Incidence and Survival Outcomes of Breast Cancer with Synchronous Hepatic Metastases: A Population-Based Study

Background: Little is known about the clinical features of breast cancer with synchronous hepatic metastases (BCSHM). In this retrospective study, we aimed to feature the incidence and survival outcome of BCSHM. Methods: Data from the 2016 SEER*Stat database (version 8.3.2) was used. The effect of patient and tumor characteristics on the odds of developing of BCSHM was analyzed. Survival was investigated using Kaplan-Meier and Cox regression analyses. A competing risk model was also applied to further investigate cancer-specific survival. Results: Of 240911 patients with breast cancer, we identified 3468 patients (1.44%) with BCSHM. Tumor subtypes distribution of BCSHM were 45.3% HR+/HER2-, 12.2% HR+/HER2(+), 7.83% HR-/HER2(+) and 15.0% triple-negative subtype. The median OS of the entire cohort was 14 months, and only about 13.5% of patients survived at 3 years. Median survival was significantly shorter in triple-negative cohort (8 months) and gradually increased in HR+/HER2(-) (19 months), HR-/HER2(+) (22 months) and HR+/HER2(+) (33 months) cohorts (P<0.05). Patients BCSHM were more likely to be young age (odds ratio [OR] 1.4, 95% CI 1.0-2.0), black race (OR 1.13, 95% CI 1.11-1.37), higher tumor grade (OR 3.58, 95% CI 2.29-5.59), unmarried status (OR 3.5, 95% CI 2.1-5.7), HR-/HER2(+) (OR 4.07, 95% CI 3.56-4.67), HR+/HER2(+) (OR 2.5, 95% CI 2.24-2.80) and triple-negative subtypes (OR 1.64, 95% CI 1.44-1.86). Poor prognostic factors were the aged (hazard ratio 3.75, 95% CI 3.56-4.67), black race (hazard ratio 1.17, 95% CI 1.03-1.31), triple-negative subtype (hazard ratio 2.23, 95% CI 1.95-2.56) and higher grade (hazard ratio 1.32, 95% CI 1.03-1.68). Conclusion: In conclusion, patients with BCSHM had a poor survival, and only 13.5% of them were alive more than 3 years. Young patients with HER2(+) tumors had higher risk for developing BCSHM, but with better prognosis.