Statewide variability in predictors of survival among geographically and racially diverse breast cancer cohorts

Document Type

Conference Proceeding

Publication Date


Publication Title

Cancer Epidemiol Biomarkers Prev


Introduction: The National Breast and Cervical Cancer Early Detection Program (NBCCEDP) provides free breast cancer screening, case management, patient navigation, and connection to treatment for medically underserved and economically-disadvantaged women aged 40-64 years. The aim of this study was to identify differences in predictors of survival between all women diagnosed with breast cancer in South Carolina versus those enrolled in the SC NBCCEDP.

Methods: We established a retrospective cohort of breast cancer patients diagnosed from 2004 to 2015 using the South Carolina Central Cancer Registry. Sociodemographic (e.g., race, age) and clinical variables were abstracted from the registry. We linked registry data to county-level variables to determine levels of social deprivation and residence in a health care professional shortage area using the Robert Graham Center's Social Deprivation Index (SDI) and the Health Provider Shortage Area (HPSA) designation. Potential exposure variables (e.g., SDI, hormone receptor status, age, HER2 receptor status, time to first treatment, region, insurance status, cancer stage, year of diagnosis, rurality, NBCCEDP enrollment, race, marital status, cancer grade, HPSA designation) were entered into a Cox proportional hazard model to identify significant predictors of survival. The multivariable model utilized a backward elimination process to obtain the best fitting model at a pvalue <0.05 for each cohort of survivors (NBCCDP participants and all other breast cancer survivors).

Results: A total of 34,518 breast cancer patients were diagnosed during this time out of which 873 (2.5 %) were NBCCEDP participants. Overall, there were nine significant predictors namely race, cancer stage, age, hormone receptor status, HER receptor, cancer grade, marital status, insurance status, and diagnosis year. Among NBCCEDP participants, there were four significant predictors namely cancer stage, age, hormone status, and region. Region was the only significant predictor variable unique to NBCCEDP participants with those living in the Midlands region having an adjusted hazard ratio of 1.8; 95% CI: 1.1-2.8 compared with participants who lived in Lowcountry region. Overall, in both cohorts, race was one of the significant independent predictor variables with Black women having an adjusted hazard ratio of 1.2; 95% CI: 1.1-1.3 compared with white women.

Conclusions: Survival was significantly poorer among NBCCEDP participants living in the Midlands region, and Black women overall. To reduce survival disparities and enhance efficiency of NBCCEDP, efforts directed at enhancing support and eliminating barriers to timely detection and treatment should be focused on NBCCEDP participants living in the Midlands region of the state and Black women generally.





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