Surgical Treatment and Predictive Factors for Atypical Meningiomas: A Multicentric Experience

Atypical meningiomas are characterized by a high rate of recurrence and shorter overall survival (OS) compared with grade I meningioma. Predictive parameters for OS and recurrence-free survival (RFS) are controversial.

Patient age, sex, preoperative symptoms, tumor localization, size, Simpson grade, postoperative complications, extent of resection, number of mitoses, MIB1 proliferation index, brain invasion, postoperative radiotherapy, and clinical outcome (Karnofsky performance scale [KPS] postoperatively and at long-term follow-up) were evaluated. Data regarding recurrence rate, mortality, OS, and RFS at 1-, 3-, and 5-year follow-up were also collected. Median follow-up was 76 months; all patients had at least 3 years of follow-up.

Between 2007 and 2017, 73 patients underwent surgery for atypical meningiomas (World Health Organization grade II) at 2 centers. Preoperative KPS score >80 as well as 1-month, 6-month, and 1-year follow-up KPS scores were related to better OS. Postoperative complications did not modify OS and RFS. Gross total removal (Simpson grade I, II) was achieved in 80.8% of patients. RFS was statistically influenced by extent of resection (P = 0.002). MIB1 proliferation index >8 was a negative predictive factor for recurrence at univariate and multivariate analysis (P = 0.001 and P = 0.021). Radiotherapy was statistically related to a worse outcome. The incidence of recurrence was 38%. RFS was 98.6% at 1-year follow-up, 81.1% at 3 years, and 57.5% at 5 years. All patients were alive at 1-year follow-up. OS was 90.5% at 3-year follow-up and 78.8% at 5-year follow-up.

Despite some limitations, our study demonstrates that aggressive surgical treatment achieving a gross total removal is a positive predictive parameter for RFS as well as a good clinical outcome (KPS score >80) and is related to a longer OS.