In oncology, and particularly in breast cancer care, the use of telemedicine has proven to be a safe and effective way to
improve the quality of life and care for patients. The Covid-19 emergency and the need to reduce hospital admissions has accelerated the development and use of telemedicine tools. The use of telemedicine can find wide application in the care of breast cancer patients who, due to the chronic nature of the disease, have a continuous need for care and availability of clear and accessible information. The
effectiveness of telehealth interventions can be improved through participatory co-design processes that involve end-users and stakeholders in all aspects of intervention development. This work reports an experience of participatory co-design aimed at developing a mHealth
application for breast cancer patients within the Trento APSS Breast Cancer Unit Network.