Associations of Proximity to Superfund Sites and Air Pollution with Breast Cancer Subtypes: Clues from a Case–Case Study and Call for Longitudinal Studies

Emerging research suggests that environmental contaminants may influence the risk of breast cancer, particularly through exposure to endocrine disruptors and carcinogens present in the air, water, and consumer products. In a recent study, Borowsky and colleagues conducted a case-case study in Florida and identified a higher likelihood of triple-negative breast cancer among women living less than 4 miles of superfund sites compared with those with other breast cancer subtypes. In addition, Borowsky and colleagues observed a higher likelihood of triple-negative breast cancer among women residing in areas with high levels of particulate matter with aerodynamic diameter <2.5 µm (PM2.5) versus other subtypes. Careful consideration when interpreting these findings is needed due to limitations in study design, including temporal misalignment in assigning exposures, conceptual disconnect between PM2.5 and toxic exposures at superfund sites, selection bias, and the absence of information on specific breast cancer subtypes as well as reproductive and hormonal factors. We suggest areas for clarification and future research. Notably, the study raises important hypotheses about the impact of environmental contaminants on the risk of distinct breast cancer subtypes. This is particularly important for populations that experience higher levels of environmental exposures because of structural and social drivers of health. See related article by Borowsky et al., p. 59.