The Preventive Role of Regular Physical Training in Ventricular Remodeling, Serum Cardiac Markers, and Exercise Performance Changes in Breast Cancer in Women Undergoing Trastuzumab Therapy—An REH-HER Study

Cardiotoxicity is known as a severe clinical problem in oncological practice that reduces the options for cancer therapy. Physical exercise is recognized as a well-established protective measure for many heart and cancer diseases. In our study, we hypothesized that supervised and moderate-intensity exercise training would prevent heart failure and its consequences induced by trastuzumab therapy. The aim of this study was to examine the effect of physical training on ventricular remodeling, serum cardiac markers, and exercise performance in women with human epidermal growth receptor 2 (HER2+) breast cancer (BC) undergoing trastuzumab therapy. This was a prospective, randomized, clinical controlled trial. Forty-six BC women were randomized into either an intervention group (IG) or a control group (CG). An exercise program (IG) was performed after 3–6 months of trastuzumab therapy at 5 d/week (to 80% maximum heart rate (HRmax)) for 9 weeks. We then evaluated their cardiac function using echocardiography, a 6-Minute Walk Test (6MWT), and plasma parameters (C-reactive protein (CRP), myoglobin (MYO), interleukin-6 (IL-6), alanine aminotransferase (ALT), aspartate aminotransferase (AST), and creatine kinase (CK)). After the physical training program, we did not observe any significant changes in the left ventricular (LV) ejection fraction (LVEF) and 6MWT (p > 0.05) in the IG compared to the CG (decrease p < 0.05). The differences in the blood parameters were not significant (p < 0.05). To conclude, moderate-intensity exercise training prevented a decrease in the LVEF and physical capacity during trastuzumab therapy in HER2+ BC. Further research is needed to validate our results.