Artikel
Local tumour control and clinical symptoms after gamma knife radiosurgery for residual and recurrent vestibular schwannomas
Lokale Tumorkontrollraten und klinische Symptome nach Gamma-Knife-Radiochirurgie von Residual- und Rezidiv-Vestibularis-Schwannomen
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Veröffentlicht: | 8. Mai 2019 |
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Gliederung
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Objective: The use of Gamma Knife radiosurgery (GKRS) for recurrent or residual Vestibular schwannoma (VS) after microsurgery (MS) has been investigated in several retrospective studies. The purpose of this study was to identify potential risk factors for both neurological deterioration and tumor progression after GKRS for previously operated VS in a prospective setting.
Methods: Patients who underwent GKRS (Elekta, AB, Stockholm, Sweden) for previously operated and histopathologically confirmed VS between 1998 and 2015 were prospectively followed-up. Risk factors for therapy side-effects and predictors for tumor control were investigated in uni- and multivariate analyses.
Results: 160 individuals with a median age of 55 years were included. Median tumor volume prior to GKRS was 1.40cm3(range: .06–35.80cm3). After a median follow-up of 36 months, hearing and facial nerve function were serviceable (modified Gardner Robertson and House&Brackmann grades I-II) in 7 (5%) and 82 (55%) patients, respectively. Deterioration to a non-serviceable facial nerve function after GKRS was found in 3% (N=3/89) and tended to increase with rising tumor volume (OR: 1.65/cm3, 95%CI;1.00–2.71; p=.051). Median tumor volume prior GKRS was higher in patients with radiological (p=.020) or clinical tumor progression (p<.001). Critical tumor volume prior to GKRS to predict clinical and radiological tumor progression was 1.30cm3 (p<0.001) and 3.30cm3 (p=.019), respectively. However, in multivariate analyses, none of the analyzed variables was found to independently predict tumor progression.
Conclusion: Intended submaximal resection followed by GKRS is a viable treatment for VS. As tumor remnant size after MS was an important predictor for recurrence after adjuvant GKRS, both brain stem and cerebellar decompression as well as maximal safely achievable resection should remain major goals of microsurgery.