WHO Grade III Meningiomas: De Novo Tumors Show Improved Progression-Free Survival Compared to Secondary Progressive Tumors

Background: Emerging evidence suggests de novo versus secondary progressive intracranial grade III meningiomas may harbor differing prognoses.

Objective: The aim of the study is to better understand the prognosis of patients treated for grade III meningioma.

Methods: A single institution, retrospective analysis of prospectively acquired patients between 1999 and 2018 was performed. Clinical data and radiographic parameters were reviewed to calculate progression-free survival and overall survival in patients undergoing microsurgical resection. Next generation targeted sequencing of meningioma associated genes was performed on 11 tumors.

Results: Between 1999 and 2018, 18 patients met the inclusion criteria for this study. Nine patients (50%) had de novo arising tumors and nine patients had secondary progressive tumors. There was an improvement in median progression-free survival for de novo resected tumors as compared with secondary progressive tumors (27 months vs. 5 months, p = 0.02). There was a trend toward improvement in overall survival for patients with de novo tumors (91 months vs. 22 months, p = 0.17). Similar trends were seen when stratifying based on the extent of resection and tumor location. Next generation sequencing of targeted genes (NF2, BAP1, TRAF7, KLF4, SMO, and AKT) revealed 5/11 tumors containing mutations in the NF2 gene, 2/11 containing BAP1 mutations, and a single tumor containing mutations in both NF2 and TRAF7. More mutations in NF2 and BAP1 were seen in the secondary progressive tumors.

Conclusion: Patients undergoing treatment for de novo arising grade III meningiomas showed improved progression-free survival compared with those patients with secondary progressive tumors. Further studies are needed to improve risk-stratification and development of therapeutics.