Formative evaluation of a mobile chat-based intervention (ChatEx) for promoting exercise behaviour in older cancer survivors

Purpose: To conduct a formative evaluation of ChatEx to increase and maintain exercise among older cancer survivors. Methods: ChatEx is a blended intervention involving 12 weeks of theory-based instant messages and two in-person training sessions. This pilot study comprises three phases: (1)intervention development: developing a message library reviewed by experts; (2)message library pretesting: exploring the views of older cancer survivors toward the message library and making modifications (n = 20); and (3)intervention pilot testing: piloting the ChatEx using a non-randomized quasi-experimental design using quantitative and qualitative methods among cancer survivors aged 65+ who do not meet current exercise guidelines and have completed treatment (n = 40). Feasibility, Acceptability, aerobic and resistance exercise, exercise capacity, grip strength, frailty, quality of life, exercise self-efficacy were assessed as the main outcomes. Results: ChatEx had a retention rate of 80%, with most participants having moderate/high levels of engagement with messaging, and 100% attendance at in-person sessions. Compared to wait-list control, the intervention group significantly increased the time spent in aerobic exercise at 24 weeks, as well as resistance exercise at both 12 weeks and 24 weeks. The intervention group also had significantly greater improvement in exercise capacity and exercise self-efficacy than control at 24 weeks. Participant interviews revealed five major themes: positive feedback, facilitators of exercise adherence, barriers to exercise adherence, negative feedback, and suggestions for improvement. Conclusion: The findings support the feasibility, acceptability, and potential efficacy of ChatEx in increasing exercise behaviour among older cancer survivors. A full-scale trial with a larger and more diverse sample is now warranted.