HopeMove: Feasibility and acceptability of a mobile exercise app for pediatric patients undergoing cancer treatment.

10034 Background: Cancer related fatigue and reduced physical activity are common during pediatric cancer treatment and negatively affect daily functioning and quality of life. Although exercise is recommended as supportive care, maintaining regular physical activity during active treatment is challenging. Digitally delivered exercise programs may offer flexible and safe supportive care options. This study evaluated the feasibility, acceptability, usability, and safety of the HopeMove mobile exercise app and explored preliminary changes in fatigue among adolescents undergoing cancer treatment. Methods: This prospective, single center pilot feasibility study included adolescents aged 13-18 years undergoing active cancer treatment (N=15). Participants completed 45 minute video guided exercise sessions at least three times per week for eight weeks. The intervention was developed through a multidisciplinary collaboration involving pediatric oncology clinicians, pediatric nurses, physiotherapists, and engineers. Exercise sessions included warm-up, aerobic, strengthening, flexibility, and cool down components, with seated and standing options tailored to individual clinical needs. Prior to patient implementation, the HopeMove mobile application was evaluated by 10 clinical experts using the Mobile Application Usability Scale (MAUS). Feasibility outcomes included recruitment, retention, adherence, and technical performance. Adherence was defined as completing at least 75% of planned exercise sessions. Participant satisfaction was measured with a Visual Analog Scale (VAS). Before the intervention, adolescents completed brief application evaluation questions. Fatigue was assessed before and after the intervention using a validated pediatric oncology specific fatigue scale. Safety was monitored throughout the study. Results: All eligible adolescents agreed to participate and completed the intervention, resulting in 100% recruitment and retention. Twelve participants (80%) met adherence criteria. The application showed high usability (mean MAUS score 6.55±0.49) and high satisfaction (VAS mean 6.66±0.48). Participants reported the application to be easy to use and age appropriate. Fatigue scores improved significantly after the intervention, increasing from 100.06±22.28 at baseline to 139.26±18.89 post-intervention (p<0.001). Significant improvements were observed across fatigue subdomains (all p<0.01). No exercise related adverse events, injuries, falls, or treatment interruptions were reported. Conclusions: HopeMove was feasible, acceptable, and safe for adolescents undergoing active cancer treatment. High adherence, favorable usability, and improved fatigue outcomes suggest that mobile, video guided exercise interventions may support supportive care in pediatric oncology. Larger controlled studies are warranted. Clinical trial information: NCT07274358 .