Title: The importance of margins for local control in oral salivary gland carcinomas

Background: To evaluate the impact of close, wide, and positive surgical margins in minor oral salivary gland carcinomas on local control and disease-specific survival.
Methods: Retrospective chart review including 49 patients. Clinicopathological data regarding margin status (negative margins were classified within ≥0.1mm), disease-specific survival (DSS), and disease-free survival (DFS) were statistically analysed.
Results: The most common subsite was the hard palate (40.8%), with mucoepidermoid carcinoma as the most common histology (30.6%). A subsequent second resection was performed in 16 (32.7%) patients due to positive margins, resulting in a final R1/2 rate of 18.4%. During the median (IQR) follow-up of 73 (30-135.5) months, 12 (25%) local, 5 (10.4%) regional, and 10 (20.4%) distant failures were observed. Positive margins were the only prognostic factor for worse DSS (HR 5.21; 95%CI:1.55 – 17.56), overall DFS (HR 0.20; 95%CI: 0.07–0.56; p=0.002), and local DFS (HR 0.15; 95%CI: 0.04–0.56; p=0.005). In a subgroup analysis of close (≥0.1mm and <5mm) vs. wide (≥5mm) negative resections, no significant differences in DSS, overall, and local, were observed.
Conclusion: Negative margins, irrespective of distance, are paramount for control and survival in oral minor salivary carcinoma. Therefore, a subsequent resection should be strongly considered in case of positive margins.