DISEASE CHARACTERISTICS:

• Histologically or cytologically confirmed incurable oligodendroglioma that progressed during or is recurrent or residual after initial therapy, including radiotherapy and/or chemotherapy
• Evidence of tumor by gadolinium-enhanced MRI, CT scan, or positron-emission tomography
• Measurable disease by MRI or CT scan
• Tumor must be at least 5 mm
• Must have received and failed prior standard therapy (i.e., radiotherapy, chemotherapy, immunotherapy, or cytodifferentiating agent)
• No brain stem tumors

PATIENT CHARACTERISTICS:

Age:

• 18 and over

Performance status:

• Karnofsky 60-100%

Life expectancy:

• At least 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/SGPT no greater than 5 times upper limit of normal
• No hepatic failure

Renal:

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

Cardiovascular:

• No severe heart disease
• No uncontrolled hypertension
• 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 serious active infections
• No other serious concurrent disease

PRIOR CONCURRENT THERAPY:

Biologic therapy:

• See Disease Characteristics
• At least 4 weeks since prior immunotherapy

Chemotherapy:

• See Disease Characteristics
• At least 4 weeks since prior chemotherapy (6 weeks for nitrosoureas)

Endocrine therapy:

• Concurrent corticosteroids allowed

Radiotherapy:

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

Surgery:

• Recovered from any prior surgery

Other:

• No prior antineoplaston therapy