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PurposeThe aim of this study is to evaluate long-term treatment outcome and toxicities among vestibular schwannoma (VS) patients treated with hypofractionated stereotactic radiotherapy (HSRT).Methods383 patients with unilateral VS treated with HSRT (25 Gy, five fractions) between 1995 and 2007 were retrospectively reviewed. Treatment failure was defined as requiring salvage microsurgery. Posttreatment new/progressive clinical symptoms or increases in baseline tumor volume (BTV) due to treatment effect or progression were noted. Symptom outcomes were reported as baseline and posttreatment ± improvement, respectively. Symptoms were grouped by cranial nerve (CN) VII or CNVIII. Audiometry was assessed baseline and posttreatment hearing. Patients were grouped as having greater than serviceable hearing [Gardner Robertson (GR) score 1–2] or less than non-serviceable hearing (GR score 3–5) by audiometry.ResultsMedian follow-up was 72.0 months. Nine (2.3%) experienced treatment failure. At last follow-up, 74 (19.3%) had new/progressive symptoms and were categorized as radiologic non-responders, whereas 300 (78.3%) had no tumor progression and were grouped as radiologic responders. Average pretreatment BTV for treatment failures, radiologic non-responders, and radiologic responders was 2.11, 0.44, and 1.87 cm3, respectively. Pretreatment CNVII and CNVIII symptoms were present in 9.4 and 93.4% of patients, respectively. Eight (24%) with pre-HSRT CNVII and 37 (10%) with pre-HSRT CNVIII symptoms recovered CN function post-HSRT. Thirty-five (9%) and 36 (9.4%) experienced new CNVII and CNVIII deficit, respectively, after HSRT. Of these, 20 (57%) and 18 (50%) recovered CNVII and CNVIII function, respectively, after HSRT. Evaluable audiograms were available in 199 patients. At baseline and at last follow-up, 65.8 and 36.2% had serviceable hearing, respectively. Fifty-one percent had preservation of serviceable hearing at last follow-up.ConclusionTreatment of VS with HSRT is effective with treatment success in 97.7% and an acceptable toxicity profile. Less than one-third of patients experience any new CNVII or CNVIII deficit posttreatment. Greater than 50% of patients with serviceable hearing at baseline maintained hearing function. Improved methods to differentiate treatment effect and tumor progression are needed.

patients. Salvage CT included Bev in 143 (41.6%) patients and further TMZ in 180 (52.3%) patients. Factors associated with poor overall survival (OS) after LF included older age at diagnosis (P<.001), lower KPS (P<.001), initial surgery (P<.001), bilateral (vs unilateral) disease on presentation (P<.001), WHO grade IV (vs III) (P<.001), lack of salvage RT (PZ.024), and lack of salvage Bev (PZ.006). On multivariable analysis, the only treatment-related factor that retained significance for all patients with LF was the use of salvage Bev (HR 0.65, 95% CI: .43-.97, PZ.036). Conclusion: In this large retrospective series of patients with HGG treated with surgery, RT and TMZ had a local failure at 1 year in keeping with other published studies. Bevacizumab was the only physiciancontrolled factor identified associated with improved survival after failure. However, only 11.3% of our cohort received salvage RT. Further controlled studies will be necessary to determine optimal parameters for salvage therapy.

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