Brain invasion was common in individuals with meningiomas World Health Organization (WHO) grade I when brain/meningioma interface was available for histology (16.5%). However, brain invasion did not impact progression-free survival (PFS).
Why this matters
The 2016 revision of the WHO classification introduced brain invasion as a single sufficient criterion for grading as meningioma grade II, which might result in more aggressive adjuvant treatment strategies in these individuals.
This study suggest that treatment decisions solely based on the presence of microscopic brain invasion should be critically discussed and investigated further in prospective controlled trials.