Assessment of treatment response with fulvestrant (F) 500 mg in standard clinical practice through a retrospective study: NCT01509625.

e11583 Background: The CONFIRM study showed greater efficacy of F500 as compared to F250.Based on these results a dosage change was authorized in Spain.The aim of this study is to describe the efficacy of F500 (progression free survival(PFS) and clinical benefit rate(CBR) in Spanish patients (P) with estrogen receptor (ER+) Metastatic Breast Cancer (MBC) through a retrospective data collection. Methods: After written informed consent, data collection was recorded from clinical records of P who previously had progressed on hormonal treatment and who received at any time F 500 from 1st January 2010 to 31st October 2011. Results: 102 P in 14 centers were included in the study, 93 P were evaluable.Median age was 65 (39-88). Histology: 80.6% ductal ;15% lobulillar. Hormonal receptors: ER+/ PgR+ 77.4%; ER+/PgR- 21.6 %. HER2 status was documented in 80P, 15% of them were HER2+. 45.4% were Ki67 +. Mean from diagnosis to metastatic disease:3.7 years, 19.3% of P had de novo metastatic disease. 21.5% of P had viscer...