INFLUENCE OF AN OLIGODENDROGLIAL COMPONENT ON THE SURVIVAL OF PATIENTS WITH ANAPLASTIC ASTROCYTOMAS - A REPORT OF RADIATION-THERAPY ONCOLOGY GROUP-83-02

Purpose: Seven percent of patients with high grade gliomas enrolled in RTOG 83-02 had mixed astrocytoma/ oligodenroglial elements on central pathology review. It has often been assumed that the most aggressive histologic component of a tumor determines biologic behavior; however in this trial, the survival of patients who had mixed glioblastomas/ol igodenrogliomas was significantly longer than that of patients with pu re glioblastomas (GBM). We therefore evaluated the effect of an oligod endroglial component on the survival of patients who had anaplastic as trocytomas (AAF) treated in the same trial, Methods and Materials: One hundred nine patients who had AAF and 23 patients with mixed AAF/olig odendrogliomas (AAF/OL) were enrolled in a Phase I/II trial of randomi zed dose-escalation hyperfractioned radiotherapy plus BCNU, AAF/OL pat ients were older and more Likely to have had more aggressive surgery t han AAF patients, Other pretreatment characteristics were balanced bet ween groups, as was assigned treatment, Results: The median survival t ime for AAF was 3.0 years versus 7.3 years for AAF/OL (p = 0.019), In a multivariate analysis, adjusting for extent of surgical resection an d age, an oligodendroglial component was an independent prognostic fac tor for survival, Conclusion: The results support the concept that AAF s with an oligodendroglial component have a better prognosis than pure AAF tumors, similar to the effect seen among patients with glioblasto ma multiforme tumors, This better survival outcome should be taken int o consideration in the design and stratification of future trials. Add itionally, in contrast to patients with GBMs, patients who have AAF/OL have the potential for prolonged survival; therefore, late sequelae o f treatment( both radiation and chemotherapy) must be weighed more hea vily in the benefits to risks analysis. (C) 1997 Elsevier Science Inc.