What is known?
Aboriginal and Torres Strait Islander peoples experience poorer survival than other Australian cancer patients. Results are typically presented in relative terms, and while absolute measures can make the implications a lot clearer, published estimates of absolute risks are lacking.
One such measure is called the crude probability of death, which considers the possibility that a person diagnosed with cancer may also die of causes other than their diagnosed cancer. Hence, this measure allows the real risk of cancer death following a cancer diagnosis to be quantified. To date, there has been no information on how crude probability of death due to cancer and due to other causes after a cancer diagnosis differs between Aboriginal and Torres Strait Islander and other Australian cancer patients.
What is new?
We used data on over 700,000 people diagnosed with cancer living in New South Wales. Queensland, Northern Territory and Western Australia; these states/territories had cancer registries with high quality information on Aboriginal and Torres Strait Islander status in their cancer registry data.
We found that across all cancer types considered, on average the nearly 13,000 Aboriginal and Torres Strait Islanders in the study cohort had consistently higher crude probability of death from cancer and from other causes after a cancer diagnosis than other Australians.
For every 100 Aboriginal and Torres Strait Islander people with cancer, 44 died from their cancer and 7 from other causes within five years of diagnosis, higher than the 37 and 3 respectively for other Australians. On average, out of every 100 Aboriginal and Torres Strait Islander cancer patients 49 were alive five years after their diagnosis, a lower number compared to 60 per 100 for other Australians.
Putting it another way, if we consider an average cohort of Aboriginal and Torres Strait Islander peoples diagnosed in a single year (about 1,270), about 133 deaths that occurred within 5 years of diagnosis were potentially avoidable if they had the same overall survival as other Australians, with 94 of these deaths due to cancer.
What does this mean?
By splitting the deaths from all causes into deaths due to cancer and deaths due to other causes this study provided a unique perspective into the impact of survival disparities and further understanding of the excess deaths among Aboriginal and Torres Strait Islander cancer patients. Interventions designed to improve early diagnosis and management, increase screening participation, and reduce the prevalence of cancer risk factors among Aboriginal and Torres Strait Islander peoples could lead to more equitable outcomes within the first five years after diagnosis.
Contact: Paramita Dasgupta
Reference: Dasgupta P, Garvey, G, Baade P. Quantifying the number of deaths among Aboriginal and Torres Strait Islander cancer patients that could be avoided by removing survival inequalities, Australia 2005-2016. 2022; 17(8):e0273244.