van Hellemond IEG et al. - The current study involved an analysis of patients with chemotherapy-induced ovarian function failure who were administered adjuvant anastrozole after tamoxifen for different lengths of time. The risk of ovarian function recover during aromatase inhibitor treatment in breast cancer patients with chemotherapy-induced ovarian function failure exists beyond 45 years of age. Ovarian function recovery was associated with, but not without, higher estradiol levels during treatment with aromatase inhibitors.