Antineoplaston Therapy in Treating Children With Low-Grade Astrocytoma

DISEASE CHARACTERISTICS: Histologically confirmed low grade astrocytoma. Evidence of persistent or progressive tumor after standard therapy by MRI scan performed within 2 weeks prior to study entry Tumor must be at least 5 mm PATIENT CHARACTERISTICS: Age: 6 months to 17 years Performance status: Karnofsky 60-100% Life expectancy: At least 2 months Hematopoietic: WBC at least 2,000/mm^3 Platelet count greater than 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 other cardiovascular conditions that contraindicate high dosages of sodium Pulmonary: No severe lung disease Other: Not pregnant or nursing Fertile patients must use effective contraception during and for 4 weeks after study participation No serious active infections or fever No other serious concurrent disease PRIOR CONCURRENT THERAPY: Biologic therapy: At least 4 weeks since prior immunotherapy and recovered No concurrent immunomodulating agents Chemotherapy: At least 4 weeks since prior chemotherapy (6 weeks for nitrosoureas) and recovered No concurrent antineoplastic agents Endocrine therapy: Concurrent corticosteroids for cerebral edema allowed (must be on stable dose for at least 1 week prior to study entry) Radiotherapy: At least 8 weeks since prior radiotherapy and recovered Surgery: Not specified Other: No prior antineoplaston therapy