Radiotherapy for medulloblastoma in children: a perspective on current international clinical research efforts.

Abstract

The North America and four European pediatric cooperative groups have undertaken prospective studies for medulloblastoma continuously since the 1970s. In this article, we will review the results of these studies with respect specifically to the use of radiotherapy, and trace the developments that have led up to the present trials for patients with this tumor. Published and unpublished data from the North American CCG and POG and now COG studies, from the UKCCG and SIOP groups, as well as from the French and German groups were reviewed. Issues of especial interest included radiotherapy dose and dose fractionation schedules, scheduling of chemotherapy and radiotherapy, and technical aspects of treatment with radiotherapy that might impact on outcome. Much progress has been made in the management of medulloblastoma in childhood as a consequence of the studies undertaken sequentially by these groups over the past two decades. It now seems clear that chemotherapy plays an important role for all patients. In patients with average risk disease, the use of chemotherapy has allowed a reduction in the dose of radiotherapy to the craniospinal axis and the combination of chemotherapy with radiotherapy appears to have brought about a significant improvement in disease-free and overall survival in this patient population. Patients with high-risk disease fare better now than in the past as a consequence of the routine use of aggressive chemotherapy and preliminary data suggest that the use of higher doses of radiation as in the POG studies is associated with a particularly favorable outcome. Accurate delivery of radiotherapy is essential for optimal results. The avail-ability of better tools at the treating centres and quality control as an integral part of cooperative studies are likely to bring about further improvements in outcome in the future.