PTH 025 Predicting polyp histology development and validation of an international simple endoscopic classification of small colorectal polyps using the novel i scan optical enhancement colonoscope
Introduction The endoscopic accuracy to predict in vivo the histology of small colorectal polyps may facilitate tailored endoscopic treatment. The aims of this study were 1) to develop a simplified endoscopic colorectal polyp classification and 2) to evaluate the performance of the classification to predict polyp histology using i scan Optical Enhancement (OE) images. Method Eight endoscopists from Europe and North America with experience in virtual electronic chromoendoscopy participated in the study. A video library of 21 small colorectal polyps (hyperplastic=7, adenomatous=7, and sessile serrated=7) was assessed. The diagnostic performance of the endoscopists was evaluated according to the histopathology of the polyp. In phase 1 of the study, a new simplified endoscopic classification system for colorectal polyps (Simplified Identification Method for Polyp Labelling during Endoscopy SIMPLE was developed. In phase 2, the accuracy, level of confidence and inter observer agreement to predict polyp histology before and after a training were evaluated. Univariate and multivariate analysis of the endoscopic features of polyps were performed to determine the strength of endoscopic predictors for adenoma vs. non adenoma. Results The SIMPLE classification was consisted of three polyp characteristics: surface, vessel pattern and lesion border. Using the SIMPLE classification, the overall accuracy for prediction of polyp histology was 83.1% (95% CI: 0.77 0.88) before training and improved to 94.0% (95% CI: 0.88 0.97; p=0.002) after training. For polyp diagnosis with high confidence the accuracy before training was 90% (95% CI: 0.83 0.94) and after was 95% (95% CI: 0.89 0.98; p=0.01) The overall sensitivity, specificity, PPV, NPV, of the SIMPLE classification after training were 96.6% 87.5% 95.0% 91.3% and 94.0% The inter observer agreement of polyp histology diagnosis using the SIMPLE classification improved from 0.46 (95% CI: 0.30 0.64) at baseline to 0.66 (95% CI: 0.48 0.82) after training. Univariate analysis showed that the surface and vessel pattern criteria were predictive of an adenoma diagnosis. The odds ratio of adenoma diagnosis were 1.8 (95% CI: 0.7 4.6) when using surface pattern alone and 4.6 (95% CI: 2.3 9.4) when using vessel pattern alone. Conclusion A new endoscopic SIMPLE classification to predict polyp histology was developed by an international expert consensus group. Using the i scan OE system, the new SIMPLE classification was validated and demonstrated a high degree of accuracy for adenoma diagnosis in small polyps, meeting the ASGE PIVI recommendations. Disclosure of Interest M. Iacucci Conflict with: Pentax, C Trovato: None Declared, D Greenwald: None Declared, S Gross: None Declared, A Hoffman: None Declared, L Jeffrey: None Declared, B Lethebe: None Declared, M Lowerison: None Declared, J Nayor: None Declared, H Neumann: None Declared, S Sanduleanu: None Declared, P Sharma: None Declared, R Kiesslich: None Declared, S Ghosh: None Declared, J Saltzman: None Declared
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