OUTLINE: Patients receive topotecan IV on days 1-5 and paclitaxel IV over 3 hours on day 1. Filgrastim (G-CSF) is administered subcutaneously every day starting on day 6 until blood counts recover. The course is repeated once beginning on day 22. After restaging, patients begin thoracic radiotherapy daily, five days per week, for 6-7 weeks. On the same day that radiotherapy begins, patients receive carboplatin IV over 1 hour (day 43) and etoposide IV over 1 hour daily for 3 days (days 43-45). The consolidation chemotherapy is repeated every 21 days for a total of 3 courses. Patients with stable or responding disease undergo prophylactic cranial irradiation. Patients are followed at least every 3 months for 2 years, every 6 months for 3 years, and then at least every year.