Histologic and clinical factors of prognostic significance in astrocytic gliomas.

The three-tiered system of classification of astrocytic gliomas that distinguishes the well differentiated astrocytoma, the anaplastic astrocytoma and the glioblastoma seems to better correlate with outcome. The knowledge of factors (histologic, clinical, radiologic and therapeutic) affecting survival in both well differentiated and anaplastic astrocytomas is limited. In both types young age and high performance status are associated with a better prognosis. The prognostic value of many factors in well differentiated tumors is still debated: this is the case for the number of mitoses, the enhancement on CT, the extent of surgery and the usefulness of postoperative radiotherapy. In anaplastic astrocytomas there is agreement about the prognostic value of endothelial proliferations: their presence is correlated with a poor prognosis. Post operative radiotherapy (5.500-6.000 cGy) significantly improves the survival time, whereas is still not known the true value of the extent of resection.