Cancer in Aboriginal and Torres Strait Islander people in Queensland

Project summary

Aboriginal and Torres Strait Islander Australians do not enjoy the high standard of health that most other Australians have, and have worse outcomes for several diseases such as cancer. However, few comparative data exist to prove this disparity. We assessed differences in disease stage at cancer diagnosis, treatment, and survival between Indigenous and non-Indigenous populations in Queensland.

Summary of outcomes

Stage at diagnosis differed significantly (p=0·007): 47% of Indigenous versus 53% of non-Indigenous patients had localised cancer, 22% versus 21% had distant metastases, and 12% versus 7% had no information on stage in the medical chart examined. Comorbidities such as diabetes mellitus or chronic renal disease were more common in Indigenous patients. These individuals were less likely to have had treatment for cancer (surgery, chemotherapy, radiotherapy), and waited longer for surgery (hazard ratio=0·84, 95% CI 0·72–0·97) than non-Indigenous patients. After adjustment for stage at diagnosis, treatment, and comorbidities, non-Indigenous patients had better survival rates than Indigenous patients (hazard ratio=1·3, 95% CI 1·1–1·5).

The main message from the research is:

• The likelihood of death from cancer was about 30% higher for Indigenous than for non-Indigenous cases, after taking into account cancer stage at diagnosis, cancer treatment, and higher rates of comorbidities in Indigenous individuals. Compared with non-Indigenous Australian cancer patients, Indigenous patients of a similar age, sex, place of residence, type of cancer, and with similar access to public healthcare, fared worse.
• Better understanding of cultural differences in attitudes to cancer and its treatment could translate into meaningful public health and clinical interventions to improve cancer survival in Indigenous Australians.

Summary of project implementation

All Indigenous people residing in Queensland and diagnosed with cancer between 1997 and 2002 were identified through Queensland public hospitals or the Queensland Cancer Registry, and were eligible for inclusion. With access to information from medical charts being the deciding factor, this eligible research cohort was reduced to 815, comprising 610 Aboriginal patients, 158 Torres Strait Islanders, and 47 who identified themselves as both Aboriginal and Torres Strait Islander. Overall, 4% of Indigenous cases were children (0–14 years), 11% were aged 15–39 years, 40% aged 40–59 years, and the remaining 45% were 60 years or older. This cohort was compared with 810 non-Indigenous cancer patients diagnosed during the same period in Queensland.

PhD student Suzanne Moore is now working on another more thorough study of surgical, chemotherapeutical and radiological cancer treatment for Indigenous patients compared with non-Indigenous patients in Queensland between 1998 and 2004.

Related publications

• Martin, J. H., Coory, M. D., Valery, P. C. & Green, A. C 2009, ‘Association of Diabetes on Survival among Cohorts of Indigenous and non-Indigenous Australians with Cancer’, Cancer Causes and Control, vol. 20(3), pp. 355–60.
• Coory, M. D., Green, A. C., Stirling, J. & Valery, P. C. 2008, ‘Matched Cohort Study Comparing Survival of Indigenous and non-Indigenous Queenslanders after a Diagnosis of Lung Cancer’, Med J Aust, vol. 188(10), pp. 56–66.
• Valery, P. C., Coory, M. D., Stirling, J. & Green, A. C. 2006, ‘Cancer Diagnosis, Treatment, and Survival in Indigenous and non-Indigenous Australians: A matched cohort study’, The Lancet, vol. 367, issue 9525, pp. 1842–8.