CLINICAL OUTCOMES OF PATIENTS WITH VESTIBULAR SCHWANNOMAS: THE RELEVANCE OF TUMOR SIZE AND RECURRENCE

Abstract INTRODUCTION Vestibular schwannomas (VS) are known to be slow-growing lesions that can present significant issues for patients. Here, we sought to better understand their outcomes and risks for recurrence. METHODS We retrospectively reviewed clinical outcomes data for patients who had VS tumor that underwent whole-exome sequencing after surgical resection between 2015 and 2018. The association between any two categorical variables was investigated using Fisher’s exact test. The mean of a continuous variable was compared between groups using either a two-tailed t-test or ANOVA. RESULTS Forty patients met our inclusion criteria. Interestingly, men were more likely than women to experience recurrence (p = 0.05). In accordance with previous research demonstrating a significant association between NF2 and bilateral vestibular schwannomas, most VS were NF2-mutants, with only four being were non-NF2. Pre-operative tumor size significantly correlated with progression-free survival time from surgical resection to recurrence, such that larger tumors were more likely to recur slower post-operatively (p = 0.043). There appeared to be no significant association between the extent of surgical resection (EOR) and recurrence (p = 0.653). In addition, there was no significant difference in post-operative complications or clinical outcomes, including EOR and facial nerve function, between different surgical approaches (p > 0.30). Patients with pre-operative intra-tumoral hemorrhage were more likely to have smaller tumors, suggesting they present more acutely (p = 0.119). Finally, patients with NF2-mutated VS had a longer time from original diagnosis to surgery than patients who had non-NF2 VS mutants (p = 0.041). CONCLUSIONS Surgery for VS offers good clinical outcomes overall with low recurrence rates, regardless of prior treatment. Though not related to Ki67, larger tumors appear to confer a slower growth potential and lower risk of recurrence over time.