Perhaps contrary to expectations, the presence of an oligodendroglial component in patients with anaplastic astrocytomas was associated with a significantly longer survival than were pure anaplastic tumors. This finding emerged from a randomized phase I-II trial from the Radiation Therapy Oncology Group (RTOG).
In this study, Dr. Bernadine Donahue of New York University, and colleagues reviewed the data on 133 adults who met the criteria defined for an anaplastic astrocytoma: the absence of tumor necrosis with the presence of two or more of the following features: nucleopleomorphism, increased cell density, mitotic figures, or vascular prominence. Of these patients, 24 were considered to have oligodendroglial elements.
There was a marginally significant difference in age, with patients who had oligodendroglial elements being slightly older than patients with pure anaplastic astrocytomas. Patients with oligodendroglial elements were also more likely to have had resection than biopsy. Although there was no difference in the performance status or neurologic function status between the patients with pure anaplastic astrocytomas and the patients who had anaplastic astrocytomas with oligodendroglial components, there was a significant difference in survival: the median survival of patients with pure anaplastic astrocytomas was 3 years vs 7.3 years for patients who had anaplastic astrocytomas with oligodendroglial elements.