a useful technique to reduce error rates in colon polyp size measurements, but in practice most endoscopists just measure polyp size by visualization. There is little information about accuracy differences between these two methods. In this study, we showed that the inter-observer difference, diagnostic accuracy, and error range of forceps estimation were better than those of visual estimation in the measurement of the polyp size. We propose that forceps estimation should be considered to measure the colon polyp size before removing the polyp.