Recurrent Malignant Gliomas Treated with Radiosurgery

Abstract

The inability to control malignant glioma results in a high incidence of local failure and poor survival. Focal therapy such as radiosurgery permits delivery of a high dose of radiation with moderate toxicity. This report summarizes the outcome of patients with recurrent malignant glioma treated with radiosurgery at University of Wisconsin Hospital, between January 1989 and December 1997, when 30 patients were treated radiosurgically. All patients had undergone and failed external beam radiotherapy (median dose of 59.4 Gy) prior to radiosurgery. All recurrences were detected by clinical deterioration and confirmed by radiographic progression. No patient was treated for radiographic progression only in the context of a screening protocol. Eight out of 30 patients underwent subtotal resection prior to radiosurgery and 3 received chemotherapy along with radiosurgery. Radiosurgery was delivered in a single fraction using a modified linear accelerator. The median tumor volume was 7.2 cm³ (range 0.42–35.1 cm³) and the median minimal tumor dose was 12 Gy at the 50–80% isodose line. Median follow-up is 70 months. The median overall survival is 8 months; the 1- and 2-year survival rates are 20% and 9%, respectively. For patients with an initial diagnosis of non-glioblastoma, the median survival is 11 months and for those with glioblastoma the median survival is 7 months. The median progression-free survival is 4 months for the entire cohort, 5 months for nonglioblastoma, and 3 months for glioblastoma. The 1-year actuarial reoperation rate after radio-surgery is 7.6%. Radiosurgery for recurrent malignant glioma may improve short-term survival for selected patients with a lower reoperation rate than brachytherapy.