Breast cancer liver metastases: systematic review and time to event metanalysis with comparison between available treatments
Session type: Proffered paper sessions
Theme: Diagnosis and therapy
Breast cancer is the most commonly diagnosed cancer in women, with 1.67 million cases and 522,000 deaths estimated in 2012. About 25-40% of the cases will eventually develop metastases and in more than half the site involved is the liver. The current standard treatment for breast cancer liver metastases is systemic chemotherapy and/or hormonal therapy, with a median survival time of 19 to 26 months. Local therapeutic strategies have gained increasing consideration in the treatment of BCLM in the past few years.
We sought to compare the outcomes in terms of survival of the available systemic and local treatments for metastatic breast cancer to the liver, focusing on surgical resection, radiofrequency ablation and systemic therapy. Our review strategy was a time-to-event data synthesis, reconstructing individual patient data from published Kaplan-Meier survival curves, using a newly developed algorithm published by Guyot et al. for a total of 1246 patients for the surgical group, 203 for the ablation group and 1487 for the chemotherapy group.
Analysis of the reconstructed data demonstrated survival rates at 1, 3 and 5 years of 91%, 65% and 52% respectively for the surgical group; 82%, 56% and 43% for the ablation group and 52%, 23% and 12% for the chemotherapy group.
In conclusion, local therapies such as liver resection and radiofrequency ablation are safe and effective techniques for BCLM treatment, giving better results when compared to palliative chemotherapy/hormonal therapy, especially in patients with metastatic disease confined to the liver. The data available in literature support the surgical approach over the remaining treatments in terms of overall survival, but randomized controlled trials are necessary to identify the best approach to oligometastatic breast cancer, in particular to liver metastases.