1245 Malignant Meningioma Survival, Recurrence and Functional Outcomes in an International Multicenter Cohort

INTRODUCTION: Meningiomas are the most common intracranial tumor. Grade 3 (malignant) meningiomas are the most aggressive subtype and represent 1-3% of all meningiomas cases. METHODS: Demographic, clinical and histopathological data from grade 3 intracranial meningioma cases were identified in the clinical databases from seven sites in North America and Europe from 1991-2022. Summary statistics and Kaplan-Meier OS and PFS curves were generated. RESULTS: We identified 108 patients, with a median age 65 years (IQR: 52, 72) and 53.7% were female. Median OS was 109 months (95% CIs: 88, 227) and 5-year OS rate was 65% (95% CIs: 56, 76). Median PFS was 38 months (95% CIs: 24, 56) and 5-year PFS rate was 37% (95% CIs: 28, 49). Older age (=65 years old) and male sex were independent predictors of worse OS and PFS in multivariate regression analysis. Postoperative radiotherapy was independently associated with improved OS in all patients and a sensitivity analysis including only patients =65 years old. Functional status, as measured by Karnofsky performance status, was stable between preoperative (median: 80 IQR: 70, 90), postoperative (median: 90 IQR: 70, 98) and 1-year postoperative (median: 70 IQR: 50, 80) timepoints. CONCLUSIONS: This study provides robust survival, recurrence, and functional outcome data for malignant meningiomas in North America and Europe over a 30-year period. We demonstrate that older age and male sex are associated with worse survival and recurrence outcomes. We further affirm that adjuvant radiotherapy confers a survival benefit in the treatment of malignant meningiomas, including in patients older than 65 years. Despite concerns around surgical and radiotherapy treatment complications, functional status remains stable in the first year following treatment of malignant meningiomas.