Vestibular schwannomas - when should conservative management be reconsidered?

To document the natural history of vestibular schwannomas treated conservatively, and to find if there are any predictive factors for growth and need for active intervention.

A retrospective review of patient notes and radiology, mostly MRIs.

Eighty-eight patients managed conservatively for unilateral vestibular schwannoma and that have had at least two radiological investigations.

Change in tumour size over time was evaluated. Linear and logistic regression, respectively, were used to determine which factors (of age, size at diagnosis, audiology at presentation, length of follow-up or growth within first year of follow-up) would predict overall growth and active intervention. Characteristics of those that required active intervention is also demonstrated.

Of the 88 patients, the average size of schwannoma at diagnosis was 10.88 mm. The mean length of radiological follow-up was 3.65 years. 51.1% of schwannomas grew, 12.5% shrank and 36.4% remained the same size. The mean rate of growth was 1.24 mm per year. 25.0% failed conservative treatment, with 19 patients having stereotactic radiosurgery and three undergoing microsurgery. Only growth in the first year of follow-up was found to significantly predict total growth. Size at diagnosis and growth in first year of follow-up were significantly found to predict active intervention.

There remains a place for conservative treatment in those with small tumours, the elderly and those with significant co-morbidities. Growth in the first year of follow-up should be considered in determining whether to treat actively or not.