Contemporary treatment patterns and outcomes of salivary gland carcinoma: a National Cancer Database review

Purpose: Salivary gland carcinomas (SGC) are rare malignancies and data regarding treatment outcomes stratified by histologic subtype are currently limited. This study aims to examine current, national treatment patterns and overall survival (OS) of patients with the major histologic subtypes of salivary gland carcinoma. Subjects and methods: A review was performed of the National Cancer Database (NCDB) of patients with confirmed diagnoses of mucoepidermoid carcinoma, acinic cell carcinoma, adenoid cystic carcinoma, adenocarcinoma, or carcinoma ex pleomorphic receiving curative treatment between 2004 and 2014. Univariate and multivariate regression modeling were performed to identify risk factors significantly associated with overall survival (OS). Adjusted survival analyses stratified by treatment and staging were performed with the primary outcome of overall survival (OS) and were further stratified based on histologic subtype. Results: The final analysis included 7342 patients [3547 men (48.3%) and 3795 women (51.7%); mean age 58.3 years (range 18–90 years)]. Mucoepidermoid carcinoma was the most common histology encountered [n = 2669 (36.4%)]. Unadjusted and adjusted analysis demonstrated improved survival with surgery and radiation therapy (RT) for adenoid cystic (HR = 0.69; p = 0.029), adenocarcinoma (HR = 0.61; p < 0.001), high-grade mucoepidermoid carcinoma (HR = 0.70; p = 0.026), and carcinoma ex pleomorphic (HR = 0.64; p = 0.028), while surgery with chemoradiation therapy (CRT) was associated with worse OS regardless of histologic subtype. The impact of advanced stage on survival varied amongst the histologic subtypes but portended the worst prognosis for patients with adenocarcinoma and carcinoma ex pleomorphic. Conclusions: The results of this NCDB review demonstrate unique treatment patterns and survival outcomes for SGC based on major histologic subtype.