Neighborhood disadvantage linked to shorter breast cancer-specific, overall survival

Key takeaways:

• Women living in disadvantaged vs. advantaged neighborhoods had higher breast cancer-specific and overall mortality risks.
• Black women had higher mortality risks vs. white women.

Women with breast cancer living in the most vs. the least disadvantaged neighborhoods had higher risks for breast cancer-specific and overall mortality, according to cohort study results published in JAMA Network Open.

“Neighborhoods reflect complex environments with unique cultural, physical and economic attributes, and disadvantaged neighborhoods contribute to the creation and persistence of under-resourced neighborhoods limiting access to care such as screening mammography and treatment, ultimately impacting breast cancer survival,” Neha Goel, MD, MPH, surgeon-scientist in the division of surgical oncology in the department of surgery at the Sylvester Comprehensive Cancer Center at the University of Miami Miller School of Medicine and the Harvard T.H. Chan School of Public Health, and colleagues wrote. “While many of these survival disparities are secondary to access to care barriers, recent literature has shown breast cancer-specific survival disparities exist after controlling for these measures.”

Goel and colleagues conducted a national retrospective population-based cohort study utilizing data from the Surveillance, Epidemiology and End Results 17 (SEER-17) database on 350,824 women with breast cancer diagnosed from 2013 to 2018. Researchers evaluated associations between neighborhood disadvantage and breast cancer-specific and overall survival among women with breast cancer after controlling for individual, tumor and treatment characteristics. Researchers measured neighborhood disadvantage using the Yost index quintiles, a composite variable including census tract-level information.

Primary outcome was breast cancer-specific mortality, and the secondary outcome was overall mortality.

Overall, 11.8% of women were Hispanic, 11.3% were Black and 66.9% were white. Overall, 27,145 women died from breast cancer, and 17,345 women died from causes not related to breast cancer.

One-quarter of the cohort lived in the most advantaged neighborhoods, and 14.9% lived in the most disadvantaged neighborhoods. More white women (76.2%) lived in advantaged neighborhoods while a higher proportion of Black (30.9%) and Hispanic (19.5%) women lived in disadvantaged neighborhoods.

When adjusting for age, race and ethnicity, rurality, breast cancer stage, tumor subtype, insurance and treatment, the most disadvantaged neighborhoods were associated with the higher risk for breast cancer-specific mortality compared with the most advantaged neighborhoods (HR = 1.43; 95% CI, 1.36-1.5). When comparing racial and ethnic groups, Black women had a higher breast cancer-specific mortality risk compared with white women (HR = 1.16; 95% CI, 1.11-1.22).

Results were similar for overall mortality with the highest overall mortality risk observed among women living in the most disadvantaged neighborhoods compared with the most advantaged neighborhoods (HR = 1.53; 95% CI, 1.48-1.59). In addition, Black women continued to have higher overall mortality risk compared with white women (HR = 1.16; 95% CI, 1.13-1.2).

“To address these residual disparities associated with neighborhood disadvantage, future research must take a translational epidemiologic approach to focus on biological and nonbiological factors through which the built environment, above the beyond individual-level factors, may influence outcomes,” the researchers wrote. “This approach to research has the potential to advance precision medicine in oncology by bringing neighborhood disadvantage into consideration when risk-stratifying vulnerable populations and to develop cancer control interventions to overcome breast cancer disparities.”