How do you explain the benefit of endocrine therapy after bilateral mastectomies in early stage breast cancer for a postmenopausal woman?

First of all, all breast cancer is considered to have seeded systemic mets. Also, early is a concept mainly for surgery and radiation while it is important to remember that single cell that became malignant took 7-10 years to reach 1 cm stage if ER positive, and it is to be presumed that some cells ...