Improving R0 Resection Rates With a Posterior-First, 2-Stage Approach for En Bloc Resection of Locally Advanced Primary and Recurrent Anorectal Cancers Involving the Deep Pelvic Sidewall

BACKGROUND: Using standard anterior approaches, consistent R0 resection of locally advanced primary and recurrent rectal and anal cancer involving the deep pelvic sidewall may be unattainable. Therefore, to improve R0 resection rates, we have used a posterior-first, then anterior 2-stage approach to resection of tumors in this location. OBJECTIVE: To assess the R0 resection rate and surgical outcomes of the first 10 patients operated on using this approach. DESIGN: We conducted a retrospective case series review of our prospectively maintained surgical pathology and tumor registries. SETTING: This study was conducted at the Mayo Clinic in Rochester, Minnesota. PATIENTS: Ten patients (6 female individuals, median age 53.5 years) with primary or recurrent anal or rectal cancer treated with a posterior-first, then anterior 2-stage approach were identified. MAIN OUTCOME MEASURES: The primary outcome measures were the R0 resection rate and surgical outcomes. RESULTS: An R0 resection was achieved in all 10 patients. Nine patients developed 1 or more 30-day Clavien-Dindo grade III complications. Nine patients developed gluteal wound complications ranging from superficial wound dehiscence to flap necrosis. During the follow-up period, 4 patients were found to have metastatic disease and 1 patient had local re-recurrence. LIMITATIONS: Small cohort with heterogeneous tumors and a short follow-up duration. CONCLUSION: A posterior-first, then anterior 2-stage approach has allowed us to achieve consistent R0 resection margins in locally advanced primary and recurrent rectal and anal cancers involving the deep pelvic sidewall. Poor wound healing of the posterior gluteal incision is a common complication. See Video Abstract. (C) The ASCRS 2023