Spontaneous tumour shrinkage in 1261 observed patients with sporadic vestibular schwannoma.

OBJECTIVE

To determine the rate of spontaneous tumour shrinkage in a group of patients with sporadic vestibular schwannoma managed with a 'wait and scan' approach.

PATIENTS: All patients with a unilateral cerebello-pontine angle tumour resembling a vestibular schwannoma were registered prospectively in a national database in Denmark. Patients registered with tumour shrinkage were identified and all computed tomography and magnetic resonance imaging scans retrieved, re-evaluated and related to the clinical data.

RESULTS

Of 1261 observed patients, 48 displayed spontaneous shrinkage (3.81 per cent). Mean absolute shrinkage was 6.25 mm, equivalent to 52.1 per cent. Absolute shrinkage correlated with tumour size and followup period, whereas relative shrinkage was significantly greater for tumours which were purely intrameatal at diagnosis. There was no correlation between age and the degree of shrinkage.

CONCLUSION

Four per cent of sporadic vestibular schwannomas shrink spontaneously. These findings substantiate the 'wait and scan' strategy for tumours with a largest extrameatal diameter of up to 20 mm.