Oncologic Safety of Preoperative Controlled Ovarian Stimulation for Fertility Preservation Among Women with Estrogen Receptor Positive Breast Cancer.

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.

RESULTS

Among 51 women with ER+ breast cancer undergoing COS, the median follow-up was 5.5 years. 5-year PFS was similar for preoperative COS (n = 32) versus postoperative COS (n = 19): 94.1% (95% CI 65.0-99.2%) versus 93.3% (95% CI 61.3-99.0%), p = 0.73. Patients undergoing neoadjuvant systemic therapy (NST) and preoperative COS (n = 30) experienced a significantly longer time from diagnosis to NST initiation than propensity-score matches who did not undergo COS (48 versus 29.5 days, p < 0.0001), but disease-free survival was similar: 94.1% (95% CI 65.0-99.2%) versus 93.3% (95% CI 75.9-98.3%), p = 0.15.

CONCLUSIONS

In this study of women with ER+ breast cancers, preoperative COS was not associated with increased risks of disease progression or death. While COS was associated with a modest delay in NST initiation, PFS was similar to propensity-score matched patients who did not undergo COS. Results support the oncologic safety of COS in the setting of an in situ ER+ tumor and provide much-needed evidence for young women with breast cancer receiving gonadotoxic NST who desire future childbearing during survivorship.