The study is designed as a single-center, randomized, double-blind, placebo-controlled study
in pre- and postmenopausal women who will undergo surgery for breast cancer. Subjects will
either receive estetrol or placebo during a 2 week treatment period.
Several biological markers, such as a cellular growth marker and cell death markers, will be
assessed in the tumor tissue and surrounding normal tissue before and after the treatment
period. During the 2 week interval between diagnosis of breast cancer and surgical resection,
no therapy for breast cancer is usually administered.