Fertility Preservation in Breast Cancer Patients

"Patients start ovarian stimulation protocol according to their menstrual cycle phase at enrollment (standard or random start). Ovarian stimulation includes gonadotropins administration in a GnRH antagonist protocol Standard Protocol: letrozole is orally administered 2 tablets per day (2,5mgx2/d) from cycle day 2 throughout the ovarian stimulation with gonadotropins protocol until ovulation triggering. GnRH antagonist is administered as soon as at least one follicle reaches 14 mm.~Random start protocol: letrozole is administered throughout the stimulation together with gonadotropins and GnRH antagonist, until ovulation triggering.~Oocytes are collected 36h after ovulation triggering. All patients receive GnRH antagonist after oocyte retrieval for 3-7 days or until chemotherapy starts, to induce luteolysis."