Great strides have been made over the past several decades with regards to our understanding and treatments of tumors arising within the central nervous system in children. We now know what features of our treatments have a positive impact on prognosis. For most tumor types, newer protocols are having a positive impact on prognosis. Still problematic, however, are late side effects from the more aggressive treatment packages required in the treatment of the more malignant tumors. This has become a central question in the development of newer treatment protocols.