The overexpression of human epidermal growth factor receptor-2 (HER2) in breast cancer is a poor prognosis. Trastuzumab improves overall survival but is associated with cardiotoxicity, especially a decline in left ventricular ejection fraction (LVEF). In addition, chemotherapy and radiotherapy increase fatigue and pain, decrease physical capacity and health-related quality of life. To date, no study has evaluated the benefits of physical activity on the side effects of treatment in patients with HER2 positive breast cancer. The aim of this study is to evaluate the impact of 3 months’ exercise intervention on myocardial function and in particular on the rate of cardiotoxicity.
This multicenter, randomized clinical trial will include 112 patients treated by adjuvant trastuzumab for HER2 positive breast cancer to investigate the effects of a 3 months’ supervised exercise program (intermittent exercise, combining moderate and high intensities; 55 minutes duration, 3 times per week), on the rate of cardiotoxicity [defined by either a decrease of the LVEF under 50% or an absolute drop of LVEF of 10%] between baseline and at 3 months and on strength, aerobic capacity, metabolic, inflammatory and hormonal parameters. Health-related quality of life, fatigue, pain and level of physical activity will also be assessed. Participants are randomly allocated to one of the two groups (“training group” vs “standard oncological care”). Performance-based and self-reported outcomes are assessed at baseline, at the end of supervised exercise program and at six months follow-up.
Although physical exercise is recommended to reduce the side effects of adjuvant treatments in breast cancer patients, no randomized study has been conducted to assess the benefits of a physical training program in patients with HER2 overexpressing breast cancer. Cardiac toxicity of trastuzumab may be minimized with an exercise program combining high and moderate intensities. This type of program may be safe, feasible and effective but also increase cardiorespiratory fitness and improve health-related quality of life. If these benefits are confirmed, this exercise intervention could be systematically proposed to patients during the course of treatment by trastuzumab in addition to standard oncological care.
Trial registration: National Clinical Trials Number (NCT02433067); Registration 28 april 2015.
Keywords : Breast cancer HER2 overexpression Cardiotoxicity Exercise Study protocol Supportive care