Adoption of adjuvant chemotherapy in high-risk salivary gland malignancies.

Background: The present study characterizes national trends in the utilization of adjuvant chemotherapy to treat salivary gland malignancies.

Methods: The National Cancer Database was queried for salivary gland malignancies treated by surgery with radiation in 2004-2019. Proportions of patients receiving adjuvant chemotherapy over the study period were analyzed by linear regression. The impact of chemotherapy on overall survival was assessed using Kaplan-Meier and Cox proportional hazards analyses.

Results: Among 15 965 patients meeting inclusion criteria, 2355 (14.8%) received adjuvant chemotherapy. Chemotherapy utilization significantly increased from 4.9% to 16.5% over the study period (p < 0.001). No survival benefit was observed with adjuvant chemotherapy on propensity score-matched Kaplan-Meier analysis (HR: 0.98; 95% CI: 0.86-1.11; p = 0.72) or multivariable Cox regression (HR: 0.92; 95% CI: 0.78-1.09; p = 0.34).

Conclusions: Adjuvant chemotherapy has been increasingly utilized to treat salivary gland malignancies in recent years. Our findings highlight the importance of obtaining high-quality prospective data regarding the benefit of chemotherapy.