Sociodemographic Disparities in First-Line Treatment and Outcome Patterns in Women with HR+/HER2− Metastatic Breast Cancer
Menée aux Etats-Unis à partir de données portant sur 6 974 patientes atteintes d'un cancer du sein HR+ HER2- de stade métastatique, cette étude de cohorte rétrospective analyse les disparités socioéconomiques dans les traitements de première ligne reçus et dans la survie globale associée
Background: Various factors such as race/ethnicity, practice settings, socioeconomic status (SES), and geographic region influence cancer outcomes. We describe treatment patterns and outcomes among women with hormone receptor–positive/human epidermal growth factor receptor 2-negative (HR+/HER2−) metastatic breast cancer treated in the United States based on these factors.
Methods: A retrospective, observational cohort study was conducted using the Flatiron Health Research Database of deidentified electronic health records in women ≥18 years in the United States who received first-line treatment for HR+/HER2− metastatic breast cancer from January 1, 2015, to February 28, 2023. Real-world overall survival (rwOS) and time to next treatment or death (rwTTNTD) were assessed using Kaplan–Meier methods.
Results: The analysis included 6,974 women, who were most commonly non-Hispanic White (64%), lived in the South (37%), and received treatment in community settings (83%). From 2015 to 2019, the early uptake period of cyclin-dependent kinase 4/6 inhibitors (CDK4/6i), non-Hispanic White women were more likely to receive endocrine therapy (ET) + CDK4/6i compared with non-Hispanic Black and Hispanic/Latino women; ET + CDK4/6i was less common in lower (Q1–Q3) versus higher (Q4–Q5) SES quintiles and in community versus academic settings. These differences were less pronounced from 2020 to 2023. Non-Hispanic White women had significantly longer rwOS compared with non-Hispanic Black women but shorter rwOS compared with Hispanic/Latino women. rwOS was longer in academic versus community settings. No substantial differences in rwTTNTD were observed.
Conclusions: We observed disparities in first-line treatment and outcomes among women with HR+/HER2− metastatic breast cancer during a time of changes to the standard of care across racial/ethnic groups and practice settings.
Impact: These findings emphasize the need for improved access to evidence-based therapies, particularly in underrepresented populations.
Cancer Epidemiology, Biomarkers & Prevention , résumé, 2026