An application of the Toronto Childhood Cancer Stage Guidelines in three population-based cancer registries: The case of central nervous tumors.

Background: Cancer stage is a determinant of survival of childhood central nervous system (CNS) cancers and could help the interpretation of survival variability among countries. Consensus guidelines to stage childhood malignancies in population cancer registries ("Toronto Childhood Cancer Stage Guidelines") have been recently proposed with the goal of data comparability. Indeed, stage is not systematically recorded in all registries and, when it is, different classification systems are used.