Autologous stem cell transplantation for solid tumors in children.

The dose-effect relationship in pediatric oncology conventional chemotherapy is emphasized. Rationales for the use of megatherapy protocols with stem cell support and associated procedures are given. It has been more than 15 years since this approach was used in neuroblastoma, and it has subsequently been applied to most of advanced, common childhood solid tumors. The ongoing use of new strategies for dose intensification with peripheral blood stem cell or autologous purged bone marrow rescue has raised expectations for cure. To date, results of megatherapy followed by autologous stem cell reinfusion are encouraging in metastatic neuroblastoma and Ewing's sarcoma, with an increase in event-free survival rates of about 30% as compared with that of conventional treatments. However, with the exception of metastatic neuroblastoma, there is still no proven role for this treatment strategy. Thus, there is still an urgent need for international collaboration to design randomized studies that could rapidly address the issue of these expensive and high-morbidity procedures in childhood cancer.