Surgical treatment of breast cancer liver metastases - A study from the Danish Liver Cancer Group.

BACKGROUND: The role of liver-directed therapy in breast cancer liver metastases (BCLM) remains controversial, and evidence guiding patient selection is limited. This study aimed to characterize patients undergoing local treatment for BCLM and identify prognostic factors associated with outcomes. METHODS: In this nationwide registry study, patients evaluated for liver resection or thermal ablation for BCLM between 2013 and 2023 were identified from the Danish Liver and Bile Duct Cancer Database. Clinicopathological data were collected retrospectively through medical record review. Overall survival (OS) and progression-free survival (PFS) were estimated using Kaplan-Meier analysis, and prognostic factors were assessed using multivariable Cox regression. RESULTS: Forty-six patients were included, of whom 45 underwent liver-directed treatment. Most had estrogen receptor-positive/HER2-negative disease (85%) and metachronous liver metastases (85%). Controlled extrahepatic disease was present in 70% of patients at the time of intervention. Median follow-up was 31 months. Median OS was 42 months, with a 5-year OS of 35% (95% CI 23-53%). Median PFS was 17.7 months, with a 5-year PFS of 10% (95% CI 4-25%). Four of 14 patients treated with curative intent remained alive and recurrence-free at the end of follow-up. There was no 90-day mortality. Increasing age was associated with worse OS (HR 1.06, p = 0.002), whereas bilobar involvement was associated with worse OS (HR 3.07, p = 0.017) and PFS (HR 4.60, p < 0.001). Controlled extrahepatic disease was not associated with either outcome, and survival did not differ between resection and ablation. CONCLUSIONS: Liver-directed treatment for BCLM appears safe and may be used in highly selected patients, although cure is uncommon. Bilobar disease and increasing age predicted poorer outcomes. Larger studies are needed to refine patient selection.