Robotic radiosurgery for benign temporal bone paragangliomas: a single-center experience
PO-1202
Abstract
Robotic radiosurgery for benign temporal bone paragangliomas: a single-center experience
Authors: Sofia Ramos1, Sara Simões2, Osvaldo Carvalhosa2, Marina Amorim2, Catarina Silva3, Adelina Costa4, Guilherme Campos4, Graça Fonseca4, Miguel Carvalho4, Pedro Vieira4, Cármen Calçada5, Paulo Costa4
1Hospital de Braga, Radiation Oncology, Braga, Portugal; 2Hospital de Braga , Radiation Oncology , Braga , Portugal; 3Hospital de Braga , Radiation Oncology, Braga , Portugal; 4Júlio Teixeira SA - Instituto CUF , Radiation Oncology, Porto, Portugal; 5Júlio Teixeira SA - Instituto CUF , Radiation Oncology , Porto , Portugal
Show Affiliations
Hide Affiliations
Purpose or Objective
The aim of this study was to report the experience of a single center in the treatment of benign temporal bone paragangliomas with Robotic Stereotactic Radiosurgery.
Material and Methods
Between August 2017 and July 2021, 8 patients with benign temporal bone paragangliomas were treated with Cyberknife® Robotic Stereotactic Radiosurgery in the Department of Radiation Oncology Júlio Teixeira SA, CUF Institute – Oporto, Portugal. Main endpoints included clinical response, local tumor control, and adverse radiation effects. Tumor response was assessed according to RECIST criteria on follow-up MRI images, and toxicities were classified based on CTCAE scale version 5.0.
Results
7 patients with tympanojugular paragangliomas and 1 with tympanomastoid paraganglioma, were treated. The most common presenting symptoms were conductive hearing loss, followed by headache and hoarseness. Other symptoms reported were pulsatile tinnitus, left scapular contracture and left vocal cord paralysis. Half of the patients were diagnosed with recurrent tumors after surgery +/- embolization. The prescription dose ranged between 12 and 25Gy, delivered in 1 to 5 fractions (reference isodose 71 - 89%). The median treatment volume was 6.9 cc (range 0.84 – 39.21cc).
The median follow-up was 33 months (range 14 – 62). Regarding clinical outcomes, 4 patients showed improvement in pre-radiosurgery symptoms, 2 patients remained symptom-free, and 2 patients demonstrated neurological stability. All tumors revealed regression (n=5) or stable dimension (n=3) during follow-up MRI, with a local control rate of 100%. Treatment-related acute side effects included nausea grade ≤2 (3 patients), vomiting grade 2 (1 patient) and headache grade ≤2 (3 patients), that were easily manageable with conservative treatment. There were no grade 3 or 4 toxicities. There were no late side effects reported.
Conclusion
Robotic Stereotactic Radiosurgery seems to be a helpful therapeutic approach in the management of temporal bone paragangliomas, either after surgery and/or embolization recurrences or as a single and radical treatment, and may be a useful alternative to surgery in such cases. The location and shape of these tumors are a challenge in radiotherapy planning, and robotic stereotactic radiosurgery showed to be safe and effective in our series of patients. Additional follow-up and a larger patient population are required to confirm these favorable outcomes.