To print: Select File and then Print from your browser's menu --------------------------------------------------------------------------------------- Title: Higher Pregnancy Rates in Women Undergoing Ovarian Hyperstimulation With Letrozole and Gonadotropins Prior to Chemotherapy: Presented at ASRM URL: http://www.pslgroup.com/dg/2162B6.htm Doctor's Guide October 23, 2007
By Crina Frincu-Mallos, PhD WASHINGTON, D.C. -- October 23, 2007 -- In a prospective study of women who underwent ovarian hyperstimulation with combined continuous letrozole and gonadotropins prior to receiving chemotherapy, researchers found letrozole was not associated with congenital abnormalities. The study also shows that embryos that were cryopreserved before cancer treatment were associated with higher pregnancy rates compared with embryos that were obtained after cancer treatment, researchers reported here at the 63rd Annual Meeting of the American Society for Reproductive Medicine (ASRM). This study is the first to provide comparative evidence that embryo cryopreservation preserves fertility in cancer patients. In addition, the study also shows that continuous administration of letrozole, a drug that minimises the increase in oestradiol levels during ovarian stimulation, is not associated with congenital abnormalities in children born after ovarian cryopreservation, the researchers reported on October 16. Freezing of eggs or ovarian tissue offers advantages to women undergoing assisted reproductive technology (ART), especially to women with cancer who are at risk of losing ovarian function subsequent to chemotherapy. Embryo or oocyte cryopreservation prior to chemotherapy has been used for a decade at the Weill Medical College of Cornell University to preserve the possibility of fertility for premenopausal women diagnosed with cancer. Lead author Alyaa Elassar, MD, Center for Reproductive Medicine and Infertility, Weill Medical College, Cornell University, New York, New York, United States, and colleagues aimed to determine whether letrozole is associated with increased risk of congenital anomalies in the newborns or with adverse obstetric outcomes. The first arm of the study enrolled a total of 14 patients diagnosed with either breast carcinoma (n=10), endometrial carcinoma (n=1), cervical adenocarcinoma (n=1), or thyroid cancer (n=2) in this prospective follow up study conducted at Weill Medical. The second arm of the study, consisting in women receiving ovarian stimulation after chemotherapy, enrolled a total of 8 women, all diagnosed with breast carcinoma. Patients underwent controlled ovarian hyperstimulation with letrozole in combination with gonadotropin, administered continuously before (n=14) or after (n=8) cancer treatment. Treatment with letrozole 5 mg was initiated on cycle day 2, while gonadotropin was started on day 4 (150-450 units range); both were administered continuously until the day of human chorionic gonadotropin production. Women that underwent ovarian hyperstimulation prior to chemotherapy had a frozen embryo transfer to themselves (n = 6) or to a surrogate (n = 8) at a later date. In the group of women that underwent ovarian hyperstimulation subsequent to chemotherapy, all but one had a fresh embryo transfer; one patient had a frozen embryo transfer. Mean duration of cryostorage was 14.4 (range, 2-44 months). Mean duration between cancer treatment and embryo transfer was 37.2 months (range, 3-137 months). When comparing the two groups, women in the pretreatment group had a basal antral follicle count of 8.58 versus 5.4 in the post-treatment group (P =.089), said the researchers. Patients in the pretreatment group had significantly more oocytes retrieved (8.35 vs 3.44, P =.0018) as well as significantly more oocytes fertilised (4.71 vs 2.44, P =.02), noted Dr. Elassar and colleagues. Regarding the obstetric and neonatal outcomes, there were 13 pregnancies resulting in nine newborns (one set of triplets, 6 singletons) in the pretreatment group. The pregnancy complications included three preterm delivery, two hypertension cases, and one placenta previa. In the post-treatment group, there were four pregnancies resulting in three newborns (one set of twins, one singleton). One pregnancy was complicated by preterm delivery, explained the researchers. Dr. Elassar and colleagues noted that pregnancy rates were significantly higher in the group that underwent embryo retrieval before undergoing cancer treatment (P <.05). In addition, after a 24-month followup, no developmental or congenital anomalies were encountered in either group, concluded the researchers. "These data will be reassuring to patients who need to freeze eggs or ovarian tissue to preserve their fertility," Steven J. Ory, MD, President, American Society for Reproductive Medicine remarked in a written release. "Although more frozen eggs are required to establish a pregnancy than fresh eggs, frozen eggs that fertilise, develop into viable embryos and implant are as likely to result in healthy children as fresh eggs." [Presentation title: Prospective Follow Up of Children Born Following Controlled Ovarian Hyperstimulation with Combined Continuous Letrozole and Gonadotropins Abstract P-696] --------------------------------------------------------------------------------------------- Copyright © 1999 P\S\L Consulting Group Inc. All rights reserved. Republication or redistribution of P\S\L content is expressly prohibited without the prior written consent of P\S\L. 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