Definitive Local Therapy in cM1 Major Salivary Gland Cancer.

Abstract

To investigate the impact of surgical resection and radiotherapy on overall survival (OS) in clinically distantly metastatic (cM1) major salivary gland cancer (MSGC). Retrospective cohort study. The 2006 to 2020 hospital-based National Cancer Database. The 2006 to 2020 National Cancer Database was queried for patients with cM1 MSGC undergoing chemotherapy. Kaplan-Meier and Cox proportional hazards regression models were implemented. Of 700 patients satisfying inclusion criteria, 219 (37.8%) underwent chemotherapy alone (ie, no local therapy), 159 (27.4%) underwent low-dose chemoradiotherapy (CRT), 56 (9.7%) underwent high-dose CRT, 47 (8.1%) underwent surgical resection + chemotherapy, 47 (8.1%) underwent surgical resection + low-dose CRT, and 52 (9.0%) underwent surgical resection + high-dose CRT; 5-year OS was 10%, 12%, 34%, 25%, 23%, and 28%, respectively (P < .001). Patients undergoing surgical resection underwent high-dose radiotherapy more frequently (N = 53, 36.1% vs N = 56, 12.9%) but multiple-agent chemotherapy less frequently (N = 105, 62.5% vs N = 363, 75.3%) than those not undergoing surgical resection (P < .005). Compared with chemotherapy alone, surgical resection + chemotherapy (aHR 0.67, 95% confidence interval [CI] 0.53-0.86), high-dose CRT (aHR 0.55, 95% CI 0.41-0.73), and immunotherapy (aHR 0.49, 95% CI 0.35-0.69) were associated with higher OS on multivariable Cox regression (P < .01). A minority of patients with cM1 MSGC underwent surgical resection or high-dose CRT. Despite the high rate of PSM, surgical resection was associated with higher OS than chemotherapy alone. High-dose CRT was associated with the highest OS. Definitive local therapy may benefit select patients with cM1 MSGC. IV.