Abstract A68: Does disparity in cancer treatment explain poorer survival for indigenous Australians?

Introduction: Cancer is the second leading cause of death for Aboriginal and Torres Strait Islander (Indigenous) Australians, the life expectancy of whom lags approximately 17 years behind the rest of Australia. In the state of Queensland overall cancer mortality is 38% higher for Indigenous people despite a 21% overall lower incidence. Possible reasons for this disparity include later stage of cancer at diagnosis, the prevalence of co-morbidities such as diabetes and heart disease, and less access to high quality cancer treatment, but to date these factors have not been fully explored. This study compared detailed surgical, chemotherapeutical and radiological cancer treatment for Indigenous people with the non-Indigenous population of Queensland between 1998 and 2004.

Methods: Indigenous people diagnosed with cancer between 1998 and 2004 were identified through the Queensland Cancer Registry and compared with randomly selected non-Indigenous cancer patients frequency matched for cancer type, year of diagnosis, age, sex and place of residence. We restricted analyses to patients treated in the public sector since under 5% of Indigenous cases were treated privately. Therefore details of treatment were obtained from public hospital medical records only. Multivariate models, primarily Cox regression analyses were used to examine the differences between Indigenous and non-Indigenous cases with regard to timing of treatment. Statistical significance was set at α =0.05. Ethical clearances were obtained from the Queensland Health Department, the Queensland Institute of Medical Research and all hospitals that assisted in the data collection.

Summary: 983 Indigenous and 905 non-Indigenous cancer patients were studied. Preliminary results from this study confirmed that cancer stage at diagnosis was not significantly different between Indigenous and non-Indigenous people in the public health system. Overall, Indigenous people were twice as likely not to receive any treatment for their cancer than their non-Indigenous counterparts. They were significantly less likely to have surgery and radiotherapy overall, but chemotherapy uptake was similar between the two groups. Indigenous people also waited longer to commence their cancer treatment.

Conclusion: Disparities in cancer treatment may go some way to explaining the differential in cancer outcome for Indigenous people when compared to the non-Indigenous population in Queensland, Australia.