Background: There are a multitude of treatment trajectories available for patients with metastatic breast cancer (MBC). Shared decision-making (SDM), which involves the incorporation of patient preferences and concerns into clinical conversations, is recommended in this context in order to encourage well-informed, patient-centered decisions. Little is known about how these conversations occur in practice. Methods: This qualitativestudy includedwomen with MBC participating in a randomized control trial (RCT) of a SDM intervention at the University of Alabama at Birmingham. Real-world MBC treatment decision-making encounters were audio-recorded, transcribed, and inductively analyzed using thematic content analysisvia NVivo software by two independent coders. Key themes and quotes were identified pertaining to patient treatment preferences and their influence on patient-oncologist treatment decisions. Results: From January 2020-December 2020, 59 decision-making encounters were recorded. Participants were primarily middle aged (Mean: 57.3, SD 10.8), White (70%), and many had travelled over an hour to their appointment (46.7%). Encounter discussions typically consisted of patient histories, scan or test results, symptoms, and treatment options. Key preference themes included logistics, ability to continue daily activities, physical side effects, previous experience with a particular treatment, survival, cosmetic concerns, and time with family. Patients most frequently expressed logistical preferences (“We were hoping that, like if I have to go through any kind of chemo, if there's things that we could do in Tuscaloosa as opposed to driving up here.”). Some preferences were indirectly expressed via questions about treatment cost, efficacy, physical side effects, and cosmetic concerns. In 44% of the conversations (n=26), the oncologist explicitly invited the patient to share in decision-making by asking about their specific preferences. Most patients (77%, n=20) accepted the invitation (“I will try [exemestane] again. I've had the same thought, maybe I should give it a wing. Maybe I'm different. And see if that helps.”), while 23% (n=8) deferred the decision to their physician (“Whatever you think, because you the doctor. You know more than I do.”). Conclusions: More work is necessary in order to incorporate patient preferences efficiently and accurately into medical decision-making. Patients have varied needs and preferences that are not all directly related to efficacy or survival and are willing to participate in SDM care when directly engaged by oncologists.