The Ki-67 proliferation index and recurrence risk of intracranial meningioma: a multicenter, retrospective cohort study of 5,050 patients

Abstract

PurposeThe Ki-67 proliferation index (Ki-67 PI) has been associated with meningioma recurrence, yet its clinical utility remains debated. Whether Ki-67 PI provides prognostic information across subgroups defined by both WHO grade and extent of resection remains to be investigated.MethodsWe analyzed 5,050 patients with intracranial meningiomas from the international PERNS cohort (42 centers, diagnosed between 1989-2019) who underwent surgical resection without postoperative radiotherapy. Ki-67 PI prognostic accuracy was assessed up to 10 years postoperatively by using ROC analyses and estimating its association with the risk of recurrence.ResultsResults demonstrated that the prognostic value of Ki-67 PI differed by subgroups defined by WHO grade and Simpson grade. For patients with the same Simpson grade (1-3), the predictive accuracy of Ki-67 PI for 10-year recurrence risk was stronger in WHO-2 than in WHO-1. Within WHO-1 and WHO-2 meningiomas, the predictive accuracy of Ki-67 PI increased with higher Simpson grade (1-3). However, no predictive value was observed in Simpson grade 4 resections regardless of WHO grade.ConclusionThese findings highlight that Ki-67 PI should be interpreted in the context of both WHO grade and extent of resection, and, if done so, may offer potential value to refine individualized surveillance strategies in meningioma patients with gross total resection in the initial 10-year postoperative timeframe. Findings cannot be extrapolated beyond 10 years, which may be particularly relevant for WHO-1 tumors with low Ki-67 PI and Simpson grade 1 resection.