Successful live birth following fertility preservation in a breast cancer patient

We present a case with early breast cancer (BC) successfully gave birth after fertility preservation (FP) before radiotherapy (RT) and hormone therapy. A 39-year-old woman presented with a 1 cm palpable mass in right breast. Following breast ultrasound, mammography, and a core needle biopsy, diagnosis of ductal carcinoma in situ (DCIS) was confirmed. Right breast partial mastectomy and sentinel lymph node biopsy were done and she was referred for FP before RT and Tamoxifen treatment. Controlled ovarian stimulation with a GnRH antagonist and letrozole was used, yielding 14 mature oocytes and seven frozen embryos. Six months post-RT, she underwent a minimal stimulation frozen embryo transfer (MS-FET) by letrozole to minimize E2 exposure. A successful pregnancy was achieved. After an uneventful prenatal course, a healthy baby girl was delivered via cesarean section. Early referral and timely fertility preservation enable women with BC to conceive and have healthy children. The optimal COS protocol as a GnRH antagonist protocol with letrozole is recommended due to minimizing estrogen exposure and short duration. A MS-FET with letrozole instead of an AC-FET can be arranged in BC women with regular cycles before commencing Tamoxifen treatment.