Vertical R1 margins are not always associated with residual neoplasia after endoscopic resection of Barrett's neoplasia: a nationwide cohort with dedicated pathology reassessment.

Histological evaluation of ER margins appears challenging as 75% of documented R1v cases were confirmed during reassessment. After ER with R1v, 50% of the patients had no residual neoplasia. Endoscopic reassessment 8-12 weeks after ER seems accurately able to detect residual neoplasia and help to determine the most appropriate strategy for patients with R1v.