Fertility preservation with random-start controlled ovarian stimulation and embryo cryopreservation for early pregnancy-associated breast cancer.

We report a case of fertility preservation using random-start controlled ovarian stimulation (COS), intracytoplasmic sperm injection (ICSI) and embryo cryopreservation in a patient with early pregnancy-associated breast cancer. A 34-year-old nulliparous woman at 5 weeks of gestation was diagnosed with estrogen receptor (ER) positive, progesterone receptor (PR) positive and human epidermal growth factor receptor-2 (HER-2) negative infiltrating intraductal carcinoma. Urgent neoadjuvant chemotherapy was deemed necessary and the patient decided to terminate the pregnancy. Random-start COS was initiated 5 days after pregnancy termination using a letrozole-based protocol. The beta human chorionic gonadotropin level on the day of COS start was 119.8 mIU/mL. Twenty-nine oocytes were retrieved after 11 days of COS. Seventeen oocytes underwent successful fertilization and 10 blastocysts were cryopreserved. The patient subsequently initiated neoadjuvant chemotherapy with her oncologist. The current case highlights the feasibility of random-start COS and embryo cryopreservation for fertility preservation immediately after the termination of an early pregnancy in a patient with pregnancy-associated breast cancer.