The PI left the Institution.

Breast cancer patients are commonly treated with drugs that eggs present in the ovary and may reduce their chance for getting pregnant. Their fertility can be preserved by stimulating their ovaries, collecting multiple eggs, fertilize them in the lab and freeze them. Ovarian stimulation increase their estrogen levels in blood.this may stimulate their cancer and increase chance for recurrence. If a medicine that prevent estrogen rise is used (letrozole), this may increase the safety of stimulation. In this study we compared ovarian stimulation in breast cancer patients using letrozole with those who did not undergo stimulation and showed that there is no increase risk for recurrence after a median follow up of 2 years

215 women with breast cancer were evaluated for fertility preservation before chemotherapy. Of those, 79 elected to undergo controlled ovarian stimulation (COH) with letrozole and gonadotropins for embryo or oocyte cryopreservation. The 136 patients who declined served as controls.There were no significant differences between the study and control groups regarding age at diagnosis, breast cancer prognostic parameters (tumor size, grade, number of positive lymph nodes, estrogen receptor status, her2-neu overexpression and vascular space invasion), and chemotherapy regimens. There was no difference between the two groups in the projected 10 year relapse, breast cancer specific mortality or overall mortality. There were 3 recurrences or contralateral breast cancers (2 distant, 1 locoregional) in the letrozole group, and 11 in the control group (9 distant, 1 locoregional, 1 contralateral breast).

Comparison; breast cancer patients that underwent ovarian stimulation with letrozole+gonadotropins and those who declined ovarian stimulation.

Inclusion Criteria:

• Age 18-45 years
• Biopsy proven breast cancer
• No prior chemotherapy or oophorectomy
• Regular menstrual cycles
• Normal basal FSH and estradiol

Exclusion Criteria:

• Stage 4 breast cancer