The MASTER Study (MAmmary Cancer STatin ER Positive Study)

Cholesterol-lowering drugs such as statins are currently used to lower cholesterol levels and prevent cardiovascular events. Statins have, however, received substantial scientific attention as cancer-inhibiting drugs. Previous findings were recently supported in a large-scaled study again demonstrating the beneficial effects of statins on breast cancer outcome this time nested within a large, international, randomized clinical trial of modern adjuvant cancer therapy. 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. Thus, the primary objective of the MASTER trial is to determine the clinical efficacy of the statin - atorvastatin - as measured by invasive disease-free survival among patients with primary breast cancer. The trial is nationwide throughout Denmark and a total of 3,360 women are to be included in the trial. Women eligible for the trial have been diagnosed with an estrogen receptor positive breast cancer and are candidates for systemic cancer therapy, either prior to or following breast surgery. Upon eligibility and signed informed consent, trial participants will be randomized in a 1:1 manner to either standard treatment and atorvastatin 80 mg/day or standard treatment and placebo. The randomization is blinded. The treatment with atorvastatin or placebo will continue for two years unless side effects are experienced and further treatment with atorvastatin or the placebo is deemed inadequate. The standard treatment will of course continue as planned. The trial participants will follow the standard clinical routines in terms of follow-up and in addition they are asked to fill in questionnaires, i.e. regarding potential side effects or new events or diagnoses, up to ten years following inclusion. Potential breast cancer recurrences are hereby identified and a follow-up of at least 61/2 years will be required for the trial the demonstrate the estimated clinical difference between the randomized groups of patients.