Alice R. T. Bergin

Objective: 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. Study Type: Retrospective, population‐based, case–control study using Victorian Cancer Registry (VCR) data and linked health administrative datasets. Setting and Participants: 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. Main Outcome Measures: 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. Results: 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. Conclusion: 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.

Bar charts showing significantly more Aboriginal females live in areas of greatest socioeconomic disadvantage and outside the greater metropolitan area

Analysis of co-variates for Aboriginal females and females from TCGA

Immune-biology data for Aboriginal females and females from TCGA with breast cancer

Background: Despite access to universal health care, Aboriginal and Torres Strait Islander females (hereafter respectfully referred to as Aboriginal) in Australia have higher breast cancer incidence and mortality rates. We investigated the factors contributing to these survival disparities. Methods: Aboriginal females (n = 395; 0.7%) and non-Aboriginal females (n = 57,618; 99.3%) with breast cancer were identified from Victoria, Australia. Clinical, pathologic, demographic, and socioeconomic variables were analyzed. Endpoints were all-cause and breast cancer–specific mortality. HRs were estimated using Cox regression. Stromal tumor–infiltrating lymphocytes were evaluated from a subset of Aboriginal females and compared with females in The Cancer Genome Atlas. Results: Registry data revealed that Aboriginal females were younger (P < 0.001), had more advanced stage disease (P = 0.007), and were more likely to live in nonmetropolitan areas (P < 0.001) and in areas of greater disadvantage (P < 0.001) compared with other females at diagnosis. Age-adjusted multivariate analysis revealed a higher all-cause mortality risk (HR 1.27; 95% confidence interval, 1–1.61) for Aboriginal females, but this risk diminished for breast cancer–specific mortality and after adjustment for stage and grade. Breast cancers from Aboriginal females had significantly reduced stromal tumor–infiltrating lymphocytes in the luminal and triple-negative subtypes compared with The Cancer Genome Atlas. Conclusions: Mortality for females with breast cancer was influenced by socioeconomic, geographic, and clinical factors. Notably, Aboriginal females with tumor features typically associated with favorable outcomes experienced poorer outcomes. The reduced immune infiltrate warrants further investigation. Impact: These findings highlight the need to address socioeconomic inequities and ensure culturally safe cancer care. Further research should explore biological and environmental factors influencing outcomes for Australian Aboriginal females.

Substantial advances in our understanding of breast cancer disease biology have led to marked improvements in cancer outcomes over the past two decades. These advances have largely focused on women from developed, high-income countries and as a result, significant disparities exist. In this issue, Bauer and colleagues provide new insight into the breast cancer immune microenvironment from women across geographic regions in sub-Saharan Africa, despite inherent infrastructure limitations. The study amassed data from 1,497 women from sub-Saharan Africa, and 117 women from Germany with breast cancer, suggesting regional variation in immune composition but with no significant prognostic impact. These important findings require validation in large, codesigned prospective studies to fully understand the impact of biology, ethnicity, and socioeconomic status on breast cancer outcomes.See related article by Bauer et al., p. 720 (2) .