Patients receive vincristine IV on days 1, 15, and 29, carboplatin IV over 1 hour on day 1, high-dose methotrexate* IV over 24 hours on day 15, cyclophosphamide IV over 1 hour on day 29, and cisplatin IV over 48 hours on days 43 and 44. Treatment repeats every 8 weeks for 7 courses in the absence of disease progression or unacceptable toxicity. Patients with residual disease after completion of treatment may receive other treatment at the discretion of the investigator.