Outcomes and Prognostic Factors in Acinic Cell Carcinoma of the Parotid Gland: Mature Results From a Single Institution

Abstract

<h3>Purpose/Objective(s)</h3> Acinic cell carcinoma is a rare subtype of salivary gland cancer, with little published data on management or survival outcomes. We aimed to describe a cohort of patients from a single institution, and to identify factors that impacted oncologic outcomes. <h3>Materials/Methods</h3> We retrospectively identified patients with acinic cell carcinoma who received treatment at our tertiary referral center. Demographic, tumor, and treatment data were collected. Locoregional control (LRC), relapse free survival (RFS), and overall survival (OS) were estimated using the Kaplan Meier method. A multivariate analysis explored the association between demographics, tumor characteristics, and receipt of postoperative radiation therapy (PORT) in non-metastatic patients with oncologic outcomes using a stepwise Cox proportional hazards model. <h3>Results</h3> Between 1/1/1984 and 12/31/2019 65 eligible patients were identified. Patient characteristics are described in Table 1. All patients had disease originating within the parotid gland, and two patients were metastatic at presentation. The majority of patients received upfront surgical resection, with 79% receiving PORT. With a median follow up of 11.7 years, the 5-year OS, LRC, and RFS estimates were 85%, 71%, and 63%, respectively. 15 patients ultimately received palliative systemic therapy. In a multivariate analysis excluding those metastatic at presentation, age at diagnosis and nodal status were associated with OS, LRC, and RFS. PORT was not associated with survival outcomes on multivariate analysis. <h3>Conclusion</h3> Acinic cell patients receiving treatment at a single tertiary referral center demonstrate excellent five-year survival outcomes. With long term follow up, only age at diagnosis and nodal status were associated with survival outcomes. Further work is necessary to assess generalizability of these results.