Progress against childhood and young adolescent cancer in the Netherlands The incidence of childhood cancer is, albeit modestly, increasing worldwide. During the last 50 years 5-year survival of childhood cancer has increased from less than 30% to more than 80%. However, recent national trend analyses in incidence, treatment patterns, survival and mortality from childhood and young adolescent cancer are lacking for the Netherlands. Within this thesis we aimed first to analyze the trends in incidence for all childhood cancers and made more detailed analyses for five specific childhood and young adolescent cancers (e.g. acute lymphoblastic leukemia, acute myeloid leukemia, Hodgkin lymphoma, non-Hodgkin lymphoma and neuroblastoma). The overall incidence for all childhood cancers combined in the Netherlands did increase with 0.6% per year, comparable with other Western countries. Tumour specific overall incidence rates did not change for the five tumours studied in more detail. The second aim in this thesis was to study changes in (childhood) cancer management by describing trends in treatment, survival and mortality for the five specific childhood and young adolescent cancers. The prognosis for childhood and young adolescent cancers in this thesis indeed improved substantially during 1990-2015 mainly by improved effective combinations of treatments. This progress was confirmed by steadily decreasing mortality rates for the leukaemias and lymphomas. While mortality from neuroblastoma is difficult to discern in cause of death statistics. The results of this thesis can be used by physicians to inform patients and parents about up-to-date incidence and prognosis and the methods used can be applied to evaluate new methods of treatment for other childhood cancers, and, lastly, the results might be the basis to start etiologic research.