J Neurol Surg B Skull Base 2022; 83(S 02): e343-e352
DOI: 10.1055/s-0041-1729977
Original Article

Gamma Knife Radiosurgery for Large Vestibular Schwannoma More Than 10 cm3: A Single-Center Indian Study

Ujwal Yeole
1   Department of Neurosurgery, National Institute of Mental Health and Neurosciences, Bengaluru, Karnataka, India
,
1   Department of Neurosurgery, National Institute of Mental Health and Neurosciences, Bengaluru, Karnataka, India
,
Arimappamagan Arivazhagan
1   Department of Neurosurgery, National Institute of Mental Health and Neurosciences, Bengaluru, Karnataka, India
,
K. V. L. Narasingarao
1   Department of Neurosurgery, National Institute of Mental Health and Neurosciences, Bengaluru, Karnataka, India
,
Vikas Vazhayil
1   Department of Neurosurgery, National Institute of Mental Health and Neurosciences, Bengaluru, Karnataka, India
,
Dhananjaya Bhat
1   Department of Neurosurgery, National Institute of Mental Health and Neurosciences, Bengaluru, Karnataka, India
,
Dwarakanath Srinivas
1   Department of Neurosurgery, National Institute of Mental Health and Neurosciences, Bengaluru, Karnataka, India
,
Bhanumathi Govindswamy
2   Division of Radiation Oncology, Department of Neurosurgery, National Institute of Mental Health and Neurosciences, Bengaluru, Karnataka, India
,
Somanna Sampath
1   Department of Neurosurgery, National Institute of Mental Health and Neurosciences, Bengaluru, Karnataka, India
› Institutsangaben
Preview

Abstract

Introduction Gamma Knife radiosurgery (GKRS) is an effective treatment for benign vestibular schwannomas (VSs). The established cutoffs have recently been challenged, as recent literature expanded the horizon of GKRS to larger tumors. Even though microsurgery remains the primary option for large VS, GKRS can provide reasonable tumor control and is more likely to avoid cranial neuropathies associated with open surgery.

Methods We analyzed patients with VS with volume exceeding 10 cm3 who underwent GKRS at our center from January 2006 to December 2016. Clinicoradiological and radiosurgical data were collected from medical records for statistical analysis. Follow-up was performed every 6 months with a clinical assessment along with magnetic resonance imaging (MRI) of the brain and audiometric evaluation in patients with serviceable hearing.

Results The study included 34 patients (18 males and 16 females) with an average age of 45.5 years. The mean tumor volume was 10.9 cm3 (standard deviation [SD], ± 0.83), with a median tumor dose of 12 Gy (interquartile range, 11.5–12) and a mean follow-up of 34.7 months (SD, ± 23.8). Tumor response was graded as regression in 50%, stable in 44.1%, and increase or GKRS failure in 2 cases (5.8%). Treatment failure was noted in five cases (14.7%), requiring microsurgical excision and a ventriculoperitoneal shunt post-GKRS. The tumor control rate for the cohort is 85.3%, with a facial preservation rate of 96% (24/25) and hearing loss in all (5/5), while three patients developed new-onset hypoesthesia. We noted that gait ataxia and involvement of cranial nerve V or VII at initial presentation were associated with GKRS failure in univariate analysis.

Conclusion Microsurgery should remain the first-choice treatment option for large VSs. GKRS is a viable alternative with good tumor control and improved or stabilized cranial neuropathies with a low complication rate.

Ethical Approval

All procedures performed in studies involving human participants were in accordance with the ethical standards of the institutional and/or national research committee (National Institute of Mental Health and Neurosciences) and with the Declaration of Helsinki 1964 and its later amendments or comparable ethical standards.


Note

For this type of study, formal consent is not required. This article does not contain any studies with human participants performed by any of the authors.


Previous Presentation

This study was presented as poster at the 14th International Stereotactic Radiosurgery Society Congress 2019, Rio De Janeiro, Brazil, in June 2019.




Publikationsverlauf

Eingereicht: 04. Oktober 2020

Angenommen: 27. Februar 2021

Artikel online veröffentlicht:
23. Mai 2021

© 2021. Thieme. All rights reserved.

Georg Thieme Verlag KG
Rüdigerstraße 14, 70469 Stuttgart, Germany