COVID-19 impacts on the breast cancer care pathway among systemically marginalized communities in Ontario

Purpose Healthcare system pauses occurred worldwide due to COVID-19, and may have worsened pre-existing disparities in breast cancer care. In this population-based, retrospective cohort study, we investigated indicators of breast cancer care (i.e., adherence to screening guidelines, early vs. late-stage diagnosis, and mastectomy vs. breast-conserving surgery) before and after COVID-19 lockdowns in Ontario, with an emphasis on immigrant women. Methods We had three binary outcomes and corresponding cohorts, and each outcome/cohort was ascertained relative to two time periods: April 1, 2018-March 31, 2020 (“pre-pandemic”) and April 1, 2020-March 31, 2022 (“pandemic”): i) up to date on screening, ii) early vs late stage of breast cancer diagnosis, and iii) mastectomy vs breast-conserving surgery at any time after diagnosis for women who were diagnosed at stages I-III during each two-year time period. We conducted descriptive analyses, and used logistic regression, both unadjusted and adjusted, to determine odds ratios for our dichotomous outcomes. Results Breast cancer screening rates dropped from 59.4% to 51.0%, and the number of women diagnosed dropped from 18,821 to 14,269, in the pre-pandemic vs pandemic period. In multivariable analyses, screening significantly dropped (AOR = 0.69 [95% CI (0.69–0.69)]), there was no significant difference for diagnostic stage (AOR = 0.99 [95% CI (0.92–1.05)]), and the use of mastectomy vs breast-conserving surgery was higher in the pandemic period (AOR = 1.14 [95% CI (1.08–1.20)]). Women from the Caribbean had lower odds of early-stage diagnosis in the pre-pandemic period despite a screening advantage. Conclusion Future work should further explore the reasons for these findings and potential system-level solutions.