High-dose chemotherapy and autologous stem cell transplantation for pediatric brain tumors

The prognosis of brain tumors in children has improved for the last 2-3 decades. However, the prognosis remains dismal in patients with relapsed tumors. The outcome for infants and young children is also poor. For younger children, the ability to use of radiotherapy (RT) is very limited because of the unacceptable long-term adverse effects of RT. The prognosis is also not satisfactory when a large residual tumor remains after surgery or when leptomeningeal seeding is present at diagnosis. In this context, a strategy using high-dose chemotherapy and autologous stem cell transplantation (HDCT/autoSCT) has been explored to improve the prognosis of recurrent or high-risk brain tumors. It was found that at least some patients with relapsed tumors can be salvaged with HDCT/autoSCT. For infants and young children, it was possible to avoid or defer RT until 3 years of age while maintaining or improving survival rates. Investigators also have explored the efficacy of HDCT/autoSCT in patients with newly diagnosed embryonal tumors to further improve the survival rate or to reduce the craniospinal RT dose without jeopardizing the survival rate. Preliminary results were encouraging although the numbers of patients was small. Recently, a few investigators have evaluated the efficacy of sequential HDCT/autoSCT to further improve the outcome. This strategy is based on the hypothesis that further dose escalation might result in further improvement in survival rates. At present, the number of studies employing a sequential HDCT/autoSCT strategy is limited. However, preliminary results of these studies suggest that sequential HDCT/autoSCT may further improve outcomes.