A multi-institutional analysis of outcomes following stereotactic body radiation therapy for management of metastases from squamous cell carcinomas of the head and neck
Raj Singh, Jan Jenkins, Joanne Davis, Shiyu Song, Sanjeev Sharma and John Austin Vargo
Background: There is limited data on clinical outcomes following SBRT for patients with metastatic head and neck squamous cell carcinoma (mHNC).
Method: An international SBRT registry was utilized to identify patients. LC and OS were evaluated with the Kaplan-Meier method and a Cox-proportional hazards model for multivariate analysis (MVA) to assess potential prognostic factors.
Results: We identified 81 patients with 98 lesions treated with SBRT. Areas treated included the lung (53.0%), non-regional lymph nodes (16.0%), and spine (12.3%). OS rates at 1 year and 2 years were 66.4% and 43.1%, respectively. Utilizing KPS, spinal disease, and GTV, 1-year OS estimates were 90.9%, 70.4%, 54.5%, and 25% for patients with 0-3 of these factors, respectively (p = 0.002). One-year and 2-year LC rates were both 93.3%. Roughly 17% of patients reported toxicities (none Grade 3+).
Conclusion: SBRT resulted in promising LC for mHNC patients. Spinal disease, GTV, and KPS should be considered in selecting patients with mHNC that may benefit from SBRT.
Keywords: Stereotactic body radiation therapy, ablation, oligometastasis, registry, overall survival, local control