Beginning in week 25, all patients in the chemotherapy arm receive consolidation therapy comprising vincristine IV on days 1, 8, and 15 and carboplatin IV over 1 hour on day 1. Treatment repeats every 6 weeks for 9 courses. Patients experiencing disease progression or an allergic reaction to carboplatin receive vincristine IV on days 1, 8, and 15 and either cyclophosphamide IV over 1 hour on day 1 or cisplatin IV over 3 hours on days 1 and 2. Treatment repeats every 6 weeks for 5 courses. All patients in the chemotherapy arm receive a total of 18 months of treatment.