Purpose: To examine trends in the surgical treatment of breast cancer by age, rurality, and among Black women in a populous, racially diverse, state in the Southeastern United States of America. Methods: We identified women diagnosed with localized or regional breast cancer between 2003 and 2016 in the North Carolina Central Cancer Registry (n = 86,776). Using Joinpoint regression we evaluated the average annual percentage change in proportion of women treated with mastectomy versus breast-conserving surgery overall, by age group, among Black women, and for women residing in rural areas. Results: Overall, the rate of mastectomy usage in the population declined 2.5% per year between 2003 and 2016 (95% CI − 3.2, − 1.7). Over this same time interval, breast-conserving surgery increased by 1.6% per year (95% CI 0.9, 2.2). These temporal trends in surgery were also observed among Black women and rural residing women. Trends in surgery type varied by age group: mastectomy declined over time among women > 50 years, but not among women aged 18–49 at diagnosis. Discussion: In contrast to national studies that reported increasing use of mastectomy, we found declining mastectomy rates in the early 2000s in a Southern US state with a racially and geographically diverse population. These decreasing trends were consistent among key subgroups affected by cancer inequities, including Black and White rural women
