The trial is prospective, randomised, double-blind and placebo-controlled. The primary objective is change in left ventricular ejection fraction (LVEF), determined by cardiac MRI (CMR). Secondary objectives are change in circulating high-sensitivity cardiac troponin I and T (hs-TnI and hs-TnT), Creatine Kinase (CK) and myoglobin, and various measurements of change in left ventricular systolic function determined by CMR and echocardiography. Additional assessments are evaluation of the patient's functional capacity and the patients will be asked to fill out questionnaires to assess quality of life.~60 patients will be randomised in a 1:1 ratio. The duration of blinded therapy will depend on the duration of anthracycline therapy. All patients will be examined at baseline and 3 months, and if the patient is scheduled for extended anthracycline therapy, an additional examination will be performed at 6 months.
Breast cancer is the most common form of cancer in women. Modern breast cancer treatments have led to increased survival, but at the same time, increased risk for cardiotoxicity and development of heart failure. In this study, the investigators want to evaluate whether nicotinamide riboside can prevent cancer-related cardiac dysfunction in metastatic breast cancer patients scheduled for anthracycline therapy. Further, the investigators will evaluate change in signs of skeletal muscle injury and functional capacity.