Long Term Surgical Outcome and Prognostic Factors of Atypical and Malignant Meningiomas

Atypical and malignant meningiomas are rare. Our aim was to examine the treatment outcomes following surgical resection, and analyze associations between clinical characteristics and overall survival (OS) or relapse free survival (RFS). 102 patients with atypical or malignant meningiomas underwent microsurgical resection between June 2001 and November 2009 were analyzed retrospectively. We compared demographics, clinical characteristics, treatment, and complications. The five-year and ten-year overall survival rates were 93.5% and 83.4%, respectively. Three factors significantly reduced OS: Malignant meningiomas (p < 0.001), which also decreased RFS (p < 0.001); female patients (p = 0.049), and patients with Karnofsky Performance Status (KPS) < 70 at diagnosis (p = 0.009). Fifty two patients (51%) experienced tumor relapse. Total resection of tumors significantly impacted RFS (p = 0.013). Tumors located at parasagittal and posterior fossa area lead to higher relapse rate (p = 0.004). Subtotal resection without adjuvant radiotherapy lead to the worst local control of tumor (p = 0.030). An MIB-1 index <8% improved OS and RFS (p = 0.003). Total resection of atypical and malignant meningiomas provided better outcome and local control. Adjuvant radiation therapy is indicated for patients with malignant meningiomas, with incompletely excised tumors; or with tumors in the parasagittal or posterior fossa area. The MIB-1 index of the tumor is an independent prognostic factor of clinical outcome.