BackgroundBreast cancer treatment is multimodal, but not all patients benefit from each treatment, and many experience morbidities significantly impacting quality of life. There is increasing interest in tailoring breast cancer treatments to optimize oncological outcomes and reduce treatment burden, but it is vital that future trials focus on treatments that most impact patients. This study was designed to explore patient experiences of treatment to inform future research.MethodsAn online survey was co-developed with patient advocates to explore respondents’ experiences of breast cancer treatment. Questions included simple demographics, treatments received, and views regarding omitting treatments if that is deemed safe. The survey was circulated via social media and patient advocacy groups. Responses were summarized by using simple statistics; free text was analyzed thematically.ResultsOf the 235 participants completing the survey, 194 (82.6%) would choose to omit a specific treatment if safe to do so. The most commonly selected treatments were chemotherapy (n = 69, 35.6%) and endocrine therapy (n = 61, 31.4%) mainly due to side effects. Fewer respondents would choose to omit surgery (n = 40, 20.6%) or radiotherapy (n = 20, 10.3%). Several women commented that survival was their “absolute priority” and that high-quality evidence to support the safety of reducing treatment would be essential.ConclusionsPatients with breast cancer are individuals who may wish to optimize different components of their treatment. A portfolio of studies co-designed with patients is needed to establish an evidence base for greater treatment personalization with studies focused on reducing avoidable chemotherapy and endocrine therapy a priority.