Associations of neighborhood deprivation with breast cancer tumor genomics, targeted treatment use, and survival.
PURPOSE: Neighborhood environments appear to influence breast cancer biology and outcomes. This study evaluated somatic, treatment, and outcome differences by Area Deprivation Index in patients with metastatic breast cancer. METHODS: Retrospective, population-based cohort study using clinical and genomic data gathered between 2015 and 2024 at four academic institutions in the United States. The outcomes were differences in circulating tumor DNA mutation profiles, PI3K inhibitor use, and survival between patients with metastatic breast cancer living in high deprivation (Area Deprivation Index ≥ 60 by national rank) and low deprivation (< 60) neighborhoods. RESULTS: Among 1127 patients with metastatic breast cancer, 335 (29.7%) lived in high deprivation areas. These patients were more likely to have TP53 mutations (Odds ratio 1.49, 95% Confidence Interval 1.07-2.08, P = 0.018). Among hormone receptor-positive, HER2-negative patients eligible for PI3K inhibitors, those from high deprivation areas were less likely to receive them (17.4% vs. 36.7%, p = 0.02). Median survival from the time of circulating tumor DNA testing was significantly shorter in the high deprivation group (24 months versus 28 months, p = 0.04) and for Black patients in the high deprivation group versus Black patients in low deprivation group and all White patients (15 months versus 25-28 months, p = 0.02). CONCLUSIONS: We found that patients with metastatic breast cancer living in high deprivation neighborhoods were more likely to have TP53 mutations, an indicator of aggressive disease biology, less likely to receive PI3K inhibitors, and had shorter overall survival compared to patients living in low deprivation neighborhoods by Area Deprivation Index.