RESEARCH ARTICLE Efficacy of fulvestrant in the treatment of postmenopausal women with endocrine-resistant advanced breast cancer in routine clinical practice I. Blancas 1 • M. Fontanillas 2 • V. Conde 3 • J. Lao 4 • E. Martı ´nez 5 • M. J. Sotelo 6 • A. Jaen 7 • J. L. Bayo 8 • F. Carabantes 9 • J. J. Illarramendi 10 • M. M. Gordon 11 • J. Cruz 12 • A. Garcı ´a-Palomo 13 • C. Mendiola 14 • E. Pe ´rez-Ruiz 15 • J. S. Bofill 16 • J. M. Baena-Can ˜ada 17 • N. M. Ja ´n ˜ez 18 • G. Esquerdo 19 • M. Ruiz-Borrego 20 Received: 19 July 2017 / Accepted: 5 November 2017 Ó Federacio ´n de Sociedades Espan ˜olas de Oncologı ´a (FESEO) 2017 Abstract Introduction This study aimed to describe the efficacy of fulvestrant 500 mg in postmenopausal women with estro- gen receptor (ER)-positive advanced/metastatic breast cancer who had disease progression after receiving anti- estrogen therapy in clinical practice, getting real-world data. Materials and methods Multicenter, retrospective, obser- vational 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 sur- vival (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 C 4th lines were 11.5, 10.6, & I. Blancas iblancas@ugr.es 1 Hospital Universitario Clı ´nico San Cecilio, Complejo Hospitalario Universitario, C/Dr. Oloriz, 16, 18012 Granada, Spain 2 Hospital Clinic de Barcelona, illarroel, 170, 08036 Barcelona, Spain 3 Hospital Universitario Virgen de las Nieves, Av. de las Fuerzas Armadas, S/N, 18014 Granada, Spain 4 Hospital Universitario Miguel Servet, Paseo Isabel la Cato ´lica, 1-3, 50009 Zaragoza, Spain 5 Hospital Provincial de Castello ´n, Av. del Dr. Clara `, 19, 12002 Castello ´ de la Plana, Spain 6 Hospital Universitario Clı ´nico San Carlos, C/del Profesor Martı ´n Lagos, s/n, 28040 Madrid, Spain 7 Hospital de Jae ´n, Avda. del Eje ´rcito Espan ˜ol, n8 10, 23007 Jae ´n, Spain 8 Hospital Juan Ramo ´n Jime ´nez, Ronda Exterior Norte s/n, 21005 Huelva, Spain 9 Hospital Universitario Carlos Haya, Av. de Carlos Haya, s/n, 29010 Ma ´laga, Spain 10 Complejo Universitario Hospital de Navarra, Calle Irunlarrea, 3, 31008 Pamplona, Spain 11 Hospital de Jerez, Ronda de Circunvalacio ´ n s/n, 11407 Ca ´diz, Spain 12 Hospital Universitario de Canarias, Carretera de Ofra, s/n, 38320 Santa Cruz de Tenerife, Spain 13 Complejo Universitario Asistencial de Leo ´n, C/Altos de Nava, s/n, Leo ´n, Spain 14 Hospital Universitario, 12 de Octubre, Avenida de Co ´rdoba, s/n, 28041 Madrid, Spain 15 Hospital Costa del Sol, Autovia A-7, Km 187, 29603 Marbella, Spain 16 Hospital Nuestra Sen ˜ora De Valme, Av. de Bellavista, s/n, 41014 Seville, Spain 17 Hospital Universitario Puerta del Mar, Av. Ana de Viya, 21, 11009 Ca ´diz, Spain 18 Hospital Ramo ´ n y Cajal, Ctra. de Colmenar Viejo, km. 9,100, 28034 Madrid, Spain 19 Clı ´nica Benidorm, Av. Alfonso Puchades, 03501 Benidorm, Spain 20 Hospital Universitario Virgen del Rocı ´o, Av. Manuel Siurot, s/n, 41013 Seville, Spain 123 Clin Transl Oncol https://doi.org/10.1007/s12094-017-1797-9