Retrospective database analysis of survival impact of radiotherapy after mandibulectomy for oral cavity squamous cell carcinoma

Retrospective analysis of the National Cancer Database evaluated the survival benefit with postoperative radiotherapy (PORT) among patients undergoing mandibulectomy for newly diagnosed pT4aN0 oral cavity squamous cell carcinoma (OCSCC) with mandibular invasion. Among 3268 patients between 2004 and 2019, 56.6% received PORT and 43.4% no PORT. PORT was associated with improved overall survival, and this relative survival benefit tended to improve with increasing tumor size: among patients with tumors greater than 4 cm, the OS aHR in favor of PORT was 0.63 (95% CI 0.48-0.82); among patients with tumors 2-4 cm the aHR was 0.76 (0.62-0.93); and among patients with tumors less than 2 cm the aHR was 0.81 (0.57-1.15). The authors conclude that tumor size should be considered in guidelines for PORT administration in the setting of OCSCC requiring mandibulectomy.