LAUSR

12101 Background: Patients with metastatic breast cancer (mBC) require knowledge on their advanced stage to fully participate in health decision making. However, both patients and oncologists face communication challenges when discussing this information. This study explored patients’ knowledge on their mBC, and patients’ and oncologists’ experiences regarding the provision of mBC information. Methods: Patients at 8 cancer centers in Mexico answered an online survey 3-7 days after mBC and treatment (Tx) were disclosed. Knowledge about stage and Tx objectives, illness uncertainty (SF-MUIS), and satisfaction were assessed. Their medical oncologists also answered an online survey exploring their perceptions, experience, and distress levels (distress thermometer) when sharing mBC information. All participants signed an informed consent. The study was funded by a Pfizer grant. Results: 19 oncologists and 50 patients were included. Patients’ median age was 52 years (31-73); most had ≤high school education (58%) and had recurrent mBC (58%). Most (74%) were aware of their mBC stage, 14% were not, and 12% were not sure. All oncologists declared having explained the non-curability of mBC. However, when asked if mBC was curable (as explained by the oncologist), only 50% of patients stated it was incurable, 40% were not sure, and 10% believed it was curable. While most considered their Tx main objective (as explained by the oncologist) was to improve lifespan and quality of life (68%); 32% believed it was to cure their mBC. Only 60% were aware their Tx had no established end date. Most (86%) were satisfied with the way their oncologist provided mBC information. Oncologists reported discussing prognosis in 96% of cases, yet only 42% of patients stated having this conversation. These patients rated having prognostic information as very useful for making Tx decisions (95%), preparing for the future (95%), and keeping hope (100%). Moderate/high levels of illness uncertainty were reported by 56% of patients. Uncertainty was associated with not discussing prognostic information (OR 7.9, 95%CI 2.2-28.1). When sharing mBC information, oncologists felt anxious and stressed in 54% and 58% of cases, respectively. In 22% of consultations, their distress thermometer score was ≥4/10, suggesting high levels of distress. Perceptions of the way mBC information was provided. Conclusions: Patients’ perceptions of the information provided by their oncologists were generally positive. Yet, a considerable proportion were unaware of their incurable mBC stage and its Tx objectives and duration. Interventions to facilitate these conversations for both patients and oncologists are crucial to improve patients’ understanding and enable their active participation in care decisions. [Table: see text]