Surgical treatment and predictive factors for atypical meningiomas: a multicentric experience

INTRODUCTION: Atypical meningiomas (AMs) are characterized by a high rate of recurrence and a lesser Overall Survival (OS), compared to grade I meningioma. Nowadays, it is still controversial which are the predictive parameters for OS and the Recurrence free survival (RFS). METHODS: Data regarding age, gender, localization of the tumor, pre-operative symptoms, tumor localization, size, Simpson grade, postoperative complications, the extent of the resection (EOR), the number of mitoses, the proliferation index (MIB1), the brain invasion, the post-operative Radiotherapy (RT) treatment and clinical outcome (Karnofsky performance status, KPS, post-operatively and long-time follow-up) were evaluated. In addition, data regarding the recurrence rate, the mortality, OS and RFS at 1-year, 3-year and 5-year follow-up were collected. The median follow-up was 76 months, all patients had at least 3-year follow-up. RESULTS: Between 2007 and 2017, 73 patients underwent a surgical procedure for AMs (WHO grade II) in Ospedali Riuniti Center of Ancona and Sestre Milosrdnice University Hospital Centre. A preoperative KPS> 80 resulted to be related to a better OS, also at the one-month follow-up, six-month and one-year follow-up KPS. The post-operative complications did not modify the OS and the RFS. A Gross total removal (GTR, Simpson grade I, II) was achieved in the 80,8% of patients. The RFS was statistically influenced by the EOR (p=0,002). A MIB-1>8 was a negative predictive factor for recurrence at univariate and multivariate analysis (p=0,001, p=0,021). RT was statistically related to a worse outcome. The incidence of recurrence was 38%. The RFS was 98,6% at 1-year follow-up, 81,1% at 3-year and, only 57,5% at 5-year follow-up. All patients were alive after 1-year follow-up. The OS at 3-year follow-up was 90, 5% and 78,8 % at 5-year follow-up. CONCLUSIONS: Despite some limitations, our study demonstrate that an aggressive surgical treatment, achieving a GTR is a positive predictive parameter for the RFS, as well as a good clinical outcome (KPS > 80) is related to a longer overall survival.