Real-life data on the effectiveness of fulvestrant (F) in postmenopausal breast cancer (BC): A multicenter study from Brazil.

e11519 Background: Despite the availability of efficacy data from clinical trials, real-life data on the effectiveness of therapy is of interest for the scientific community and for policy makers. We investigated the real-life effectiveness and tolerability of F in postmenopausal patients with advanced BC in Brazil. Methods: Eligible patients had hormone-receptor-positive, advanced BC and at least one type of hormone therapy prior to treatment with F (250 mg/month). Given the retrospective nature of the study, the primary variable of interest was treatment duration (TD), which was used as a proxy for time to tumor progression. Results: We analyzed 80 patients with a mean age of 62 years, predominantly Caucasian (79%), with ductal (74%) or other invasive carcinomas, mostly HER2-negative (92%), and with prior adjuvant therapy in 69% of cases. Patients received a median of 5 cycles of F, and disease progression was the reason for treatment discontinuation in 84% of cases. Regardless of causality, the most co...