728eP Patients and professionals united: A priority-setting partnership for pregnancy-associated breast cancer research – the MOTHER project

Background: Pregnancy-associated breast cancer (PABC) is a rare but increasingly prevalent condition, characterized by diagnostic delay, distinct tumor biology, and complex clinical and psychosocial challenges that are insufficiently addressed in current breast cancer research agendas.We aimed to develop a patient-centered research agenda for PABC through a Priority Setting Partnership (PSP), bringing together patients, clinicians, and researchers to identify and prioritize key unanswered research questions.Methods: A PSP was established comprising patients with PABC, healthcare professionals, and researchers.Four focus group sessions were conducted and facilitated by an independent moderator using Socratic dialogue techniques to elicit lived experiences.Research questions were subsequently submitted, discussed, consolidated, and prioritized through a structured weighted voting process involving both focus group participants and a broader sounding board. Results: Table 1: domains of research questions Biology Internal factors External factors Diagnostics Delayed diagnosis Systemic therapy Chemotherapy Novel targeted therapies Reproductive outcomes Pregnancy after PABC Fertility preservation Mothers and children Hormonal fluctuations Effects in children Maternal-infant bondThe focus group included seven patients, four healthcare professionals, and three researchers.The sounding board consisted of 12 patients and four clinicians.Fourteen research questions were identified and prioritized using a weighted voting system, resulting in a consensus-based top-10 PABC research agenda (Table ), alongside five key signals aimed at improving clinical care.Priorities differed between patient participants and healthcare/research professionals, underscoring the importance of joint consensus-based priority setting. Conclusions:This PSP identified critical evidence gaps across biological, clinical, and psychosocial domains in PABC.The resulting research agenda underscores the need for integrated, multidisciplinary, and patient-informed research approaches to advance knowledge and improve care for women affected by PABC.