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Prognostic significance of brain invasion in meningiomas: systematic review and meta-analysis
Satoshi Nakasu1,2, Yoko Nakasu3,4
1Division of Neurosurgery, Kusatsu General Hospital, Yabase-cho 1660, Kusatsu, Shiga, 525-8585, Japan. neuro-nakasu@kfx.biglobe.ne.jp.
Abstract:
The WHO 2016 classification introduced brain invasion as a standalone criterion for grade II meningioma (GIIM). We systematically reviewed studies published after 2000 and performed a PRISMA-compliant meta-analysis of the hazard ratios (HRs) for progression-free survival (PFS) between brain-invasive and noninvasive meningiomas. In five studies that included both benign and higher-grade meningiomas, brain invasion was a significant risk factor for recurrence (HR = 2.45, p = 0.0004). However, in 3 studies comparing "brain-invasive meningioma with otherwise benign histology (BIOB)" with grade I meningioma, brain invasion was not a significant predictor of PFS (HR = 1.49, p = 0.23). Among GIIM per the WHO 2000 criteria, brain invasion was a significant predictor of shorter PFS than noninvasive GIIM (HR = 3.40, p = 0.001) but not per the WHO 2016 criteria (HR 1.13, p = 0.54), as the latter includes BIOB. Meta-regression analysis of seven studies of grade II meningioma showed that more frequent BIOB was associated with lower HRs (p < 0.0001). Hence, there is no rationale for brain invasion as a standalone criterion for grade II meningioma, although almost all studies were retrospective and exhibited highly heterogeneous HRs due to differences in brain-tumor interface data availability.
Insights
Brain invasion is not a reliable standalone criterion for grade II meningioma. Studies show it does not significantly predict progression-free survival, especially when considering benign histology.
Area of Science:
- Neuropathology
- Oncology
- Neurosurgery
Background:
- The World Health Organization (WHO) 2016 classification introduced brain invasion as a standalone criterion for grading II meningioma.
- Meningiomas are tumors arising from the meninges, with varying degrees of aggressiveness.
- Accurate grading is crucial for determining prognosis and treatment strategies.
Purpose of the Study:
- To evaluate the validity of brain invasion as an independent criterion for grade II meningioma.
- To assess the impact of brain invasion on progression-free survival (PFS) in meningiomas.
- To analyze the influence of histology on the prognostic significance of brain invasion.
Main Methods:
- Systematic review of studies published after 2000.
- PRISMA-compliant meta-analysis of hazard ratios (HRs) for PFS.
- Meta-regression analysis to explore factors influencing HRs.
Main Results:
- Brain invasion was a significant risk factor for recurrence in studies including benign and higher-grade meningiomas (HR=2.45, p=0.0004).
- Brain invasion was not a significant predictor of PFS in "brain-invasive meningioma with otherwise benign histology" (BIOB) compared to grade I meningioma (HR=1.49, p=0.23).
- Brain invasion predicted shorter PFS in grade II meningioma per WHO 2000 criteria (HR=3.40, p=0.001) but not per WHO 2016 criteria (HR=1.13, p=0.54).
- Increased proportion of BIOB was associated with lower HRs (p<0.0001).
Conclusions:
- Brain invasion lacks a strong rationale as a standalone criterion for grade II meningioma.
- The prognostic significance of brain invasion is influenced by histological subtypes, particularly BIOB.
- Heterogeneity in data and retrospective study designs limit definitive conclusions.
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