Clinicopathologic and outcome characteristics of breast cancer with liver metastases (BCLM): a population study of the SEER database and a registry analysis of 1728 women

Abstract Background Breast cancer patients generally have a worse prognosis in presence of liver metastasis. The purpose of this study was to evaluate the risk factors and prognosis of breast cancer patients with liver metastases (BCLM). Methods Data on 311,573 breast cancer patients from the Surveillance, Epidemiology, and End Results (SEER) database diagnosed 2010 to 2016 and 1728 BCLM patients from Fudan University Shanghai Cancer Center (FUSCC) were analyzed for further exploration. We extracted the clinicopathological characteristics for analysis by two independent authors. Logistic regression was used to identify factors associated with the risk of liver metastases. Survival analysis was completed using Cox proportional hazards regression model and Kaplan-Meier analysis. Results Young age, invasive ductal carcinoma, higher pathological grade, and subtype of triple-negative and human epidermal growth factor receptor 2 positive (HER2+), were associated with increased risk of the liver metastases. The median overall survival (OS) after BCLM diagnosis was 20.0 months in the SEER database and 27.3 months in the FUSCC dataset. We observed that hormone receptor-positive (HR+)/HER2+ patients had the longest median OS 38.0 for SEER vs. 34.0months for FUSCC), whereas triple-negative breast cancer had the poorest OS (9.0 vs. 15.6 months) in both SEER and FUSCC. According to the results from the FUSCC, the subtype of HR+/HER2+ (hazard ratio (HR)=2.62; 95% confidence interval (CI)= 1.88-3.66; P<0.001) and HR-/HER2+ (HR=3.43; 95% CI=2.28-5.15; P<0.001) were associated with a significantly increased death risk in comparison with subtype of HR+/HER2-, if the patients did not receive HER2-targeted therapy. For BCLM patients who had received HER2-targeted therapy, however, HR+/HER2+ was an indicator for decreased death risk in comparison of the subtype of HR+/HER2- (HR=0.74; 95% CI=0.58-0.95; P<0.001). Conclusions BCLM is associated with poor survival, depending on HR/HER2-defined subtypes. Patients with HR+/HER2+ subtype displayed the longest median survival than HR+/HER2- and triple-negative BCLM patients. HER2-targeted therapy should be recommended for HER2+ BCLM patients.