Effect of home-based exercise intervention on fasting insulin and Adipocytokines in colorectal cancer survivors: a randomized controlled trial

Background and Aims Elevated circulating insulin is associated with increased risk of recurrence and cancer mortality in early-stage colorectal cancer (CRC). We conducted a randomized controlled trial to determine the effect of a 12-week home-based exercise program on fasting insulin, adipocytokines, and physical function in CRC survivors. Methods One hundred and twenty-three stage II-III CRC patients were randomly assigned to either a home-based exercise (n = 62) or standard care control group (n = 61) for 12 weeks. Home-based exercise consisted of aerobic and resistance training, with a goal of obtaining ≥ 18 metabolic equivalent task (MET)-h/wk. Participants in the exercise group were instructed to participate in > 18 MET-h/wk. of aerobic and resistance exercise while the participants in the control group were asked to maintain their usual daily activity. The primary outcome was fasting insulin levels. Secondary outcomes were adiponectin, TNF-α levels and 6 min walk distance from baseline to post-intervention. Results After the 12-weeks, moderate-vigorous physical activity participation increased from 9.1 ± 14.7 MET-h/wk. to 26.6 ± 21.7 MET-h/wk. in the exercise group, with no change in the control group (p < 0.01 for group and time interaction). Circulating insulin level decreased by 1 μU/ml (6.0 ± 3.9 vs. 5.0 ± 3.5, p = 0.009) in the exercise group with no change in the control group (p = 0.022 for group and time interaction). A similar trend was observed in TNF-α (p = 0.030 for group and time interaction). Six minute walk distance increased by 25.2 m in the exercise group with no change in the control group (p = 0.061 for group and time interaction). Conclusions The 12 week home-based exercise program increased level of physical activity and decreased circulating insulin levels in CRC survivors.