Effectiveness of intraoperative radiation therapy for recurrent supratentorial low grade glioma.

Twelve adult patients in the records of 38 patients with histologically verified supratentorial low grade glioma showed recurrence at the Gifu University Hospital between 1980 and 1992. A mean period to recurrence from the initial surgery and postoperative radiation was 38 months. Six of these patients underwent intraoperative radiation therapy. The other six patients received chemotherapy with conventional cytoreductive surgery in three cases and additional external irradiation in three cases. The 2-year survival rate of the former patients was 83.8% and significantly higher than that of the latter ones, 16.7% (p < 0.05). Most cases showing recurrence of supratentorial low grade glioma were occurred locally, and dissemination or remote metastasis of the lesion were rare. The results revealed that the local control is important for recurrent tumors of supratentorial low grade gliomas. The effectiveness of the intraoperative radiation therapy as the second operation for the recurrent supratentorial benign glioma is discussed.