Background: During the past decade, the growing number of treatment options for men with metastatic prostate cancer (mPC) has resulted in longer survival and treatment duration. Both the metastatic disease and the treatments’ side-effects may cause distressing physical and psychological and symptoms that lower quality of life. Regularly planned follow-up consultations at an oncology or urology department to monitor such symptoms are standard practice. Patient-reported outcome measures (PROMs) have been broadly incorporated into cancer care during the last decade despite scarce evidence regarding the benefits of using PROMs for men with mPC. Aims: We aim to investigate whether the use of PROM, based on EORTC QLQ-C15-PAL, filled in online prior to the consultation and displayed on a monitor at the consultation, influences the patients’ experience of: having an adequate discussion about their most distressing symptom, and shared decision-making, measured using the CollaboRATE questionnaire Methods: Multicenter cluster randomized trial. Patients with mPC scheduled for consultation at the clinic during the study period will be asked to participate and, if they accept, to fill out forms before and after the consultation. Primary outcome measure will be the proportion of patients who report that their most distressing symptom was inadequately discussed, defined as score ≤ 6 on a 10-point scale reported directly after the consultation. We aim to include 300 patients; this will give 80% power to detect a reduction from 30% to 15% of the proportion of patients who feel their most important symptom was inadequately discussed with a significance level of 0.05. Clinical significance: If the use of PROMs during clinical consultations is shown to enhance symptom communication, this approach should be advocated in clinical practice to improve the care for men with metastatic prostate cancer. If not, the ongoing implementation of PROMs in clinical practice should be reconsidered.