World Health Organization Grade III Meningiomas: A Retrospective Study at an Academic Medical Center

Abstract

Meningiomas are the most common primary brain tumors and are generally considered benign. However, a rare subgroup of meningiomas, classified as World Health Organization (WHO) grade III meningiomas, can show extremely aggressive behavior and high rates of recurrence. Despite ongoing research, data on the clinical outcome of this subgroup of meningiomas are still limited. Medical records of patients with WHO grade III meningiomas diagnosed between 2000 and 2018 at the Coimbra University Hospital Center were retrospectively reviewed and several variables of interest and their relation to patients' survival were analyzed. Of the 26 patients included in the final analysis, 23 had anaplastic meningiomas, 2 had papillary meningiomas, and 1 had a rhabdoid meningioma. Median overall survival and median progression-free survival were 2.45 and 1.22 years, respectively. Overall survival at 1, 2 and 5 years was 73%, 57%, and 35%, respectively. Adjuvant radiotherapy correlated with improved survival for subtotally resected meningiomas but not for gross totally resected meningiomas. There was a trend toward improved overall survival with gross total resection versus subtotal resection, but this difference failed to reach statistical significance. This study provides insight into the clinical outcomes of WHO grade III meningiomas and suggests that adjuvant radiotherapy may not be beneficial for patients who underwent gross total resection. This rare subset of meningiomas still portends a devastating prognosis and the impact of extent of resection and adjuvant therapies in these patients needs further clarification.