Beyond the urban-rural divide: Exploring spatial variations in breast cancer outcomes in Queensland, Australia.

Background: Breast cancer is the most commonly diagnosed cancer among women worldwide. While previous studies have reported urban and rural differences in breast cancer outcomes, the level of heterogeneity within these broad regions is currently unknown.

Methods: Population-level data from Queensland Cancer Register including 58,679 women aged at least 20 years who were diagnosed with breast cancer in Queensland, Australia, 2000-2019 were linked to BreastScreen Queensland and Queensland Hospital Admitted Patients Data Collection to estimate five breast cancer outcomes: incidence, proportion of localised disease and screen-detected cases (via public-funded program), surgical rates, and 5-year survival. Bayesian spatial models were used to smooth outcomes across 512-517 small areas in Queensland.

Results: The incidence of breast cancer was not proportionally distributed, with urban regions having higher rates. Less than half (47 %) of women were diagnosed with localised disease, 91 % had surgery, with five-year relative survival of 92 %. There was no evidence of geographic variation in the proportion of localised disease, surgical rates, or survival over Queensland. Publicly-funded screening detected 38 % of cases, with lower proportion of screen-detected cases observed in Queensland's urbanised south-east corner.

Conclusion: Although the disparities in health outcomes faced by Australians living in rural areas have received increased attention, this study found limited evidence for spatial variation in breast cancer outcomes along the continuum of care across Queensland. These results suggest the detection and management practices for breast cancer may provide an achievable benchmark for other cancer types in reducing the geographical disparity in cancer outcomes.