Surgical Margins After Neoadjuvant Radiation for Locally Advanced Vulvar Carcinoma: What is an Adequate Margin?

Abstract

We aim to explore whether the surgical tumor free margin is important for overall survival (OS) and local control in patients who undergo neoadjuvant radiation (RT) for vulvar cancer. A retrospective review from 2004 to 2021 of patients who underwent RT followed by surgical resection was performed. Patients were categorized into groups based on margin status (no residual disease, >8mm, close margins defined as 1 to 7mm, or positive). Local control and OS were analyzed using the Kaplan-Meier with log rank test. Multivariate analysis was performed with cox hazards model. Eighty-three patients were included. A complete pathologic response (pCR) was found in 56% (n=46) of patients. The median follow-up time was 35 months (range: 4 to 216). The median OS for the entire cohort was 46 months (95% CI: 32.3-59.7). Having a pCR improved both OS and disease-free survival (DFS) compared with residual disease by 81 and 91 months, respectively (P<0.001). In the 2 patients with a margin >8mm, there was no statistical difference in survival between those with close margins (46 vs. 25mo, P=0.485). Factors that significantly impacted both OS and DFS were depth of invasion (DOI) and LVSI. On multivariate analysis of those with residual disease, there was no difference in OS or DFS by margin status but having a DOI >9mm showed decreased OS (HR: 3.654; 95% CI: 1.317-10.135). In this cohort, response to RT, not margin status drives survival and recurrence. Given residual disease, the optimal margin is not clear, as there were only 2 patients with >8mm margins. A close or positive margin had no impact on OS or local recurrence. A DOI >9mm significantly impacts both OS and local recurrence even when accounting for other factors.