Cancer
Area Deprivation as a Risk Factor for Distant-Stage Breast Cancer in South Korea (2012–2019): A Multilevel Study Jeehyun Kim* Jeehyun Kim Eunhye Park
Background: Breast cancer is the most common cancer in women globally, with rising incidence in South Korea. Regional disparities in breast cancer show higher incidence in affluent areas but higher mortality in deprived ones, likely due to delayed diagnosis and limited health access. Few studies adjust for individual-level risks, leaving gaps in understanding how the areal deprivation index (ADI) affects distant-stage breast cancer.
Objective: To determine how ADI increases distant-stage breast cancer incidence, beyond individual factors
Methods: Data from the Korea Central Cancer Registry linked to the National Health Information Database (2012–2019) were analyzed. Breast cancer stages were classified using SEER summary stages: Localized, Regional, and Distant. Age-standardized incidence rates were calculated using Segi’s world population. Regional variables, including ADI and mammography devices, were sourced publicly. Multilevel analysis evaluated individual- and regional-level impacts on distant- versus local-stage incidence.
Results: Of 164,292 cases, 163,152 were includedThe 45–49 age group had the highest prevalence (N= 31,568, 19.3%), while distant-stage proportions were highest in the youngest (<29 years, 6.0%) and oldest (≥85 years, 11.5%). Multilevel analysis showed higher odds of distant-stage cancer in younger and older individuals, those with higher BMI, lower insurance premiums, severe disabilities and residents in areas with higher deprivation (OR=1.06, p<.001) or fewer mammography devices (OR=0.93, p=.003).
Conclusions: Regional socioeconomic characteristics significantly influence breast cancer stage at diagnosis, even after accounting for individual factors. Addressing healthcare disparities through early detection and equitable access to quality care is essential to improve breast cancer outcomes.
