EE-4A regimen (BWT with complete resection of all gross tumors at diagnosis with stage I-II favorable histology; BWT with complete response [CR] by imaging after 6 weeks of preoperative chemotherapy; completely necrotic stage I-II BWT; intermediate-risk stage I BWT; unilateral WT stage I-II with CR by imaging after 6-12 weeks of preoperative chemotherapy; completely necrotic stage I-II unilateral WT; or intermediate-risk stage I-II unilateral WT): Patients receive vincristine sulfate IV over 1 minute on days 43, 50, 57, 64, 85, 106, and 127 (weeks 7-10, 13, 16, and 19) and dactinomycin IV over 1-5 minutes on days 43, 64, 85, 106, and 127 (weeks 7, 10, 13, 16, and 19).