Introduction: An emphasis on patient-centered care has led to a growing interest in collecting patient-reported outcomes (PROs) in the setting of cancer care. Routine collection of actionable PROs has been shown to improve patient satisfaction with care and even prolong survival. However, completion rates of PROs outside of the research setting are low, which may be due to an incomplete understanding of the outcomes patients value most. Prior work has focused primarily on symptom burden, but patients are also affected by disease and treatment across multiple domains (e.g. physical, psychological, social, and financial). To address this knowledge gap, we conducted a qualitative study among women with metastatic breast cancer (MBC) to identify the optimal patient-centered approach to collecting PRO data. Methods: We conducted 1-on-1 interviews with patients who had started a treatment regimen for MBC within the past 6 weeks at the Breast Center at Smilow Cancer Hospital of Yale New Haven Hospital to determine which PROs were most personally relevant. We assessed heterogeneity across patients in their prioritization. Patients were asked which of a list of six PRO domains they would like their provider to have information about and then ranked the domains by order of importance (from most to least important). The following domains were created from the NCCN Distress Thermometer: physical well-being, emotional well-being, treatment burden, functional status, financial concerns, and social well-being. For each ranked domain, patients were asked to rank items within the domain using a card sorting exercise where the number of items ranged from 5 to 15. Patients were then asked where and how often they preferred to report PROs. Results: Ten women with MBC completed the card sorting exercise: mean age was 58 years (+/- 12), 7 were white, 2 African American and 1 Asian; 1 identified as Hispanic. After 10 interviews, it was apparent that no single set of domain rankings was common across patients. Patient prioritization of PRO domains was unique and varied. Selection and prioritization of PRO domains and items within each domain were unique and varied. Five women reported “physical well-being” as the most important domain; treatment burden and emotional well-being were also selected as most important or ranked as highly important. Participants preferred reporting MBC PROs while in the waiting room for all domains except emotional well-being (from home was the preference). However, participants were willing to complete PRO assessment in the waiting room for about ten minutes and at home for twenty minutes. Conclusion: Substantial variation exists in how women with MBC rate the importance of specific PRO domains and items within each domain. Importantly, “physical symptoms” was not the top concern for half of the interviewed patients. This is an important finding, given that previous published studies of patient-reported outcomes have focused on one domain, such as symptoms and side effects or the financial burden of treatment. Our findings support the development of multi-dimensional tools for the collection of PROs. Although toxicity and physical symptoms are of utmost concern, clinicians should not neglect other dimensions of quality of life in women with MBC. Citation Format: Mougalian SS, Aminawung JA, Presley C, Canavan ME, Holland ML, Hu X, Gross CP. Prioritization of patient reported outcomes by women with metastatic breast cancer [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P5-14-06.