Can exercise prevent chemotherapy-induced cardiac dysfunction? an echocardiographic assessment of cardiac mechanics in women with breast cancer

BACKGROUND Cardiotoxicity from breast cancer (BC) therapy, specifically with anthracyclines, is a significant cause of morbidity and mortality in women with BC. Although aerobic exercise (AE) during anthracycline therapy has been shown to reduce side effects including fatigue, nausea, and pain, the cardioprotective benefits of exercise remain unclear. Thus, we investigated the effect of a 24-week home-based AE program on cardiac function in women with BC receiving anthracyclines using echocardiography. METHODS AND RESULTS Women with BC were randomized to either a control group (standard of care) or to standard of care with a 24-week home-based AE program. Based on our previous exercise feasibility study in this patient population, the graduated exercise program consisted of 2 self-directed sessions per week (performed at 35-85% incremental heart rate reserve intensity) to achieve a minimum of 90 minutes of exercise weekly. Serial transthoracic echocardiography (TTE) was conducted at baseline and at 24-weeks to assess cardiovascular systolic and diastolic function, and strain parameters. A total of 11 women with BC (49 ± 10 years old) were recruited and randomized to either control (n = 5) or AE (n = 6). Ten patients received adriamycin and cyclophosphamide for 8 weeks and 1 patient received fluorouracil, epirubicin, and cyclophosphamide for 9 weeks. Additionally, 5 patients received adjuvant radiation therapy. A total of 5 women had baseline cardiovascular risk factors including hypertension (n=1), hyperlipidemia (n=1), smoking history (n=2), and family history of premature coronary artery disease (n=2). The characteristics of patients in the two groups were similar. Participants randomized to AE demonstrated an average of 94% adherence to the program. There were no significant differences between the two groups in the measured cardiovascular morphologic or functional parameters (Table 1). At baseline, mean LVEF was 63±1% in the control group and 63±2% in the AE group (Figure 1). At 24-weeks, mean LVEF was 60±2% and 59±8% in the control and exercise groups, respectively (p = NS). Additionally, at baseline, mean GLS was -18.8±0.4% in the control group and -18.7±1.1% in the AE group. At 24-weeks, mean GLS was -17.6±1.0% in the control group and -17.7±2.1% in the AE group (p = NS). CONCLUSION These preliminary echocardiographic findings indicate that although a 24-week home-based AE program was feasible, we were unable to demonstrate cardioprotection in women with BC receiving chemotherapy in comparison to standard of care.