Retrospective study of association of Ki-67 labeling index with clinical outcomes after stereotactic radiosurgery for atypical meningiomas

A retrospective study at the University of Tokyo (Japan) investigated association of Ki-67 labeling index (LI) with clinical outcomes after stereotactic radiosurgery (SRS) for atypical meningioma. Ki-67 LI was categorized into 3 groups: low (<5%), intermediate (5%-10%), and high (>10%).The median follow-up was 26 months. The figure shows that low versus intermediate versus high LI was associated with better local tumor control rates, progression-free rates, and disease-specific survival rates. In multivariable analysis high versus intermediate LI was associated with lower tumor control rate (HR 3.92; p=0.026), lower progression-free rate (3.80; p=0.006) and shorter disease-specific survival (6.55; p=0.0031). Adverse radiation-induced events were seen in 8% of all patients. The authors conclude that among patients receiving SRS for atypical meningiomas, Ki-67 LI was predictive for clinical outcomes.