For breast cancer liver metastases, it is still uncertain whether liver resection or ablation is beneficial. The study's objectives were to evaluate surgical vs systemic treatment regimens and determine survival following isolated breast cancer liver metastases in national cohorts. Surgery for breast cancer liver metastases is safe and may improve survival in certain patients, but to prevent selection bias, prospective trials are necessary. Metastases to the liver from breast cancer National Breast Cancer RegisterNBCRMetastatic Breast Cancer Swedish Registry for Liver and Bile Duct Cancer.