Impact of Vertical Margin Clearance Following Endoscopic Resection of T1 Colorectal Cancer: A Single-Center Experience

Abstract Objective: The optimal management of T1 colorectal cancer following endoscopic resection remains an area of clinical uncertainty, particularly when vertical margin clearance is minimal. This study aimed to evaluate the impact of vertical margin clearance on recurrence and management in patients with T1 colorectal cancer who underwent endoscopic resection at a single academic center. Results: A total of 96 patients with T1 colorectal cancer were identified between 2010 and 2020 at a single academic center. Among 27 patients who underwent en bloc endoscopic resection, 8 had vertical margin clearance less than 1 mm. None of these patients developed local or distant recurrence, nor were residual tumor or lymph node metastases identified at subsequent surgery. In contrast, patients undergoing piecemeal resection had higher rates of residual carcinoma. Across the full cohort, only two patients had lymph node involvement and seven developed recurrence, most of whom had undergone surgery without prior endoscopic resection. These findings suggest that minimal vertical margin clearance alone may not confer increased oncologic risk when other adverse features are absent. This supports the consideration of surveillance, rather than surgery, in selected patients undergoing en bloc resection with otherwise low-risk histologic profiles.