ARM I: Patients undergo conformal radiotherapy over 6-7 weeks. Patients then receive vincristine sulfate IV on days 1, 8, and 15 (courses 1-3 only); etoposide IV over 1-2 hours on days 1-3; cisplatin IV over 1-8 hours on day 1; and cyclophosphamide IV over 30-60 minutes on days 1-2. Treatment repeats every 21 days for 4 courses in the absence of disease progression or unacceptable toxicity.