Fertility preservation in breast cancer with case-based examples for guidance.

With more young breast cancer survivors, a trend toward having children later in life, and improvements in assisted reproductive technology (ART), fertility preserving techniques are of growing importance prior to initiation of gonadotoxic treatments. The American Society for Clinical Oncology (ASCO) updated their Fertility Preservation in Patients with Cancer guidelines in April of 2018. ASCO continues to recognize oocyte and embryo cryopreservation as standard practice for women interested in preserving fertility and sperm cryopreservation as standard practice for men. ASCO has clarified their statement on ovarian suppression during chemotherapy as an option when standard methods are unavailable but should not be used as the sole method of fertility preservation (FP) due to conflicting evidence. ASCO also updated their statement on ovarian tissue cryopreservation, which is still labeled experimental but ASCO acknowledges that it can restore global ovarian function and could be of use in specific patients. The NCCN's Version 1.2018 Clinical Practice Guidelines® for treatment of breast cancer include fertility counseling as part of their work-up in all types of breast cancer for premenopausal women.The purpose of this review is to explain the indications and evidence for the different methods of FP for young breast cancer patients in accordance with ASCO and NCCN guidelines. The guidance will then be applied to three theoretical clinical cases in order to highlight actual use in clinical practice.