Effect of a 1-year tailored exercise program according to cancer trajectories in patients with breast cancer: study protocol for a randomized controlled trial.

Background: Patients with breast cancer undergo various treatments according to their tumor subtype and cancer stages within 1 year after being diagnosed. Each treatment may cause treatment-related symptoms that have negative impacts on patients' health and quality of life (QoL) The symptoms can be mitigated when exercise interventions are appropriately applied to patients' physical and mental conditions. Although many exercise programs were developed and implemented during this period, the effects of tailored exercise programs according to symptoms and cancer trajectories on patients' long-term health outcomes have not yet been fully elucidated. Therefore, this randomized controlled trial (RCT) aims to investigate the effect of tailored home-based exercise programs on short-term and long-term physiological outcomes in patients with breast cancer.

Methods: This 12-month RCT includes 96 patients with (stages 1-3) breast cancer randomly assigned to the exercise or control groups. Participants in the exercise group will receive an exercise program tailored to their phase of treatment, type of surgery, and physical function. During post-operative recovery, exercise interventions will be emphasized to improve shoulder range of motion (ROM) and strength. During chemoradiation therapy, exercise intervention will focus on improving physical function and preventing loss of muscle mass. Once chemoradiation therapy is completed, exercise intervention will focus on improving cardiopulmonary fitness and insulin resistance. All interventions will be home-based exercise programs supplemented with once-monthly exercise education and counseling sessions. The main outcome of the study is fasting insulin level at baseline, 6 months, and 1 year post-intervention. Our secondary outcomes include shoulder ROM and strength at 1 month and 3 months, body composition, inflammatory markers, microbiome, QoL, and physical activity levels at 1 month, 6 months, and 1 year post-intervention.

Conclusion: This trial is the first tailored home-based exercise oncology trial to better understand the comprehensive phase-dependent short- and long-term effects of exercise on shoulder function, body composition, fasting insulin, biomarkers, and microbiome. The results of this study will inform the development of effective exercise programs tailored to the needs of patients with breast cancer post-operatively.

Trial Registration: The protocol for this study is registered with the Korean Clinical Trials Registry (KCT0007853).