A Real-World Analysis of Oncological Outcomes in Patients with Oral Squamous Cell Carcinoma Requiring Marginal Mandibulectomy for Achieving Clear Surgical Margins.

Introduction: Marginal mandibulectomy (MM) offers a conservative alternative to segmental resections for patients with oral squamous cell carcinoma (OSCC) requiring clear margins without evident bone invasion. Despite its potential benefits, real-world outcomes related to surgical margins and oncological outcomes have not been studied sufficiently. Methods: This ambispective cohort study analyzed 183 patients undergoing MM from January 2015 to March 2021 to achieve clear margins without clinical bone involvement. The primary objective is to assess the disease-free survival (DFS) in patients with OSCC requiring MM to achieve clear surgical margins, and the secondary objective is to assess the impact of microscopic bone involvement on these outcomes. Kaplan-Meier estimates facilitated the survival analysis. Results: The cohort primarily comprised males (83.2%) with a median age of 50 years, the predominant subsite being the bucco-alveolar complex (94%). Microscopic bone involvement was found in 8.74% of patients. The distribution of surgical margins was 84.24% negative, 15.22% close, and 0.54% positive. The cohort's 3-year DFS and overall survival (OS) rates are 65 and 70%, respectively. Patients with microscopic bone involvement experienced lower DFS (odds ratio [OR] = 0.251, p  = 0.013), and perineural invasion was also a significant negative prognostic factor for DFS (OR = 0.4, p  = 0.01). Statistical analyses revealed significant differences in survival distributions based on bone involvement ( p  = 0.049). Conclusion: While MM can achieve favorable surgical margins in selected OSCC patients, microscopic bone involvement compromises DFS. Given the low incidence of bone involvement and high rate of negative margins, more conservative approaches might be justified in select patients. However, these findings require further validation in a larger cohort.