Breast cancer liver metastases: systematic review and time to event meta-analysis with comparison between available treatments.

INTRODUCTION:The current gold standard treatment for breast cancer liver metastases (BCLM) is systemic chemotherapy and/or hormonal therapy. Nonetheless, greater consideration has been given to local therapeutic strategies in recent years. We sought to compare survival outcomes for available systemic and local treatments for BCLM, specifically surgical resection and radiofrequency ablation. METHODS:A review of the PubMed (MEDLINE), Embase and Cochrane Library databases was conducted. Data from included studies were extracted and subjected to time-to-event data synthesis, algorithmically reconstructing individual patient-level data from published Kaplan-Meier survival curves. FINDINGS:A total of 54 studies were included, comprising data for 5,430 patients (surgery, n=2,063; ablation, n=305; chemotherapy, n=3,062). Analysis of the reconstructed data demonstrated survival rates at 1, 3 and 5 years of 90%, 65.9% and 53%, respectively, for the surgical group, 83%, 49% and 35% for the ablation group and 53%, 24% and 14% for the chemotherapy group (p<0.0001). CONCLUSION:Local therapeutic interventions such as liver resection and radiofrequency ablation are effective treatments for BCLM, particularly in patients with metastatic disease localised to the liver. Although the data from this review support surgical resection for BCLM, further prospective studies for managing oligometastatic breast cancer disease are required.