for Jean who is looking for comparison studies of AIS
 

J Clin Endocrinol Metab. 2007 Mar 13; [Epub ahead of print]
Relative potencies of anastrozole and letrozole to suppress estradiol in breast cancer patients undergoing ovarian stimulation before in vitro fertilization.

Azim AA,
Costantini-Ferrando M,
Lostritto K,
Oktay K.
Fertility Preservation Program, Center for Reproductive Medicine & Infertility, Weill Medical College of Cornell University, New York, New York.
Context: Breast cancer patients undergoing controlled ovarian hyperstimulation (COH) for embryo or oocyte cryopreservation should be induced by the method that leads to least increase in estradiol levels. Objective: To determine the potency of anastrozole to suppress serum estradiol levels in breast cancer patients undergoing COH. Design: Prospective sequential cohort study between May 2003 and November 2005 for letrozole, and December 2005 and April 2006 for anastrozole. Setting: Academic center for reproductive medicine. Patients: Breast cancer patients presenting for fertility preservation Intervention: COH using FSH and letrozole (n=47) or anastrozole (n=7), followed by oocyte retrieval and embryo cryopreservation. Main outcome measures: Serum estradiol levels, area under the curve (AUC) for estradiol, and outcomes of COH cycles. Results: There were no significant differences between the two groups regarding length of stimulation, total gonadotropin dose, number of follicles >17mm and the lead follicle size on hCG day and number of embryos cryopreserved. The mean E2 on the day of hCG and post-hCG days were higher in the anastrozole group compared to the letrozole group (1325.89+/-833.17 and 2515.07+/-1368.52 vs. 427.78+/-278.24 and 714.38+/-440.83 pg.d/mL, p </= 0.01), respectively, even when anastrozole dose was increased up to 10mg per day. The mean AUC was significantly higher in the anastrozole group compared to the letrozole group (4402.93 +/- 1526.7 pg.d/mL vs. 1287.48 +/- 732.17 pg.d/mL, p <0.004). Conclusions: Breast cancer patients who underwent ovarian stimulation with anastrozole had a significantly higher exposure to estradiol than those who were stimulated with letrozole.
PMID: 17356042 [PubMed - as supplied by publisher]

Thanks Lani,

Regards,
Jean