Postoperative Radiotherapy in Advanced Stage Squamous Cell Carcinoma Requiring Maxillectomy

Abstract

Objective: To 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 Design: Retrospective analysis. Setting: National Cancer Database from 2004 to 2019. Methods: Included 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. Results: We 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). Conclusion: The 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.