Physical Activity Monitoring in Adolescents and Young Adults With Cancer: Observational Feasibility Study

Abstract Background There is a growing interest in characterizing the relationship between long-term physical activity (PA) habits and cancer-related outcomes such as treatment-related toxicities, recurrence, and complications. Wearable devices can provide critical information to achieve this goal; however, inferences are significantly influenced by device wear adherence. Objective This study aimed to assess the feasibility of using wearable devices to monitor short- and long-term PA in adolescent and young adult (AYA) patients with sarcoma during and after chemotherapy in a free-living environment and evaluate the ability to accurately capture changes in PA over 3 years. Methods A total of 63 AYA patients with sarcoma were provided with a Fitbit Charge 3 to track daily steps, sedentary time, and heart rate for up to 3 years. Results On average, during the first 30 days of follow-up, 57.1% (36/63) of patients wore their device at least 10 hours per day, and only 23.8% (15/63) of patients wore their devices thereafter. Patients spent a mean of 80% (SD 11%) of their day in a sedentary state. Despite low adherence, daily step count trends increased over time. Conclusions This study highlights the adherence challenges met with longitudinal PA monitoring in AYA patients with sarcoma. Wearer discomfort, lost devices, and lack of data uploading compliance contributed to data missingness and attrition. Caution is warranted when relying on wearable activity trackers to inform program decisions, accurately assess PA outcomes, and monitor program adherence longitudinally without consideration of wearer bias. Alternative methods that would be more broadly accepted by AYA patients for effective long-term monitoring should be considered.