British Skull Base Society Consensus on vestibular schwannoma surveillance

Objective Surveillance plays a crucial role in managing patients with vestibular schwannomas (VSs). Consensus is lacking on the optimal duration, frequency, and modality of imaging. Standardizing this approach would ensure safe and effective care, reduce patient distress, and promote consistency in management decisions among clinicians. Methods In July 2022, a multi-disciplinary Delphi consensus was conducted at the British Skull Base Society Meeting. Expert United Kingdom-based skull-base surgeons and neuroradiologists were presented semi-systematic literature reviews summarizing current evidence on VS management. Anonymized opinions were collated and discussed to reach a majority vote, which was deemed the final consensus opinion. Results Recommendations for VS managed by surveillance are: (1) surveillance frequency should decrease over time; (2) surveillance may be discontinued when the remaining lifetime risk of VS growth is <0.5% (∼8.5 years); (3) factors such as age, VS size, VS location, and cystic components should be considered. Surveillance after surgery or radiotherapy has limited evidence but recommendations are: (4) surveillance should be adjusted based on residual tumor size or nodular enhancement. Imaging modality and sequences are recommended to be (5) high-resolution magnetic resonance imaging with T1, T2, FIESTA/CISS multiplanar sequences, contrast is not required in untreated cases, and linear reporting of measurements is pragmatically sufficient. Conclusion This consensus and literature review provides an evidence and expert opinion-based guide to help clinicians with the surveillance of patients with VS. Further research should focus on better understanding the dynamic nature of growth risks and the growth characteristics of postintervention VS to enable personalized growth risk stratification.