Temporal changes in childhood cancer incidence and survival by stage at diagnosis in Australia, 2000–2017

Abstract

Background

The Toronto Paediatric Cancer Stage Guidelines are a compendium of staging systems developed to facilitate collection of consistent and comparable data on stage at diagnosis for childhood cancers by cancer registries.

Material and Methods

This retrospective, observational cohort study investigated changes in stage-specific incidence and survival for children diagnosed between 2000-2008 compared to 2009-2017 using the population-based Australian Childhood Cancer Registry. Information on mortality for each patient was available to 31^st December 2020. Shifts in incidence by stage were evaluated using chi-square tests, and differences in stage-specific five-year observed survival for all causes of death over time were assessed using flexible parametric models.

Results

Stage was assigned according to the Toronto Guidelines for 96% (n = 7944) of the total study cohort (n = 8292). Changes in the distribution of incidence by stage between the two diagnosis periods were observed for retinoblastoma, with stage 0 increasing from 26% to 37% of cases (p = 0.02), and hepatoblastoma, with metastatic disease increasing from 22% to 39% of cases (p = 0.04). There were large gains in stage-specific survival over time for stage IV rhabdomyosarcoma (five-year adjusted mortality hazard ratio for 2009–2017 compared to 2000–2008 of 0.38, 95% CI 0.19–0.77; p = 0.01), stage M3 for medulloblastoma (HR = 0.41, 95% CI 0.21–0.79; p = 0.01) and metastatic neuroblastoma excluding stage MS (HR = 0.61, 95% CI 0.44-0.84; p < 0.01).

Conclusion

These results indicate that improvements in childhood cancer survival in Australia are most likely due to refined management rather than changes in stage at diagnosis, particularly for metastatic solid tumours. Wide international uptake of the Toronto Guidelines will allow comprehensive evaluation of differences in survival between countries.

Keywords:

• Childhood cancer
• cancer staging
• epidemiological studies
• survival analysis
• Australia

Acknowledgments

The Australian Childhood Cancer Registry operates with the assistance of all Australian State and Territory Cancer Registries, the Australian Institute of Health and Welfare and the Medical Records Department at each of the major paediatric oncology treating hospitals throughout Australia. The authors wish to acknowledge the work performed by the staff of the ACCR, including Leisa O’Neill, Chloe Henshaw, Leanne Keeley and Anne Currell.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Data availability statement

Unit record data that support the findings of this study are not publicly available through the Australian Childhood Cancer Registry due to privacy and ethical restrictions but may be requested directly from the data custodians at the state and territory cancer registries and treating hospitals (subject to all necessary ethics approvals). Please contact [email protected] for further details.

Additional information

Funding

This work was supported through a national initiative by Cancer Australia as part of an approach to improving national cancer data on stage, treatment and recurrence [contract number CA-DATA-211117]. The funding body did not contribute to the preparation or content of the manuscript.