Abstract
BACKGROUND: Kentucky is within the top five leading states for breast cancer mortality nationwide. This study investigates the association between neighborhood socioeconomic disadvantage and breast cancer outcomes, including surgical treatment, radiotherapy, chemotherapy, and survival, and how associations vary by race and ethnicity in Kentucky. METHODS: We conducted a retrospective cohort analysis using data from the Kentucky Cancer Registry for patients with breast cancer diagnosed between 2010 and 2017, with follow-up through December 31, 2022. We linked Kentucky Cancer Registry data with census tract data to examine the relationship between area deprivation index (ADI) and breast cancer outcomes. Logistic regression and Cox proportional hazards models analyzed binary outcomes and time-to-event data, respectively. RESULTS: Women in the most disadvantaged (ADI fourth quartile) neighborhoods were more likely to be diagnosed at later stages (OR, 1.26; 95% confidence interval, 1.12-1.41) and 34% more likely to die from breast cancer (HR, 1.34; 95% confidence interval, 1.14-1.57) after adjusting for age, race, tobacco use, tobacco pack-years, marital status, insurance status, family history, stage at diagnosis, breast cancer subtype, and residence in Appalachia when compared with women living in the least disadvantaged neighborhoods (ADI first quartile). CONCLUSIONS: Women in disadvantaged neighborhoods had significantly higher odds of late-stage diagnosis and breast cancer death, regardless of race, indicating that neighborhood factors contribute to breast cancer disparities. IMPACT: Socioeconomic and neighborhood factors may contribute to breast cancer outcomes, suggesting the necessity for targeted interventions. Future research should explore the effectiveness of such interventions and investigate additional social determinants contributing to disparities.