Overview
Cancer survivors face unique health challenges, including fatigue, reduced physical function, and mental distress. Physical activity (PA) is a safe, evidence-based strategy that can mitigate these burdens and improve quality of life. The WExercise app—a smartphone-based program grounded in the multi-process action control (M-PAC) framework—was designed to promote PA among cancer survivors. This randomized controlled trial (RCT) examined whether WExercise could boost PA, improve exercise capacity, and enhance cancer-specific quality of life (QoL), compared with self-directed PA education.
Background and Theoretical Framework
Traditional PA interventions for survivors have shown promise but often struggle to translate exercise intentions into sustained action. The M-PAC framework addresses this intention‑to‑behavior gap by layering reflective, regulatory, and reflexive processes to sustain physical activity. WExercise operationalizes M-PAC in a mobile format, delivering weekly lessons with text, visuals, videos, and self-monitoring features to cultivate attitudes, planning, self-regulation, and identity as an exerciser. Notably, few RCTs have evaluated a theory-based, smartphone app for cancer survivors, and long-term follow-up has been limited.
Methods
The assessor-blinded trial ran from November 2022 to May 2024 in Hong Kong. Eligible participants were adults (≥18 years) who were at least 12 months post-treatment, not meeting PA guidelines, and able to use a smartphone. A total of 98 were recruited; 81 completed the study (36 in the WExercise group; 45 in the control group). Randomization was 1:1, with outcome assessors blinded to allocation.
Interventions included:
- Control: Standard PA information (one-page guide) and safety precautions, with encouragement to reach 150 minutes/week of moderate-to-vigorous activity.
- WExercise: Access to a 12-lesson app program designed around the M-PAC framework. Ten weekly lessons focus on reflective (attitudes, capability, opportunity), regulatory (planning, self-monitoring, coping), and reflexive (habit, identity) processes; two introductory/safety lessons preceded the program. The app integrates phone sensor data for self-monitoring, includes quizzes, and provides an activity diary. Reminders were sent to sustain engagement.
Primary outcome: physical activity behavior measured both objectively (ActiGraph MVPA) and subjectively (Godin Leisure Time Exercise Questionnaire, GLTEQ). Assessments occurred at baseline (T0), post-intervention (T1, ~10 weeks), and 12 weeks post-intervention (T2). Secondary outcomes included exercise capacity (6-minute walk test, 6MWT), cancer-specific QoL (EORTC QLQ-C30), and M-PAC component scores.
Outcomes and Key Findings
Primary outcomes:
- ActiGraph-measured MVPA showed no significant group-by-time interaction (P = .74). There were non-significant between-group differences at T1 and T2 in objectively measured MVPA.
- Self-reported MVPA (GLTEQ) revealed a significant between-group difference over time (P = .003). The intervention group reported larger increases at both T1 and T2, suggesting a notable impact on perceived activity levels.
- The proportion meeting the 150 minutes/week MVPA guideline was higher in the WExercise group at both follow-ups (T1 and T2). Adjusted odds ratios indicated meaningful group differences in achieving guideline-level activity.
Secondary outcomes:
- 6MWT improved more in the WExercise group at T1, indicating enhanced functional capacity (though the between-group difference approached, but did not consistently reach, statistical significance across all time points).
- QoL did not show significant changes attributable to the intervention.
- M-PAC constructs displayed mixed results. Within the intervention group, affective attitude, behavioral regulation, habit, and PA identity improved, while the control group improved in behavioral regulation and PA identity. Between-group differences over time were not statistically significant for the overall M-PAC composite scores.
Engagement with WExercise was favorable: roughly 70% of participants completed more than 75% of lessons, though completion dwindled across all lessons over the program. No adverse events were reported, underscoring the safety of a technology-driven PA promotion strategy for this population.
Interpretation and Implications
The trial provides evidence that a theory-based, smartphone app can meaningfully improve self-reported PA and exercise capacity among cancer survivors, with sustained benefits at 12 weeks post-intervention. The discrepancy between self-reported and objective PA highlights a common challenge in PA research; self-reports may capture perceived activity and exertion that accelerometers underdetect, or reflect social desirability biases. Nevertheless, improvements in 6MWT and higher self-reported activity are clinically relevant, suggesting real-world benefits for cardiovascular fitness and daily functioning.
From a practical standpoint, WExercise offers scalable, low-cost support to inactive survivors who can access a smartphone. Healthcare providers could consider recommending tools like WExercise as part of a blended approach that includes occasional in-person sessions to reinforce capability, opportunity, and social support. Future work should explore enhancements to boost perceived capability and opportunity, integrate personalized feedback, and examine combinations with tele-exercise sessions to maximize engagement and outcomes. Longer-term follow-up would help determine the durability of gains and their impact on cancer recurrence risk and overall survivorship.
Strengths and Limitations
Strengths include a theory-driven design, rigorous randomization, assessor blinding, and dual PA assessment. Limitations involve a single-site sample with predominantly educated, female participants, potential self-selection bias, and incomplete ActiGraph wear data. Adherence challenges and reliance on self-reported outcomes for primary PA endpoints also warrant consideration in future studies.
Conclusion
WExercise demonstrates potential to promote physical activity and improve exercise capacity among cancer survivors in an accessible, scalable format. While objective PA gains were modest, the overall pattern supports the value of M-PAC–based smartphone interventions as part of a comprehensive survivorship care plan. Further refinement and testing in diverse populations will help determine how best to translate these gains into lasting health benefits.
