Patients and Study Design
We performed a retrospective review of presenting features and outcomes
of all children aged between 1 day and <18 years who were
diagnosed with acute leukaemia between January 1st 2009 and December
31st 2018 at the Women’s and Children’s Hospital (WCH) in SA, and Perth
Children’s Hospital (PCH) in WA. The WCH and PCH are the sole referral
sites for children with cancer for their states, with WCH also serving
as the primary referral centre for children with suspected malignancies
from the NT.
Cases were ascertained from hospital-based registries at WCH and PCH.
Demographic characteristics, Indigenous status (self-reported) and
diagnostic features at presentation, including full blood count,
biochemistry, peripheral blast count, blast immunophenotype, blast
genotype, molecular studies, central nervous system status, final risk
stratification, treatment regimen and outcome were collected from
medical records. The World Health Organisation classification of myeloid
neoplasms and acute leukaemia was used for classification into
diagnostic categories10. Final risk stratification was
according to the co-operative group treatment protocols used in the
respective centres, i.e. primarily the Children’s Oncology Group for WA
and the Berlin-Frankfurt-Munster protocols for SA/NT.
Residential address at diagnosis was categorised, first, by geographic
remoteness using the Australian Statistical Geography Standard
Remoteness Index (‘remote/very remote’, ‘outer regional,’ ‘inner
regional’ or ‘major city’)11 and, second, by
area-based socioeconomic status (SES) using the Index of Relative
Socio-economic Disadvantage (‘least disadvantaged’ (quintile 5 scores),
‘middle SES’ (quintiles 2 to 4) and ‘most disadvantaged’ (quintile
1)12. The latter (referred to as Socio-economic Index)
is derived from national census data and incorporates income,
educational attainment, employment and type of occupation.