Current Evidence on Medical Therapy for Sporadic Vestibular Schwannoma: A Systematic Review and Meta-analysis.

OBJECTIVE

To systematically review studies evaluating systemic medical therapies for sporadic vestibular schwannoma (VS) and perform meta-analyses to assess associations with tumor control.

STUDY

DESIGN

Systematic review and meta-analysis.

SETTING

Not applicable.

PATIENTS: Sporadic VS patients.

INTERVENTIONS: Systemic medical therapies.

MAIN OUTCOME MEASURES: Tumor growth.

RESULTS

Nine retrospective studies met criteria: 5 on nonsteroidal anti-inflammatory drugs (NSAIDs), 3 on metformin, and 1 on losartan (all level 3 evidence). A meta-analysis of ORs from 5 studies demonstrated no significant association between aspirin use and tumor growth (pooled OR: 0.77; 95% CI: 0.48-1.23; I²: 76%). Conversely, a meta-analysis of ORs from 3 studies on metformin showed significantly lower odds of tumor growth (pooled OR: 0.46; 95% CI: 0.30-0.72; I²: 0%). The study on losartan did not identify a statistically significant association of losartan with tumor growth. Less than half of the studies reported HRs to appropriately reflect the inherently time-dependent nature of tumor growth.

CONCLUSIONS

Evidence for systemic therapies in sporadic VS remains preliminary. Our meta-analysis of ORs demonstrates that NSAID use is not significantly associated with tumor growth, metformin users had lower odds of tumor growth, and evidence for losartan remains limited; however, all available studies provide only level 3 evidence. At present, there is insufficient data to recommend routine use of aspirin, metformin, or losartan with the intent of mitigating VS tumor growth during wait-and-scan management. High-quality prospective studies with appropriate time-to-event methodology to assess tumor growth are required to establish the clinical utility of systemic therapies in the management of patients with sporadic VS.