Effects of a home-based exercise program on the insulin-like growth factor axis in patients operated for colorectal cancer in Sweden: Results from the randomised controlled trial PHYSSURG-C

Objectives: We report results from a subgroup within the ongoing PHYSSURG-C trial with the aim to examine effects of exercise on IGF-1 and IGFBP-3 in patients undergoing colorectal cancer surgery. Design: Randomised controlled trial. Setting: A Swedish university hospital. Participants: Between 2015 and 2016, 217 patients were enrolled (I = 106, C = 111), with 122 patients that had given blood samples at baseline and at least at one follow-up (I = 51, C = 71). Patients 20 year or older with colorectal cancer were eligible. Exclusion criteria were emergency surgery, local surgery, language problems or inability to perform intervention. Interventions: Patients were computer-randomised to either a daily home-based aerobic exercise intervention (I), or to usual care (C). The intervention lasted two weeks before surgery and four weeks after discharge from hospital and consisted of medium-intensity aerobic exercise and inspiratory muscle training. Circulating concentrations of IGF-1 and IGFBP-3 were determined by blinded personnel at baseline, time of surgery and 4-6 weeks postoperatively. Primary and secondary outcome measures: The outcome of this subpopulation report was change in IGF-1/IGFBP-3 ratio, IGF-1 and IGFBP-3 concentrations from baseline to surgery, and 4-6 weeks postoperatively. Results: The IGF-1/IGFBP-3 ratio increased from baseline to surgery by 11% in I and 8% in C with no difference between groups (I vs. C: 1.04, 95%CI: 0.97-1.11; p= 1.000). Postoperative change was 5% in I and 3% in C with no difference between groups (I vs. C:1.03, 95%CI: 0.96-1.10; p = 1.000). Results concerning IGF-1 and IGFBP3 also showed statistically significant dynamics over time with no difference between groups. No adverse events were reported. Conclusions: The home-based exercise program in our trial did not have any effect on IGF-1, or IGFBP-3.