Effect of breast cancer prognostic factors on ovarian reserve and response in fertility preservation

Abstract

Research question: Do breast cancer prognostic factors influence ovarian reserve and response to ovarian stimulation in the context of fertility preservation?

Design: Observational, bicentric retrospective study of 352 women with breast cancer who underwent ovarian stimulation using a random start gonadotrophin releasing hormone antagonist protocol and vitrified oocytes between November 2015 and August 2022. Serum anti-Müllerian hormone (AMH) levels and antral follicle count (AFC) were measured. The number of oocytes recovered, maturation rate and follicular output rate (FORT) were analysed according to patients' characteristics and breast cancer prognostic factors.

Results: Median age was 34 years (31.1-37.1). Median AFC and serum AMH level were 17 (12-26) follicles and 2 (1.2-3.4) ng/ml, respectively. After ovarian stimulation, 10.5 (6.0-16.0) oocytes were recovered, with eight (4-13) being mature. Mean oocyte maturation rate was 79% (62-92). Antral follicle count (>12) significantly affected the risk of recovering fewer than eight mature oocytes (P < 0.0001, multivariate analysis). Follicular responsiveness to FSH, assessed by the follicular output rate (FORT index) and number of oocytes recovered, were 31% (21-50) and 10.5% (6.0-16.0), respectively. FORT index and ovarian stimulation outcomes were not influenced by breast cancer prognostic factors.

Conclusion: Breast cancer prognostic factors do not influence ovarian reserve markers or response to ovarian stimulation in fertility preservation. Therefore, tumour grade, triple-negative status, HER2 overexpression and high Ki67 should not alter the fertility-preservation strategy when considering ovarian stimulation for oocyte vitrification.

Keywords: breast cancer; fertility preservation; oocyte vitrification; ovarian reserve; ovarian stimulation.