Is controlled ovarian stimulation safe in patients with hormone receptor-positive breast cancer receiving neoadjuvant chemotherapy?

Introduction: Controlled ovarian stimulation (COS) for oocyte/embryo cryopreservation is the method of choice for fertility preservation (FP) in young patients diagnosed with early-stage breast cancer (eBC). Nevertheless, some challenges still question its role, particularly in the neoadjuvant setting, where concerns arise about potential delay in the onset of anticancer treatment, and in hormone receptor-positive (HR+) disease, as cancer cells may proliferate under the estrogenic peak associated with stimulation. Therefore, this review aims to examine the available evidence on the safety of COS in eBC patients eligible for neoadjuvant treatment (NAT), particularly in HR+ disease.

Methods: A comprehensive literature search was conducted to identify studies evaluating the feasibility and safety of COS in eBC and including patients referred to NAT and/or with HR+ disease. Time to NAT and survival outcomes were assessed.

Results: Of the three matched cohort studies assessing the impact of COS on time to start NAT, only one reported a significant small delay in the cohort undergoing COS compared with the control group, whereas the other studies found no difference. Regarding survival outcomes, overall, no increased risk of recurrence or death was found, either in patients undergoing COS in the neoadjuvant setting regardless of HR expression or in HR+ disease regardless of the timing of COS relative to surgery. However, there are no data on the safety of COS in the specific combined scenario of HR+ disease undergoing NAT.

Conclusion: Neither the indication to NAT nor the HR positivity constitutes per se an a priori contraindication to COS. Shared decision making between clinicians and patients is essential to carefully weigh the risks and benefits in each individual case. Prospective studies designed to specifically investigate this issue are warranted.