World Health Organization grade 3 meningioma
Accumulation of MCs in meningiomas could contribute to the aggressiveness of tumors and to brain inflammation that may be involved in the pathogenesis of additional disorders 1).
From the available data, surgical resection followed by RT and salvage therapy can lead to extended survival 2).
Adjuvant radiotherapy and stereotactic radiosurgery
For a systematic review, studies analyzing the effectiveness of adjuvant radiotherapy and stereotactic radiosurgery in grade 3 (gr. 3) meningioma were reviewed. Thirty studies met the inclusion criteria for qualitative synthesis, and 6 studies were assessed in quantitative analysis. In quantitative analysis, the weighted average of hazard ratios for adjuvant RT in univariate analyses of overall survival (OS) was 0.55 (CI: 0.41; 0.69). The median 5-year OS after adjuvant RT in gr. 3 meningiomas were 56.3%, and the median OS ranged from 24 to 80 months for patients treated with adjuvant RT versus 13 to 41.2 months in patients not treated. For stereotactic radiosurgery, the 3-year progression-free survival was 0% in one study and 57% in another. The 2-year OS ranged from 25 to 75% in 2 studies. The quality of evidence was rated as “very low” in 14 studies analyzed, and considerable allocation bias was detected. Treatment toxicity was reported in 47% of the studies. The severity, according to the CTCAE, ranged from grades I-V and 5.3 to 100% of patients experiencing complications. Adjuvant RT is usually considered the standard of care for WHO grade 3 meningiomas, although supporting evidence was of low quality. Better evidence from registries and prospective trials can improve the evidence base for adjuvant fractionated radiotherapy in malignant meningiomas 3).