Advancing Education, Research, and Quality of Care for the Head and Neck oncology patient.
Background: Positive surgical margins (PSM) in primary surgery for oral cavity cancer (OCC) represent an independent risk factor for recurrence and survival. Facility volume may influence PSM rates and overall survival, particularly in early-stage (ES) OCC, where surgical quality is most impactful. With more early-onset OCC (EO-OCC, age ≤50 years) patients diagnosed each year, the impact on person-years lost may be significant. This study aimed to evaluate PSM incidence and overall survival (OS) among all OCC, ES-OCC, and EO-OCC patients treated at facilities with varying surgical volumes.
Methods: We conducted a retrospective cohort study of OCC patients treated with primary surgery from the National Cancer Database (NCDB) between January 2004 and December 2021. Facilities were categorized into high-volume centers (HVC) (N=133), medium-volume centers (MVC) (N=538), and low-volume centers (LVC) (N=651), with volume calculated based on total annual cases divided by years a facility reported cases. Facilities below the 50th percentile were categorized as low-volume, while those above the 90th percentile were high-volume. Multivariate logistic regression models were used to assess PSM predictors, stratified by facility volume and disease stage. Cox proportional hazard models evaluated survival outcomes.
Results: The analysis included 63,372 patients, with a mean age of 63 years (SD 14); most were male (58%) and non-Hispanic white (80%). The majority lived within 50 miles of their treatment center (78%), had negative surgical margins (89%), were diagnosed at an early disease stage (54%), and received care at an HVC (68%). EO-OCC patients represented 18% of the cohort (n=11,396). The average annual case volume cutoffs for LVC and HVC were three and eighteen, respectively. Overall, 11% of patients had PSM, with a significantly lower incidence at HVCs (9.6%) compared to LVCs (15%, p < 0.001). In the ES-OCC group, receiving treatment at a LVC was associated with a worse OS (HR = 1.41, CI: 1.29 – 1.54, p<0.001), and had a similar impact on OS as PSM (HR = 1.66, CI: 1.55 – 1.78, p<0.001) and CDCC index of 3 (HR = 1.80, CI: 1.60 – 2.02, p = <0.001) in multivariate analysis. EO/ES-OCC patients treated at LVCs had lower 5-year survival compared to those at HVCs (83.6% vs. 90%, p = 0.0002). In this subgroup, a positive surgical margin increased the hazard of death regardless of surgical volume (HR = 1.31, 95% CI: 0.59–2.87, p = 0.508).
Conclusions: LVC are associated with higher rates of PSMs in ES-OCC and ES/EO-OCC, which correlate with worse survival outcomes. Treatment at LVC imparts a nearly equivalent risk to survival as PSMs and extensive comorbidity. The effect of PSMs on OS did not vary between LVCs and HVCs, potentially as a result of salvage in HVCs. Enhancing surgical expertise and resource allocation in LVC may reduce PSM rates and improve survival for OCC patients.