BACKGROUND: Liver disease and hepatocellular carcinoma (HCC) are important contributors to the mortality gap between Indigenous and non-Indigenous Australians. However, there is a lack of population based high quality data assessing the differences in HCC epidemiology and outcomes according to Indigenous status. The aim of this study was therefore to perform a large epidemiological study of HCC investigating differences between Indigenous and non-Indigenous Australians with HCC.
METHODS: Study design was a retrospective cohort study. Data linkage methodology was used to link data from cancer registries with hospital separation summaries across three Australian jurisdictions during 2000-2017. Cumulative survival (Kaplan-Meier) and the differences in survival (Multivariable Cox-regression) by Indigenous status were assessed.
FINDINGS: A total of 229 Indigenous and 3587 non-Indigenous HCC cases were included in the analyses. Significant epidemiological differences identified for Indigenous HCC cases included younger age at onset, higher proportion of females, higher rurality, lower socioeconomic status, and higher comorbidity burden (all  < 0.001). The distribution of cofactors was also significantly different for Indigenous Australians including higher prevalence of alcohol misuse, hepatitis B, and diabetes and more frequent presence of multiple HCC cofactors (all  < 0.001). Indigenous Australians received curative HCC therapies less frequently (6.6% vs. 14.5%,  < 0.001) and had poorer 5-year survival (10.0% vs. 17.3%,  < 0.001; unadjusted hazard ratio (HR) =1.42 96%CI 1.21-1.65) compared to non-Indigenous Australians. The strength of the association between indigenous status and survival was weaker and statistically non-significant after adjusting for rurality, comorbidity burden and lack of curative therapy (adjusted-HR=1.20 95%CI 0.97-1.47).
INTERPRETATION: Such data provide a call to action to help design and implement health literacy, liver management and HCC surveillance programs for Indigenous people to help close the liver cancer mortality gap.