Post-breast cancer diagnosis screening mammography among First Nations and non-First Nations women in Ontario

Objectives First Nations women in Canada have historically experienced lower breast cancer screening participation and worse outcomes than non-First Nations women. While most research has focused on pre-diagnosis screening, less is known about follow-up care. This study examined post-diagnosis mammography use among First Nations and non-First Nations women in Ontario and identified factors associated with follow-up screening among First Nations women. Methods This retrospective cohort study included 190 First Nations and 506 non-First Nations women diagnosed with invasive breast cancer between 1995 and 2004, with follow-up screening data available through 2019. Descriptive statistics compared demographic, clinical, and treatment characteristics. Logistic regression models were used among First Nations women to identify factors associated with follow-up screening. Results No statistically significant differences were observed in the unadjusted comparisons of post-treatment screening rates, frequency, timing, and intervals between First Nations and non-First Nations women. Among First Nations women, older age (OR = 0.42; 95% CI, 0.19–0.94), rural residence (OR = 0.35; 95% CI, 0.17–0.73), and lower income (OR = 0.20; 95% CI, 0.06–0.69) were among the factors associated with reduced screening. Radiotherapy (OR = 7.48; 95% CI, 3.38–16.56) and less severe surgery (OR = 7.19; 95% CI, 3.31–15.63) were associated with higher odds of screening. Conclusion While screening rates among First Nations women are improving, disparities persist. Strengthening continuity of care, primary care access, and culturally safe survivorship support is essential to achieving equity.