Is Letrozole needed for controlled ovarian stimulation in patients with estrogen receptor-positive breast cancer?

Abstract

SummaryObjective: To assess the advantages and disadvantages of using Letrozole for controlled ovarian stimulation (COH) in young patients with estrogen receptorpositive (ER+) breast cancer, wishing to cryopreserve oocytes. Design: Retrospective cohort analysis.Setting: Sixteen Italian Units for Reproductive Medicine and In Vitro Fertilization.Methods: Data of 50 ER+ breast cancer patients undergoing COH to cryopreserve oocytes before gonadotoxic chemotherapy with a Letrozole plus gonadotropins (Le+Gn) protocol were compared with those of 25 young women with ER-breast cancer, submitted to COH using a protocol with gonadotropins alone (Gn-only). Results:The Le+Gn protocol implied a significantly lower total Gn consumption and allowed to maintain significantly lower circulating E2 levels at all checkpoints throughout stimulation (peak E2 value 446 ± 357 vs.1553 ± 908 pg/ml, respectively; p=0.001). On the other side, the Le+Gn protocol allowed a significantly lower yield of oocytes available for cryostorage (6.6 ± 3.5 vs. 8 ± 5, respectively; p=0.038).. Conclusions:In breast cancer patients, the association of Letrozole to Gn significantly reduces the number of oocytes available for cryostorage in comparison with the use of Gn alone. On the other side, it is associated with significantly lower E2 levels during the whole stimulation cycle, a safety issue that has been traditionally considered advantageous in case of ER+ cancers.

Update on fertility preservation in young women undergoing breast cancer and ovarian cancer therapy

“…On the first point, alternative approaches for ovarian stimulation with the use of letrozole [24] or tamoxifen [25] have been developed for patients with breast cancer with no observed negative consequence on the quality of the oocytes and embryos collected [25,26]. Furthermore, one small retrospective study suggests no clear detriment from ovarian stimulation with concurrent administration of letrozole and gonadotropins before chemotherapy on breast cancer prognosis [27].…”

Viable Options for Fertility Preservation in Breast Cancer Patients: A Focus on Latin America

“…Conflicting results have been reported regarding the number of mature oocytes yielded in letrozole-associated COH compared to patients undergoing COH without letrozole 48,49 . Nonetheless, in 2015, Oktay, et al reported the success rate of oocytes/embryos cryopreservation using letrozole-associated COH in the largest breast cancer cohort reported to date 45 .…”

IVF for fertility preservation in breast cancer patients—efficacy and safety issues

“…However, even when implementing this triggering threshold, high rate of oocyte immaturity was still described by other groups [19,58]. Additionally, in a retrospective cohort study of 16 IVF units, a significantly lower oocyte yield in patients treated with this protocol was observed [59]. In terms of safety, although E2 reduction is clearly achieved when using letrozole, some patients still exhibit levels which are higher than those observed during a natural ovulatory cycle.…”