Conservative management of vestibular schwannomas: third review of a 10‐year prospective study

Abstract

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.

An update on unilateral sporadic small vestibular schwannoma

“…38,39,75,101 This obviously does not account for patients who develop hearing loss without any significant tumor growth (as described earlier in this paper).…”

“…68 There are very few prospective studies that report tumor growth in the patients followed with observation. Régis et al 83 reported tumor growth in 77% of their patients (mean follow-up 5.3 years); Hajioff et al, 39 in their 10-year follow-up prospective study (median duration of follow-up 121 months), reported tumor growth in 78% of patients (< 1 mm/year in 38% and > 1 mm/year in 40%); and Stangerup et al 96 found that only 17% of intrameatal tumors became extrameatal and that only 28.9% of extrameatal tumors showed growth (mean follow-up 3.6 years). It is difficult to develop a scientific rationale that would explain this variation.…”

“…7,51 Compression of labyrinthine vessels has been shown to cause degeneration in the organ of Corti and the spiral ganglion (cochlear dysfunction). 22,37,43,71 Of note, the progression of hearing loss in VS is most often gradual, 39,96 although sudden deterioration is also possible. 32,65 …”

“…Table 2 lists various factors that may have prognostic implications for VS growth patterns. 2,5,13,28,39,41,59,62,68,101,104 But there is clearly a need for long-term prospective data documenting annual trends in tumor growth rates.…”

“…57,81 The data, however, do not always show a linear correlation between the rate of tumor growth and deterioration of hearing. 38,39,82,96,104 …”