Antineoplaston Therapy in Treating Patients With Primary Central Nervous System Lymphoma

DISEASE CHARACTERISTICS: Histologically confirmed stage I-IV primary central nervous system lymphoma for which no curative therapy exists Measurable tumor by MRI or CT scan Tumor must be greater than 2 cm in largest diameter PATIENT CHARACTERISTICS: Age: 18 and over Performance status: Karnofsky 60-100% Life expectancy: At least 2 months Hematopoietic: WBC greater than 2,000/mm^3 Platelet count greater than 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 insufficiency Renal: Creatinine no greater than 2.5 mg/dL No history of renal conditions that contraindicate high dosages of sodium Cardiovascular: No cardiac insufficiency No hypertension No history of congestive heart failure No history of other cardiovascular conditions that contraindicate high dosages of sodium Other: Not pregnant or nursing Fertile patients must use effective contraception during and for at least 4 weeks after study participation No serious infection requiring antibiotics, antifungals, or antivirals PRIOR CONCURRENT THERAPY: Biologic therapy: At least 4 weeks since prior immunotherapy and recovered No concurrent immunomodulatory agents (e.g., interferon or interleukin-2) Chemotherapy: At least 4 weeks since prior chemotherapy (6 weeks for nitrosoureas) and recovered No concurrent antineoplastic agent Endocrine therapy: Concurrent corticosteroids allowed Must be on stable dose for at least 4 weeks prior to study entry Radiotherapy: At least 8 weeks since prior radiotherapy and recovered Surgery: Not specified Other: No prior antineoplastons