How Neighborhood Impacts Breast Cancer, Death Rates
Living in a disadvantaged neighborhood also lowers breast cancer survival, according to new research. A disadvantaged neighborhood is generally defined as a location associated with higher concentrations of poverty, higher rates of unemployment, and less access to health care, quality housing, food, and community resources, according to the Centers for Disease Control and Prevention.
Authors of a study published in JAMA Network Open on April 18 identified 350,824 patients with breast cancer. Of these, 41,519 (11.8%) were Hispanic, 39,631 (11.3%) were non-Hispanic Black, and 234,698 (66.9%) were non-Hispanic White. Investigators divided the patients into five groups representing the lowest to highest neighborhood socioeconomic indices using the Yost Index. (The Yost Index is used by the National Cancer Institute for cancer surveillance and is based on variables such as household income, home value, median rent, percentage below 150% of the poverty line, education, and unemployment.)
Of the Black and Hispanic patients in the study, the highest proportions of both demographics lived in the most disadvantaged neighborhoods. (16,141 Black patients [30.9%]) and 10,168 Hispanic patients [19.5%]). Although 45% of White patients also fell into that same category, the highest proportion of White patients in the study lived in the most advantaged neighborhoods (66,529 patients [76.2%]).
Findings showed patients in the most disadvantaged neighborhoods had the highest proportion of triple-negative breast cancer. Patients in this group also had the lowest proportion of patients who completed surgery and radiation, and the highest proportion of patients who received chemotherapy, compared with all other neighborhood groups. The most advantaged neighborhoods group had higher proportions of localized-stage cancer, a higher proportion of patients who underwent surgery and radiation, and the lowest proportion of patients receiving chemotherapy treatment.
Patients in the most disadvantaged neighborhoods also had the highest risk of mortality (hazard ratio [HR,] 1.53; 95% CI, 1.48-1.59; P less than .001) compared with patients living in the most advantaged neighborhoods. Non-Hispanic Black patients in particular, had the highest risk of mortality, compared with non-Hispanic White patients (HR, 1.16; 95% CI, 1.13-1.20; P less than .001).
Authors wrote that the findings suggest neighborhood disadvantage is independently associated with shorter survival in patients with breast cancer, even after controlling for individual-level factors, tumor characteristics, and treatment.
“To address these residual disparities associated with neighborhood disadvantage, research must focus on which components of the built environment influence outcomes,” the authors said.
Another recent study also found correlations among where breast cancer patients lived and how they fared with the disease.
Jasmine M. Miller-Kleinhenz, PhD, an assistant professor at University of Mississippi Medical Center in Jackson, studied how historical redlining impacts breast cancer development and outcomes in her research published in JAMA Network Open, earlier this year. Redlining refers to the practice of denying people access to credit because of where they live. Historically, mortgage lenders widely redlined neighborhoods with predominantly Black residents. The 1968 Fair Housing Act outlawed racially motivated redlining, but consequences from historical redlining still exist.
University of Mississippi Medical Center
Dr. Jasmine M. Miller-Kleinhenz
Dr. Miller-Kleinhenz and her colleagues analyzed a cohort of 1764 women diagnosed with breast cancer between January 2010 and December 2017, who were followed up through December 2019. Investigators accessed the cohort based on three exposures: historic redlining (HRL), contemporary mortgage discrimination (CMD), and persistent mortgage discrimination (PMD). Contemporary mortgage discrimination refers to current-day discriminatory mortgage practices and persistent mortgage discrimination refers to neighborhoods that have experienced both HRL and CMD.
Findings showed that Black women living in historical redlined areas had increased odds of being diagnosed with aggressive forms of breast cancer, while White women in redlined areas had increased odds of late-stage diagnosis.
White women exposed to persistent mortgage discrimination were twice as likely to die of breast cancer, compared with their White counterparts living in areas without historical redlining or contemporary mortgage discrimination, the study found.
That is not to say that Black women did not have an increased risk of breast cancer mortality, Dr. Miller-Kleinhenz explained. Black women had a more than threefold elevated risk of breast cancer mortality compared with White women no matter where they lived, according to the findings.
“These results were surprising because it is showing that while neighborhood conditions might be a major driver of breast cancer mortality in White women, there are factors beyond the neighborhood that are additional drivers that are contributing to poor outcomes in Black women,” she said.