Preoperative and Histological Predictors of Recurrence and Survival in Atypical Meningioma After Initial Gross Total Resection

OBJECTIVE: Atypical (World Health Organization grade II) meningiomas (AMs) have been associated with a substantial risk of recurrence even after complete, gross total resection (GTR). The present study evaluated the clinical and AM tumor histopathological features that might predict for the risk of recurrence and survival within this patient population. METHODS: The data from 72 consecutive patients who had undergone primary GTR for AM from 2007 to 2016 and corresponding tumor specimens at a single institution were reviewed. The preoperative patient and tumor characteristics were correlated with the post-resection outcomes, including recurrence and 1-year survival. Cox regression models on recurrence-free survival (RFS) and Kaplan-Meier survival estimates were performed. RESULTS: The overall 1-, 3-, and 5-year RFS estimates for the AM cohort were 100.0%, 82.4%, and 78.1% after resection, respectively. A high mitotic index was an independent predictor of RFS on Cox regression analysis (hazard ratio, 1.26; P = 0.008), and the tumor volume showed a trend toward a significant association (hazard ratio, 0.93; P = 0.079). Patient age and the mitotic index were significantly associated with 1-year mortality (odds ratio, 1.11 and 1.36, respectively; P = 0.028 and P = 0.045, respectively). CONCLUSIONS: AM tumors with a high proliferative index showed an increased likelihood of recurrence and short-term survival even after complete GTR. A smaller tumor volume might also have contributed to an increased risk of recurrence for patients with AM. Although other histopathological features were not linked to recurrence or mortality for patients with AM, the biopsy findings can indicate key predictive information, and further molecular analysis might reveal additional prognostic markers.