S2316 Preliminary Evaluation of Outcomes Following Endoscopic Submucosal Dissection and Endoscopic Mucosal Resection of Anal Verge Polyps

Introduction: Anal verge polyps occurring at the junction of the anus and rectum close to or involving the dentate line present a challenge. Although most of these lesions are benign the incidence of malignancy is reported as high as 40% in polyps over 20 mm. Endoscopic mucosal resection (EMR) has been reported to have recurrence rates of up to 11%. Other complications thought to be associated with resection in this area include higher delayed bleeding rate, defecatory issues like tenesmus or incontinence due to sphincter injury and bacteremia due to venous drainage below dentate line bypassing portal system with direct systemic drainage. Methods: Herein we report a series of 7 patients with anal verge polyps who underwent endoscopic resection utilizing either ESD or a hybrid ESD/EMR technique to achieve a negative anal margin with follow up and outcomes assessments addressing above-mentioned common complications. Results: Polyps mainly involved the dentate line or were near it. Polyp sizes ranged from 10-60 mm. 2 of 7 patients had malignant polyps extracted with negative margins, one of whom had no recurrence in 1 year with the other pending surveillance. Positive margins noted in 2 patients with serrated adenomas, one of whom had recurrence noted in short surveillance endoscopy. One patient with 50 mm polypectomy without post resection hemostasis experienced delayed bleeding managed with supportive care. No defecatory complications or bacteremia reported during our follow up period. Some reasons for positive resection margins include limited space on the anal side for endoscopist to deploy snare without the endoscope falling out. Conclusion: This small series shows a low risk of complications. The primary challenge with snare endoscopic mucosal resection at the anal verge is the risk of residual due to the narrow working space but ESD techniques to ensure an adequate anal margin may be effective in mitigating this risk. Delayed bleeding may still be an issue as prophylactic hemostasis options (i.e. clips, suturing) are typically not possible in this location. More work is needed with a larger sample size and longer follow-up time to analyze the efficacy and long-term outcomes of EMR.