Tumors of the central nervous system (CNS) in children are a diverse group of neoplasms representing specific histologic types and widely varying clinical behaviors. The 2000 cases presenting annually in the United States account for one in five childhood cancers. Appropriately perceived as a unique challenge within pediatric oncology, the overall survival rate for CNS tumors has improved only among certain tumor types over the past 30 years.<sup>30Jenkin D., Greenberg M., Hoffman H., et al. Brain tumors in children: Long-term survival after radiation treatment Int J Radiat Oncol Biol Phys 1995 ;  31 : 445-451 [cross-ref]

Cliquez ici pour aller à la section Références</sup> The past decade has witnessed substantive technological innovations in both neurosurgery and radiation therapy. With the introduction of effective chemotherapy for several clinicohistologic presentations, there is cautious optimism that improvement in both long-term disease control and quality of life will be demonstrated through ongoing clinical investigations.

The major types of brain tumors occurring in this age group are listed in Table 1. The 2% annual increase in the incidence of childhood brain tumors noted since 1974 has largely been a reflection of increased astroglial tumors and ependymomas.<sup>25Gurney J.G., Davis S., Severson R.K., et al. Trends in cancer incidence among children in the U.S Cancer 1996 ;  78 : 532-541 [cross-ref]

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It is in the major tumor histiotypes that therapeutic advances have stimulated interest in studying modifications of treatment strategies. Prospective investigations in the pediatric cooperative groups (primarily the Children's Cancer Group [CCG], Pediatric Oncology Group [POG], and International Society of Paediatric Oncology [SIOP]) have focused productively on medulloblastoma, ependymoma, and tumors arising in infants and very young children. The rationale and directions of protocol-based research in these areas are the major focus of this review.