Outcomes of fertility preservation before or after anticancer treatments in young breast cancer patients and survivors: a single-center retrospective study and clinical experiences

Abstract Background Fertility preservation (FP) is gradually becoming a crucial cure during fertility counseling for all breast cancer (BC) women of reproductive age, but certain limiting factors hinder patients' decisions. This study aimed to collect cases involving fertility preservation before anticancer treatments and assisted reproductive technology (ART) after anticancer therapies in young breast cancer (BC) patients and survivors and to share some clinical experiences. Methods We retrospectively analyzed 18 BC patients who underwent FP before (neo)adjuvant chemotherapy and 8 survivors who chose ART after completing anticancer treatments in a single reproductive medicine center between January 2015 and June 2023. Baseline characteristics and outcomes of FP and ART were analyzed. Results 8 survivors of a median age of 35.5 years (range 32.3–41.0 years) underwent ART after anticancer therapies and behaved diminished ovarian reserve (DOR) or even premature ovarian insufficiency (POI) with undesirable outcomes. Receiving FP before (neo)adjuvant chemotherapy in 18 patients does not delay subsequent treatments, patients receiving neoadjuvant chemotherapy tend to prefer RS-COS protocol that shorten the time from diagnosis to initiation of chemotherapy (median days 26.0 vs. 42.0, p = 0.002) compared to the majority of patients receiving cCOS protocol, and there is no difference in other FP results. COS with letrozole can control the serum estradiol level in a relatively safe condition. During a median follow-up period of 17.5 months (range 8.8–31.0 months), only 1 (5.6%) woman suffered recurrence with bone metastasis when she received neoadjuvant chemotherapy after FP, 2 (11.1%) patients experienced ovarian hyperstimulation syndrome (OHSS) after COS, and 3 (37.5%) survivors had a live birth after ART. Conclusions Embryo and oocyte cryopreservation after COS based on letrozole is a preferred and optimal FP option for young BC patients before (neo)adjuvant chemotherapy. Using ART to get pregnant in BC survivors is feasible and not associated with adverse cancer outcomes. It is important that these patients are closely monitored to reduce the potential risks of OHSS and recurrence.