Stereotactic radiosurgery ensures an effective and safe long-term control of Koos grade IV vestibular schwannomas: a single-center, retrospective, cohort study

Abstract

Purpose: Stereotactic radiosurgery (SRS) is a standard treatment modality for vestibular schwannomas (VSs).However, there is a paucity of data on tumor control and neurological preservation for larger VSs. We aimed to investigate the long-term effectiveness of SRS for Koos grade IV compared with I-III VSs.Methods: We included 452 patients with VSs (50 Koos grade IV and 402 Koos grade I-III) who were treated with SRS at our institution from 1990 to 2021. Tumor control and functional preservation were calculated using the Kaplan-Meier method and compared between groups with the log-rank test.Results: The median post-SRS follow-up period was 68 months. Tumor control rates were 96% at 5 and 10 years for Koos grade IV VSs, and 97% and 95%, respectively, for Koos grade I-III VSs (p = 0.744). In Koos grade IV VSs, functional preservation rates of the facial and trigeminal nerves were both 96% at 5 years (both 98% for Koos grade I-III VSs; facial, p = 0.410; trigeminal, p = 0.107). Hearing preservation rates were 61% at 5 years for Koos grade IV VSs and 78% for Koos grade I-III VSs (p = 0.645). Symptomatic transient tumor expansion was more common with Koos grade IV VSs (8.0% vs. 2.5%, p = 0.034), although all related symptoms diminished in accordance with tumor shrinkage.Conclusion: SRS may contribute to long-term tumor control and adequate neurological preservation in the treatment of Koos grade IV VSs, comparable to those in the treatment of Koos grade I-III VSs.

Stereotactic Radiosurgery for Vestibular Schwannoma With Radiographic Brainstem Compression

“…Data supporting SRS for VS in the latter setting are limited, but an increasing number of studies have been published in recent years supporting its use. [11][12][13][14][15][16][17][18] Our study FIGURE 2. Estimation of brainstem compression and contact from vestibular schwannoma.…”

“…While surgery is clearly indicated when the VS is causing serious symptoms related to mass effect, the best treatment in the absence of these symptoms is less clear. Data supporting SRS for VS in the latter setting are limited, but an increasing number of studies have been published in recent years supporting its use 11–18 . Our study distinguishes itself from existing studies in the following ways: 1) patients were treated with linac-based SRS, usually to the 70% isodose line, as opposed to the 50% isodose line with GK; 2) we did not limit the population based on tumor size, so long as there was radiographic evidence of brainstem compression at the time of SRS; and 3) we describe brainstem DVH parameters in the context of TG101 constraints.…”

Wait-and-scan management in sporadic Koos grade 4 vestibular schwannomas: A longitudinal volumetric study

“…First, the median size of 2.7 cm 3 , or 20 mm extrameatal diameter, is small when compared to the median VS sizes with upfront therapy in our center (initial SRS: 7.6 cm 3 ; initial MS: 12.4 cm 3 ; see Supplementary Table S3 ) and to other Koos grade 4 SRS and MS studies. 6 , 7 , 34 , 35 This also proves how the definition of Koos grade 4 VSs consists of a very wide range of tumor sizes and could be a misleading classification. 34 , 36 , 37 While most centers opt for upfront treatment for tumors larger than 15–20 mm extrameatal diameter, 1 , 16 , 17 our center generally holds a higher threshold of 25–30 mm, depending on tumor shape and risk of missing the window of opportunity for SRS.…”

Central Neurocytoma Treated Using Supratentorial Ventricle Radiotherapy: A Single-Institution Analysis of Five Cases in Adjuvant or Salvage Settings After Surgery

“…Stereotactic radiosurgery (SRS) has recently been considered an alternative surgical approach for intracranial benign tumors [16][17][18][19] It is important to note that this study is limited by its small sample size. Further research with a larger patient population is warranted to confirm these promising results.…”