Recurrences of meningiomas: predictive value of pathological features and hormonal and growth factors

Objective: Recurrence of apparently completely resected benign meningiomas is a rather frequent event, the mechanisms of which are still unclear. The aim of this study is to define the pathological features, proliferation indexes, growth factors and hormone receptor expression in predicting the meningioma recurrence. Methods: Two groups of 50 completely resected benign WHO I meningiomas, with and without recurrence respectively, have been reviewed. Tumor location, consistency, vascularity, and histological types have been considered. Immunohistological studies include mitotic index (MI), Ki-67 LI, estrogen and progesterone receptors (ER and PR), Vascular Endothelial Growth Factor (VEGF), Epidermal Growth Factor (EGF), and Bcl-2. All these factors have been correlated with the recurrence. Results: The tumor recurrence was not correlated with the patient age, tumor location, consistency, vascularity and histology. There was not difference in the histological pattern between local and diffuse recurrences. M.I. and Ki-67 LI were significantly correlated with the recurrence (P < 0.0001). PR negativity had a strong predictive value of recurrence (P < 0.0001), whereas the ER status was not relevant. VEGF and EGF-R were not correlated with the recurrence of meningiomas, whereas the Bcl-2 protein positivity showed a tendency to the significativity (P=0.0294). The negative association between Bcl-2 and PR is an interesting finding of our study. Conclusions: Higher MI and Ki-67 LI and PR negativity are predictive factors of recurrence of benign (WHO I) completely resected meningiomas, particularly when Bcl-2 positivity is associated.