DISEASE CHARACTERISTICS: Histologically confirmed malignant glioma: Anaplastic astrocytoma Anaplastic oligodendroglioma Glioblastoma multiforme Unifocal disease Progressive or recurrent disease following radiation therapy and/or chemotherapy Must be eligible for surgical resection of the tumor mass No unresectable leptomeningeal spread or ventricular invasion outside the radiation treatment volume No exophytic ventricular tumors Must have a maximal cross-sectional diameter enhancing tumor greater than 2.0 cm but not greater than 5.0 cm by preoperative MRI Ratio of major axes of the tumor should not exceed 1.5 No marked edema by preoperative MRI or CT that cannot be corrected by tumor resection