Neighborhood Disadvantage and Breast Cancer-Specific Survival in the US.

IMPORTANCE

Despite improvements in breast cancer screening, treatment, and survival, disparate breast cancer-specific survival outcomes persist, particularly in disadvantaged neighborhoods. Most of these disparities are attributed to disparities in individual, tumor, and treatment characteristics. However, a critical knowledge gap exists as to whether disparities in breast cancer-specific survival remain after accounting for individual, tumor, and treatment characteristics.

OBJECTIVE

To evaluate if neighborhood disadvantage is associated with shorter breast cancer-specific survival after controlling for individual, tumor, and treatment characteristics in a national population.

DESIGN, SETTING, AND PARTICIPANTS: This national retrospective cohort study included patients with breast cancer diagnosed from 2013 to 2018 from the Surveillance, Epidemiology, and End Results 17 Census tract-level socioeconomic status and rurality database of the National Cancer Institute. Data analysis was performed from September 2022 to December 2023.

EXPOSURES

Neighborhood disadvantage measured by Yost index quintiles.

MAIN OUTCOMES AND MEASURES

Breast cancer-specific survival was evaluated using a competing risks cause-specific hazard model controlling for age, race, ethnicity, rurality, stage, subtype, insurance, and receipt of treatment.

RESULTS

A total of 350 824 patients with breast cancer were included; 41 519 (11.8%) were Hispanic, 39 631 (11.3%) were non-Hispanic Black, and 234 698 (66.9%) were non-Hispanic White. A total of 87 635 patients (25.0%) lived in the most advantaged neighborhoods (group 5) and 52 439 (14.9%) lived in the most disadvantaged neighborhoods (group 1). A larger number of non-Hispanic White patients (66 529 patients [76.2%]) lived in advantaged neighborhoods, while disadvantaged neighborhoods had the highest proportion of non-Hispanic Black (16 141 patients [30.9%]) and Hispanic patients (10 168 patients [19.5%]). Breast cancer-specific survival analysis found the most disadvantaged neighborhoods (group 1) had the highest risk of mortality (hazard ratio, 1.43; 95% CI, 1.36-1.50; P < .001) compared with the most advantaged neighborhoods.

CONCLUSIONS AND RELEVANCE

In this national cohort study of patients with breast cancer, neighborhood disadvantage was independently associated with shorter breast cancer-specific survival even after controlling for individual-level factors, tumor characteristics, and treatment. This suggests potential unaccounted-for mechanisms, including both nonbiologic factors and biologic factors.