RT Journal Article T1 Efficacy of fulvestrant in the treatment of postmenopausal women with endocrine-resistant advanced breast cancer in routine clinical practice. A1 Blancas, I A1 Fontanillas, M A1 Conde, V A1 Lao, J A1 Martinez, E A1 Sotelo, M J A1 Jaen, A A1 Bayo, J L A1 Carabantes, F A1 Illarramendi, J J A1 Gordon, M M A1 Cruz, J A1 Garcia-Palomo, A A1 Mendiola, C A1 Perez-Ruiz, E A1 Bofill, J S A1 Baena-Cañada, J M A1 Jañez, N M A1 Esquerdo, G A1 Ruiz-Borrego, M K1 Área de Gestión Sanitaria de Jerez, Costa Noroeste y Sierra de Cádiz K1 Área de Gestión Sanitaria Sur de Sevilla K1 Metastatic breast cancer K1 Postmenopausal women K1 Hormone receptor-positive advanced breast cancer K1 Fulvestrant AB Introduction: This study aimed to describe the efficacy of fulvestrant 500 mg in postmenopausal women with estrogen receptor (ER)-positive advanced/metastatic breast cancer who had disease progression after receiving antiestrogen therapy in clinical practice, gathering real-world data. Materials and methods: A multicenter, retrospective, observational study conducted in Spain. Postmenopausal women with locally advanced/metastatic ER-positive breast cancer who received treatment with fulvestrant 500 mg after progression with a previous anti-estrogen therapy were eligible. The primary endpoint was progression-free survival (PFS); secondary endpoints were overall survival (OS), clinical benefit rate (CBR), duration of clinical benefit (DoCB), and safety profile. Results: A total of 263 women were evaluated (median age, 65.8 years). At a median follow-up of 21.5 months, median PFS and OS were 10.6 and 43.2 months, respectively. PFS according to 1st, 2nd, 3rd, and 4th lines were 11.5, 10.6, 9.9, and 8.5 months, respectively (p = 0.0245). PFS in patients with visceral involvement was 10 months vs 10.6 months in patients without visceral involvement (p = 0.6604), 9.6 months in patients with high Ki67 vs 10 months in patients with low Ki67 (p = 0.7224), and 10.2 months in HER2+ patients vs 10.3 months in HER2- patients (p = 0.6809). The CBR was 56.5% and the DoCB was 18.4 months. The most frequent adverse events were injection site pain (10.3%) and musculoskeletal disorders (7.6%). Conclusions: Fulvestrant 500 mg administered in clinical practice was shown to be effective (PFS, 10.6 months; CBR, 56.5%) and well tolerated, in accordance with previous trials. PB Springer YR 2017 FD 2017-11-24 LK http://hdl.handle.net/10668/13021 UL http://hdl.handle.net/10668/13021 LA en NO Blancas I, Fontanillas M, Conde V, Lao J, Martínez E, Sotelo MJ, et al. J. Efficacy of fulvestrant in the treatment of postmenopausal women with endocrine-resistant advanced breast cancer in routine clinical practice. Clin Transl Oncol. 2018 Dec;20(12):1631-1632. doi: 10.1007/s12094-018-1956-7. Erratum for: Clin Transl Oncol. 2018 Jul;20(7):862-869 DS RISalud RD Apr 10, 2025