Childhood cancer survival in Europe: an overview.

Other articles in this issue of the European Journal of Cancer have described population-based survival analyses of specific types of childhood cancer included in the EUROCARE database, diagnosed since 1979. The present paper summarises the relevant estimates and comments on intercountry differences, focusing on possible distortions in the intercountry comparisons based on data produced by the cancer registries. Potential biases include a lack of exhaustiveness of both case ascertainment and follow-up for living status and also a lack of consistency in the use of classification of the childhood cancer types. Nevertheless, despite such biases, consistent differences are observed between European countries in the probability of survival following the diagnosis of a paediatric cancer. In most cases, poor population-based survival rates are probably explained by inadequacies in the adoption and implementation of therapeutic protocols that have been proved to be effective. In some instances, the cause of unsatisfactory estimates was the inclusion of a sizeable proportion of children with cancer in clinical trials which were found to be ineffective. A regression analysis of incidence, mortality and survival rates during 1978-1989 over the whole EUROCARE database strongly indicates that the prognostic improvements over time are real and cannot be attributed to changes in diagnostic procedures.