Sorry have not seen that one (do you have an authors name or journal?) However, this may be of interest
Conservative management of vestibular schwannomas:
third review of a 10-year prospective study
Hajioff, D.,* Raut, V.V.,†Walsh, R.M.,†Bath, A.P.,†Bance, M.L.,†Guha, A., Tator, C.H.
& Rutka, J.A.â€Â
Seventy-two patients with a unilateral vestibular schwannoma have been treated conservatively for a median of 121 months. They have been followed prospectively by serial clinical examination, MRI scans and audiometry.
• Twenty-five patients (35%, 95% CI: 24–47) failed conservative management and required active intervention during the study. No factors predictive of tumour growth or failure of conservative management could be identified. Seventy-five per cent of failures occurred in the first half of the 10-year study.
• The median growth rate for all tumours at 10 years was 1 mm/year (range −0.53–7.84). Cerebellopontine angle tumours grew faster (1.4 mm/year) than intracanalicular tumours (0 mm/year, P < 0.01); 92% had growth rates under 2 mm/year.
• Hearing deteriorated substantially even in tumours that did not grow, but did so faster in tumours that grew significantly (mean deterioration in pure tone average at 0.5, 1, 2 and 3 kHz was 36 dB; speech discrimination scores deteriorated by 40%).
• Patients who failed conservative management had clinical outcomes that were not different from those who underwent primary treatment without a period of conservative management.