Preoperative and histological predictors of recurrence and survival in atypical meningioma after initial gross total resection.

OBJECTIVE: Atypical (WHO grade II) meningiomas (AM) are associated with a substantial risk for recurrence even following a complete, gross total resection (GTR). The present study aimed to evaluate clinical and AM tumor histopathological features that may predict risk of recurrence and survival within this patient population.

METHODS: 72 consecutive patients and corresponding tumor specimens who received a primary GTR for an AM from 2007-2016 at a single institution were reviewed. Preoperative patient and tumor characteristics were correlated with 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: Overall 1, 3, and 5-year RFS estimates for the AM cohort were 100.0, 82.4, and 78.1%, respectively post-resection. High mitotic index was found to be an independent predictor of RFS on Cox regression analysis (HR=1.26, p=0.008), while tumor volume trended towards a significant association (HR=0.93, p=0.079). Age and mitotic index were significantly associated with 1-year mortality (OR=1.11 and 1.36, p=0.028 and 0.045, respectively).

CONCLUSIONS: AM tumors with a high proliferative index increased the likelihood of recurrence and short-term survival even after complete resection. Smaller tumor volume may also contribute to an increased risk of recurrence within AM patients. While other histopathological features were not linked to recurrence or mortality within AM patients, biopsy examination can indicate key predictive information, and further molecular analysis may reveal additional prognostic markers.