Hypofractionated Stereotactic Radiotherapy for Recurrent Malignant Gliomas

Objective: The results of hypofractionated stereotactic radiotherapy (SRT) for the treatment of unselected patients with malignant glioma recurrent after conventional therapy were analyzed. Materials and Methods: Between January 1997 and March 1999, 21 patients with recurrent malignant glioma received SRT at UCLA. All patients received prior conventional radiotherapy (median 6000 cGy). The interval from initial diagnosis to SRT varied from 3 to 99 months (median 11). Tumor volume ranged from 4.5 to 33.7 cc (median 12). Fifteen patients had glioblastoma multiforme and 3 had anaplastic astrocytoma with an oligodendroglial component. Two patients with prior low-grade astrocytoma and one with an unbiopsied brainstem tumor did not have pathological confirmation of tumor grade at time of relapse. Five patients had multifocal recurrences and 11 had imaging evidence of indistinct tumor. Twelve patients had progressive disease after receiving salvage chemotherapy. Patients received 4–6 daily fractions of 400 to 600 cGy. Median total SRT dose was 2500 cGy. Follow-up ranged from 1 to 20 months and no patients were lost. Results: The actuarial median and one-year survival were 6.7 months and 15%, respectively. Fifteen patients died of progressive glioma and one of a pulmonary embolus. Sixteen patients relapsed after SRT: 11 local, 4 local plus distant, one marginal. All patients with distant relapse also had local failure at some time. The median time to local relapse for the 14 patients with an initial component of local failure was 5 months. There were trends to superior survival for those with an initial diagnosis of nonglioblastoma and those with frontal/occipital lobe recurrences. No patient developed documented radionecrosis. Two patients underwent operation following SRT. Histopathological analysis of the operative specimen revealed malignant glioma. Conclusions: The authors conclude that hypofractionated SRT is a feasible, safe alternative for patients with recurrent malignant glioma. Local failure represents the overwhelming pattern of relapse after SRT, regardless of the clinical or imaging characteristics of patients with recurrent tumor. Improving the outcome for this group of patients may require a multimodality approach of SRT plus concurrent chemotherapy.