Facility Volume and Changing Facilities for Postoperative Radiotherapy in Salivary Gland Cancer.

ABSTRACT

OBJECTIVES: Changing location of postoperative radiotherapy (PORT) after treatment at a high-volume facility (HVF) is associated with worse survival in various head and neck cancers. Our study investigates this relationship in salivary gland cancer (SGC). METHODS: The 2004-2016 National Cancer Database was queried for all cases of adult SGC treated with surgery and PORT with or without adjuvant chemotherapy. Patients with multiple cancer diagnoses, metastatic disease, or unknown PORT facility were excluded. Reporting facilities with >95th percentile annual case volume were classified as HVFs, the remainder were classified low-volume facilities (LVFs). RESULTS: A total of 7885 patients met inclusion criteria, of which 418 (5.3%) were treated at an HVF. Patients treated at an HVF had higher rates clinical nodal positivity (18.2% vs. 14.0%, p < 0.001) and clinical T3/T4 (27.3% vs. 20.7%, p = 0.001) disease. Patients at HVFs changed facility for PORT at lower rates (18.9% vs. 24.5%, p = 0.009). Patients treated at an HVF had higher 5-year overall survival (5-OS) than those treated at an LVF (79.0% vs. 72.0%, p = 0.042). Patients treated at an HVF that changed PORT facility had worse 5-OS (60.8% vs. 83.2%, p < 0.001). Radiation facility change was an independent predictor of worse survival in patients treated at an HVF (HR 8.99 [3.15-25.67], p < 0.001) but not for patients treated at a LVF (HR 1.11 [0.98-1.25], p = 0.109). CONCLUSIONS: Patients treated at an HVF changing facility for PORT for SGC experience worse survival. Our data suggest patients treated surgically at an HVF should be counseled to continue their PORT at the same institution. LEVEL OF EVIDENCE 3 Laryngoscope, 2024.