Rural-urban disparities in stage of breast cancer at diagnosis in Australian women

Objective: To examine urban-rural differences and individual risk factors for a late stage of breast cancer at diagnosis in Australian women. Design: Individual-level longitudinal data were linked with cancer registry data from New South Wales (New South Wales Cancer Registry linked by the Centre for Health Record Linkage (CHeReL)), Queensland (Queensland Cancer Registry) and Victoria (The Cancer Council Victoria). Setting: Participants were drawn from the Australian Longitudinal Study on Women's Health 1946-1951 cohort (n = 13 715). Participants: The sample included 195 women identified from the linked cancer registry data with a breast cancer diagnosis. Interventions: Rural or urban residence was measured using Accessibility/Remoteness Index of Australia Plus (ARIA+). Individual characteristics and socio-demographic variables examined included survey year, menopausal status, country of birth, education and marital status. Main outcome measures: A late stage of breast cancer at diagnosis was defined based on the TNM Classification of Malignant Tumours. Results: A late stage of breast cancer diagnosis was observed in 36% of women residing in urban areas and 40% of women residing in rural areas. After adjusting for individual characteristics, we found that obesity was the strongest risk factor for a late stage of breast cancer at diagnosis. Conclusions: Given that women are becoming increasingly obese, and that the rate of obesity is higher in the Australian rural population, this paper provides further evidence for targeting interventions for obesity, particularly in rural Australia, as a public health priority.