BackgroundPeople affected by cancer experience a wide range of symptoms which have a major impact on their functioning and health-related quality of life (HRQoL). One way to measure the impact of cancer symptoms is through the use of patient-reported outcomes.MethodsAn electronic patient-reported outcome (ePRO) application (ChemoPRO®) was designed to be used by cancer patients to report their symptoms and communicate with their clinical team. Usability testing sessions were conducted with people with lived experience of cancer to understand how real users interact with the ChemoPRO® system. One-to-one testing sessions were conducted to assess use of the system and identify areas for further refinement. User satisfaction was assessed using a brief satisfaction questionnaire previously used by Aiyegbusi et al. (date).ResultsTen people with lived experience of cancer took part in the usability study. Symptoms and HRQoL measures, including the Euroqol EQ5D5L and the PRO-CTCAE™ were included in the ePRO system.Participantshad a mean age of 62.3 years. Three critical errors and 21 non-critical errors were reported. All participants were enthusiastic about the app. Participants liked the simplicity and responsiveness of the patient-facing app and highlighted the potential for communicating with their clinical team. The overall usability and satisfaction score was 4.5 (sd = 0.09).ConclusionThis usability study suggests that people with lived experience of cancer found the ChemoPRO® app acceptable and easy to use. One of the key features of this particular ePRO system that should be developed further is system functionality to facilitate communication between patients and clinicians. Future testing should include testing in a clinical setting and testing with people from ethnic minorities.