A comparative analysis of sinonasal and salivary gland mucoepidermoid carcinoma using population-based data

Mucoepidermoid carcinoma (MEC) is the most common salivary gland (SG) malignancy. Primary sinonasal MEC (SN-MEC) is rare. This study analyzes the demographic, clinicopathologic, and survival characteristics of SN-MEC and establishes comparisons with primary major SG-MEC.

The Surveillance, Epidemiology, and End Results (SEER) database (1973 to 2010) was queried for SN-MEC (149 cases) and SG-MEC (4234 cases). Data were analyzed comparatively with respect to various demographic and clinicopathologic factors. Survival was analyzed using the Kaplan-Meier and Cox proportional hazards models.

Mean ± standard deviation (SD) age at diagnosis for SN-MEC was 58.6 ± 16.6 years. High histologic grade (ie, grades III and IV) at the time of diagnosis was more common among SN-MEC than SG-MEC (42.3% vs 25.5%, p < 0.0001). Overall 5-year disease-specific survival (DSS) was 61.7% for SN-MEC and 84.1% for SG-MEC (p < 0.001). For SN-MEC, factors associated with poor prognosis were age (75+ years; hazard ratio [HR], 3.38; 95% confidence interval [CI], 1.25 to 9.51), higher tumor grade (grade III and IV; HR, 3.62; 95% CI, 1.75 to 8.22), larger tumor size (>4 cm; HR, 8.36, 95% CI, 1.59 to 153.74), and primary tumor site (ethmoid sinus; HR, 2.95; 95% CI, 1.28 to 6.23) (all p < 0.05). Survival was better among those treated with surgery (with [64.4% survival] or without [81.3% survival] adjuvant radiation therapy) than those treated with primary radiation therapy alone (25.6% survival) (p < 0.05).

This report represents the largest series of SN-MEC to date. Although SN-MEC and SG-MEC share a common histology, there are important clinical differences between the 2 conditions.