Response to Ovarian Stimulation for Urgent Fertility Preservation before Gonadotoxic Treatment in BRCA -Pathogenic-Variant-Positive Breast Cancer Patients.

BRCA 1/2 pathogenic variants increase the risk of developing early and aggressive breast cancers (BC). For these patients, fertility potential can be directly affected by oncologic treatments. In addition, evidence indicates that BRCA -mutated women had a significant reduction in their ovarian reserve. In order to improve their chances of conception after the completion of cancer treatments, fertility preservation should be proposed before the administration of gonadotoxic drugs, ideally by oocyte vitrification after controlled ovarian hyperstimulation (COH). The present investigation aims to assess the ovarian response to COH in BRCA 1/2 -pathogenic-variant carriers diagnosed with BC. Patient characteristics and COH outcomes were compared between BRCA -positive ( n = 54) and BRCA -negative ( n = 254) patients. The number of oocytes recovered did not differ between the two groups. However, the oocyte maturation rate and the number of mature oocytes obtained (7 (4.5-11.5) vs. 9 (5-14) oocytes, p = 0.05) were significantly lower in the BRCA -mutated patients. Although individualized COH protocols should be discussed, BRCA -mutated patients would benefit from FP before BC occurs, in order to cope with the potential accelerated decline of their ovarian reserve, optimize the success rate of FP by repeating COH cycles, and to preserve the feasibility of PGT-M by collecting a large amount of eggs.