BACKGROUND: Recent Children's Oncology Group trials for low-risk rhabdomyosarcoma attempted to reduce therapy while maintaining excellent outcomes. D9602 delivered 45 weeks of outpatient vincristine and dactinomycin (VA) for patients in Subgroup A. ARST0331 reduced the duration of therapy to 22 weeks but added four doses of cyclophosphamide to VA for patients in Subset 1. Failure-free survival was similar. We undertook a cost minimization comparison to help guide future decision-making. PROCEDURE: Addressing the costs of treatment from the healthcare perspective we modeled a simple decision-analytic model from aggregate clinical trial data. Medical care inputs and probabilities were estimated from trial reports and focused chart review. Costs of radiation, surgery and off-therapy surveillance were excluded. Unit costs were obtained from literature and national reimbursement and inpatient utilization databases and converted to 2012 US dollars. Model uncertainty was assessed with first-order sensitivity analysis. RESULTS: Direct medical costs were $46,393 for D9602 and $43,261 for ARST0331 respectively, making ARST0331 the less costly strategy. Dactinomycin contributed the most to D9602 total costs but varied with age (42-69%). Chemotherapy administration costs accounted for the largest proportion of ARST0331 total costs (39-57%). ARST0331 incurred fewer costs than D9602 under most alternative distributive models and alternative clinical practice assumptions. CONCLUSIONS: Cost analysis suggests that ARST0331 may incur fewer costs than D9602 from the healthcare system's perspective. Attention to the services driving the costs provides directions for future efficiency improvements. Future studies should prospectively consider the patient and family's perspective. Pediatr Blood Cancer 2014;61:970-976. (c) 2014 Wiley Periodicals, Inc.