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

Background: Alveolar ridge squamous cell carcinoma (ARSCC) is poorly represented in randomized trials.

Methods: 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.

Results: 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.

Conclusion: PORT for resected ARSCC with adverse pathologic features is associated with significantly improved OS.