Feasibility of 24-hour physical behavior monitoring with thigh-worn accelerometers after childhood cancer. The Swiss Childhood Cancer Survivor Study (SCCSS) - Activity

Background: A healthy lifestyle, including sufficient physical activity, limited sedentary behavior, and adequate sleep (24-hour physical behaviors) can mitigate late effect risks for childhood cancer survivors (CCS). Most research on 24-hour physical behaviors has been questionnaire-based, while device-based assessment is lacking. Here, we assess the feasibility of 24-hour physical behavior monitoring using thigh-worn accelerometers in an age-heterogenous CCS population. Methods: SCCSS-Activity is nested in the Swiss Childhood Cancer Survivor Study (SCCSS), a nation-wide questionnaire-based cohort study. As part of the 2024/2025 mailing, we asked participants if they are willing to participate in an accelerometer-based sub-study. Participants wore an activPAL4 accelerometer continuously for eight days. We investigated feasibility using the following indicators: recruitment rate, acceptability and suitability of contact procedures and measurement scheduling, accelerometer return and adherence, summary reports, and overall impression. We analyzed quantitative data descriptively and conducted semi-structured interviews with nine participants. Results: Of 367 CCS returning the baseline questionnaire (median: 14 years [IQR: 10-21]; 50% female), 157 (43%) expressed interest in the accelerometer study, 100 were enrolled as of June 2025, and 90 wore and returned the accelerometer, with all except two containing valid data. Participants wore the device for a median of seven days (IQR 7-8). Interview results indicated high acceptability and minimal burden. Conclusion: Twenty-four-hour physical behavior assessment using thigh-worn accelerometers is feasible and well accepted among pediatric, adolescent, and adult CCS. This holds promise for future research to better understand and intervene on physical behaviors and to understand their compositional impact on CCS health.