Persistent Neighborhood Poverty and Breast Cancer Outcomes.

Importance: Patients with breast cancer residing in socioeconomically disadvantaged communities often face poorer outcomes (eg, mortality) compared with individuals living in neighborhoods without persistent poverty.
Objective: To examine persistent neighborhood poverty and breast tumor characteristics, surgical treatment, and mortality.
Design, Setting, and Participants: A retrospective cohort analysis of women aged 18 years or older diagnosed with stage I to III breast cancer between January 1, 2010, and December 31, 2018, and followed up until December 31, 2020, was conducted. Data were obtained from the Surveillance, Epidemiology, and End Results Program, and data analysis was performed from August 2023 to March 2024.
Exposure: Residence in areas affected by persistent poverty is defined as a condition where 20% or more of the population has lived below the poverty level for approximately 30 years.
Main Outcome and Measures: All-cause and breast cancer-specific mortality.
Results: Among 312 145 patients (mean [SD] age, 61.9 [13.3] years), 20 007 (6.4%) lived in a CT with persistent poverty. Compared with individuals living in areas without persistent poverty, patients residing in persistently impoverished CTs were more likely to identify as Black (8735 of 20 007 [43.7%] vs 29 588 of 292 138 [10.1%]; P < .001) or Hispanic (2605 of 20 007 [13.0%] vs 23 792 of 292 138 [8.1%]; P < .001), and present with more-aggressive tumor characteristics, including higher grade disease, triple-negative breast cancer, and advanced stage. A higher proportion of patients residing in areas with persistent poverty underwent mastectomy and axillary lymph node dissection. Living in a persistently impoverished CT was associated with a higher risk of breast cancer-specific (adjusted hazard ratio [AHR], 1.10; 95% CI, 1.03-1.17) and all-cause (AHR, 1.13; 95% CI, 1.08-1.18) mortality. As early as 3 years following diagnosis, mortality risks diverged for both breast cancer-specific (rate ratio [RR], 1.80; 95% CI, 1.68-1.92) and all-cause (RR, 1.62; 95% CI, 1.56-1.70) mortality.
Conclusions and Relevance: In this cohort study of women aged 18 years or older diagnosed with stage I to III breast cancer between 2010 and 2018, living in neighborhoods characterized by persistent poverty had implications on tumor characteristics, surgical management, and mortality.