Meta-analyses of visceral versus non-visceral metastatic hormone receptor-positive breast cancer treated by endocrine monotherapies

• Published in: NPJ breast cancer Vol. 7; no. 1; p. 11
• Main Authors: Robertson, John F. R., Di Leo, Angelo, Johnston, Stephen, Chia, Stephen, Bliss, Judith M., Paridaens, Robert J., Lichfield, Jasmine, Bradbury, Ian, Campbell, Christine
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 12.02.2021; Nature Publishing Group; Nature Portfolio
• Subjects: 692/4028/67/1059; 692/4028/67/322; Biomedical and Life Sciences; Biomedicine; Breast cancer; Cancer Research; Cell Biology; Clinical outcomes; Human Genetics; Meta-analysis; Metastasis; Oncology
• ISSN: 2374-4677; 2374-4677
• DOI: 10.1038/s41523-021-00222-y

Endocrine therapy (ET) is recommended as first-line therapy for the majority of patients with hormone receptor-positive (HR+), human epidermal growth factor 2-negative advanced breast cancer (ABC); however, the efficacy of ET in patients with visceral metastases (VM) versus patients whose disease is limited to non-visceral metastases (non-VM) is debated. Meta-analyses including available data from randomised controlled trials of first- and second-line endocrine monotherapies for patients with HR+ ABC were performed to address this question. In one and two-stage meta-analyses, progression-free survival (PFS), overall survival (OS), clinical benefit rate (CBR) and duration of clinical benefit (DoCB) outcomes were analysed. In the first-line meta-analysis (seven trials; n  = 1988) tamoxifen and fulvestrant significantly improved PFS, OS and CBR for patients with non-VM versus those whose disease included VM. The most substantial hazard ratios were observed for fulvestrant 500 mg; 0.56 (95% confidence interval [CI] 0.45−0.70) and 0.55 (95% CI 0.42−0.72) for PFS and OS, respectively. In the second-line meta-analysis (seven trials; n  = 2324), all ET combined was more effective (in terms of PFS, OS and DoCB) for non-VM versus VM. In both meta-analyses, patients with non-liver VM had better clinical outcomes than patients with liver VM for all types of ET. Patients whose disease included non-VM sites had better clinical outcomes with endocrine monotherapy compared with patients whose disease included VM. These findings may facilitate better informed treatment decision-making.