The Long-Term Outcome of Cyberknife Therapy for Head and Neck Paraganglioma: Management Suggestion From a Single Center Experience

IntroductionTo analyze the long-term follow-up data of CyberKnife treatment (CKT) for head and neck paragangliomas (HNPGs). MethodsPatients who received CKT to HNPGs from 2010 to 2019 were retrospectively reviewed. ResultsA total of 34 HNPGs from 29 patients were identified. The mean age was 50 (± 16) years old, and 15 patients (52%) were female. Previous operation was done in 15 patients (55%). Four cases (14%) were functional in hormone production. According to Fisch classification, one case (3%) was B, 12 (42%) were C, 14 (48%) were D, and two cases (7%) were out of classification. The median prescribed dose covered 95% of the planning target volume was 2500 (IQR 2100 – 2600) cGy and the median target volume was 10 (IQR 5.8 – 21.3) cm3. The local control rate was 97%. The median progression-free survival was 66 (IQR 27.5 – 95.0) months and 93.8%, and 91.7% were free of tumor progression at five, and seven years respectively. During the follow-up, one case (3%) resulted in permanent facial nerve palsy (CTCAE 1, House-Brackmann grade II), and another case (3%) resulted in asymptomatic cerebellar radiation necrosis. Univariate and multivariate analysis showed no previous surgical history (OR 10.3, 95% CI 1.5 – 69.3, p = 0.02) was a positive predictor of symptom improvement. We devised a treatment flow-chart based on our finding. ConclusionsCKT for HNPGs was an effective treatment with little side effect over the long term and should be considered the first-line therapy for symptomatic nonfunctional HNPGs for better symptom control.