Cardiac Rehabilitation Improves Fitness In Patients With Subclinical Markers Of Cardiotoxicity While Receiving Chemotherapy

Abstract

Cardiotoxicity is the leading non-cancer related cause of morbidity and mortality in cancer survivors. Cardiac rehabilitation (CR) improves function and reduces morbidity and mortality in patients with heart failure, but little is known about its ability to ameliorate or attenuate the known cardiotoxic effects of chemotherapy agents. PURPOSE: Determine if participation in CR improves fitness and quality of life (QOL) in patients undergoing treatment with either Doxorubicin or Trastuzumab who exhibit markers of subclinical cardiotoxicity. METHODS: 20 female patients with breast cancer and evidence of subclinical cardiotoxicity (i.e. >10% decrease in global longitudinal strain (GLS) or a cardiac troponin > 20 ng·L-1) were randomized to 10 weeks of CR or usual care (UC). Exercise training was performed at a cardiac rehabilitation facility and included 2-3 days per week of interval training on a treadmill or cycle at 70-90% of heart rate reserve for 40 minutes. RESULTS: Cardiorespiratory fitness, as measured by peak oxygen uptake (VO2), significantly improved with CR and decreased in the UC group (between group change, 0.009; Table). No changes were observed between or within groups with respect to QOL or high sensitivity troponin. GLS, improved overtime in both groups, but no differences were observed between groups. CONCLUSIONS: This pilot study suggests the use of CR may be a viable option to attenuate the reduction in fitness that occurs in patients undergoing cardiotoxic chemotherapy. While trends were observed for improvements in both predictors of cardiotoxicity (GLS and troponin) with CR, these changes were not significant when compared to UC. The long-term effects of exercise on these predictors and left ventricular function warrants further investigation.