This will be a prospective, multicenter, observational study. The primary objective is to record the choice, in clinical practice, of adjuvant hormone therapy (tamoxifen, tamoxifen + LhRh, aromatase inhibitors + LhRh) in premenopausal patients with estrogen-receptor positive breast cancer.
The secondary objective is to correlate adjuvant hormone therapy choices with biological characteristics of the tumor (T size, lymph node status, grade, receptor level, Ki67, HER2 status) and patient characteristics (age, prior chemotherapy treatment).