Correlation Between Aspirin Intake and Reduced Growth of Human Vestibular Schwannoma

OBJECTIVE: To determine whether people with sporadic vestibular schwannoma (VS) who take aspirin for unrelated medical reasons exhibit less tumor growth than nonaspirin users. We previously demonstrated the efficacy of salicylates in inhibiting VS growth in vitro, corroborating the results of our retrospective clinical study, which found halted VS growth (based on linear tumor measurements) in aspirin users. The current study evaluates this association using more accurate tumor volumetric measurements, and quantifies the degree of frequency-specific, VS-induced hearing loss. STUDY DESIGN: Retrospective analysis. SETTING: Tertiary care hospital. PATIENTS: Diagnosed with VS between 1980 and 2012, followed by serial magnetic resonance imaging for at least 1 year. MAIN OUTCOME MEASURES: Patient history of aspirin intake; change in VS volume over time of observation; frequency-specific, VS-induced audiometric threshold shifts. RESULTS: Of the 347 patients followed by serial magnetic resonance imaging scans, 86 had sequential scans available for 3D-segmented volumetric analysis for up to 11 years of follow-up (median 53 mo). Twenty-five (29%) had documented history of aspirin intake; 8 (32%) of these demonstrated VS growth. Of the 61 (71%) nonusers, 36 (59%) demonstrated growth. A significant inverse association was found among aspirin users and VS growth: odds ratio 0.32, 95% confidence interval 0.11 to 0.91. VS-induced audiometric thresholds shifts were larger above than below 2000 Hz. CONCLUSION: Our volumetric analysis of VS growth reaffirms the results of our linear analysis and suggests that aspirin may inhibit VS growth. The audiometric findings are consistent with the previously reported VS-induced predominantly high-frequency sensorineural hearing loss.