Anastrozole after tamoxifen in early breast cancer patients with chemotherapy-induced ovarian function failure.

523Background: The DATA study compared 6 and 3 years of anastrozole therapy in postmenopausal women with hormone-receptor positive early breast cancer previously treated with 2-3 years tamoxifen (oral presentation SABCS 2016 #S01-03). The study included postmenopausal women, allowing those with chemotherapy-induced ovarian function failure (CIOFF). However, these may be at risk of ovarian function recovery (OFR). The current analysis compared the survival of women with CIOFF with definite postmenopausal women and examined the influence of OFR on survival. Methods: We selected patients from the DATA study aged 45-57 years at randomization who had received (neo-)adjuvant chemotherapy. They were classified by menopausal status at randomization (definite postmenopausal before chemotherapy or by ovariectomy, versus CIOFF). The latter were monitored by estradiol measurements for OFR during anastrozole. Endpoints: Disease-free Survival (DFS), Distant Recurrence-free Survival (DRFS), and Overall Survival (OS), co...