Hearing Preservation for Vestibular Schwannomas Treated with Stereotactic Radiosurgery or Fractionated Stereotactic Radiotherapy Methma Udawatta 1,7 , Isabelle Kwan 1 , Komal Preet 1,7 , Thien Nguyen 1,7 , Vera Ong 1 , John P. Sheppard 1,7 , Courtney Duong 1 , Prasanth Romiyo 1 , Percy Lee 2 , Stephen Tenn 2 , Tania Kaprealian 1,2,4 , Quinton Gopen 3 , Isaac Yang 1-7 - BACKGROUND: Vestibular schwannomas (VS) are benign intracranial neoplasms arising from the eighth cranial nerve for which targeted radiation therapy (RT) has proved increasingly successful. However, long-term hear- ing and related cranial nerve outcomes have been disputed for the 3 current RT modalities. - OBJECTIVE: To determine differences in hearing pres- ervation for patients treated with stereotactic radio- surgery (SRS), fractionated stereotactic radiotherapy (FSRT), or hypofractionated stereotactic radiotherapy (hypoFSRT) for VS. - METHODS: A retrospective electronic chart review was conducted for all patients with unilateral VS treated with primary RT at a single academic medical center between 2000 and 2017. The primary outcome measure was preser- vation of serviceable hearing status in the affected ear at last follow-up. Secondary outcomes included tinnitus, vertigo, and imbalance. - RESULTS: A total of 33 FSRT cases, 21 SRS cases, and 6 hypoFSRT cases were identified. Postoperative dete- rioration in serviceable hearing and tinnitus showed significant differences across cohorts. The SRS cohort had a higher baseline incidence of nonserviceable hearing and disequilibrium compared with other cohorts before RT (P [ 0.001 and 0.022, respectively); no dif- ferences in baseline morbidity were observed for vertigo and tinnitus. The 5-year tumor control rate was 95.2%, 93.9%, and 100% with SRS, FSRT, and hypoFSRT, respectively. - CONCLUSIONS: Our series indicated an excellent tumor control rate in all the modalities. Our SRS cohort showed increased incidence and shorter time to hearing deterio- ration compared with the FSRT and hypoFSRT cohorts. The FSRT and hypoFSRT cohorts have shown comparable overall outcomes. Onset of post-RT tinnitus was observed only with FSRT. INTRODUCTION V estibular schwannomas (VS), benign intracranial tumors of the eighth cranial nerve, have an average incidence rate of 1.09 per 100,000 individuals and account for around 90% of all intracranial neuromas at the cerebellopontine angle. 1,2 Common clinical presentations of VS include sensorineural hearing loss, neuralgia, facial spasms, tinnitus, vertigo, and disequilibrium, corresponding to disturbances in the acoustic, vestibular, trigeminal, and facial nerves. 3-5 Depending on the tu- mor size, shape, location, and progression and the patient’s medical history, VS can be managed through 3 main approaches: observation with magnetic resonance imaging (MRI) and audio- metric evaluation, microsurgery (MS), and radiologic treatments. 6,7 Key words - Fractionated stereotactic radiotherapy - Hypofractionated stereotactic radiotherapy - Stereotactic radiosurgery - Vestibular schwannoma Abbreviations and Acronyms FSRT : Fractionated stereotactic radiotherapy FU: Follow-up hypoFSRT : Hypofractionated stereotactic radiotherapy MRI: Magnetic resonance imaging MS: Microsurgery PFS: Progression-free survival SD: Standard deviation SRS: Stereotactic radiosurgery VS: Vestibular schwannoma From the 1 Departments of Neurosurgery, 2 Radiation Oncology, and 3 Head and Neck Surgery, 4 Jonsson Comprehensive Cancer Center, 5 Los Angeles Biomedical Research Institute, 6 Harbor-UCLA Medical Center, and 7 David Geffen School of Medicine, University of California, Los Angeles, California, United States To whom correspondence should be addressed: Isaac Yang, M.D. [E-mail: iyang@mednet.ucla.edu] Citation: World Neurosurg. (2019) 129:e303-e310. https://doi.org/10.1016/j.wneu.2019.05.133 Journal homepage: www.journals.elsevier.com/world-neurosurgery Available online: www.sciencedirect.com 1878-8750/$ - see front matter ª 2019 Published by Elsevier Inc. WORLD NEUROSURGERY 129: e303-e310, SEPTEMBER 2019 www.journals.elsevier.com/world-neurosurgery e303 Original Article