Hearing preservation after cyberknife stereotactic radiosurgery for vestibular schwannomas

Hearing preservation after cyberknife stereotactic radiosurgery for vestibular schwannomas: Shao-Wei Feng, Chih-Chuan Hsieh, Yun-Ju Yang, Yuan-Hao Chen, Chi-Tun Tang, Da-Tong Ju



Journal of Medical Sciences 2019 39(1):10-17



Background: The aim of this study is to evaluate retrospectively prognosis and auditory function after CyberKnife (CK) stereotactic radiosurgery (SRS) for vestibular schwannomas (VS) and to determine the radiation effects on hearing loss/preservation. Materials and Methods: The records of forty-one41 patients (24 males, 17 females) with VS who had received CK-SRS treatment were enrolled and retrospectively analyzsed. All patients underwent SRS (18 Gy in 3 sessions) between 2007 and 2012 at Tri-Service General Hospital, Taipei, Taiwan. Audiograms had been obtained before and after radiosurgery, and magnetic resonance imagingMRI and computed tomographyCT had been repeated to evaluate the tumour control rate. Age, percent tumour coverage, conformality index, new conformality index, cochlear dose, and audiometric test results were collected and analyzsed for all patients. Results: There were 41 patients enrolled in this study. The mean follow-up period of imaging studies was 56.6 ± 15.5 mo. At the postoperative assessment, there are 13 patients (76%) of Gardner–Robertson (GR) hearing maintained in Grade I and four4 patients (23%) of GR hearing changed to Grade II within those levels after treatment. There are 15 patients (62%) of GR hearing had been maintained in Grade II, and 9 patients (37%) of GR hearing changed to Ggrade I within those levels after treatment. After CK-SRS radiotherapy, 22 patients (22/41, 53%) had GR Ggrade I hearing, and 19 patients (19/41, 46%) had GR Ggrade II hearing. The patients with hearing deterioration had larger tumour volumes, lower cochlear volumes, higher cochlear radiation doses, and poorer hearing beforeprior to radiosurgery. Conclusions: Excellent tumour control and hearing preservation rates were observed for VS patients treated by CK SRS, with rates consistent with those reported in the literature. Compared with therapeutic alternatives, CK SRS is an effective tool for VS treatment and preserves hearing well.