- Patients aged 18 to 85 years - First HER2 positive breast cancer, confirmed histologically - WHO Performance status ≤ 1 - Completed chemo-radiotherapy - Normal renal function (creatinine clearance ≥ 60 ml.min−1) - Normal heart function with LVEF ≥ 50% (As assessed by echocardiography dating from less than 3 months previously) - Normal liver function (normal ASAT and ALAT) - Certificate of non-contraindication to the practice of physical activity - Active contraception or menopaused. This evidence concerns the gene ERBB2 and breast cancer.