2026 Poster Presentations
P511: INTEGRATING FRAILTY INTO RISK STRATIFICATION FOR SRS OUTCOMES IN VESTIBULAR SCHWANNOMA
Savi Agarwal, BS; Anubhav Chandla; Yelena Malkhasyan; Isaac Yang, MD, FAANS, FACS; UCLA Department of Neurosurgery
Introduction: A benign tumor and the most common lesion in the cerebellopontine angle, vestibular schwannoma (VS), is often targeted by stereotactic radiosurgery (SRS) due to satisfactory tumor control. The most common presenting complaint of VS is unilateral and progressive hearing loss, however other symptoms may include tinnitus, loss of balance, and/or deficits of cranial nerves (CNs) V and VII due to their proximity to CN VIII and the cerebellopontine angle. Although SRS is typically associated with adequate symptom management, it may also have toxic effects on surrounding tissue and nervous structures such as CNs V, VII, and VIII, although the exact incidence of post-treatment symptom progression or development is underexplored. Furthermore, clinicians do not currently have standardized guidelines for how their patient’s pre-treatment clinicopathologic demographics may impact the predicted efficacy of SRS, both immediately after radiosurgery and in the long-term. Specifically, there is further investigation required to understand the relationship between age-related hearing loss and iatrogenic causes of vestibulocochlear damage after SRS.
Objective: To evaluate the development, prevalence, and long-term progression of clinical outcomes secondary to SRS for VS patients, specifically assessing for the impact of patient frailty.
Methods: A retrospective study was conducted of 46 patients at the UCLA Medical Center with a confirmed diagnosis of sporadic VS treated with SRS between 2012 and 2021. Hearing loss was assessed through pure-tone audiometry, balance and gait were assessed on physical exam, and tinnitus and dizziness were symptoms documented subjectively.
Results: Out of the 46 included patients, 18 were female and 28 male, with an average age of 59.6 years (SD 14.2 years) and median follow-up of 3.5 years. The average pre-treatment tumor volume was 3.28cm3, with 19 patients receiving hyperfractionated radiation, 5 hypofractionated, and 22 single fraction. Before undergoing SRS, 89% of patients had unilateral hearing loss, 63% had same-sided unilateral tinnitus, and 63% had loss of balance or disequilibrium. After controlling for tumor location, patient gender, pre-operative tumor volume, and length of follow-up, symptom persistence for greater than 6 months after SRS, delayed development of symptoms more than 1 year after SRS, and symptom improvement from pre-treatment baseline were measured. Most experienced stability or improvements in their symptoms, with tinnitus (p = 0.026) and loss of balance (p = 0.042) demonstrating lower rates of persistence in patients 60 years or older. Similarly, patients 60 years or older complained of significantly lower rates of delayed onset in dizziness (p=0.003) and loss of balance (p=0.0001). Finally, rates of no improvement in tinnitus (p = 0.001) and dizziness (p = 0.004) were seen to be significantly lower in patients 60 years or older.
Conclusion: SRS remains a promising clinical intervention for patients suffering from dysfunction in CNs V, VII, and/or VIII due to VS, although a subset of patients may experience delayed or persistent auditory and vestibular symptoms. This unique, preliminary analysis of the long-term clinical outcomes highlights the role of patient frailty as a potential modifier of symptom progression.