Adjuvant postoperative high-dose radiotherapy for atypical and malignant meningioma: A phase-II parallel non-randomized and observation study (EORTC 22042-26042)

PURPOSE: The therapeutic strategy for non-benign meningiomas is controversial. The objective of this study was to prospectively investigate the impact of high dose radiation therapy (RT) on the progression-free survival (PFS) rate at 3 years in WHO grade II and III meningioma patients. MATERIALS AND METHODS: In this multi-cohorts non-randomized phase II and observational study, non-benign meningioma patients were treated according to their WHO grade and Simpson's grade. Patients with atypical meningioma (WHO grade II) and Simpson's grade 1-3 [Arm 1] entered the non-randomized phase II study designed to show a 3-year PFS > 70% (primary endpoint). All other patients entered the 3 observational cohorts: WHO grade II Simpson grade 4-5 [Arm 2] and Grade III Simpson grade 1-3 or 4-5 [Arm 3&4] in which few patients were expected. RESULTS: Between 02/2008 and 06/2013, 78 patients were enrolled into the study. This report focuses on the 56 (median age, 54 years) eligible patients with WHO grade II Simpson's grade 1-3 meningioma who received RT (60 Gy). At a median follow up of 5.1 years, the estimated 3-year PFS is 88.7%, hence significantly greater than 70%. Eight (14.3%) treatment failures were observed. The 3-year overall survival was 98.2%. The rate of late signs and symptoms grade 3 or more was 14.3%. CONCLUSIONS: These data show that 3-year PFS for WHO grade II meningioma patients undergoing a complete resection (Simpson I-III) is superior to 70% when treated with high-dose (60 Gy) RT.