Postoperative Radiotherapy in Advanced Stage Squamous Cell Carcinoma Requiring Maxillectomy

ObjectiveTo evaluate whether postoperative radiotherapy (PORT) improves survival among patients who received maxillectomy for pT4aN0 maxillary gingival or hard palate squamous cell carcinoma (SCC) with respect to tumor size. Study DesignRetrospective analysis. SettingNational Cancer Database from 2004 to 2019. MethodsIncluded adult patients who received maxillectomy (partial, subtotal, or total) and neck dissection for treatment-naive margin negative pT4aN0 SCC of the maxillary gingiva or hard palate. Adjusted for age, gender, race, insurance status, income, education, urban/rural, facility type, region, comorbidity index, tumor grade, and tumor extension. Inverse probability weights were incorporated into a multivariable Cox proportional hazards model. A priori post hoc subgroup analysis was performed according to tumor size. ResultsWe included 416 patients who underwent maxillectomy for pT4aN0 SCC of the maxillary gingiva or hard palate (mean [standard deviation] age, 71.5 [11.3] years; male, 190 [45.7%]; tumor size 2 cm, 362 [87%]). Overall, 49.3% of patients received PORT (205 patients). PORT was associated with a 50% improvement in survival compared to surgery alone (adjusted hazard ratio [aHR], 0.50; 95% confidence interval [95% CI], 0.32-0.81). On subgroup analysis, PORT was associated with improved survival for tumors 2 cm (aHR, 0.47; 95% CI, 0.29-0.77), but not for tumors < 2 cm (aHR, 1.15; 95% CI, 0.33-4.08). ConclusionThe vast majority of patients with pT4aN0 bone-invading SCC of the maxillary gingiva and hard palate benefit from PORT. Patients with tumors < 2 cm did not demonstrate a survival benefit from adjuvant treatment, suggesting that bony invasion alone may not be sufficient criteria for treatment escalation.