Racial inequities in second-line treatment and overall survival among patients with metastatic breast cancer.

Background: Black women in the USA have a higher incidence and mortality of metastatic breast cancer (mBC) than White women, while Hispanic women have lower rates. Previous studies have focused on first-line (1L) treatment, but little is known about racial differences in treatment beyond 1L and their impact on outcomes.

Methods: This analysis utilized data from an electronic health record derived de-identified database and included patients with HR+HER2- mBC initiating 2L treatment (including CDK4/6-inhibitor [CDKi]-based, endocrine monotherapy, everolimus combination therapy, and chemotherapy and other systemic therapies) between 2/3/2015 and 7/31/2021.