Methotrexate and Thiotepa in Treating Patients With Newly Diagnosed Primary CNS Lymphoma

You may be eligible if

• DISEASE CHARACTERISTICS:
• Histologically confirmed primary CNS lymphoma
• * Confirmed by 1 of the following:
• * Brain biopsy or resection
• * CSF cytology
• * Positive cytology or immunohistochemical diagnosis of monoclonality and measurable intracranial tumor
• * Vitreal biopsy
• Measurable and contrast-enhancing disease on the postoperative, pretreatment MRI or CT scan
• No radiographic evidence of ascites or pleural effusions
• PATIENT CHARACTERISTICS:
• Age
• 18 and over
• Performance status
• Karnofsky 60-100%
• Life expectancy
• Not specified
• Hematopoietic
• Absolute neutrophil count at least 1,500/mm\^3
• Platelet count at least 100,000/mm\^3
• Hepatic
• Bilirubin no greater than 2.0 mg/dL
• SGOT no greater than 4 times upper limit of normal
• Renal
• Creatinine no greater than 2 mg/dL
• Creatinine clearance at least 50 mL/min
• Other
• Mini mental score of at least 15
• HIV negative
• Able to achieve hydration
• No other malignancy within the past 5 years except curatively treated basal cell or squamous cell skin cancer or carcinoma in situ
• No allergy to methotrexate
• No serious infection
• No medical illness that would preclude study participation
• Not pregnant or nursing
• Negative pregnancy test
• Fertile patients must use effective contraception
• PRIOR CONCURRENT THERAPY:
• Biologic therapy
• No prior immunotherapy or biologic therapy for this disease
• Chemotherapy
• No prior chemotherapy for this disease
• No other concurrent chemotherapeutic agents
• Endocrine therapy
• No prior hormonal therapy for this disease
• Prior glucocorticoid therapy allowed
• Radiotherapy
• No prior radiotherapy for this disease
• No prior cranial irradiation
• Surgery
• See Disease Characteristics
• Other
• At least 1 week since prior salicylates, non-steroidal anti-inflammatory drugs, probenecid, folic acid, or sulfonamide medications
• No other concurrent investigational agents