OUTLINE: Patients receive carboplatin IV on day 1 and etoposide IV over 1 hour daily on days 1-3 of weeks 0, 6, and 12, plus cyclophosphamide IV or orally daily on days 1-7, doxorubicin IV on day 8 and carboplatin IV over 1 hour on day 10 on weeks 3, 9, and 15. Beginning on week 6, patients receive concurrent radiotherapy 5 days a week over 4-6 weeks. Patients with meningeal involvement receive topotecan intrathecally twice weekly for 3 weeks and then weekly for 3 weeks before starting radiotherapy. Beginning one day after each treatment course, patients receive filgrastim (G-CSF) subcutaneously daily for 10 days.