Breast Cancer Risk and Hormone Replacement Therapy: A Study of Rhetorical Uncertainty across Technical, Public, and Personal Spheres of Argumentation

Abstract: This paper examines how the uncertain relationship between hormone replacement therapy (HRT) and breast cancer risk functions as a rhetorical topos across different spheres of argumentation. Following the 2002 Women's Health Initiative (WHI) study that suggested increased breast cancer risk among HRT users, medical practice shifted dramatically away from use of HRT. Twenty-three years later, with those findings in doubt, we are witnessing a "kairotic moment" for menopause discourse as stakeholders reconsider HRT's risk-benefit profile. Drawing on Goodnight's three-sphere model of argumentation—as adapted by Walsh and Walker for risk communication—I analyze how breast cancer risk is characterized across technical (medical literature), public (news media), and personal (patient narrative) spheres of argumentation. Rather than treating uncertainty as an epistemological gap that must be closed, this analysis demonstrates how the uncertain HRT-breast cancer connection serves as a boundary object generating new forms of discourse and new discourse communities. This research also reveals how uncertainty travels between spheres, creating hybrid arguments that reflect the competing interests of different stakeholders. Further, by tracking these characterizations through multiple spheres, this research shows how medical uncertainties are constructed, contested, and negotiated—ultimately shaping treatment options available to menopausal women. This work contributes to bioethics by highlighting how rhetorical framings of uncertainty influence medical decision-making and patient autonomy, while demonstrating that scientific controversies are never solely technical but always embedded in public and personal spheres of meaning-making.

Keywords: breast cancer risk, spheres of argumentation, rhetorical boundary object