The role of conservative management of vestibular schwannomas

Although microsurgery is generally regarded as the conventional treatment o f choice for most vestibular schwannomas, there remains a group of patients in whom a conservative management approach may be a desirable alternative. The aim of this study was to determine the natural history and outcome fol lowing the conservative management of 72 patients with unilateral vestibula r schwannomas. The reasons for conservative management included poor genera l health, age, patient preference, small tumour size, minimal or no symptom s, and tumour in the only/better hearing ear. The mean duration of follow-u p was 39.8 months (range 12-194 months). All patients underwent serial magn etic resonanace imaging (MRI) for assessment of tumour growth. Patients wer e deemed to have failed conservative management if there was evidence of co ntinuous or rapid radiological tumour growth and/or increasing symptoms or signs. The mean tumour growth rate, according to the 1995 guidelines of the American Academy of Otolaryngology/Head and Neck Surgery, was 1.16 mm/year (range: 0.75-9.65 mm/year). Approximately 83% of tumours grew at < 2 mm/ye ar. Significant tumour growth was seen in 36.4%, no or insignificant growth in 50%, and negative growth in 13.6% of tumours. The growth rate of CPA tu mours (1.4 mm/year) was significantly greater than that of IAC tumours (0.2 mm/year) (P = 0.001). Failure of conservative management, in which active treatment was required, occurred in 15.3%. The outcome of these patients ap peared to be as favourable to a comparable group who underwent primary trea tment, without a period of conservative management. The mean growth rate of tumours in patients who failed conservative management (4.2 mm/year) was s ignificantly greater than that in patients who did not fail (0.5 mm/year) ( P < 0.01). No factors predictive of tumour growth or failure of conservativ e management were identified. Deterioration of mean pure tone average (0.5, 1, 2, 3 kHz) and speech discrimination scores occurred regardless of wheth er radiological tumour growth was demonstrated or not. This study suggests that in a select number of cases of vestibular schwannoma, a conservative m anagement approach may be appropriate. Regular follow-up with serial MRI is mandatory. Deterioration of auditory function occurs even in the absence o f tumour growth.