對需要接受新輔助性、具性腺毒性治療的ER+乳癌年輕患者，在乳房原發腫瘤尚未切除前，採用以letrozole為主的COS進行卵子或胚胎冷凍，短至中期看來不會增加疾病進展、復發或乳癌死亡風險。

Abstract

Background The oncologic safety of preoperative controlled ovarian stimulation (COS) for fertility preservation in women with an in situ estrogen receptor positive (ER+) breast cancer is unclear. The purpose of this study was to compare oncologic outcomes of women with ER+ breast cancer undergoing preoperative COS versus (1) postoperative COS or (2) matched controls not undergoing COS.

Patients and Methods

This was a single-institution retrospective cohort study of women with ER+ breast cancer receiving oncofertility counseling who pursued COS from 2014–2024. The primary outcome was progression-free survival (PFS). A subcohort of patients who received neoadjuvant systemic therapy was compared with a matched cohort of similar patients with ER+ breast cancer who did not undergo COS. Propensity score matching criteria were age, HER2 receptor status, and clinical stage.