A Smartphone App (WExercise) to Promote Physical Activity Among Cancer Survivors: Randomized Controlled Trial.

Background: Cancer survivors face unique health challenges that may be addressed through physical activity (PA) interventions. Technology-based tools provide innovative, resource-efficient alternatives to traditional approaches, delivering PA interventions. Objective: This study aimed to examine the effectiveness of a smartphone app (WExercise) in promoting PA among cancer survivors. Methods: This study was an assessor-blind, 2-arm randomized controlled trial. The intervention group used WExercise, which consisted of automated weekly lessons developed based on the multi-process action control (M-PAC) framework. The control group received written PA recommendations. Ninety-eight physically inactive cancer survivors who had completed curative treatment were recruited from an oncology clinic and the community. Outcomes included exercise behavior (primary), exercise capacity, quality of life, and M-PAC constructs. Results: The majority (81/98, 82.7%) of participants remained in the study. The proportion of participants completing at least 75% of lessons was 69.44%. For exercise behavior, mixed findings were identified: the intervention group had a significantly greater increase in self-reported moderate-to-vigorous PA compared to the control group at postintervention (mean difference in change 89.02 minutes, 95% CI 34.87-143.16) and 3 months postintervention (mean difference in change 49.37 minutes, 95% CI 8.63-90.10; group × time interaction; P=.003), while no significant effect on ActiGraph-measured moderate-to-vigorous PA was observed at postintervention (mean difference in change -8.54 minutes, 95% CI -36.19 to 19.11) and 3 months postintervention (mean difference in change 2.56 minutes, 95% CI -27.29 to 32.41; group × time interaction; P=.74). WExercise was also effective in increasing cancer survivors' exercise capacity but not their quality of life or M-PAC constructs. Conclusions: WExercise demonstrated a significant effect on increasing self-reported PA, but this was not corroborated with ActiGraph-measured PA. The application may be a useful addition for clinicians aiming to promote physical activity in people with cancer.