Geographic Variations in Demographics, Socioeconomic Status, and Stage at Diagnosis Among Hormone Receptor-positive...

Although hormone receptor-positive (HR+) invasive ductal carcinoma (IDC) is the most common breast cancer subtype, there is limited evidence describing how demographic and clinical features vary across U.S. regions. Understanding geographic disparities is essential for improving screening and treatment planning. To examine regional variations in demographic, socioeconomic status (SES), and stage-at-diagnosis characteristics among U.S. patients with HR+ IDC.

This cross-sectional study used data from the National Cancer Database (NCDB) for patients diagnosed with HR+ IDC between 2004 and 2020. Patients were categorized into 6 U.S. geographic regions: Northeast, Southeast, Midwest, Southwest, Mountain, and Pacific, based on the Commission on Cancer facility location. Descriptive and comparative analyses evaluated age, sex, race and ethnicity, insurance type, income, urban-rural residence, and American Joint Committee on Cancer stage.

Among 136,280 patients (mean age, 64.4 years; 98.8% female), racial and SES composition differed significantly across regions. Black patients comprised 19.5% of the Southeast cohort and 18.1% of the Southwest cohort, compared with 2.9% in the Mountain region. The Asian population was highest in the Pacific (13.1%). Low-income households (<$63,000) were most prevalent in the Southwest (74.7%) and Southeast (69.5%), while the Pacific region had the highest proportion of higher-income households (46.4%) and metropolitan residents (94.3%). Stage III-IV disease at diagnosis occurred most often in the Southwest (17.6%) and least in the Northeast (14.0%).

Significant variation exists in the demographic and SES profile of patients with HR+ IDC, corresponding to differences in stage at diagnosis, and BC-related overall outcomes. These disparities likely reflect inequities in screening access, SES, and healthcare infrastructure, underscoring the need for region-specific public health strategies. Targeted regional interventions and equitable screening expansion are warranted to reduce geographic disparities and improve overall BC-related outcomes.