A review of treatment modalities for vestibular schwannoma

Vestibular schwannomas are benign intracranial tumors arising from the vestibular nerve. Treatment options include observation, stereotactic radiosurgery, fractionated radiotherapy, and microsurgery. We review the evidence describing efficacy and side-effect profiles of each of these modalities. This was accomplished by outlining the results of published meta-analyses and performing a systematic search of the literature for individual studies published between 2004 and June 2009. Without intervention, 29-54% of tumors will grow and 16-26% of patients require additional treatment, with 54-63% preserving functional hearing. With radiosurgery, only 2-4% require additional treatment and hearing preservation is accomplished in 44-66% of cases. Reviewing contemporary studies, it appears that reduced marginal doses may have decreased morbidity risks associated with radiosurgery without sacrificing efficacy. With fractionated radiotherapy, 3-7% will require additional treatment and hearing preservation is reported at 59-94% of patients, although long-term outcomes are not known. Microsurgery is an alternative for eligible patients, with fewer than 2% requiring additional treatment; however, the risk of hearing loss, facial neuropathy, and other morbidities is relatively high. There are significant limitations with comparing the efficacy and morbidity rates across interventions because of selection bias and confounding factors. Additional prospective comparative trials and randomized studies are needed to improve our understanding of the relative benefits of each modality.