Antineoplaston Therapy in Treating Patients With Low-Grade Astrocytoma

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) Measurable tumor by MRI scan performed within two weeks prior to study entry 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