Fertility preservation strategies and long-term reproductive outcomes in women treated for breast cancer.

PURPOSE: What are the fertility preservation(FP) strategies and long-term reproductive outcomes in women with breast cancer? METHODS: Cohort study including women aged 18-40 years referred for FP counseling between 2015 and 2019 at a tertiary care centre. FP strategies comprised controlled ovarian stimulation (COS) or in vitro maturation (IVM) with oocyte and/or embryo vitrification, and ovarian tissue cryopreservation (OTC), used alone or in combination. Long-term follow-up (≥ 5 years) assessed ovarian function, pregnancy intention, conception modalities, and reproductive outcomes. RESULTS: A total of 165 patients were included (mean age 33.2 ± 3.9 years). Chemotherapy was administered as adjuvant setting in 47.3% (n = 78) and as neoadjuvant in 41.2% (n = 68) of patients, while 11.5% (n = 19) did not receive chemotherapy. A FP strategy was proposed to 151 patients (91.5%) and performed in 123(74.5%). COS was the most frequently used technique (40,6%), followed by IVM (33,3%) and OTC (5,4%). Forty-two patients (25.5%) did not undergo FP. Long-term follow-up was available for 94 patients (57.0%). Among them, 45(47.9%) reported an attempt to conceive. 60.0% (27/45) achieved a live birth (LB). 18(66.7%) conceived spontaneously, whereas 9(33.3%) achieved a LB using assisted reproductive technologies. Cryopreserved material was used by 9 women (9/45, 20.0%) resulting in 2 LB. Compared with women without a pregnancy intention, women who reported an attempt to conceive more frequently had hormone receptor negative disease, received less adjuvant chemotherapy, and more often reported regular cycles; embryo cryopreservation was also more frequent. CONCLUSION: FP is feasible in young women with breast cancer. Despite exposure to potentially gonadotoxic treatments, pregnancy and LB remain achievable, most often spontaneously.