Patients not undergoing transplantation or who are ineligible for consolidation therapy receive maintenance therapy comprising cyclophosphamide IV over 30 minutes followed by topotecan IV over 30 minutes on days 0-4. Patients receive G-CSF SC or IV beginning on day 5 and continuing until blood counts recover. Maintenance therapy repeats every 3 weeks for 3 courses. After completion of maintenance therapy, patients receive radiotherapy as outlined above. Patients then receive oral isotretinoin twice daily for 14 days. Isotretinoin therapy repeats every 4 weeks for 6 courses.