Purpose: The purpose of this study was to estimate the overall survival (OS) in real-world clinical practice in patients with metastatic breast cancer (MBC) and visceral metastases (liver or lung) treated in the third-line setting with eribulin, gemcitabine or capecitabine overall and in the major clinical categories of MBC (TNBC, HR+/HER2-, and HER2+).
Methods: A retrospective, observational study was conducted with de-identified patient electronic health records from the Cancer Treatment Centers of America (CTCA). Patients with a diagnosis of metastatic breast with lung or liver metastases, and treated with eribulin, gemcitabine, or capecitabine as third-line therapy were included in the analysis. Landmark survival was calculated as percentage of patients alive at 6, 12, 24, and 36 months. Overall survival was compared between treatment arms within TNBC and HR+/HER2- using log-rank analysis. Cox regression analyses was performed to estimate hazard ratios for comparison of treatments within TNBC and HR+/HER2- subtype.
Results: 443 patients with liver or lung metastases received third-line therapy with eribulin (n = 229), gemcitabine (n = 134), or capecitabine (n = 80). Eribulin patients had a higher percentage of patients alive at all landmark timepoints vs. gemcitabine, and a higher percentage of patients alive until 36 months vs. capecitabine. Median survival times showed that overall, and within the TNBC and HR+/HER2- subtype, patients receiving eribulin had a numerically higher median overall survival.
Conclusions: This real-world evidence study is consistent with randomized clinical trial data and demonstrates consistency of eribulin effectiveness in MBC patients with lung or liver metastases overall and in TNBC and HR+/HER2- disease.
Keywords: Eribulin; Metastatic breast cancer; Overall survival; Real-world evidence; Visceral metastases.