Background Fertility preservation is an important concern in breast cancer patients. In the present investigation, we set out to create a specific protocol of controlled ovarian stimulation (cos) for oocyte cryopreservation in breast cancer patients.Methods From November 2014 to December 2016, 109 patients were studied. The patients were assigned to a specific random-start ovarian stimulation protocol for oocyte cryopreservation. The endpoints were the numbers of oocytes retrieved and of mature oocytes cryopreserved, the total number of days of ovarian stimulation, the total dose of gonadotropin administered, and the estradiol level on the day of the trigger.Results Mean age in this cohort was 31.27 ± 4.23 years. The average duration of cos was 10.0 ± 1.39 days. The mean number of oocytes collected was 11.62 ± 7.96 and the mean number of vitrified oocytes was 9.60 ± 6.87. The mean estradiol concentration on triggering day was 706.30 ± 450.48 pg/mL, and the mean dose of gonadotropins administered was 2610.00 ± 716.51 IU. When comparing outcomes by phase of the cycle in which cos was commenced, we observed no significant differences in the numbers of oocytes collected and vitrified, the length of ovarian stimulation, and the estradiol level on trigger day. The total dose of follicle-stimulating hormone and human menopausal gonadotropin administered was statistically greater in the group starting cos in the luteal phase than in the group starting in the late follicular phase.Conclusions Our results suggest that using a specific protocol with random-start ovarian stimulation for oocyte cryopreservation in breast cancer patients is effective and could be offered to young women undergoing oncologic treatment.

Aim of the studyThe authors present a novel and specific controlled ovarian stimulation protocol for fertility preservation in women with estrogen-positive receptor breast cancer undergoing neoadjuvant chemotherapy. The protocol foresees random start ovarian stimulation and the use of letrozole associated to tamoxifen.Material and methodsForty breast cancer patients were included in the study. COS was performed either with recombinant FSH or hMG. Concomitantly with COS, letrozole in a dose of 5 mg and tamoxifen in a dose of 20 mg were given orally on a daily basis. The trigger was performed with 0.2 mg of triptorelin, in the presence of follicles ≥ 19 mm. Oocyte retrieval was scheduled 35–36 hours after triptorelin injection. Our main outcome measures were the number of oocytes collected and number of oocytes vitrified, the length of ovarian stimulation, total dose of gonadotropins administered, and levels of estradiol on the day of the trigger.ResultsThe mean age of patients was 30.43 ±4.25 years. Nineteen women commenced COS in the luteal phase, eleven in the early follicular phase and ten in the late follicular phase. The mean number of collected oocytes was 11.78 ±9.12 and the mean number of vitrified oocytes was 9.72 ±7.36. The mean duration of COS was 10.03 ±1.33 days. The mean estradiol concentrations on the triggering day was 623.10 ±441.27, and the mean dose of gonadotropins administered was 2540 ±713.10.ConclusionsThe authors suggest that the protocol is efficient and may be a safe option for oocyte vitrification in these patients.

Objective: Patients submitted to oncological fertility preservation with letrozole and gonadotropins seem to present a higher rate of immature oocytes and lower fertilization rates in comparison to infertile patients submitted to IVF cycles with gonadotropins. The aim of this study was to evaluate the influence of letrozole on oocyte morphology in patients with breast cancer submitted to fertility preservation. Methods: Retrospective analysis performed at a public tertiary hospital in São Paulo, Brazil. The oocytes were retrieved from patients with breast cancer undergoing fertility preservation (n=69), and from infertile women undergoing in vitro fertilization (n=92). We evaluated 750 oocytes obtained from breast cancer patients submitted to ovarian stimulation with letrozole and gonadotropins, and 699 oocytes from patients without breast cancer submitted to ovarian stimulation for in vitro fertilization with gonadotropins only due to male factor infertility. The mature oocytes retrieved were analyzed for the presence of refractile bodies, ooplasm color and regularity, central granulation degree, cortical granules, zona pellucida staining and regularity, perivitelline space, presence of vacuoles or abnormal smooth-surfaced endoplasmic reticle and oocyte retraction. Results: There was a higher incidence of alterations in oocyte morphology in the letrozole group when compared to the control group: increased perivitelline space ( p =0.007), irregular zona pellucida ( p <0.001), refractile bodies ( p <0.001), dark ooplasm ( p <0.001), granular ooplasm ( p <0.001), irregular ooplasm ( p <0.001) and dense central granulation ( p <0.001). Conclusion: Letrozole is a risk factor for worse oocyte morphology. However, the clinical impact of ovarian stimulation protocol with combined use of gonadotropins and letrozole for fertility preservation remains unclear in this setting. These data underline the importance of establishing the predictive potential of morphological dimorphisms of human oocytes in IVF outcomes.

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