Neighborhood Deprivation Linked to Increased Breast Cancer Deaths for White Women, but Not Black Women

Representation of diverse populations is important for patients with breast cancer to reduce risk of mortality. | Image Credit | mihail - stock.adobe.com

A study published in JAMA Oncology found that increased breast cancer mortality was linked to neighborhood deprivation among non-Hispanic White women, but not among non-Hispanic Black women.¹ The findings suggest there are factors beyond race, residential mobility, and rurality that contribute to higher mortality rates among Black women.

Following lung cancer, breast cancer is the second leading cause of cancer-related death among US women. About 1 in 40 women will die from breast cancer, but Black women have higher death rates compared with other racial and ethnic groups.² Research has hypothesized the higher risk of mortality among Black women could be due to their greater risk of triple-negative breast cancer compared with other racial or ethnic groups. However, cases have shown Black women are more likely to die from breast cancer at every age, regardless of the cancer type, compared with women of other races and ethnicities.

Some states have wider gaps in racial disparities—for instance, Georgia reported breast cancer as the leading cause of death for Black women, but not white women.¹ Various factors may contribute to these outcomes, like access to quality treatment, a high prevalence of comorbidities, and unfavorable tumor characteristics.

Neighborhood environments are often a social determinant that is racially patterned. In the US, individuals living in deprived, low socioeconomic neighborhoods that lack physical, economic, and social resources are 4 times more likely to be occupied by Black people rather than White populations. Ultimately, such disparities often impact health and breast cancer mortality by increasing exposure to chronic stress, reduction to health care access, and limited opportunities for healthy behaviors.

Researchers conducted a population-based cohort study utilizing the Georgia Cancer Registry (GCR) data that included women diagnosed with breast cancer between 2010 through 2017, then followed-up until December 31, 2022. Participants included non-Hispanic Black women and White women with invasive early-stage (I-IIIA) breast cancer.

The primary outcome was breast cancer-specific mortality identified by the GCR through associations to the Georgia vital statistics registry and National Death Index (NDI). The 8 indicators that comprise the NDI include percentage of people with annual incomes below federal poverty lines, households receiving public assistance, female-headed households with children younger than 18, households with annual income less than $35,000, unemployed individuals, employed individuals in managerial or administrative jobs, households with more than 1 person per room, and those aged 25 years or older without a high school degree or General Educational Development credentials.

A total of 36,795 patients with breast cancer were enrolled in the study, including 11,044 non-Hispanic Black women (30%) and 25,751 non-Hispanic White women (70%), with the average population age being 60.3 years old. About half of the participants had access to private health insurance (51.4%). Women living in the highest quintile of the NDI included non-Hispanic Black women that were single, Medicaid insured, diagnosed with triple-negative breast cancer, and living in a rural area with high poverty, mobility, and a larger percentage of Black residents.

In the follow-up period, 2942 deaths due to breast cancer occurred, with 1728 among non-Hispanic White women (58.7%) and 1214 among non-Hispanic Black women (41.3%).

After adjusting to reflect age, neighborhood deprivation was linked with higher breast cancer mortality rates only among non-Hispanic White women (quintile 5 vs 1, HR, 1.47; 95% CI, 1.21-1.79). No statistically significant associations between neighborhood deprivation and breast cancer mortality were found among non-Hispanic Black women.

Out of the 8 NDI components, the number of households that received public assistance and crowding had the highest hazard ratio estimates for breast cancer mortality.

Overall, the study results displayed evidence of a 36% increase in breast cancer mortality for patients living in the most deprived neighborhoods. A 47% increase in risk of breast cancer mortality was associated with neighborhood deprivation among non-Hispanic White women, but not in non-Hispanic Black women.

"In jointly stratified analyses, the association among non-Hispanic White women persisted across strata of rurality, neighborhood residential mobility, and neighborhood racial composition," the authors wrote. "These results highlight the impact of neighborhood on breast cancer mortality among non-Hispanic White women and suggest that further investigation is necessary among non-Hispanic Black women."

Past research has explored the potential mechanisms behind persistent racial disparities in health care. In a study published in Cancer Medicine, Black participants in qualitative interviews said they felt breast and ovarian cancer research was underdeveloped for their racial and ethnic groups.³ References to past historical abuse, like the Tuskegee syphilis study, Henrietta Lacks, and involuntary sterilization, were addressed by participants as a reason why Black populations are less interested in clinical trial research participation. Many participants felt Black individuals were used as “guinea pigs” rather than viewed as equal and valued like White populations. The fostered mistrust from previous racist based medical methods had led Black populations to stray away from clinical participation.

Other research has highlighted the potential link between high mortality among Black patients with breast cancer and a lack of diversity throughout clinical trials, including among clinical trial staff.⁴ By diversifying the medical staff, a higher level of trust can be built between patients, health care professionals, and eventually the systems themselves. Physicians that are a part of minority populations are more likely to serve patients in minority populations as well, highlighting the importance of Black people working in the medical field.

Authors of he current study noted several limitations, including the complexity of the NDI, which limits analysis and restricts interpretability.¹ Socioeconomic focus also overlooks potentially relevant factors like crime, health care access, and food or built environments. Additionally, single-time-point measurement ignores residential history and cumulative exposure. The study's generalizability may also be limited to Georgia's specific geographies.

"In this cohort study, we found that neighborhood deprivation was associated with increased breast cancer mortality among non-Hispanic White women but not non-Hispanic Black women," the authors concluded. "Further investigation of neighborhood residential mobility may help identify subgroups of non-Hispanic Black women at increased risk. However, other factors beyond those explored may contribute to increased breast cancer mortality among Black women and should be interrogated."

References

1. Barber LE, Maliniak ML, Moubadder L, et al. Neighborhood deprivation and breast cancer mortality among black and white women. JAMA Oncol. 2024;1-12. doi:10.1001/jamanetworkopen.2024.16499

2. Breast cancer statistics: how common is breast cancer?. Cancer.org. January 17, 2024. Accessed June 11, 2024. https://www.cancer.org/cancer/types/breast-cancer/about/how-common-is-breast-cancer.html#:~:text=50%20(1.0%25).-

3. Riggan KA, Rousseau A, Halyard MY, et al. “There’s not enough studies”: Views of black breast and ovarian cancer patients on research participation. Cancer Medicine. 2023;12(7)1-10. doi.org/10.1002/cam4.5622

4. Taye A, Elkhanany A, Stringer-Reasor E. Increasing inclusion and equity for black women in breast cancer clinical trials. Clin Adv Hematol Oncol. 2024;22(4):175-182.