Oral Presentation Clinical Oncology Society of Australia Annual Scientific Meeting 2024

Australian Aboriginal and Torres Strait Islander females and survival from breast cancer (#59)

Alice RT Bergin 1 2 , Luc te Marvelde 3 , Luis Lara Gonzalez 1 2 , Katie Meehan 4 5 , Lisa Spalding 4 5 , Peter Savas 1 2 , Stephen Luen 1 2 , Jia-Min Pang 1 , Jasmine Kay 1 2 , Franco Caramia 1 2 , Jianan Wang 1 2 , Leanne Pilkington 6 , Andrea Casey 1 , Jay Hamman 1 , Nicole Watt 7 , Roger Milne 8 , Roberto Salgado 9 , Andrew Redfern 4 5 , Gail Garvey 10 , Sue Evans 3 , Sherene Loi 1 2
  1. PeterMacCallum Cancer Centre, Melbourne, VIC, Australia
  2. Sir Peter MacCallum Department of Oncology, University of Melbourne, Parkville, Victoria, Australia
  3. Victorian Cancer Registry, Melbourne
  4. Harry Perkins Institute of Medical Research, Nedlands, WA
  5. University of Western Australia, Crawley, WA
  6. Community member, Perth, Western Australia
  7. St Vincent's Hospital, Melbourne
  8. Cancer Epidemiology Division, Cancer Council Victoria, Melbourne
  9. Department of Pathology, GZA-ZNA Hospitals, Antwerp, Belgium
  10. Faculty of Medicine, University of Queensland, Brisbane

Background

Despite access to universal health care, Aboriginal and Torres Strait Islander females (respectfully referred to hereon as Aboriginal) in Australia have higher breast cancer incidence and mortality rates. In this study we investigate survival outcomes for Aboriginal females in Victoria.

Methods

Aboriginal females (n=275; 0.52%) and non Aboriginal females (n=52,780; 99.48%) with breast cancer were identified using the Victorian Cancer Registry (VCR). Clinical, pathological, demographic and socioeconomic variables were correlated. Endpoints were overall (OS) and breast cancer specific (BCSS) survival. Survival analyses were adjusted for above using Cox regression. Bulk RNA-Seq expression data was obtained from archival tumours from Aboriginal females (n=123) compared with the Cancer Genome Atlas (TCGA) (n=663). Tumour infiltrating lymphocyte (TIL) quantity and immune deconvolution was performed

Results

Registry data showed that Aboriginal females were significantly younger (P<0.001) and had higher stage disease (P=0.007). In addition Aboriginal females were more likely to live in rural areas (P<0.001) and in areas of greater socioeconomic disadvantage (P<0.001) than non Aboriginal females. Multivariate analyses for OS showed that Aboriginal females were at increased risk of death from any cause (OS) but not BCSS, after adjustment for age. Increasing age, stage and tumour grade was significantly associated with worse OS and BCSS. All breast cancer subtypes from Aboriginal females had a significantly reduced TIL infiltrate and TNBC from Aboriginal females had significantly reduced TIL compared to TNBC in TCGA.

Conclusions

In this population level cohort, survival outcomes for Aboriginal females diagnosed with breast cancer are determined by known clinical and pathological factors. The lower quantities of immune infiltrate warrants further investigation.