Breast cancer is a disease where the tumor size, lymph node involvement and histological grade provide rich information about prognosis and enable to stage the disease. As in any other oncological pathology, stage of disease at diagnosis is the major determining factor for estimating survival. Ovarian stimulation for fertility preservation is performed in this study, in patients with stage I-II (TNM) after the neoplasia is treated (surgical removal of the tumor) prior to systemic therapy, when indicated.