Clinical Factors Associated with Spontaneous Regression and Progression of Vestibular Schwannoma: An Exploratory Case-Control Study

Abstract Objective: Spontaneous regression of vestibular schwannoma (VS) is a rare and poorly understood phenomenon. This study aimed to identify clinical, radiographic, and lifestyle factors associated with spontaneous regression compared with tumours requiring surgical resection. Methods: Patients demonstrating ≥2 mm spontaneous regression (SR) at a single tertiary centre between 2001 and 2025 were compared to surgically treated controls (SC) exhibiting tumour progression. Imaging and clinical characteristics were reviewed, and participants completed a survey assessing demographics, medical history, viral history, and lifestyle factors. Results: Eighteen SR patients and eighteen SC patients completed the survey. A higher proportion of SR patients reported a history of oral herpes or varicella-zoster virus compared with SC patients (55% vs 17%, p = 0.035). SR patients reported fewer years of cellphone use prior to diagnosis (5 vs 15.8 years, p < 0.001). No radiographic features were predictive of spontaneous regression. Conclusion: In this exploratory cohort, spontaneous regression of VS was associated with self-reported active HSV/VZV expression, while patients with spontaneous regression reported fewer years of cellphone use than surgically treated controls. Larger prospective studies are required to clarify underlying mechanisms and identify reliable predictive markers.