Local treatment for liver oligometastases in breast cancer patients: identification of prognostic factors and exploration of appropriate treatment strategy

BACKGROUND: The role of local treatment for liver oligometastases in breast cancer patients has been controversial. The aim of the study was to evaluate the prognostic factors for overall survival (OS) and progression-free survival (PFS) after hepatic local treatment and to explore appropriate therapy strategy in breast cancer patients with liver oligometastases. METHODS: A cohort of 91 patients with oligometastatic liver lesions identified from around 34,000 breast cancer patients between 2002 and 2018 were retrospectively reviewed. We collected and analyzed their clinicopathologic and outcome data. RESULTS: With a median follow up of 20.6 months [standard deviations (SD): 35.4], median OS and median PFS were 75.1 months [95% confidence interval (CI): 14.3–135.9 months] and 7.4 months (95% CI: 4.4–10.4 months), respectively. N3 stage, triple-negative breast cancer (TNBC) subtype, progressive disease (PD) after preoperative systemic therapy and older age of operation were associated with worse OS and PFS while postoperative systemic therapy alone, preoperative [partial response (PR)/stable disease (SD)] combined with postoperative systemic therapy indicated improved OS and PFS by univariate analysis. On multivariate analysis, N3 stage [hazard ratios (HR) 23.567; 95% CI: 1.751–317.277; P=0.017] and TNBC subtype (HR 10.758; 95% CI: 1.120–103.301; P=0.040) were related to worse OS. Likewise, N3 stage (HR 3.324; 95% CI 1.604–6.890; P=0.001) and TNBC subtype (HR 3.134; 95% CI: 1.015–9.674; P=0.047) remained associated with worse PFS. The postoperative mortality and morbidity were 0% and 1.099%, respectively. CONCLUSIONS: In well-selected patients, local treatment of breast cancer liver oligometastases is safe and achieves relatively long OS, except patients with advanced N stage or aggressive subtype. Postoperative systemic treatment and effective preoperative systemic therapy combined with postoperative systemic therapy are the recommended treatment strategies.