Long-Term Safety of Letrozole and Gonadotropin Stimulation for Fertility Preservation in Women With Breast Cancer.

<h4>Context and objective</h4>There has been increased attention to the issue of fertility preservation (FP). We aimed to investigate the long-term safety of FP via controlled ovarian stimulation with letrozole supplementation (COSTLES) prior to breast cancer treatment.<h4>Design, setting, and parti... View More