New insights into cardioprotection in breast cancer patients undergoing physical exercise during chemotherapy: A systematic review and meta-analysis

Background: Chemotherapy associated with breast cancer often induces cardiotoxicity, which compromises patients' health and quality of life. Objective: To verify the effect of physical exercise on chemotherapy-induced cardiotoxicity, through the assessment of cardiac function in patients with breast cancer. Methods: A systematic review and meta-analysis of clinical studies was conducted to evaluate the effectiveness of physical training in chemotherapy-induced cardiomyopathy in the PubMed, Web of Sciences and Scopus databases. Thirteen studies were included in the systematic review and eleven studies in the data meta-analysis. Results: Global longitudinal strain presents a cardioprotective effect when compared to the control group (Heterogeneity: Chi(2) = 12.81, df = 10 (p = 0.23); I-2 = 22 %.) Test for global effect: Z = 2, 13 (p = 0.03). Physical training is more effective (test for subgroup differences, p = 0.031) in attenuating the impairment of %GLS induced by chemotherapy if performed concomitantly with exposure to chemotherapy (95 % CI; Heterogeneity: Chi(2) = 7.49, gl = 5 (p = 0.19); I-2 = 33 %; Test for global effect: Z = 2.33 (p = 0.02) when compared after chemotherapy treatment, or in the long term (for 12 months or more). However, without benefits in LVEF (Heterogeneity: Chi(2) = 42.14, df = 10 (p < 0.00001); I-2 = 76 %) Test for global effect: Z = 2.51 (p = 0.01) Conclusion: Exercise training is a cardioprotective approach in breast cancer patients who experience chemotherapy-induced cardiotoxicity. Exercise during exposure to chemotherapy has greater effects on preserving cardiac function.