Hepatic resection for breast cancer liver metastases: Impact of intrinsic subtypes

Introduction: The role of surgery for breast cancer liver metastases (BCLM) remains controversial. This study aimed to analyze survival in patients treated with hepatectomy plus systemic therapy or systemic therapy alone for BCLM and to determine selection factors to guide surgical therapy. Materials and methods: Patients who underwent hepatectomy plus systemic therapy (n = 136) and systemic therapy alone for isolated BCLM (n = 763) were compared. Overall survival (OS) was analyzed after propensity score matching. Intrinsic subtypes were defined as: luminal A (estrogen receptor [ER]+ and/or progesterone receptor positive [PR]+, human epidermal growth factor receptor 2 [HER2]-), luminal B (ER and/or PR+, HER2+), HER2-enriched (ER and PR-, HER2+), and basal-like (ER, PR, HER2-). Results: After hepatectomy, independent predictors of poor OS were number and size of liver metastases, and intrinsic subtype (hazard ratios, 1.11, 1.16, and 4.28, respectively). Median OS was 75 and 81 months among patients with luminal B and HER2-enriched subtypes, compared with 17 and 53 months among patients with basal-like and luminal A subtypes (P < .001). Median progression-free survival (PFS) was 60 months with the HER2-enriched subtype, compared with 17, 16, and 5 months with luminal A, luminal B, and basal-like subtypes, respectively (P < .001). After propensity score matching, 5-year OS rates were 56% vs. 40% in the surgery vs. systemic therapy alone groups (P = .018). Conclusion: Surgical resection of BCLM yielded higher OS compared with systemic therapy alone and prolonged PFS among patients with the HER2-enriched subtype. These findings support the use of surgical therapy in appropriately selected patients, based on intrinsic subtypes. (C) 2020 Elsevier Ltd, BASO - The Association for Cancer Surgery, and the European Society of Surgical Oncology. All rights reserved.