Inclusion Criteria

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