Post-Operative Outcomes in CNS Who Grade 2 and 3 Meningioma: A Systematic Review and Meta-Analysis

Abstract AIMS WHO grade 2 and 3 meningioma constitute approximately 20% of all meningioma. The lower incidence of these more aggressive meningioma has led to under-representation of clinical outcomes in the literature. Therefore only broad estimates of post-operative outcomes exist. We aimed to establish incidence of recurrence and 5-year PFS and OS rates in grade 2 and 3 meningioma. METHODS A PRISMA-compliant systematic review was conducted (PROSPERO CRD42023441009). MEDLINE, EMBASE, and Cochrane Library databases were searched between inception and September 2023. Studies of adults (16 y.o.) with histologically proven WHO grade 2 and 3 cranial meningioma who underwent surgery with/without adju- vant radiation and/or stereotactic radiosurgery were included. Primary outcome was pooled annual incidence of meningioma recurrence and secondary outcomes were pooled 5-year progression-free survival (PFS) and 5-year overall survival (OS) using random effects models. RESULTS A total of 68 and 6 articles reporting the primary outcome were included for grade 2 and 3 meningioma, respec- tively. (5039 grade 2 patients, 78 grade 3 patients). Pooled annual incidence of recurrence was 6% (68 studies, 955 confidence interval CI: 5-7%) and 20% (6 studies, 95% CI: 10-37%) for grade 2 and 3 meningioma, respectively. Pooled 5-year PFS and OS for grade 2 meningioma was 69% (16 studies, 95% CI: 63-74%) and 85% (9 studies, 95% CI: 78-89%), respectively. There was only one study reporting 5-year PFS (42 patients, 5-year PFS 12%) 5-year OS (35.8%) for grade 3 meningioma. CONCLUSION This is the first large systematic review of a large number of studies of grade 2 meningioma and reports pooled recurrence rate, 5-year PFS, and 5-year OS. Studies of grade 3 meningioma are limited due to their rarity. Our findings are limited by the retrospective nature of most included studies and clinical heterogeneity among the studies.