Sovereignty and Survival: Understanding Lung Cancer Outcomes for Aboriginal and Torres Strait Islander People in Australia, a Case-Control Study.

Abstract

To identify factors contributing to the known increased age-standardised incidence and mortality rates for lung cancer for Aboriginal and Torres Strait Islander people in Victoria, Australia. Retrospective, population-based, case-control study using Victorian Cancer Registry (VCR) data and linked health administrative datasets. Self-identified Aboriginal and Torres Strait Islander people (respectfully referred to hereon as Aboriginal) and non-Aboriginal people (aged > 18 years) diagnosed with lung cancer from 1 January 2008 to 31 December 2022. Clinical, pathological, demographic, socio-economic factors and biomarkers (programmed cell death-ligand 1 [PD-L1], anaplastic lymphoma kinase [ALK] and c-ros oncogene [ROS1]) were assessed. Endpoints were all-cause and lung cancer-specific mortality. Survival analyses were conducted using Cox regression. Aboriginal people (N = 512) were younger (p < 0.001), more likely to live outside a major city (p < 0.001) and in areas of greatest disadvantage (p < 0.001) than non-Aboriginal people (N = 43,468). More Aboriginal females had small cell lung cancer compared with non-Aboriginal females (17% vs. 10%), more Aboriginal males had adenocarcinomas (41% vs. 36%) and squamous cell carcinomas (26% vs. 20%), compared with non-Aboriginal males. There were no differences in the proportions of PD-L1-positive disease nor ALK or ROS1 gene rearrangements. A higher risk of all-cause mortality (hazard ratio, 1.12; 95% CI, 1.01-1.24; p = 0.03) for Aboriginal people after stratification for age, sex and lung cancer subtype was identified. This study identified that Aboriginal people were younger, more likely to be living outside of major cities and in areas of greatest inequity than non-Aboriginal people, which is an ongoing manifestation of colonisation. Aboriginal people diagnosed with lung cancer had an increased all-cause mortality compared with non-Aboriginal people.