Background
Cancer control initiatives are informed by quantifying the capacity to reduce cancer burden through effective interventions. Burden measures using health administrative data are a sustainable way to support monitoring and evaluating of outcomes among patients and populations. The PREmature Mortality to IncidencE Ratio (PREMIER) is one such burden measure. We use data on Aboriginal and non-Aboriginal South Australians from 1990 to 2010 to show how PREMIER quantifies disparities in cancer burden: between populations; between sub-population cohorts where stage at diagnosis is available; and when follow-up is constrained to 24-months after diagnosis.
Method
PREMIERcancer is the ratio of years of life expectancy lost due to cancer (YLLcancer) to life expectancy years at risk at time of cancer diagnosis (LYAR) for each person. The Global Burden of Disease standard life table provides referent life expectancies. PREMIERcancer was estimated for the population of cancer cases diagnosed in South Australia from 1990 to 2010. Cancer stage at diagnosis was also available for cancers diagnosed in Aboriginal people and a cohort of non-Aboriginal people matched by sex, year of birth, primary cancer site and year of diagnosis.
Results
Cancers diagnoses (N=144,891) included 777 among Aboriginal people. Cancer burden described by PREMIERcancer was higher among Aboriginal than non-Aboriginal (0.55, 95%CIs 0.52-0.59 versus 0.39, 95%CIs 0.39-0.40). Diagnoses at younger ages among Aboriginal people, 7 year higher LYAR (31.0, 95%CIs 30.0-32.0 versus 24.1, 95%CIs 24.1-24.2) and higher premature cancer mortality (YLLcancer=16.3, 95%CIs 15.1-17.5 versus YLLcancer=8.2, 95%CIs 8.2-8.3) influenced this. Disparities in cancer burden between the matched Aboriginal and non-Aboriginal cohorts manifested 24-months after diagnosis with PREMIERcancer 0.44, 95%CIs 0.40-0.47 and 0.28, 95%CIs 0.25-0.31 respectively.
Conclusion
PREMIER described disproportionately higher cancer burden among Aboriginal people in comparisons involving: all people diagnosed with cancer; the matched cohorts; and, within groups diagnosed with same staged disease. The extent of disparities were evident 24-months after diagnosis. This is evidence of Aboriginal peoples substantial capacity to benefit from cancer control initiatives, particularly those leading to earlier detection and treatment of cancers. PREMIERs use of readily available, person-level administrative records can help evaluate health care initiatives addressing this need.
The premature mortality to incidence ratio (PREMIER): a person-centred measure of cancer burden