A novel protocol of ovarian stimulation for fertility preservation in breast cancer patients

To present a novel controlled ovarian stimulation (COS) protocol for breast cancer patients undergoing oocyte retrieval. Case series. 21 patients underwent the following protocol: Random-start COS with 225-300 UI r-FSH; Pituitary suppression with GnRH-antagonists; Concomitant use of letrozole and tamoxifen; Ovulation trigger with a depot formulation of GnRH agonist. When COS was commenced in the early follicular phase, antagonist was administered when the leading follicle reached>13 mm. If commenced in the late follicular phase, antagonist was administered together with FSH. If commenced in the luteal phase, antagonist was given two days before FSH administration. Letrozole in a dose of 5 mg and tamoxifen in a dose of 20 mg, were given orally on a daily basis. Oocyte maturation was triggered by a depot GnRH agonist formulation. Oocyte retrieval was scheduled 36 hours later. Results are shown in Table 1.Tabled 1Results of COS for fertility preservationAge (years)Days of stimulationFSH total doseEstradiol levels (day of trigger)Number of oocytes collectedNumber of oocytes vitrifiedRange22-388-121800-3000 IU163-1332 pg/mL1-370-34Mean±SD29.1±4.39.4±1.22471.4±498.5 IU582±408 pg/mL12.3±8.89.4±7.4 Open table in a new tab This novel protocol is a random-start COS with r-FSH, letrozole and tamoxifen. Letrozole blocks the conversion of androgens to estrogens, and tamoxifen inhibits the activity of estrogen by binding to its receptor. Being so, this strategy may contribute to render COS a safe procedure in breast cancer patients, by associating two different methods of protection against high estradiol levels.The use of a GnRH-agonist depot formulation for ovulation triggering has the advantages of, at the same time, inducing final oocyte maturation and initiating ovarian suppression for ovarian function protection against adverse effects of chemotherapy. With regard of number and maturity of oocytes collected, the outcomes are comparable to conventional ovarian stimulation protocols.