OBJECTIVES: Primary * Determine the response in patients with newly diagnosed glioblastoma multiforme treated with high-dose methotrexate and leucovorin calcium. Secondary * Determine the acute toxicity of this regimen in these patients. * Determine the duration of survival of patients treated with this regimen. OUTLINE: This is a multicenter study. Patients receive high-dose methotrexate IV over 4 hours on day 1 and oral or IV leucovorin calcium every 6 hours beginning on day 2 and continuing until blood methotrexate levels are acceptable. Treatment repeats every 14 days for up to 6 courses in the absence of disease progression or unacceptable toxicity. Patients then receive standard radiotherapy with or without chemotherapy. Patients with disease progression proceed to standard radiotherapy with or without chemotherapy upon stopping methotrexate therapy. Patients are followed at 30 days and then every 2 months for up to 2 years. PROJECTED ACCRUAL: A total of 19-36 patients will be accrued for this study.
DISEASE CHARACTERISTICS: * Histologically confirmed glioblastoma multiforme (GBM) * Supratentorial grade IV disease * Measurable and contrast-enhancing disease ≥ 1 cm by CT scan or MRI * No radiographic evidence of ascites or pleural effusion PATIENT CHARACTERISTICS: Age * 18 and over Performance status * ECOG 0-2 Life expectancy * Not specified Hematopoietic * Absolute neutrophil count ≥ 1,500/mm\^3 * Platelet count ≥ 100,000/mm\^3 Hepatic * SGOT ≤ 4.0 times upper limit of normal * Bilirubin ≤ 2.0 mg/dL Renal * Creatinine ≤ 2.0 mg/dL * Creatinine clearance ≥ 50 mL/min Cardiovascular * No uncontrolled hypertension * No unstable angina * No symptomatic congestive heart failure * No uncontrolled cardiac arrhythmia * No myocardial infarction within the past 6 months Other * Not pregnant or nursing * Negative pregnancy test * Fertile patients must use effective contraception * Able to achieve hydration * No diabetes insipidus * No known hypersensitivity to methotrexate or leucovorin calcium * No concurrent serious infection or medical illness that would preclude study participation * No other malignancy within the past 2 years except basal cell or squamous cell skin cancer or carcinoma in situ of the cervix PRIOR CONCURRENT THERAPY: Biologic therapy * No prior immunotherapy for GBM * No prior administration of any of the following biologic agents for GBM: * Immunotoxins * Immunoconjugates * Antisense therapy * Peptide receptor antagonists * Interferons * Interleukins * Tumor-infiltrating lymphocytes * Lymphokine-activated killer cells * Gene therapy * No concurrent prophylactic growth factors (e.g., filgrastim \[G-CSF\] or sargramostim \[GM-CSF\]) Chemotherapy * No prior chemotherapy for GBM * No other concurrent chemotherapy Endocrine therapy * Prior glucocorticoid therapy allowed * No prior hormonal therapy for GBM * Patients must be maintained on a stable corticosteroid regimen for at least 1 week Radiotherapy * No prior cranial irradiation * No prior radiotherapy for GBM Surgery * Recovered from prior surgery Other * At least 1 week since prior treatment with any of the following: * Salicylates * Non-steroidal anti-inflammatory drugs * Sulfonamide medications * Vitamin C * No other concurrent investigational agents