Real-world data of fulvestrant as first-line treatment of postmenopausal women with estrogen receptor-positive metastatic breast cancer.

Goals of endocrine therapy for advanced breast cancer (ABC) include prolonging survival rates, maintaining the quality of life, and delaying the initiation of chemotherapy. We evaluated the effectiveness of fulvestrant as first-line in patients with estrogen receptor (ER)-positive ABC with relapse during or after adjuvant anti-estrogenic therapy in real-world settings. Retrospective, observational study involving 171 postmenopausal women with ER-positive ABC who received fulvestrant as first-line between January 2011 and May 2018 in Spanish hospitals. With a median follow-up of 31.4 months, the progression-free survival (PFS) with fulvestrant was 14.6 months. No differences were seen in the visceral metastatic (14.3 months) versus non-visceral (14.6 months) metastatic subgroup for PFS. Overall response rate and clinical benefit rate were 35.2% and 82.8%. Overall survival was 43.1 months. The duration of the clinical benefit was 19.2 months. Patients with ECOG performance status 0 at the start of treatment showed a significant greater clinical benefit rate and overall survival than with ECOG 1-2. Results in real-world settings are in concordance with randomized clinical trials. Fulvestrant continues to demonstrate clinical benefits in real-world settings and appears be well tolerated as first-line for the treatment of postmenopausal women with ER-positive ABC.

Correction to: Efficacy of fulvestrant in the treatment of postmenopausal women with endocrine-resistant advanced breast cancer in routine clinical practice.

A sentence under 'Results' heading in the Abstract section was published incorrectly. The correct sentence should read as follows.

Efficacy of fulvestrant in the treatment of postmenopausal women with endocrine-resistant advanced breast cancer in routine clinical practice.

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 anti-estrogen therapy in clinical practice, getting real-world data. MATERIALS AND METHODS: 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 frequently 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.