Effective sequence of endocrine therapy for ER-positive and HER2-negative metastatic breast cancer.

Abstract

e11504 Background: Sequential endocrine therapy (ET) is recommended for ER positive metastatic breast cancer (MBC). A previous ET, including adjuvant settings, for MBC may have an influence on the effect of the next-line ET. However, the best sequence of ET for MBC is unclear. From the point of view of mechanism of resistance, we hypothesize that changing to different type of endocrine agents (EAs) is more effective than sequencing within the same kind of EAs. To investigate factors affecting effect of ET for MBC, we analyzed clinicopathological factors in relation to the treatment efficacy. Methods: From 2000 December to 2012 December, 149 patients with ER-positive and HER2-negative breast cancer recurred in our hospital. Items investigated were progesterone receptor status and Ki-67 index of primary tumors, disease free intervals, recurrence sites, type of EAs for adjuvant treatment and treatment for MBC, progression free survival (PFS) for each ET. We also focused on changing of ET from an AI to other ...