The Long-Term Outcome of CyberKnife-Based Stereotactic Radiotherapy for Head and Neck Paragangliomas: A Single-Center Experience.

Objective To assess long-term outcomes of hypofractionated stereotactic radiotherapy (hSRT) for head and neck paragangliomas (HNPGs). Methods Patients who underwent hSRT with CyberKnife for HNPGs from 2010 to 2019 were retrospectively reviewed. Results A total of 34 HNPGs in 29 patients were identified. Mean patient age was 50 ± 16 years, and 15 patients (52%) were female. Fifteen patients (55%) had undergone previous procedures. Four cases (14%) were functional in hormone production. According to the Fisch classification, 1 (3%) case was B, 12 (42%) cases were C, 14 (48%) cases were D, and 2 (7%) cases were unclassified. 1 The median prescribed dose covering 95% of the planning target volume was 2500 cGy (interquartile range 2100–2600 cGy), and the median target volume was 10 cm3 (interquartile range 6.0–18.3 cm3). The local control rate was 97%. The median progression-free survival was 66 months (interquartile range 28–95 months), and 96% of patients were free of tumor progression at 8 years. During follow-up, 1 case (3%) resulted in permanent facial nerve palsy (House-Brackmann grade II), and another case (3%) resulted in asymptomatic cerebellar radiation necrosis. Univariate and multivariate analysis showed that no previous surgical history (odds ratio 8.58, 95% confidence interval 1.2–59.7, P = 0.03) was a positive predictor of symptomatic improvement. Conclusions hSRT for HNPGs was an effective treatment with minimal side effects over the long term and may have a role as first-line therapy, especially for symptomatic nonfunctional HNPGs, for better symptom control.