Stereotactic radiosurgery for facial nerve schwannomas: meta-analysis and clinical review.

Abstract

Although several small individual series on stereotactic radiosurgery (SRS) for facial nerve schwannomas (FNSs) have been published, we aim to systematically aggregate data from the literature as well as from our institution to better understand the safety and efficacy of SRS for FNS. PubMed English language search for keywords "facial nerve schwannoma" AND "radiation therapy" published from January 1995 to 2014. Data from our institution were also included in the analysis. Minimum study inclusion criteria included tumor treatment outcomes yielding 10 studies in the literature. In addition, our institution's data on six patients were included. Data included radiation treatment type, radiation dose, tumor size, tumor control, tumor control definition, FN function, hearing outcome, and duration of follow-up. In total, there were 45 patients with at least 2-year follow-up. Forty-two patients (93.3%) had tumor control. Of those patients with described growth/shrinkage definitions, 50.0% had no growth, 43.3% had shrinkage, and 6.7% had growth. Of those articles that included FN functional outcomes, 26 patients (66.6%) had stable FN function, 8 (20.5%) had improved function, and 5 (12.8%) had worsened FN function after treatment. In total, there were 30 patients whose hearing outcomes were discussed in the literature. Of those with serviceable hearing before SRS (n = 14), nine (64.3%) had stable hearing and five (36.7%) had worsened function after SRS. The mean posttreatment follow-up period was 42.1 months. SRS seems to be effective at either stabilizing or shrinking FNS. However, significant morbidities of FN paralysis hearing loss do exist.