Effects of aerobic exercise on body composition and exerkines in colorectal cancer survivors.

INTRODUCTION: Physical activity improves immune competency and is associated with a lower rate of cancer recurrence in colorectal cancer survivors. However, the exact mechanisms underlying these improvements remain unclear. Exercise-derived cytokines (exerkines), particularly IL-7 and IL-15, are crucial in maintaining optimal immune health. This study investigated whether a 12-week structured exercise training intervention increases IL-7 and IL-15 in colorectal cancer survivors. METHODS: Sixty colorectal cancer survivors were randomized to a moderate-intensity home-based aerobic exercise group (150†min/week) or a control group for 12 weeks. IL-7 and IL-15 were quantified using ELISA, and body composition was measured using dual-energy x-ray absorptiometry. RESULTS: At baseline, participants treated with chemotherapy had lower IL-7 than those not treated with chemotherapy [-3.3†pg/ml (95% CI: -1.3, -5.4); p = 0.002]. Baseline fitness capacity correlated with IL-15 (r = -0.37; p = 0.004). IL-7 increased in the exercise group [2.3†pg/ml (95% CI: 0.9, 3.8; p = 0.003)], but not in the control group [1.2†pg/ml (95% CI: 0.3, 2.8; p = 0.31)]. IL-15 did not differ between groups. Longitudinal changes in IL-15 were associated with changes in body composition. DISCUSSION: Aerobic exercise may improve immune function in colorectal cancer survivors by restoring IL-7 after chemotherapy and improving IL-15 by altering body composition. CLINICAL TRIAL REGISTRATION: [https://clinicaltrials.gov/study/NCT03975491], identifier [NCT03975491].