Background: Patient-reported outcome (PRO) can give information to caregivers and doctors about adverse effects and give real-world data on symptom burden for patients during treatment. We here report PROs from patients with metastatic castration resistant prostate cancer (mCRPC) receiving oncological treatment. Our findings are compared with adverse events from published findings in relevant registration studies and we discuss possible applications by looking at the level of interference with usual or daily activities. Material and methods: An electronic PRO-Common Terminology Criteria for Adverse Events (ePRO-CTCAE) questionnaire, with 41 items corresponding to 22 symptoms/adverse events associated with the treatment regimens commonly used for mCRPC, were collected from 54 patients with mCRPC receiving medical oncological treatment. Eleven symptoms attributing interference with usual or daily living were selected and stratified by antineoplastic treatment administered. The responses were pooled and compared with data from relevant registration studies for docetaxel, cabazitaxel, radium-223 and abiraterone. Results: 168 questionnaires were completed, and among responses from patients receiving docetaxel, 89% of responses shows that fatigue interfered with their usual or daily activities to some degree and 22% to a high or very high degree. In the registration study for docetaxel fatigue is reported with 53% for all grades and 5% for grade 3 or above. For cabazitaxel, radium-223 and abiraterone the percentage of responses with interference of daily activities from fatigue range from 58% to 82%. Between four and six of the eleven chosen PRO-CTCAE symptoms are not reported in the registration studies as common side effects. Conclusion: PRO may help inform caregivers about symptoms not previously reported, interfering with usual or daily activities but also point to the use of this information to inform new patients. This may help clinicians and patients decide a treatment plan with an acceptable benefit-to-harm ratio.