Management of NF2-associated vestibular schwannomas in children and young adults: influence of surgery and clinical factors on tumor volume and growth rate

Abstract

<jats:sec><jats:title>OBJECTIVE</jats:title><jats:p>The authors’ aim was to evaluate the tumor volume and growth rate of neurofibromatosis type 2 (NF2)–associated vestibular schwannomas (VSs) and the clinical factors or type of mutations before and after surgery in children and adults younger than 25 years at the time of diagnosis.</jats:p></jats:sec><jats:sec><jats:title>METHODS</jats:title><jats:p>A total of 579 volumetric measurements were performed in 46 operated tumors in 28 NF2 patients, using thin-slice (&lt; 3 mm) T1-weighted contrast-enhanced MRI. The follow-up period ranged from 21 to 167 months (mean 75 months). Growth rate was calculated using a multilinear regression model. Mutation analysis of the <jats:italic>NF2</jats:italic> gene was performed in 25 patients.</jats:p></jats:sec><jats:sec><jats:title>RESULTS</jats:title><jats:p>Surgery significantly (p = 0.013) slowed the VS growth rate from 0.69 ± 1.30 cm<jats:sup>3</jats:sup>/yr to 0.23 ± 0.42 cm<jats:sup>3</jats:sup>/yr. Factors significantly associated with a higher growth rate of VSs were increasing patient age (p &lt; 0.0005), tumor volume (p = 0.006), tumor size (p = 0.001), and constitutional truncating mutations in the <jats:italic>NF2</jats:italic> gene (p = 0.018). VS growth rates tended to be higher in patients with spinal ependymomas and in right-sided tumors and lower in the presence of peripheral schwannomas; however, no statistical significance was achieved.</jats:p></jats:sec><jats:sec><jats:title>CONCLUSIONS</jats:title><jats:p>Decompression of the internal auditory canal with various degrees of tumor resection decreases the postoperative tumor growth rate in children and young adults with NF2-associated VS. Patients with potential risk factors for accelerated growth (e.g., large volume, truncating mutations) and with increasing age should be monitored more closely before and after surgery.</jats:p></jats:sec>

Contribution of mTOR and PTEN to Radioresistance in Sporadic and NF2-Associated Vestibular Schwannomas: A Microarray and Pathway Analysis

“…Even though they are slow growing tumors, VS can cause hearing loss, tinnitus, dizziness, facial palsy, and, if large enough, hydrocephalus and death [1,3,4]. Established treatment options are microsurgery [6,7], radiation treatment [8,9], or, for patients with NF2-associated VS, systemic therapy (e.g., with bevacizumab) [10,11]. Particularly in young patients with NF2, good short-to-medium-term hearing results and growth control can be achieved by electrophysiological-guided microsurgery [7,12].…”

Minimal Effect of Bevacizumab Treatment on Residual Vestibular Schwannomas after Partial Resection in Young Neurofibromatosis Type 2 Patients

“…Indications for surgery as previously described [6] were: 1) large tumors (T4, Hannover Classification System [18]) on both sides with brainstem compression, and 2) continuing tumor growth and deterioration of brainstem auditory evoked potentials (BAEPs) and/or impairment of pure-tone audiometry and/or speech discrimination score (SDS).…”

“…Clinical and radiological follow-ups were routinely performed every 3 to 6 months. Tumor volumetry, growth rate and resection amount were performed, classified and calculated in 284 data sets as previously described [6]. Patients with hearing aids or implants (e.g., cochlear or auditory brainstem implant) were excluded.…”

“…Radical microsurgery with total tumor removal carries a high risk of hearing loss and facial palsy. By contrast, partial resection aiming at the decompression of the internal auditory canals in young NF2 patients provides a more conservative option with improved growth control and hearing stabilization [6,7]. However, the risk of continuing growth of the residual tumor and hearing deterioration remains.…”

Managing NF2-associated vestibular schwannomas in children and young adults: review of an institutional series regarding effects of surgery and bevacizumab on growth rates, tumor volume, and hearing quality

“…This review paper summarizes our institutional experience with adolescents and young adults with NF2 regarding the VS management, aiming at preservation of a functional hearing as long as possible. We related to and condense the results of three original publications on the topics of growth rate [24], effects of surgery on hearing [25], and effects of second line bevacizumab [26] into one review, to create a comprehensive overview on the topic for the reader. We discuss the results in the light of the recent literature.…”