Hospital-level variation in resection margins after oral cavity cancer surgery and associated survival outcomes.

The main goal of surgery for oral squamous cell carcinoma (OSCC) is to obtain adequate resection margins as inadequate margins are associated with a worse prognosis and treatment intensification. However, reported rates of inadequate resections vary from 30%-85%. Clinical auditing is an upcoming tool to improve margin status. This study investigates resection margins after OSCC surgery and differences in hospital results, disease-free, and overall survival for <1 and ≤5 mm cut-offs. This Dutch nationwide registry-based cohort study includes all patients who underwent surgery for first primary OSCC between 2018 and 2021. Resection margins were categorised as <1, 1-5, and >5 mm. Hospital variation was visualised in funnel plots and corrected for case-mix and treatment variables. Two-year overall and disease-free survival were determined. A total of 2,085 patients from 14 hospitals could be included for analysis. Nationally, margins <1 mm were present in 16.4% which varied from 6.5%-31.6% at hospital level. For margins ≤5 mm, the national average was 61.3%, with hospital outcomes ranging from 50.0%-78.6%. Significant outliers remained after correction for case-mix and treatment variables. Two year overall and disease-free survival was worse in the <1 mm group. Obtaining negative or adequate margins during the resection of invasive OSCC is challenging. Significant hospital differences in resection margin outcomes remained after correction for case-mix characteristics. By identifying best practices in OSCC, surgical and survival outcomes can be improved.