Postoperative radiotherapy is associated with improved overall survival for alveolar ridge squamous cell carcinoma with adverse pathologic features.

Abstract

Alveolar ridge squamous cell carcinoma (ARSCC) is poorly represented in randomized trials. Adults in the National Cancer Database diagnosed with ARSCC between 2010 and 2014 who should be considered for postoperative radiotherapy (PORT) based on National Comprehensive Cancer Network (NCCN)-defined risk factors were identified. Eight hundred forty-five (58%) of 1457 patients meeting the inclusion criteria received PORT. PORT was associated with improved overall survival (OS) on unadjusted (hazard ratio [HR] 0.83, 95% confidence interval [CI] 0.70-0.98, P = .02) and multivariable (HR 0.78, 95% CI 0.64-0.94, P = .002) analyses. PORT was associated with significantly improved 5-year OS for patients with 1 (68% vs 58%, P < .001), 2 (52% vs 31%, P < .001), and ≥3 (38% vs 24%, P < .001) NCCN-defined risk factors. Prognostic variables significantly associated with worse OS on multivariable analysis included advanced age, primary tumor size ≥3 cm, high grade, positive margin(s), stage N2-3, level IV/V nodal metastasis, and extranodal extension. PORT for resected ARSCC with adverse pathologic features is associated with significantly improved OS.