Survival Impact of Elective Neck Dissection and Adjuvant Radiation in N0 High-Grade Mucoepidermoid Carcinoma.

Abstract

We aim to evaluate the role of elective neck dissection (END) and adjuvant radiation on survival in N0 high-grade mucoepidermoid carcinoma (MEC). Retrospective cohort study. National Cancer Institute's Surveillance, Epidemiology, and End Results (SEER) database. All patients diagnosed with high-grade MEC with node-negative disease (N0) from 2004 to 2018 were included. Demographic, clinicopathologic, treatment, and outcomes were analyzed. Kaplan-Meier survival curves were used to evaluate 5-year disease-specific survival (DSS) and 5-year overall survival (OS). Multivariate Cox regression analysis was used to control for confounders. A total of 310 patients with high-grade MEC and N0 (clinical and pathologic) disease were identified. The parotid was the most common primary site (266, 86%). Of included patients, 133 (42.9%) were T3-T4 tumors and 212 (68%) received adjuvant radiation. END was performed on 223 (71.9%) of cases. END in T3-T4 high-grade MEC led to significant improvements in DSS (74.3% vs 34.0%, P < .01) and OS (55.2% vs 20.5%, P < .01) as compared to no END. Subanalysis shows that in patients who received neck dissections and were pathologic N0, adjuvant radiation had no impact on DSS (84.0% vs 72.1%, P = .45) and OS (52.1% vs 55.8%, P = .91). Benefits persisted when controlling for confounders using multivariate Cox proportional regression. Patients with T3-T4 high-grade MEC who underwent END and found to be pathologically node-negative (pN0) had significantly improved 5-year DSS and 5-year OS than patients who were cN0 and did not undergo END. Importantly, although 68% of patients received adjuvant radiation, we show no benefit of this treatment modality on outcomes in pN0 high-grade MEC.