LAUSR

Abstract Background and aims: Piecemeal endoscopic mucosal resection (pEMR) allows resection of larger non-invasive colorectal lesions. Adenoma recurrence is an important limitation and occurs in ≤20%. The present study aimed to validate the Sydney EMR recurrence tool (SERT) score as a predictor of both endoscopic and histologic recurrence and evaluate interobserver agreement in adenoma recurrence based on endoscopic scar assessment, among nonexperts in EMR. Methods: Retrospective cohort and cross-sectional study, in which all patients submitted to pEMR in a tertiary care center in Portugal, between 2012 and 2018 were included. SERT-score was calculated for all lesions and compared with the SMSA (size, morphology, site, access) score already validated as a predictor of adenoma recurrence. Image based offline analysis was performed to evaluate adenoma recurrence prediction and assess the interobserver agreement within a heterogeneous group of participants, mostly composed by nonexperts in EMR. Results: There was a moderate positive correlation between the SERT and SMSA scores (p <.001; r = 0.61). SERT-score was significantly associated with endoscopic recurrence (p =.005) and histologic recurrence (p = .015). Endoscopic prediction of recurrence had high coefficient of agreement (k-0.806; p < .001). Conclusion: Histologic recurrence after pEMR can be predicted by SERT score and optical diagnosis of recurrent adenoma has high interobserver agreement between nonexperts in EMR.