Artikel
Radiosurgery for recurrent or residual vestibular schwannoma – volumetric evaluation of MRI follow-up and patterns of change in tumour volume
Radiochirurgie bei rezidivierten oder residuellen Vestibularisschwannomen – eine volumetrische Analyse der Tumorverläufe
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Autoren
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Susanne Fichte
- Cyberknife Mitteldeutschland, Erfurt, Deutschland
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Hans-Ulrich Herold
- Cyberknife Mitteldeutschland, Erfurt, Deutschland
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Klaus Hamm
- Cyberknife Mitteldeutschland, Erfurt, Deutschland
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Gunnar Surber
- Cyberknife Mitteldeutschland, Erfurt, Deutschland
| Veröffentlicht: | 4. Juni 2021 |
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Gliederung
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Objective: Radiosurgery (RS) is a therapeutic option for recurrent or residual vestibular schwannoma (VS) after microsurgery or progression after initial RS. Tumors treated with RS show different patterns of tumor volume changes after treatment. We report on the volumetric analysis after RS for recurrent or residual VS.
Methods: All patients treated for recurrent or residual VS with at least two high-resolution MRI follow-up exams were analyzed. 2 patients with NF2 were excluded. Patient data, planning details and imaging were analyzed retrospectively. Volumetric analysis was performed on Iplan-Software (Brainlab, Munich). 4 patterns of tumor changes were defined as adapted from the literature: transient volume expansion, stable/regression, continuous enlargement and alternating enlargement/regression.
Results: 26 patients (17 female, 9 male) treated from July 2013 to July 2019 were included in the analysis. Mean patient age was 60,7 years (range 31,6-78,8). 24 patients were previously treated with microsurgery, 2 patients had recurrence after RS. RS (mean margin dose 12 Gy, n=16) or multisession RS (mean margin dose 3x6 Gy, n=10) were performed at a mean time of 60,9 months after pretreatment (range 4,6 – 181,7 months). When performed after microsurgical resection, RS was applied upfront in only 2 cases, all other patients were treated upon tumor progression. Mean radiographic follow-up was 46,8 months (12,6-71,4). 117 data sets of follow-up MRI were evaluated. Transient enlargement was noted in 15 patients. 5 tumors showed sustained regression, 1 showed continuous progression. In 5 patients, volumetric analysis showed an atypical pattern with alternating regression and enlargement, with stabilization over time. Only one patient with continuous progression needed further intervention and was treated with microsurgery.
Conclusion: Recurrent or residual VS show different patterns of volume changes after RS that compare to those treated with primary RS. In our series, local control was favorable and the need for further intervention was low.
