Open AccessThe Workgroup Serrated Polyps and Polyposis (WASP) classification for optical diagnosis of colorectal diminutive polyps with iScan and the impact of the revised World Health Organization (WHO) criteria
Author(s) -
Soons Elsa,
Bisseling Tanya M.,
Post Rachel S.,
Nagtegaal Iris D.,
Hazewinkel Yark,
Kouwen Mariette C. A.,
Siersema Peter D.
Publication year - 2021
Publication title -
united european gastroenterology journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.667
H-Index - 35
eISSN - 2050-6414
pISSN - 2050-6406
DOI - 10.1002/ueg2.12129
Subject(s) - medicine , diminutive , colorectal polyp , gastroenterology , workgroup , pathological , colonoscopy , colorectal cancer , cancer , computer network , philosophy , linguistics , computer science
Background and aims The Workgroup Serrated Polyps and Polyposis (WASP) developed criteria for optical diagnosis of colorectal polyps. The aims of this study were: (1) to improve optical diagnosis of diminutive colorectal polyps, especially SSLs, after training endoscopists in applying WASP criteria on videos of polyps obtained with iScan and (2) to evaluate if the WASP criteria are still useful when polyps are pathologically revised according to the World Health Organization (WHO) 2019 criteria. Methods Twenty‐one endoscopists participated in a training session and predicted polyp histology on 30 videos of diminutive polyps, before and after training (T 0 and T 1 ). After three months, they scored another 30 videos (T 2 ). Primary outcome was overall diagnostic accuracy (DA) at T 0 , T 1 and T 2 . Polyps were histopathologically classified according to the WHO 2010 and 2019 criteria. Results Overall DA (both diminutive adenomas and SSLs) significantly improved from 0.58 (95% CI 0.55–0.62) at T 0 to 0.63 (95% CI 0.60–0.66, p = 0.004) at T 1 . For SSLs, DA did not change with 0.51 (95% CI 0.46–0.56) at T 0 and 0.55 (95% CI 0.49–0.60, p = 0.119) at T 1 . After three months, overall DA was 0.58 (95% CI 0.54–0.62, p = 0.787, relative to T 0 ) while DA for SSLs was 0.48 (95% CI 0.42–0.55, p = 0.520) at T 2 . After pathological revision according to the WHO 2019 criteria, DA of all polyps significantly changed at all time points. Conclusion A training session in applying WASP criteria on endoscopic videos made with iScan did not improve endoscopists' long‐term ability to optically diagnose diminutive polyps. The change of DA following polyp revision according to the revised WHO 2019 criteria suggests that the WASP classification may need revision.