FICHE-YOUNG: FIrst-line treatment CHoicE in hormone receptor positive (HR+)/HER2- negative metastatic breast cancer patients (MBC) ≤45 years old. A large observational multicenter cohort survival analysis

Abstract

Background: Metastatic breast cancer (MBC) in young patients (pts) is traditionally considered at poor prognosis. Although current guidelines recommend endocrine therapy (ET) as first line treatment (1st trt) for HR+ HER2- MBC, younger age can lead to more extensive use of first line chemotherapy (CT). In the present analysis, we aimed to assess overall survival (OS) of younger MBC pts compared to older ones, and to explore 1st trt choices in a large real-life multicenter cohort. Methods: The Epidemiological Strategy and Medical Economics (ESME) Research program aims to collect high-quality real-world data in oncology from 18 French Comprehensive Cancer Centers. Pts who started treatment for a newly diagnosed MBC between Jan 2008 and Dec 2014 were selected in the MBC ESME database. The primary end point of the FICHE-Young study was to compare adjusted OS in pts diagnosed with endocrine-sensitive HR+ HER2- MBC and aged ≤ 45 vs>45 at diagnosis. We also evaluated 1st trt choices in both categories and its correlation with OS. Analyses will be adjusted on a propensity score, in order to control selection biases associated with non-randomization. Results: 6265 pts out of 16703 in ESME had HR+/HER2- MBC. Characteristics and 1st trt choices are listed in the Table. Median OS was 62.3 months (mos) (95% CI 56.5-69) in pts ≤ 45 and 52.8 mos in those >45 (95% CI 50.7-55), p