Prognostic factors for patients with World Health Organization grade III meningiomas treated at a single center

We analyzed the characteristics of patients with World Health Organization (WHO) grade III meningioma to identify factors that may predict tumor recurrence and overall survival (OS).We retrospectively reviewed the patients diagnosed with WHO grade III meningioma who were surgically treated at our institute between 2008 and 2016. Survival outcome was assessed by Kaplan-Meier analysis. Cox regression analyses were performed to identify the prognostic factors associated with tumor recurrence and OS.Forty-two patients were included. The mean follow-up time was 23.2 months (range 2-75 months). At the end of analysis, 30 patients were found with tumor recurrence. The 1-year, 3-year, and 5-year recurrence-free survival (RFS) were 51.6%, 33.9%, and 12.0%, respectively. At final follow-up, 23 patients were deceased, the 1-year, 3-year, and 5-year OS were 66.2%, 39.7%, and 35.8%, respectively. Twenty-eight newly diagnosed patients were included, and the 1-year, 3-year, and 5-year RFS were 63.5%, 44.3%, and 19.4%, respectively, and the 1-year, 3-year, and 5-year OS were 74.6%, 52.5%, and 46.7%, respectively. Extent of resection was the only factor associated with tumor recurrence and OS.WHO grade III meningioma is rare, and difficult to manage with a high rate of recurrence and poor OS. Extent of resection is an independent prognostic factor related to tumor recurrence and OS. We could not confirm the usefulness of Ki-67. We suggest that more aggressive treatment, such as safety maximizing cytoreduction by surgery, would improve treatment outcomes.