Protocol of a Randomized Trial Investigating the Value of a Reminder App to Increase Physical Activity During Radiotherapy or Radio-Chemotherapy for Locally Advanced Lung Cancer.

Background: Radiation therapy with or without systemic treatment for lung cancer can cause adverse reactions, e.g., fatigue. Affected patients may experience a decrease in physical activity and, as a consequence, be unable to receive the complete assigned treatment. Physical exercise may be helpful. A benefit of exercise regarding completion of systemic treatment and quality of life was previously suggested. Irradiated patients may benefit as well. A smartphone-based app reminding patients to make a minimum number of steps might positively influence physical activity. The prototype of an app called "Step Reminder" was recently finalized. The randomized APPAREL trial (NCT07627022) evaluates whether this app can improve physical activity during irradiation for lung cancer. Methods: The primary endpoint of this phase 2 trial focuses on the within-patient change regarding the mean number of daily steps (week 5 minus week 1). Secondary objectives include satisfaction with the application and its impact on the perception of digital health technology. Patients are randomized 1:1 to be treated with a standard approach (conventionally fractionated irradiation with or without systemic treatment) supported by the "Step Reminder" app (Arm A) or standard treatment without the app (Arm B). The app provides reminders several times per day to walk a pre-defined number of steps. To make sure that the required 28 patients are included in the primary analysis population (full analysis set), 32 patients have to be randomized. Results: At this stage, results are not available. Conclusions: It is expected that the app will have a positive effect on the patients' physical activity (number of steps).