P.015 Spontaneous regression of acoustic schwannomas: a predictive model

Background: Vestibular schwannomas are the most common tumour of the CPA with an annual incidence of 17.4/1 million. Approximately 5-10% of these tumours demonstrate spontaneous regression without intervention while under observation. Previous research studies have assessed patient factors and imaging characteristics through chart review to attempt to identify predictive factors of spontaneous regression. There have not been any studies where patient questionnaires are used to assess patient lifestyle factors or characteristics which may predict spontaneous regression. Methods: Using a clinical database of acoustic schwannomas treated by one team at our institution, we have identified approximately 40 patients, of a database of 900 patients, who have demonstrated significant spontaneous regression (>5mm in size reduction in one dimension) or complete resolution of their acoustic schwannoma. Clinical, radiological, and lifestyle factors are reviewed though clinical records and patient questionnaire. Regression analysis is performed. Results: Using patients who have tumors with significant spontaneous regression, we attempt to create a model that predicts regression of these tumours. Conclusions: In conclusion, this is the first study to consider patient lifestyle factors obtained through patient survey in addition to clinical and radiographic factors to attempt to create a predictive model of spontaneous regression of acoustic schwannoma.