Purpose
This study aims to evaluate the variation in breast cancer stage at diagnosis and survival rates based on socioeconomic status(SES) using a population-based retrospective cohort.
Methods
We used data from the Korean Clinical Data Utilization for Research Excellence project(K-CURE) to analyze the SEER stage, SES by medical insurance status and mortality for 127,475 female breast cancer patients diagnosed between 2014 and 2019.
Results
SES was categorized into five groups based on statistical percentiles: medical benefit group (lowest SES, n=4,127, 3.2%), 1st quartile (n=31,274, 24.5%), 2nd quartile (n=30,287, 23.8%), 3rd quartile (n=25,641, 20.1%), and 4th quartile group (highest SES, n=36,146, 28.4%).
In terms of stage distribution by SES, the 4th quartile group had the highest percentage of local stage cases (62.6%) compared to the medical benefit group (51.8%), 1st quartile (57.4%), 2nd quartile (57.4%), and 3rd quartile (58.8%). Conversely, advanced stage cases were more prevalent in the medical benefit group (7.9%) compared to the 1st quartile (5.3%), 2nd quartile (5.3%), 3rd quartile (4.5%), and 4th quartile (3.8%).
Regarding overall survival rates, the medical benefit group had a poorer prognosis across all stages: local stage (90.5% in the medical benefit group vs. 97.9% in the 1st quartile, 97.8% in the 2nd quartile, 97.9% in the 3rd quartile, and 97.7% in the 4th quartile, p-value < 0.0001), regional stage (83.9%, 92.8%, 93.7%, 93.6%, and 93.6%, p-value < 0.0001), and distant stage (37.7%, 48.8%, 54.9%, 54.8%, and 56.4%, p-value < 0.0001). These results were consistent in the breast cancer-specific survival rate analysis.
Conclusions
Despite South Korea’s health insurance system covering most treatment costs our study indicates that economically disadvantaged patients are diagnosed at more advanced stages and have poorer overall survival rates. These findings suggest the need for enhanced and targeted social support for economically disadvantaged breast cancer patients.