Socioeconomic Disparities in Breast Cancer Diagnosis, Treatment and Survival: Analysis of the Korean K-CURE cohort

BACKGROUND: Breast cancer is the most commonly diagnosed cancer worldwide and in South Korea. Although Korea provides universal health coverage, the extent to which socioeconomic status (SES) influences breast cancer care and outcomes remains unclear. This study evaluated SES-related differences in screening participation, stage at diagnosis, treatment patterns, and survival within a universal healthcare system. METHODS: We analyzed 111,585 women aged ≥40 years diagnosed with breast cancer between 2014 and 2019 using the K-CURE dataset. SES was classified into five income- and insurance-based groups: Medical Benefit status and four NHI premium quartiles. Variables included screening participation, cancer stage, and treatment. Kaplan-Meier estimates compared unadjusted survival, and multivariable Cox proportional hazards models estimated adjusted hazard ratios for mortality outcomes. RESULTS: Lower SES was associated with reduced screening participation, more advanced stage at diagnosis, and lower treatment receipt. The Medical Benefit group showed the highest proportion of distant-stage cancer (8.4%) and the highest no-treatment rate (2.7%). Mortality was substantially higher among non-screened patients across all SES groups. In multivariable analyses, low SES, advanced stage, and non-receipt of standard treatments were significant predictors of increased breast cancer-specific mortality. Despite high overall treatment rates, disparities persisted among socioeconomically disadvantaged groups. CONCLUSION: Significant income- and insurance-based socioeconomic disparities in breast cancer detection, treatment receipt, and survival remain even within a universal healthcare system. Targeted strategies to improve screening participation and ensure equitable access to care for vulnerable populations are essential to reduce SES-related survival gaps. IMPACT: Socioeconomic disparities persist despite universal health coverage.