(439) Salvage Treatment of Sporadic Vestibular Schwannoma Following Failed Primary Radiosurgery

Monday, October 2, 2023

2:45 PM – 3:45 PM East Coast USA Time

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Presenting Author(s)

John P. Marinelli, MD

Resident Physician; Editor, Headmirror's ENT in a Nutshell & OtoRecall
Brooke Army Medical Center
San Antonio, TX, United States

Co-Author(s)

KK

Karl R. Khandalavala, MD

Mayo Clinic, USA
CL

Christine M. Lohse, MS

Mayo Clinic
Rochester, Minnesota, USA
CD

Colin LW Driscoll, MD

Professor
Mayo Clinic
Rochester, Minnesota, United States
ML

Michael J. Link, MD

Professor of Neurologic Surgery
Mayo Clinic
Rochester, Minnesota, USA

Senior Author(s)

MC

Matthew L. Carlson, MD

Professor
Mayo Clinic, Minnesota
Rochester, Minnesota, United States

Disclosure(s):

John P. Marinelli, MD: No relevant relationships to disclose.

Colin LW Driscoll, MD: No relevant relationships to disclose.

Matthew L. Carlson, MD: No relevant relationships to disclose.

Introduction: With generally good long-term control rates of sporadic vestibular schwannoma (VS) following primary stereotactic radiosurgery (SRS) or fractionated stereotactic radiotherapy (FSRT), there exist limited data characterizing post-treatment outcomes surrounding salvage therapy in the setting of failed primary radiation treatment. The aim of the current work was to describe the clinical outcomes of salvage microsurgery (MS) following failed primary SRS/FSRT.

Methods: Review of all patients with sporadic VS who underwent salvage MS following failed primary SRS/FSRT from 2004-2021 at a large tertiary referral center.

Results: Thirty-eight patients underwent salvage MS following failed primary SRS/FSRT. At time of primary SRS/FSRT, the median (IQR) age was 56 (50-63) with 83% harboring tumors with cerebellopontine angle extension (median 1.65 cm; IQR 0.99-2.05) and 17% having tumors confined to the internal auditory canal (median 0.63 cm; IQR 0.6-0.7). Most (82%) patients underwent salvage MS following evidence of growth on serial MRI scans (≥2 mm on ≥2 post-treatment MRI scans) while intractable trigeminal neuropathy prompted salvage MS in the remaining patients. Symptoms typically worsened by time of salvage, with 24% experiencing worsening dizziness/imbalance, 21% trigeminal neuralgia, and 16% trigeminal hypesthesia. HB 2 facial nerve function was seen in 5%. Gross total resection (GTR) during salvage MS was achieved in 47%, with 68% retaining HB ≤2 facial nerve function postoperatively. Trigeminal neuralgia improved in 88%. Four patients developed a postoperative CSF leak; 1 patient developed meningitis; no patients suffered a stroke. At a median of 3.7 years of follow-up following salvage MS, 1 patient exhibited further tumor growth and required additional salvage MS.

Conclusions: Salvage MS following primary SRS/FSRT is associated with higher morbidity and risk of less than GTR than primary MS, especially with increasing tumor size. These data can be used during patient counseling and when estimating the aggregate risk of undergoing primary SRS/FSRT.