Factors Associated With Cancer-Specific and Overall Survival Among Indigenous and Non-Indigenous Gynecologic Cancer Patients in Queensland, Australia: A Matched Cohort Study

Objective Aboriginal and Torres Strait Islander women have a higher mortality rate due to gynecologic cancer compared with non-Indigenous women. For cervical cancer, Australian Indigenous women are less likely to survive 5 years following diagnoses than non-Indigenous women. This study investigates the factors associated with gynecologic cancer treatment and survival among Queensland indigenous and non-Indigenous women. Methods Australian Indigenous women diagnosed with uterine, cervical, ovarian, or other gynecologic cancers during 1998–2004 in the public hospital system were included. They were frequency matched on age (±5 years), residential remoteness, and cancer type to a random sample of non-Indigenous women. One- and 5-year cancer-specific survival was examined according to Indigenous status using Cox proportional hazards regression. Results Indigenous women (n = 137) compared with non-Indigenous women (n = 120) were less likely to be diagnosed with localized disease (49% vs 65%, P = 0.02) and had more comorbidities (52% vs 21%, P < 0.001). Indigenous women were less likely to receive any cancer treatment compared with non-Indigenous women (91% vs 98%, P = 0.01), although when excluding those with metastatic cancer, there was no significant difference in uptake of treatment (95% vs 91%, respectively, P = 0.31). Among those who did undergo treatment, there was no difference in time to treatment (median difference 0.5 days, P = 0.98). Gynecologic cancer–specific survival differences between Indigenous and non-Indigenous women were most prominent in the first year following diagnosis (hazard ratio [HR], 1.89; 95% confidence interval [CI], 1.06–3.38) and were no longer significant 5 years after diagnosis (HR, 1.47 [95% CI, 0.97–2.25]). For cervical cancer, crude 1-year survival was poorer for Indigenous women compared with non-Indigenous women (HR, 2.46 [95% CI, 1.03–5.90]), but was no different when adjusted for stage and treatment of cancer (HR, 1.00 [95% CI, 0.45–2.24]). Conclusions Improving the early diagnosis of cervical cancer in Indigenous women may increase cancer-specific survival in the year following diagnosis.

[1]  J. Condon,et al.  How well is the National Cervical Screening Program performing for Indigenous Australian women? Why we don't really know, and what we can and should do about it. , 2014, European journal of cancer care.

[2]  F. Bray,et al.  Survival disparities in Australia: an analysis of patterns of care and comorbidities among indigenous and non-indigenous cancer patients , 2014, BMC Cancer.

[3]  M. Coory,et al.  Cancer survival for Aboriginal and Torres Strait Islander Australians: a national study of survival rates and excess mortality , 2014, Population Health Metrics.

[4]  P. Baade,et al.  The first year counts: cancer survival among Indigenous and non‐Indigenous Queenslanders, 1997–2006 , 2012, The Medical journal of Australia.

[5]  J. Condon,et al.  Women's cancers and cancer screening in the Northern Territory , 2012 .

[6]  M. Coory,et al.  A study of head and neck cancer treatment and survival among indigenous and non-indigenous people in Queensland, Australia, 1998 to 2004 , 2011, BMC Cancer.

[7]  J. Condon,et al.  Incidence, aetiology, and outcomes of cancer in Indigenous peoples in Australia. , 2008, The Lancet. Oncology.

[8]  M. Coory,et al.  Survival of Indigenous and non‐Indigenous Queenslanders after a diagnosis of lung cancer: a matched cohort study , 2008, The Medical journal of Australia.

[9]  C. Luke,et al.  Benchmarking epidemiological characteristics of cervical cancer in advance of change in screening practice and commencement of vaccination , 2007, Australian and New Zealand journal of public health.

[10]  J. Condon,et al.  Cancer diagnosis and treatment in the Northern Territory: assessing health service performance for indigenous Australians , 2006, Internal medicine journal.

[11]  M. Coory,et al.  Cancer diagnosis, treatment, and survival in Indigenous and non-Indigenous Australians: a matched cohort study , 2006, The Lancet.

[12]  Tony Barnes,et al.  Stage at diagnosis and cancer survival for Indigenous Australians in the Northern Territory , 2005, The Medical journal of Australia.

[13]  J. Semmens,et al.  Ovarian cancer in Western Australia (1982–98): incidence, mortality and survival , 2003, Australian and New Zealand journal of public health.

[14]  Aged Care,et al.  Measuring Remoteness: Accessibility/Remoteness Index of Australia (ARIA) Revised Edition. Occasional Papers: New Series Number 14 , 2001 .

[15]  S. Perry.  Reports from the Australian Institute of Health and Welfare (AIHW) , 1995, International Journal of Technology Assessment in Health Care.

[16]  C. Mackenzie,et al.  A new method of classifying prognostic comorbidity in longitudinal studies: development and validation. , 1987, Journal of chronic diseases.