RESUMEN
Patients are the stewards of their own care and hence their voice is important when designing and implementing research. Patients should be involved not only as participants in research that impacts their care, as the recipients of that care and any associated harms, but also as research collaborators in prioritising important questions from the patient perspective and designing the research and the ways in which is it most appropriate to involve patients. The PIONEER Consortium, an international multistakeholder collaboration lead by the European Association of Urology, has developed a core outcome set (COS) for localised and metastatic prostate cancer relevant to all stakeholders in particular patients. Throughout the work of PIONEER, patient representatives were involved as collaborators in setting the research agenda, and a wider group of patients was involved as participants in developing COSs, for instance in consensus meetings on choosing important outcomes and appropriate definitions. This publication showcases the process for COS development and highlights the most important recommendations to ultimately inform future research projects co-created between patients and other stakeholders. PATIENT SUMMARY: An important step in involving patients in the selection of outcomes for clinical trials, clinical audits, and real-world evidence is the development of a core outcome set (COS) that is relevant to all stakeholders. This report highlights the patient participation throughout our PIONEER COS development. TAKE HOME MESSAGE: An important step in involving patients in the selection of outcomes for clinical trials, clinical audits, and real-world evidence is to develop a core outcome set (COS) that is relevant to all stakeholders. As part of the work of the PIONEER Consortium, we aim to highlight the patient participation throughout our PIONEER COS development.