Effects of Exercise on Motivational Outcomes in Rectal Cancer Patients During and After Neoadjuvant Chemoradiation: A Phase II Randomized Controlled Trial

Objectives: Understanding exercise motivation in rectal cancer patients during and after neoadjuvant chemo-radiation therapy is important to improve adherence and achieve potential benefit. We report the motivational effects of exercise from the Exercise During and After Neoadjuvant Rectal Cancer Treatment trial.Data Sources: We randomized 36 rectal cancer patients to supervised high-intensity interval training during neoadjuvant chemoradiation therapy followed by unsupervised moderate-to-vigorous exercise after therapy, or usual care. Using the theory of planned behavior, we assessed motivation, perceived benefits/harms, and perceived barriers for exercise during and after therapy. Supervised exercise during neoadjuvant chemo-radiation therapy was experienced as meaningfully (d=0.33) more controllable (p=0.08, d=0.60), more enjoy-able (p=0.25, d=0.45), and less difficult (p=0.45, d=-0.38) than anticipated. Unsupervised exercise after therapy was experienced as meaningfully more enjoyable (p=0.047, d=0.50) and less difficult (p=0.43, d=-0.36), but also less controllable (p=0.14, d=-0.80) than anticipated. Common self-reported benefits of exercise both during and after neoadjuvant chemoradiation therapy were cardiovascular endurance, physical functioning, and quality of life. Common self-reported harms were exacerbation of treatment side effects. Frequently reported barriers to exercise during therapy were side effects of treatment, whereas exercise barriers after therapy were lack of motivation and lingering side effects.Conclusion: Exercise during and after therapy generally had positive effects on exercise motivation, however, perceived harms and barriers related to treatment side effects were identified.