- Regimen B: Patients receive vincristine as in regimen A; dactinomycin IV over 1 minute weekly on weeks 6, 9, 12, 23, 26, 29, 32, 35, 38, and 41 and cyclophosphamide IV over 30-60 minutes weekly on weeks 6, 9, 12, 16, 19, 23, 26, 29, 32, 35, 38, and 41. Patients receive radiotherapy as in regimen A.