How many growing vestibular schwannomas tend to stop growing without any treatment?

OBJECTIVE: To determine the long-term, spontaneous growth arrest rates in a large cohort of vestibular schwannoma patients. METHODS: This paper describes a retrospective case series of 735 vestibular schwannoma patients organised into four groups: group A patients showed tumour growth which then stopped without any treatment; group B patients showed tumour growth which continued, but were managed conservatively; group C patients had a growing vestibular schwannoma and received active treatment; and group D patients had a stable, non-growing vestibular schwannoma. Demographics, tumour size and vestibular schwannoma growth rate (mm/month) were recorded. RESULTS: A total of 288 patients (39.2 per cent) had growing vestibular schwannomas. Of the patients, 103 (35.8 per cent) were managed conservatively, with 52 patients (50.5 per cent of the conservative management group, 18 per cent of the total growing vestibular schwannoma group) showing growth arrest, which occurred on average at four years following the diagnosis. Eighty-two per cent of vestibular schwannomas stopped growing within five years. Only differences between age (p = 0.016) and vestibular schwannoma size (p = 0.0008) were significant. CONCLUSION: Approximately 20 per cent of growing vestibular schwannomas spontaneously stop growing, predominantly within the first five years; this is important for long-term management.

Growing versus non-growing vestibular schwannomas: assessment of natural history.

OBJECTIVE: Vestibular schwannomas can demonstrate great heterogeneity in their behaviour; approximately one-third will grow and two-thirds will not. This study aimed to determine whether there are factors present at diagnosis that can help predict outcomes. METHODS: This retrospective cohort study compared data from 735 patients from the past 20 years. Analysis of serial magnetic resonance imaging was carried out to place patients into growing and non-growing cohorts. Factors including size, age, follow-up time and presence of balance symptoms were compared. RESULTS: The median size of a growing vestibular schwannoma at diagnosis was 13 mm, whereas the non-growing median size was 10.65 mm (p < 0.001). Balance symptoms were present in 60.76 per cent of growing vestibular schwannoma patients but only in 38.75 per cent of patients with non-growing vestibular schwannomas (p < 0.001). CONCLUSION: This study highlights initial tumour size and balance symptoms as potential predictors of whether or not a vestibular schwannoma will grow; these results better facilitate our understanding of vestibular schwannoma natural history.