Possibilities of new therapeutic strategies in brain tumors

Advances in the management of pediatric brain tumors have been less successful than in other areas of pediatric oncology. This gap in outcome is essentially related to specific aspects of these tumors in this age group such as the fact that the surrounding brain is still developing, vital structures limit aggressive attempts at removing infiltrating lesions, drug penetration into the central nervous system is often poor and short and long term toxicities of some treatments to the surrounding brain are significant. This review describes new therapeutic strategies and their impact in the pediatric neuro-oncology practice. Although the number of new active antineoplastic agents has been limited during the last decade, significant improvements in the chemotherapeutic management of pediatric brain tumors have been observed. These relate to the optimization of chemotherapy protocols, the development of new schedules of administration such as metronomic schedules, sequential high dose chemotherapy, concomitant administration of chemotherapy and radiation, or the introduction of intrathecal or intraventricular chemotherapy in specific protocols. Technological advances in radiotherapy allow delivering optimal doses to the target volume while decreasing the volume of normal surrounding tissue receiving radiation. As a consequence, conformal radiation therapy currently plays a major role in the management of several pediatric brain tumors, including in infants where radiation has been traditionally avoided. The role of molecularly targeted agents is still unclear and a number of phase I and II trials are ongoing to better define the future of these new therapies in pediatric brain tumors.