DISEASE CHARACTERISTICS:

• Histologically confirmed high-grade glioma, including any of the following:

  • Glioblastoma multiforme and its variants (e.g., gliosarcoma)

  • Anaplastic glioma, including any of the following types:

    • Anaplastic astrocytoma
    • Anaplastic oligodendroglioma
    • Anaplastic mixed oligoastrocytoma
    • Malignant astrocytoma or glioma not otherwise specified
    • Brainstem glioma by radiography or clinical diagnosis
• Unequivocal evidence of tumor progression by MRI or CT scan while on a steroid dosage that has been stable for ≥ 5 days
• Patients who have undergone prior surgical resection of recurrent or progressive tumor must have subsequent residual disease
• Failed prior radiotherapy
• No documented tumor progression during prior treatment with tamoxifen

PATIENT CHARACTERISTICS:

Age

• 18 and over

Performance status

• Karnofsky 60-100%

Life expectancy

• More than 8 weeks

Hematopoietic

• WBC ≥ 3,000/mm^3
• Absolute neutrophil count ≥ 1,500/mm^3
• Platelet count ≥ 100,000/mm^3
• Hemoglobin ≥ 10 g/dL (transfusion allowed)

Hepatic

• SGOT < 2 times upper limit of normal (ULN)
• Bilirubin < 2 times ULN
• No hepatocellular and/or cholestatic dysfunction by liver biopsy, liver ultrasound, or liver function tests
• No other hepatic disease

Renal

• Creatinine < 1.5 mg/dL AND/OR
• Creatinine clearance ≥ 60 mL/min
• No renal disease by renal biopsy, ultrasound, MRI, CT scan, or blood test

Cardiovascular

• No coronary artery disease
• No congestive heart failure
• No arrhythmia requiring medication
• No other significant active cardiac disease

Other

• Not pregnant or nursing
• Negative pregnancy test
• Fertile patients must use effective double-method contraception during and for 2 months after study participation
• Able to swallow tamoxifen tablets
• No other significant uncontrolled medical illness that would preclude study participation
• No significant severe psychiatric disease that requires hospitalization or would preclude study compliance
• No other active malignancy except nonmelanoma skin cancer or carcinoma in situ of the cervix
• No active infection requiring IV antibiotics
• No other disease that would obscure study drug toxicity or dangerously alter drug metabolism
• No peripheral neuropathy ≥ grade 2

PRIOR CONCURRENT THERAPY:

Biologic therapy

• At least 1 week since prior interferon or thalidomide
• No concurrent immunotherapy

Chemotherapy

• At least 2 weeks since prior vincristine
• At least 6 weeks since prior nitrosoureas
• At least 3 weeks since prior procarbazine
• No concurrent standard anticancer chemotherapy

Endocrine therapy

• See Disease Characteristics
• More than 6 months since prior tamoxifen

Radiotherapy

• See Disease Characteristics
• At least 4 weeks since prior and no concurrent radiotherapy

Surgery

• See Disease Characteristics

Other

• Recovered from all prior therapy
• At least 4 weeks since prior and no concurrent investigational agents
• At least 4 weeks since prior cytotoxic therapy
• At least 1 week since other prior noncytotoxic agents (e.g., isotretinoin) except radiosensitizers
• No concurrent enzyme-inducing anti-epileptic drugs (e.g., phenytoin, phenobarbital, or carbamazepine)