Israel Medical Association Journal

Background: Controlled ovarian hyperstimulation (COH) followed by oocyte retrieval is a leading option for fertility preservation before chemotherapy, yet this procedure causes excessive serum levels of estradiol (E2), which are often detrimental for cancer patients. Aromatase inhibitors are often used in breast cancer patients during COH to prevent elevated levels of E2.

Objectives: To describe our experience with COH for oocyte cryopreservation in non-breast cancer patients using aromatase inhibitors.

Methods: Of the five patients treated, two had an aggressive abdominal desmoid tumor, one had endometrial carcinoma, one had uterine sarcoma, and one patient had a brain oligodendroglioma. In all cases the treating oncologist suggested an association between estrogen and possible tumor progression. All patients were treated with a standard in vitro fertilization antagonist protocol combined with aromatase inhibitors, similar to the protocol used for breast cancer patients.

Results: The average duration of treatment was 10.5 days, mean peak E2 was 2348 pmol/L, mean number of oocytes aspirated was 17.3, and a mean of 14.6 embryos/oocytes were cryopreserved.

Conclusions: COH with aromatase inhibitors is apparently effective in non-breast cancer patients and spares exposure to high E2 levels.

Background: Adjuvant/neoadjuvant chemotherapy in breast cancer patients may be associated with amenorrhea and a marked reduction in ovarian reserve.

Objectives: To assess the use of letrozole with follicle-stimulating hormone (FSH) in gonadotropin-releasing hormone (GnRH) analogue protocols, based on reported attempts to avoid the estradiol (E2) increase during controlled ovarian hyperstimulation for embryo cryopreservation in breast cancer patients using a combination of low dose FSH and aromatase inhibitor (letrozole) in a GnRH-antagonist protocol.

Methods: Twenty-four breast cancer patients were treated with recombinant FSH (150–450 U/day) and letrozole (5 mg/day) in a long GnRH-agonist (n=7) or GnRH-antagonist (n=17) protocol. After oocyte retrieval, insemination and/or intracytoplasmic sperm injection was performed. The embryos were frozen.

Results: The average interval from surgery to oocyte retrieval was 40 days. Average duration of treatment was 9.6 days and mean peak E2 level 1342 ± 1091 pmol/L, yielding 16.0 ± 16.3 oocytes (range 0–82). Mean fertilization rate was 69.5 ± 20.4% and mean number of embryos cryopreserved 10.3 ± 9.3. More oocytes were retrieved with the long GnRH protocol, but the difference was not statistically significant (24.8 ± 24.6 vs. 12.0 ± 8.8 pmol/L, P = 0.07).

Conclusions: As previously reported, ovarian stimulation with letrozole and FSH, in both the long GnRH-agonist and GnRH-antagonist protocols, is apparently effective in breast cancer patients and spares them exposure to high E2 levels.