Objectives This study aimed to explore the acceptability, feasibility, usability, and preliminary effect of an electronic patient-reported outcome (ePRO) intervention for patients with breast cancer in Mexico.Design We conducted a multimethod non-randomised pilot study. We used a pre-test/post-test design for quantitative assessment of the intervention’s effect on patients’ supportive care needs and quality of life. We conducted in-depth interviews (IDIs) with participants and healthcare workers to explore the intervention’s benefits and barriers and understand its feasibility.Participants 50 women aged 20–75 diagnosed with stage I–III breast cancer were enrolled within 2 weeks of starting neoadjuvant or adjuvant treatment with chemotherapy or radiotherapy. We excluded illiterate women and those with visual impairment, cognitive disability or severe depression. IDIs were conducted with 18 participants and 10 healthcare providers.Setting Oncology services in three public hospitals of the Mexican Social Security Institute.Intervention The ePRO intervention consisted of a responsive web application for weekly symptom reporting combined with proactive follow-up by nurses guided by predefined clinical algorithms for 6 weeks.Results 50 women were enrolled out of 66 eligible patients approached (75.8%). All 50 completed the 4-week follow-up assessment (100% retention). Completion of the symptom registry declined from 100% in week 1 to 66% in week 6. Participants experienced decreases in supportive care needs and increased quality of life. The ePRO application was rated highly usable. Participants and health professionals both perceived intervention benefits. Drawbacks included poor fit for women receiving radiotherapy and challenges using the application for women with low digital literacy or experiencing severe symptoms.Conclusions This pilot study provided evidence of the high usability and potential efficacy of a web-based ePRO intervention. We revised recruitment during the pilot to include multiple facilities, and we will further revise for the randomised trial to address barriers to successful ePRO implementation.Trial registration number ClinicalTrials.gov ID: NCT05925257.
