Vestibular schwannomas - when should conservative management be reconsidered?

OBJECTIVE: 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.

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

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

OUTCOME MEASURES: 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.

RESULTS: 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.

CONCLUSIONS: 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.