Value of KI-67/MIB-1 labeling index and simpson grading system to predict the recurrence of who grade I intracranial meningiomas compared to who grade II.

Simpson grading of resection has been used as a predictor of intracranial meningioma (IM) recurrence. Histopathological findings, like the Ki-67/MIB-1 labeling index, may be useful in the assessment risk of recurrence. Our objective was to analyze the predictive value of meningioma recurrence using both parameters. We retrospectively studied 322 consecutive patients with histopathological diagnosis of IM WHO grade I and 43 patients with IM WHO grade II in a 13-year period. Multivariate survival analysis was performed. In the WHO grade I IM group, recurrence was observed in 28 patients (8.69%). The Cox regression model for WHO grade I IM, provided a significative hazard ratio (HR) for Ki-67/MIB-1 index ≥3 (HR = 36.35, p < 0.001) and Simpson's grading resection, grade II (HR = 2.03, p = 0.045), grade III (HR = 3.41, p = 0.034) and grade IV (HR = 19.75, p ≥ 0.001). In the WHO grade II IM group, recurrence was observed in 10 patients (23.25%). The Cox regression model for WHO grade II IM, provided a significative hazard ratio (HR) for Ki-67/MIB-1 index ≥3% (HR = 1.66, p < 0.001) and Simpson's grading resection grade III (HR = 3.96, p = 0.027). The Kaplan-Meier survival curve showed a similar distribution of survival between WHO grade I IM with Ki-67/MIB-1 ≥3% and WHO grade II IM. In WHO grade I meningiomas, the Ki-67/MIB-1 index and Simpson grading were both independent predictors of recurrence. A similar management protocol should be advisable for WHO grade I with Ki-67/MIB-1 ≥3% and WHO grade II meningiomas.