Thermal Ablation of Breast Cancer Liver Metastases Is Associated with Durable Local Control and Chemotherapy-Free Intervals in Selected Patients

Background/Objectives: In selected patients with oligometastatic breast cancer liver metastases (BCLM), liver-directed therapies may provide durable local control and may delay escalation of systemic therapy. This study reports a single-center experience of percutaneous thermal ablation (radiofrequency ablation [RFA] or microwave ablation [MWA]) for BCLM, including conventional oncologic outcomes and therapy-based endpoints. Methods: This retrospective cohort included consecutive patients treated with percutaneous ablation for BCLM following multidisciplinary team approval between 2005 and 2025. Outcomes were defined according to the Society of Interventional Oncology (SIO) and DATECAN consensus terminology. Lesion-level outcomes included primary/secondary technique efficacy and local tumor progression-free survival (LTPFS). Patient-level outcomes included progression-free survival (PFS), overall survival (OS), time to change in systemic therapy (TTCST) and chemotherapy-free survival (CFS). Kaplan–Meier and Cox regression analyses were performed. Results: Forty-six patients underwent 58 ablation sessions treating 80 metastases (median tumor size 19 mm, interquartile range [IQR] 13–27 mm). Primary and secondary technique efficacy were 95% (76/80) and 99% (79/80), respectively. Major complications occurred in 2/58 sessions (3%). Local tumor progression occurred in 16/79 tumors (20%) after a median follow-up of 28 months; LTPFS rates at 1, 3 and 5 years were 84%, 75% and 75%, respectively. Median OS was 44 months (1-, 3- and 5-year OS 94%, 58%, and 40%), and median PFS was 8.3 months. Median TTCST was 13 months, and median CFS was 16.4 months. Triple-negative disease was associated with worse LTPFS and shorter CFS. Oligopersistent disease was associated with improved PFS compared with oligoprogression. Conclusions: In this selected cohort, percutaneous thermal ablation for BCLM achieved high technique efficacy, durable local control and low major complication rates. Therapy-based endpoints suggest a clinically meaningful interval without systemic therapy escalation in appropriately selected patients, although comparative studies are needed to quantify the incremental benefit.