Salivary Gland Cancers of the Nasopharynx: A Population-Based Analysis of 383 Cases

Objectives/Hypothesis: Salivary gland nasopharynx cancers (SGNPCs) are rare malignancies with few cases discussed in the literature. This study represents the largest cohort of SGNPC to date. Study Design: Retrospective population-based analysis. Methods: The Surveillance, Epidemiology, and End Results registry from 1973 to 2015 was utilized to extract 383 cases of SGNPC. Data were analyzed for demographic characteristics, incidence, clinicopathologic traits, and outcome prognosticators. Results: White female patients aged >40 years were most commonly affected. The incidence was measured as 0.019 per 100,000 people. The majority of tumors presented at advanced stages (stage III/IV, 60.8%). Adenoid cystic carcinoma, adenocarcinoma, and mucoepidermoid carcinoma were the most commonly encountered histologies (43.1%, 31.6%, 13.3%, respectively). Cervical node involvement and distant metastasis were measured at 23% and 11.9%, respectively. Mucoepidermoid carcinomas presented with the best disease-specific survival at 5 and 10 years. Asian ethnicity, age <80 years, and earlier American Joint Committee on Cancer stages were positive prognostic factors. The inclusion of surgical therapy improved 5-year outcomes among the most common histologies, except for mucoepidermoid carcinoma. Conclusions: Salivary gland nasopharyngeal cancer represents a group of rare histologies with similar outcomes as squamous cell carcinomas. However, prognosis is primarily dependent on histologic subtype, race, age, and American Joint Committee on Cancer stage.