A Population-Based Study on Liver Metastases in Women with Newly Diagnosed Breast Cancer

Background: Population-based estimates for prognosis among patients with liver metastases in newly diagnosed breast cancer are not generally available. Methods: Within the Surveillance, Epidemiology and End Results (SEER) database, we identified 298,370 patients with breast cancer and 4,285 patients diagnosed with initial liver metastases between 2010 and 2014. Data were stratified according to subtype, age, and race. Multivariate logistic and Cox regression were used to identify predictors for the presence of initial liver metastases and prognostic factors, respectively. Kaplan-Meier procedure was used for survival analysis. Results: A total of 4,285 patients with initial liver metastases (1.4% of the entire cohort, 29.6% of the subset with metastatic disease) were identified. Patients with hormone receptor (HR)-negative human epidermal growth factor receptor 2 (HER2)-positive (4.4% of entire cohort, 52.5% of patients with metastatic disease to any distant site) and HR-positive HER2-positive (2.8% of entire cohort, 40.4% of patients with metastatic disease to any distant site) subtypes had highest incidence proportions. The median survival of patients with liver metastases in the entire cohort was 15.0 months. Patients with HR-positive HER2-positive subtype showed the longest median survival (31.0 months); however, patients with triple-negative subtype showed the shortest median survival (8.0 months). Conclusions: Our findings provide population-based estimates of epidemiologic characteristics and prognosis in breast cancer patients diagnosed with initial liver metastases. Impact: This study lends support to the diagnosis of the liver among patients at high risk of liver metastases, including those with HER2-positive and other systemic metastases.