Influence of clinical and histological criteria on meningioma recurrence: The decisive role of Ki-67.

Objective: The risk of meningioma recurrence depends mainly on the extent of resection and tumor grade. In a series of 196 meningiomas, we investigated the influence of clinical and histopathological criteria and sought to identify simple and reproducible criteria associated with meningioma recurrence.

Materials and methods: Clinical data (age, sex, location), preoperative embolization (POE), presence of peritumoral edema, Simpson grade, histological grade and histopathological parameters (Ki-67 index labeling index (LI), mitotic index, hypercellularity, small cells, prominent nucleoli, sheeting pattern, necrosis, nuclear atypia, microvascular proliferation as well as infiltration of the dura mater, bone and brain), and dura mater were collected. The prognostic value of each parameter for recurrence-free survival (RFS) was assessed using the Kaplan-Meier method and log-rank test. Multivariate analysis was carried out using a Cox regression model on single features identified by univariate analysis.

Results: The Ki-67 LI was the factor most strongly associated with recurrence. In multivariate analysis, independent factors for shorter RFS were male sex, subtotal resection, and a Ki-67 LI > 5%, which was the most significant factor. In addition, a Ki-67 LI > 5% was strongly associated with shorter RFS (p = 9.79e-05) for grade 1 meningiomas in multivariate analysis. Ki-67 LI assessment and POE did not modify the Ki-67 LI evaluation.

Conclusion: Importantly, for grade 1 meningiomas, which are tumors that lack histological criteria for aggressiveness, a Ki-67 > 5% is a predictive factor for recurrence. These data, which are easy to collect and reproduce, could be used in practice to select patients who would benefit from closer clinical follow-up or to identify tumors requiring further molecular analysis at the time of first surgery.