IMPORTANCE: Women aged 70 years or older with hormone receptor-positive breast cancer have an excellent prognosis, but because of their age and comorbidities, they are at higher risk for treatment-related adverse events. Despite studies demonstrating the safety of omitting previously routine therapies, including sentinel lymph node biopsy (SLNB) and postlumpectomy radiotherapy, these treatments continue to be used at high rates. Physicians cite patient preference as one factor associated with overuse. However, little is known about how women view potential de-escalation of therapies. OBJECTIVE: To evaluate older women's preferences for SLNB and radiotherapy in the setting of guidelines recommending them or allowing for their omission. DESIGN, SETTING, AND PARTICIPANTS: This qualitative study was performed from October 2019 to January 2020. Midwestern women aged 70 years and older who had never received a diagnosis of breast cancer were recruited online and interviewed. Guided by an interpretive description approach, interviews were analyzed to produce a thematic description. Data analysis was performed from January to March 2020. EXPOSURES: Participants were presented with hypothetical scenarios in which they received a diagnosis of low-risk, hormone receptor-positive breast cancer and were given treatment options in accordance with current guidelines. MAIN OUTCOMES AND MEASURES: The interviews elicited perspectives on breast cancer treatment, including surgery, SLNB, chemotherapy, and postlumpectomy radiotherapy. RESULTS: The median (interquartile range) age of the 30 participants was 72.0 (71.0-76.5) years. Most of the women were White (26 participants [87%]), lived in metropolitan areas (29 participants [97%]), and were college educated (20 participants [67%] had a 4-year degree or higher). Overall, women expressed the belief that age-based guidelines were appropriate on the basis of decreased recurrence risk and increased frailty in older patients. However, many participants stated that these guidelines should not apply to healthy older women with a long life expectancy. Some participants struggled to understand that the basis for treatment de-escalation in older patients is a favorable, not poor, prognosis. Women who said they would undergo SLNB (12 participants [40%]) perceived the procedure as low risk and providing peace of mind. Most participants (22 participants [73%]) expressed a preference for omitting postlumpectomy radiotherapy because of the perceived risks, lack of benefit, and inconvenience. CONCLUSIONS AND RELEVANCE: Positive reframing of the excellent prognosis driving national recommendations for de-escalation may reduce breast cancer overtreatment in older women. Strategies for reducing SLNB use will likely require education on the risks vs benefits and addressing patient preferences for peace of mind. In contrast, efforts to reduce radiotherapy use may need to address clinician or organizational factors.