Can recurrence of meningiomas be predicted

After resection of meningiomas the clinical evolution remains problematic, as no clear-cut predictive criteria are available. In vitro evaluation of meningiomas might help to predict their evolution in vivo after resection. For this goal a confrontation model was tested. A group of 105 patients operated for meningiomas between 1986 and 1997 were reviewed at 3,5,10 and 15 years for tumour evolution by tomodensitometry or magnetic resonance. At operation a fragment of these resected tumours was explanted for cell culture and was confronted with embryonic chick heart as a host tissue. The confrontation between tumour- derived cells and host tissue resulted in three different patterns: respectively a regressive, a non-invasive and an invasive pattern. Resection type, proliferation markers (Ki67 and PCNA) and in vitro confrontation patterns were significant (p<0.05) factors in predicting the postsurgical evolution of meningiomas. No correlation was found between proliferation markers and the behaviour in vitro, but invasion in vitro was strictly correlated with recurrence and malignancy of meningiomas. Meningiomas can be considered as benign tumours since their clinical outcome after total resection normally leads to complete healing. However, some tumours cannot be completely resected and a number of these partially resected meningiomas might show relapses and become even clinically malignant. This clinical malignancy is, in a number of cases, not correlated strictly with the histopathological criteria of malignancy (1). The biological behaviour of meningiomas after resection is a clinical problem for which no clearcut predictive criteria are available at the moment. The histopathological analysis on fixed material can be completed by in vitro methods that might give information on the viability, proliferation and motility of meningioma cells and, as such, on their clinical evolution. The in vitro behaviour of 117 meningiomas derived from 105 patients, who were operated on between 1986-1997, was evaluated. Primary cell cultures from freshly dissected meningiomas were prepared and, at confluency, these viable cells were allowed to form three-dimensional spheroids. The spheroids of tumour-derived cells were confronted with spheroids of normal tissue. The objectives of this study were two-fold: first, to study the interaction between meningioma-derived cells and normal tissue in vitro; second, to compare the in vitro behaviour with the postsurgical evolution in vivo with special attention to relapses. The post surgery period covers fifteen years.