BACKGROUND: Myeloablative megatherapy is commonly used to improve the poor outlook of children with high-risk neuroblastoma, yet its role is poorly defined. We aimed to assess whether megatherapy with autologous stem-cell transplantation could increase event-free survival and overall survival compared with maintenance chemotherapy. METHODS: 295 patients with high-risk neuroblastoma (ie, patients with stage 4 disease aged older than 1 year or those with MYCN-amplified tumours and stage 1, 2, 3, or 4S disease or stage 4 disease and