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Abstract
Objective: To assess the advantages and disadvantages of using Letrozole for controlled ovarian stimulation (COH) in young patients with estrogen receptor-positive (ER+) breast cancer, wishing to cryopreserve oocytes.
Design: Retrospective cohort analysis.
Setting: Sixteen Italian units for reproductive medicine and in vitro fertilization.
Methods: Data of 50 ER+ breast cancer patients undergoing COH to cryopreserve oocytes before gonadotoxic chemotherapy with a Letrozole plus gonadotropins (Le+Gn) protocol were compared with those of 25 young women with ER– breast cancer, submitted to COH using a protocol with gonadotropins alone (Gn-only).
Results: The Le+Gn protocol implied a significantly lower total Gn consumption and allowed to maintain significantly lower circulating E2 levels at all checkpoints throughout stimulation (peak E2 value 446 ± 357 versus 1553 ± 908 pg/ml, respectively; p = 0.001). On the other side, the Le+Gn protocol allowed a significantly lower yield of oocytes available for cryostorage (6.6 ± 3.5 versus 8 ± 5, respectively; p = 0.038).
Conclusions: In breast cancer patients, the association of Letrozole to Gn significantly reduces the number of oocytes available for cryostorage in comparison with the use of Gn alone. On the other side, it is associated with significantly lower E2 levels during the whole stimulation cycle, a safety issue that has been traditionally considered advantageous in case of ER+ cancers.
Acknowledgements
The Authors thank all Italian Reproductive Units that have contributed to this study by sending their data: Dipartimento Materno-Infantile, Istituto di Ostetricia e Ginecologia Università di Modena e Reggio Emilia, Modena; Centro Sterilità Policlinico Mangiagalli Regina Elena, Milano; Centro di Medicina della Riproduzione Biogenesi, Monza; Tecnobios Procreazione, Bologna; Centro di Fisiopatologia della Riproduzione Ospedale di Lugo di Romagna, Lugo di Romagna; Centro Fisiopatologia della Riproduzione, Ginecologia e Ostetricia, Bari; Centro di PMA, Università di Padova, Padova; Centro GENERA, Roma; Dipartimento di Scienze Ostetriche e Ginecologiche, Medicina della Riproduzione, Università degli Studi di Napoli Federico II, Napoli; Centro di Fisiopatologia della Riproduzione, IRCCS San Raffaele, Milano; Centro PMA, Ospedale Luigi Sacco, Milano; Azienda Ospedaliera San Giuseppe Moscati, Avellino.