Background: As childhood cancer survival improves, it is important to monitor health of survivors, because they have an elevated risk of developing subsequent primary neoplasms (SPN). Population-based cancer registries can monitor long-term risk of cancer among childhood cancer survivors (CCS). However, the ability to study this risk depends on the quality, completeness, and longitudinal extent of registration whereby information on treatment, stage, and predisposing characteristics is systematically recorded.
Objective: Within the Cancer Risk in Childhood Cancer Survivors (CRICCS) study, supported by Children with Cancer UK (grant reference 19–306), we assessed the ability of population-based cancer registries to collect information relevant for studying cancer risk in childhood cancer survivors.
Methods: In June 2021, we invited 552 population-based cancer registries worldwide to provide detailed information on their data collection practices, including coverage of the underlying population, years of operation, and routine collection of information on diagnosis, stage, treatment, follow-up, and predisposing characteristics in an online survey. The survey remained open until September 2025. Registries were categorized according to the 2010 Human Development Index (HDI) of their country into low, medium, high, and very high HDI. Descriptive analyses were used to summarize response rate, population coverage, and the availability of key data elements across HDI categories.
Results: A total of 175 registries (31.7% of those invited), including 19 paediatric, completed the survey. Together, these registries covered 18.4% of the world population in 2020, with marked regional differences ranging from 6.3% in Africa to 94.0% in North America. The majority of registries (83.4%) responded from countries with high or very high HDI, which strongly influenced the overall distribution of reported capabilities. The registries had been collecting data for a median of 24 years, spanning the period 1944-2023. Follow-up information was available in 148 registries (84.6%), including all 19 paediatric. Cancer stage was collected in 143 (81.7%), including 16 paediatric (84.2% of 19) registries. Treatment data were recorded in 98 (56.0%), including 14 paediatric (73.7%) registries. Predisposing characteristics were recorded in only 21 (12.0%) registries (10 paediatric, 52.6%). Eighty-five registries (48.6%) simultaneously collected incidence, follow-up, stage, and treatment data, and among these, 18 (10.3% of all respondents) also recorded predisposing characteristics.
Conclusions/Implications: Most responding registries demonstrated capacity to contribute to survivorship research in childhood cancer, given the availability of follow-up data. However, more information on treatment and predisposing characteristics, and extended follow-up, would increase the informative value of registry data, especially in low and medium HDI countries. Such improvements, combined with international data sharing, would enable more robust and equitable research on SPN, ultimately supporting prevention strategies and better long-term outcomes for CCS worldwide.