Given the compelling evidence supporting a protective effect of statins on breast cancer recurrence, calls for prospective clinical trials have been expressed. In this trial - the MASTER trial - we hypothesize that the addition of statin treatment to the current breast cancer treatment will improve the prognosis of women with early breast cancer. This trial is designed as follows: a randomized, multicenter, double-blind, placebo-controlled comparison of standard (neo)adjuvant therapy plus placebo versus standard (neo)adjuvant therapy plus atorvastatin in patients with early breast cancer.