Combination Chemotherapy With or Without Radiation Therapy in Treating Children With Brain Tumors

OBJECTIVES: * Determine the response rate in children under 36 months of age with primary brain or brain stem tumors treated with vincristine, methotrexate, carboplatin, cyclophosphamide, and cisplatin with or without radiotherapy. * Determine the event-free survival and overall survival in children treated with this regimen. * Determine the pattern of local recurrence or occurrence of CNS metastases in children treated with this regimen. * Determine the quality of life in children treated with this regimen. * Determine the tolerability and long-term toxicity of this regimen in these children. * Determine the proportion of children who require radiotherapy after treatment with this regimen. * Determine the prognosis of children who receive both chemotherapy and radiotherapy. * Determine the nature and behavior of brain tumors in very young children. OUTLINE: This is a multicenter study. * Chemotherapy: Patients receive vincristine IV on days 0, 14, and 28; carboplatin IV over 4 hours on day 0; methotrexate IV continuously over 24 hours on day 14; cyclophosphamide IV over 4 hours on day 28; and cisplatin IV continuously over 48 hours on days 42 and 43. Courses repeat every 56 days (8 weeks) for up to 12 months. Patients who achieve a complete response proceed to observation, as do those achieving a partial response with no tumor present on biopsy. Patients with biopsy proven residual tumors after 12 months of chemotherapy or recurrent tumors that don't have the potential to spread through the cerebrospinal fluid (CSF) proceed to local radiotherapy. Patients with unresponsive disease or progressive disease that has the potential to spread through the CSF proceed to craniospinal radiotherapy. * Local radiotherapy: Patients undergo local radiotherapy 5 days a week for 5-5½ weeks. * Craniospinal radiotherapy: Patients undergo craniospinal radiotherapy 5 days a week for 4 weeks. Quality of life is assessed periodically. After completion of study treatment, patients are followed periodically for at least 2 years. PROJECTED ACCRUAL: A total of 50 patients will be accrued for this study.