Carmustine in Treating Patients With Progressive or Recurrent Glioblastoma Multiforme

DISEASE CHARACTERISTICS: Histologically proven supratentorial malignant glioblastoma multiforme Clear evidence of disease progression by MRI Unresectable tumor that has spherical, spheroid, or ovoid shape (not multicentric or multilobulated) Central necrosis and/or central cystic areas allowed in the presence of enhancing rim thickness greater than 5 mm No brainstem (pons or medulla) or midbrain (mesencephalon) involvement No involvement of primary sensorimotor cortex in the dominant hemisphere or within 1.5 cm of the optic chiasm, either optic nerve, or any other cranial nerve No tumor extension into the ventricular system Tumor volume no greater than 33.4 cm3 At least one prior radiotherapy PATIENT CHARACTERISTICS: Age: 18 to 75 Performance status: Karnofsky 60-100% Life expectancy: Not specified Hematopoietic: Absolute neutrophil count at least 1,500/mm^3 Platelet count at least 100,000/mm^3 No evidence of bleeding diathesis Hepatic: Bilirubin no greater than 2.0 mg/dL SGOT/SGPT no greater than 2.5 times normal Renal: Creatinine no greater than 2.0 mg/dL OR Creatinine clearance at least 40 mL/min BUN no greater than 30 mg/dL Other: Not pregnant or nursing Negative pregnancy test Fertile patients must use effective contraception No active uncontrolled infection Afebrile unless fever due to presence of tumor No other concurrent serious medical or psychiatric illness that would preclude study PRIOR CONCURRENT THERAPY: Biologic therapy: Not specified Chemotherapy: At least 4 weeks since prior chemotherapy (6 weeks for nitrosoureas or mitomycin including Gliadel wafer therapy) and recovered Endocrine therapy: Not specified Radiotherapy: See Disease Characteristics At least 4 weeks since prior radiotherapy and recovered No prior intracranial brachytherapy Surgery: Recovered from any prior surgery Other: No prior anticoagulants No other concurrent investigational agents