LAUSR

1052Background: For HR+/HER2– metastatic breast cancer (mBC), International guidelines recommend multiple lines of endocrine therapy (ET) before starting chemotherapy. Few studies have assessed the efficacy of such strategy on large populations. Our objective was to evaluate multiple ET activity according to clinical and biological characteristics and type of ET. Methods: All patients (pts) who initiated treatment for a newly diagnosed mBC between January 2008 and December 2014 in all 18 French Comprehensive Cancer Centers were included in the real life ESME database. ESME collects retrospective data using a clinical trial-like methodology. Database lock was 8 Dec 2016. Primary endpoint of the current study was progression free survival (PFS) on successive ET lines. Only pts with ET alone were assessed (pts receiving ET after chemotherapy as maintenance therapy, or combined with targeted treatment were excluded). Results: 9921 pts out of 16703 in ESME, had HR+/HER2- mBC (median age 62.0 years[range 23-96]...