Factors associated with 5- and 10-year survival among a recent cohort of childhood cancer survivors (France, 2000-2015).

Background: Childhood cancer survival currently exceeds 80 % five years after diagnosis in high-income countries. In this study, we aimed to describe long-term trends and to investigate socioeconomic and spatial disparities in childhood cancer survival.
Methods: The study included 28,073 cases recorded in the French National Registry of Childhood Cancers from 2000 to 2015. Contextual census data (deprivation indices, population density, spatial accessibility to general practitioners) were allocated to each case based on the residence at diagnosis. Overall survival (OS) and conditional 10-year OS for 5-year survivors were estimated for all cancers combined and by diagnostic group and subgroup. Comparisons were conducted by sex, age at diagnosis, period of diagnosis, and contextual indicators. Hazard ratios for death were estimated using Cox models.
Results: All cancers combined, the OS reached 82.8 % [95 % CI: 82.4-83.3] at 5 years and 80.8 % [95 % CI: 80.3-81.3] at 10 years. Conditional 10-year OS of 5-year survivors reached 97.5 % [95 % CI: 97.3-97.7] and was higher than 95 % for all subgroups except osteosarcomas and most subgroups of the central nervous system. In addition to disparities by sex, age at diagnosis, and period of diagnosis, we observed a slight decrease in survival for cases living in the most deprived areas at diagnosis, not consistent across diagnostic groups.
Conclusion: Our results confirm the high 5-year survival for childhood cancer and show an excellent 10-year conditional survival of 5-year survivors. Additional individual data are needed to clarify the factors underlying the slight decrease in childhood cancer survival observed in the most deprived areas.
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