Role of physical exercise in modulating the insulin-like growth factor system for improving breast cancer outcomes: A meta-analysis.

BACKGROUND

Physical activity prevents cancer and improves cancer outcomes. Insulin-like growth factor (IGF) signaling plays a significant role in cancer development and progression. However, there are heterogeneous results regarding physical activity and its effect on the IGF system. This study meta-analyzed the results of randomized clinical trials which evaluated the effects of physical exercise on the changes of physiologic markers to identify the role of physical exercise in modulating the IGF system in women with breast cancer.

METHODS

PubMed, Embase, CENTRAL, and SPORTDiscus were systematically searched until October 2020. Eligibility criteria included randomized controlled trials that evaluated the effects of physical exercise on the insulin-like growth factor system among women with breast cancer.

RESULTS

Twelve randomized controlled studies involving 736 participants were analyzed. Physical exercise significantly reduced levels of serum insulin (MD -1.24 μIU/mL, 95% CI -2.12 to -0.36, p = 0.006), IGF-II (MD -54.21 ng/mL, 95% CI -61.41 to -47.00, p < 0.00001), IGFBP-1 (MD -2.90 ng/mL, 95% CI -3.91 to -1.90, p < 0.00001), and HOMA score (MD -0.47, 95% CI -0.87 to -0.06, p = 0.02). In addition, serum glucose (MD -0.71 mg/dL, 95% CI -2.57 to 1.15; p = 0.45) and IGF-I levels (MD -5.23 ng/mL, 95% CI -13.00 to 2.53; p = 0.19) were decreased after physical exercise although they did not show a statistical significance.

CONCLUSION

Physical exercise had a positive effect on the IGF system in women with breast cancer.