Long-Term Hearing Outcome After Radiosurgery for Vestibular Schwannoma: A Systematic Review and Meta-Analysis

Abstract

Background: Stereotactic radiosurgery (SRS) is one of the main treatment options in the management of small to medium size vestibular schwannomas (VSs), because of high tumor control rate and low cranial nerves morbidity. Series reporting long-term hearing outcome (>3 years) are scarce.

Objective: To perform a systematic review of the literature and meta-analysis, with the aim of focusing on long-term hearing preservation after SRS.

Methods: Using Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines, we reviewed articles published between January 1990 and October 2020 and referenced in PubMed or Embase. Inclusion criteria were peer-reviewed clinical study or case series of VSs treated with SRS (single dose), reporting hearing outcome after SRS with a median or mean audiometric follow-up of at least 5 years. Hearing preservation, cranial nerves outcomes, and tumor control were evaluated.

Results: Twenty-three studies were included. Hearing preservation was found in 59.4% of cases (median follow-up 6.7 years, 1409 patients). Main favorable prognostic factors were young age, good hearing status, early treatment after diagnosis, small tumor volume, low marginal irradiation dose, and maximal dose to the cochlea. Tumor control was achieved in 96.1%. Facial nerve deficit and trigeminal neuropathy were found in 1.3% and 3.2% of patients, respectively, both significantly higher in Linear Accelerator series than Gamma Knife series ( P < .05).

Conclusion: Long-term hearing preservation remains one of the main issues after SRS, with a major impact on health-related quality of life. Our meta-analysis suggests that hearing preservation can be achieved in almost 60% of patients after a median follow-up of 6.7 years, irrespective of the technique.

Graphical abstract

FIGURE 1.

Preferred Reporting Items for Systematic Reviews and Meta-Analyses flow diagram with study selection details. Studies included in qualitative synthesis correspond to peer-reviewed clinical studies or case series of vestibular Schwannoma treated with SRS (single dose), irrespective of the technique, reporting hearing outcome after SRS with a median or mean audiometric follow-up of at least 5 years. Studies included in quantitative synthesis correspond to the subset of those at least reporting hearing preservation rates; different subsets have been used for meta-analyses focusing on facial nerve deficit, trigeminal neuropathy, and tumor control based on available respective rates. SRS, stereotactic radiosurgery.

FIGURE 2.

Hearing preservation rates after stereotactic radiosurgery for GK and LINAC series. Overall hearing preservation at last follow-up was found in 59.4% with no statistically significant difference observed between GK and LINAC series. GK, Gamma Knife; LINAC, linear accelerator.

FIGURE 3.

Facial nerve deficit rates after stereotactic radiosurgery for GK and LINAC series. New overall facial nerve deficit or worsening of facial deficit was found in 1.3% with statistically significantly (P = .00) higher rates of facial nerve deficit in LINAC series. GK, Gamma Knife; LINAC, linear accelerator.

FIGURE 4.

Trigeminal neuropathy rates after stereotactic radiosurgery for Gamma Knife and LINAC series. New trigeminal neuropathy was found in 3.2% with statistically significantly (P < .01) higher rates of trigeminal neuropathy in LINAC series. LINAC, linear accelerator.

FIGURE 5.

Tumor control rates after stereotactic radiosurgery for GK and LINAC series. Overall tumor control at last follow-up was achieved in 96.1% with no statistically significant difference observed between GK and LINAC series. GK, Gamma Knife; LINAC, linear accelerator.