INDUCTION THERAPY: Patients receive vincristine sulfate intravenously (IV) over 1 minute or infused via minibag on days 1, 15, and 29; cyclophosphamide IV over 1 hour on days 1-3; methotrexate IV over 24 hours on days 15 and 29; etoposide IV over 60-120 minutes on days 43-45; and carboplatin IV over 1 hour on days 43-45. Treatment repeats every 63 days for 3 courses in the absence of disease progression or unacceptable toxicity.