A Multiscale Spatiotemporal Epidemiological Analysis of Neighborhood Correlates of Triple-Negative Breast Cancer.

BACKGROUND: Women living in disadvantaged neighborhoods present with increased prevalence rates of triple-negative breast cancer (TNBC). This study takes a spatiotemporal epidemiological approach to understand the impact of socioenvironmental contextual factors on TNBC prevalence rates. METHODS: We analyzed 935 TNBC cases from a major cancer center registry, between 2005 and 2017, to explore spatial and space-time clusters of TNBC prevalence rates at the census tract and neighborhood scales. Spatial regression analysis was performed to examine relationships between nine socioenvironmental factors and TNBC prevalence rates at both ecological scales. RESULTS: We observed spatial clustering of high TNBC prevalence rates along a north-south corridor of Miami-Dade County along Interstate 95, a region containing several majority non-Hispanic Black neighborhoods. Among the ecologic measures, the percent of a region designated as a brownfield was associated with TNBC prevalence rates at the tract-level (ß = 4.27; SE = 1.08; P < 0.001) and neighborhood-level (ß = 8.61; SE = 2.20; P < 0.001). CONCLUSIONS: Our spatiotemporal analysis identified robust patterns of hot spots of TNBC prevalence rates in a corridor of several disadvantaged neighborhoods in the northern half of the county. These patterns of TNBC align with the literature regarding at-risk groups and neighborhood-level effects on TNBC; however, remain to be validated in a population-based sample. IMPACT: Spatial epidemiological approaches can help public health officials and cancer care providers improve place-specific screening, patient care, and understanding of socioenvironmental factors that may shape breast cancer subtype through gene-environment and epigenetic interactions.

Structural Racism and Breast Cancer-specific Survival: Impact of Economic and Racial Residential Segregation.

OBJECTIVE: To analyze the effect of economic and racial/ethnic residential segregation on breast cancer-specific survival (BCSS) in South Florida, a diverse metropolitan area that mirrors the projected demographics of many United States regions. SUMMARY BACKGROUND DATA: Despite advances in diagnosis and treatment, racial and economic disparities in BCSS. This study evaluates these disparities through the lens of racial and economic residential segregation, which approximate the impact of structural racism. METHODS: Retrospective cohort study of stage I to IV breast cancer patients treated at our institution from 2005 to 2017. Our exposures include index of concentration at the extremes, a measurement of economic and racial neighborhood segregation, which was computed at the census-tract level using American Community Survey data. The primary outcome was BCSS. RESULTS: Random effects frailty models predicted that patients living in low-income neighborhoods had higher mortality compared to those living in high-income neighborhoods [hazard ratios (HR): 1.56, 95% confidence interval (CI): 1.23-2.00]. Patients living in low-income non-Hispanic Black and Hispanic neighborhoods had higher mortality compared to those living in high-income non-Hispanic White (NHW) neighborhoods (HR: 2.43, 95%CI: 1.72, 3.43) and (HR: 1.99, 95%CI: 1.39, 2.84), after controlling for patient characteristics, respectively. In adjusted race-stratified analysis, NHWs living in low-income non-Hispanic Black neighborhoods had higher mortality compared to NHWs living in high-income NHW neighborhoods (HR: 4.09, 95%CI: 2.34-7.06). CONCLUSIONS: Extreme racial/ethnic and economic segregation were associated with lower BCSS. We add novel insight regarding NHW and Hispanics to a growing body of literature that demonstrate how the ecological effects of structural racism-expressed through poverty and residential segregation-shape cancer survival.