Liver Metastases-directed Therapy in the Management of Oligometastatic Breast Cancer

Standard of care for metastatic breast cancer is systemic therapy, but attention has been focused on local treatments in patients with oligometastatic disease. We treated 72 patients with surgery, stereotactic body radiation therapy, or thermal ablation on liver oligometastases, demonstrating durable disease control. Tumor biology, prior treatment, and disease extent are useful to add metastasis-directed therapy to standard therapy. Introduction: In the context of metastatic breast cancer, dissemination to the liver is a frequent occurrence. We aimed to evaluate the outcome and toxicity of metastatic breast cancer with liver oligometastases treated with metastases-directed therapies (MDTs), including surgery, stereotactic body radiation therapy, or thermal ablation (radiofrequency or microwaves). Patients and Methods: We included patients with diagnosis of 1 to 5 liver metastases. Selection criteria included also age > 18 years; Eastern Cooperative Oncology Group performance status 0 to 2; absence of extra-hepatic disease or other controlled metastatic sites. Endpoints were liver progression-free survival (LPFS), progression-free survival (PFS), and overall survival. Results: A total of 72 patients were included. Previous local treatments were performed in 13 (18.1%) patients, whereas systemic therapy was used in 81.9% of cases. Treatment of choice was stereotactic body radiation therapy in 54 (75%) patients followed by surgery (13 patients; 18%) and thermal ablation (5 patients; 7%). With a median follow-up of 26.2 months, LPFS at 1 and 2 years was 52.4% and 38.8%, respectively. The number of metastases predicted LPFS (hazard ratio [HR], 1.70; P = .004). Rates of PFS were 38.7% and 22% at 1 and 2 years, respectively. Systemic therapy before MDT (HR, 2.89; P = .016) was correlated with PFS. Overall survival at 1 and 2 years was 95.5% and 76.9%, respectively. Human epidermal growth factor receptor 2 status correlated with survival (HR, 1.82; P = .010). Conclusion: Combination of systemic therapy with liver MDT in oligometastatic breast cancer results in durable disease control in a significant proportion of patients. Tumor biology, prior treatment, and extent of disease may be useful to guide the decision to add MDT to standard therapy. (C) 2020 Elsevier Inc. All rights reserved.