A Comparative Analysis of WHO Classifications and Molecular Signatures in Predicting Patient Outcomes

Introduction: The 2021 WHO classification of central nervous system tumors introduced a new classification system for meningiomas, breaking it into 15 subtypes. Given the rising importance of molecular integration into WHO meningioma classification, previous histopathological classifications of meningiomas may not accurately stratify risk of recurrence and survival in patients. We aimed to compare the previous WHO classification of central nervous system tumors with the updated 2021 integrated classification in predicting outcomes after meningioma surgery.

Methods: All patients with primary and recurrent meningiomas during the span of January 2016 to May 2023 were identified from an institutional tissue bank . A retrospective review was conducted to identify clinical data, overall and progression-free survival. Clinical data, demographics, tumor characteristics, and outcomes were evaluated. Chi-square and t tests were conducted for statistical analysis.

Results: Of the 256 patients evaluated, 102 (39.8%) possessed molecular mutations and 12 saw an increase in tumor grade under the WHO classification. CDKN2A mutations were found to be predictive of reduced overall survival in the older WHO classification (p=0.03). The incidence of NF2 mutations was significantly greater in recurrent grade I tumors compared to primary grade I tumors (p < 0.01), indicating a higher frequency in recurrence.

Conclusion : CDKN2A mutations were found to be predictive of worse survival and NF2 mutations were found to be predictive of reduced progression free-survival. Previous tissue banks and databases may find value in updating their histopathological grading to more accurately portray meningioma behavior.