Stage at diagnosis for children with blood cancers in Australia: application of the Toronto Paediatric Cancer Stage Guidelines in a population-based national childhood cancer registry

Abstract

BACKGROUND: Information on stage at diagnosis for childhood blood cancers is essential for surveillance but is not available on a population basis in most countries. Our aim was to apply the internationally endorsed Toronto Paediatric Cancer Stage Guidelines to children (<15 years) with acute lymphoblastic leukemia (ALL), acute myeloid leukemia (AML), Hodgkin lymphoma (HL), or non-Hodgkin lymphoma (NHL) and to assess differences in survival by stage at diagnosis. PROCEDURE: Stage was defined by extent of involvement of the central nervous system (CNS) for ALL and AML and using the Ann Arbor and St Jude-Murphy systems for HL and NHL, respectively. The study cohort was drawn from the population-based Australian Childhood Cancer Registry, consisting of children diagnosed with one of these four blood cancers between 2006 and 2014 with follow-up to 2015. Five-year observed survival was estimated from the Kaplan-Meier method. RESULTS: Stage was assigned to 2201 of 2351 eligible patients (94%), ranging from 85% for AML to 95% for ALL, HL, and NHL. Survival following ALL varied from 94% (95% CI = 93%-95%) for CNS1 disease to 89% (95% CI = 79%-94%) for CNS2 (P = 0.07), whereas for AML there was essentially no difference in survival between CNS- (77%) and CNS+ disease (78%; P = 0.94). Nearly all children with HL survived for five years. There was a trend (P = 0.04) toward worsening survival with higher stage for NHL. CONCLUSIONS: These results provide the first population-wide picture of the distribution and outcomes for childhood blood cancers in Australia by extent of disease at diagnosis and provide a baseline for future comparisons.