Endoscopy-based decision is sufficient for predicting completeness in lateral resection margin in colon endoscopic submucosal dissection

Background and Aims: Our aim was to investigate the incidence of tumor recurrence in cases in which there was a discrepancy in the diagnosis of complete resection by pathologists and colonoscopists, especially in the lateral resection margin. Methods: We reviewed 245 patients with colorectal tumors that were treated by endoscopic submucosal dissection (ESD) between March 2006 and June 2011. We evaluated the recurrence rate in cases judged as pathologically incomplete resection despite endoscopically complete resection. Results: Of the 24 cases with tumor cells on the lateral resection margin, the histologies of the colorectal tumors were found to be tubular adenoma (TA) with low-grade dysplasia (n = 19), TA with high-grade dysplasia (n = 3) and differentiated adenocarcinoma (n = 2). No tumor recurrence was observed in 22 patients after ESD. Four patients did not receive surveillance colonoscopy. The median tumor size was 28 mm (12-35) and the median follow-up period was 19 months (5-42). Conclusions: This retrospective analysis was limited by a short follow-up period. However, surveillance colonoscopy could be attempted without additional ESD in those cases in which incomplete resection on the lateral margin was judged pathologically, if endoscopic complete resection was grossly achieved.