DISEASE CHARACTERISTICS:

• Histologically or cytologically confirmed low-grade astrocytoma that has progressed, recurred, or persisted after initial therapy, including radiotherapy

• Previously treated with at least 1 prior standard therapy (e.g., radiotherapy, chemotherapy, immunotherapy, or cytodifferentiating agent)

  • Must have failed standard therapy

• Measurable disease by MRI or CT scan

  • Tumor must be at least 5 mm
• No brain stem tumors

PATIENT CHARACTERISTICS:

Age:

• 18 and over

Performance status:

• Karnofsky 60-100%

Life expectancy:

• More than 2 months

Hematopoietic:

• WBC at least 2,000/mm^3
• Platelet count at least 50,000/mm^3

Hepatic:

• Bilirubin no greater than 2.5 mg/dL
• SGOT and SGPT no greater than 5 times upper limit of normal
• No hepatic failure

Renal:

• Creatinine no greater than 2.5 mg/dL
• No renal insufficiency
• No history of renal conditions that contraindicate high dosages of sodium

Cardiovascular:

• No uncontrolled hypertension
• No chronic heart failure
• No history of congestive heart failure
• No history of other cardiovascular conditions that contraindicate high dosages of sodium

Pulmonary:

• No severe lung disease (e.g., chronic obstructive pulmonary disease)

Other:

• Not pregnant or nursing
• Fertile patients must use effective contraception during and for 4 weeks after study participation
• No other concurrent serious disease
• No active infection

PRIOR CONCURRENT THERAPY:

Biologic therapy:

• See Disease Characteristics
• At least 4 weeks since prior immunotherapy and recovered
• No concurrent immunomodulating agents

Chemotherapy:

• See Disease Characteristics
• At least 4 weeks since prior chemotherapy (6 weeks for nitrosoureas) and recovered
• No concurrent antineoplastic agents

Endocrine therapy:

• Concurrent corticosteroids allowed

Radiotherapy:

• See Disease Characteristics
• At least 8 weeks since prior radiotherapy and recovered

Surgery:

• Must recover from prior surgery

Other:

• No prior antineoplastons