Trends in breast cancer incidence rates by race/ethnicity: Patterns by stage, socioeconomic position, and geography in the United States, 1999-2017

Background: The incidence rate of breast cancer has been increasing over time across race/ethnicity in the United States. It is unclear whether these trends differ among stage, poverty, and geography subgroups. Methods: Using data from the North American Association of Central Cancer Registries, this study estimated trends in age-adjusted breast cancer incidence rates among women aged 50 to 84 years from 1999 to 2017 by race/ethnicity (non-Hispanic Black, non-Hispanic White, and Hispanic) and across subgroups (stage, county-level poverty, county urban/rural status, and geographic region [West, Midwest, South, and Northeast]). Results: From 2004 to 2017, breast cancer incidence rates increased across race/ethnicity and subgroups, with the greatest average annual percent increases observed for non-Hispanic Black women, overall (0.9%) and those living in lower poverty areas (0.8%), rural areas (1.2%), and all regions except the West (0.8%-1.0%). Stronger increases among non-Hispanic Black women were observed for local-stage disease and for some subgroups of distant-stage disease. Non-Hispanic Black women had the smallest decrease in regional-stage disease across most subgroups. Similarly, Hispanic women had the strongest increases in some subgroups, including areas with higher poverty (0.6%-1.2%) and in the West (0.8%), for local- and distant-stage disease. Conclusions: These trends highlight concerns for an increasing burden of breast cancer among subpopulations, with some already experiencing disparate breast cancer mortality rates, and they highlight the need for targeted breast cancer prevention and efforts to reduce mortality disparities in areas with increasing incidence.