What is the best treatment approach for a single liver metastasis (mets) in breast cancer?

Treatment of Single Liver Metastasis in Breast Cancer

For a single liver metastasis from breast cancer, surgical resection combined with systemic therapy offers the best survival outcomes in carefully selected patients, with 5-year survival rates of 53% compared to only 14% with chemotherapy alone. 1

Immediate Referral and Evaluation

• Refer immediately to a tertiary hepatobiliary center before initiating chemotherapy to allow surgeons to visualize and plan resection of all metastatic sites, as chemotherapy-responsive lesions become difficult to locate radiologically after treatment begins. 2, 3
• Prolonged chemotherapy before surgical evaluation causes hepatic steatosis and hepatocyte damage, compromising post-resection liver function and surgical candidacy. 2, 3
• All cases must be discussed in a multidisciplinary tumor board with hepatobiliary surgery, medical oncology, and radiology expertise. 2, 3

Patient Selection Criteria for Surgical Resection

Surgery should be offered if ALL of the following criteria are met:

• Complete resection is technically feasible with ability to preserve at least 30% of functional liver volume (up to 70% can be safely resected in normal liver). 2, 3
• Good performance status (Karnofsky score adequate for major surgery). 3
• No uncontrolled extrahepatic disease, with the exception of isolated bone metastases controllable with radiation or isolated pulmonary metastases. 2, 3
• No disease progression on systemic chemotherapy, indicating chemotherapy-responsive biology. 2
• Normal baseline liver function without significant chemotherapy-induced liver damage. 2, 3

Treatment Algorithm by Surgical Candidacy

For Surgical Candidates (Single Resectable Metastasis)

• Hepatic resection is the preferred approach, offering median overall survival of 38.1 months (range 10.9-57 months) compared to 17.9 months with chemotherapy alone. 4
• Survival rates with surgery: 90% at 1 year, 65.9% at 3 years, and 53% at 5 years versus chemotherapy alone (53%, 24%, and 14% respectively). 1
• Surgery should be considered adjuvant to systemic therapy rather than primary treatment—this differs fundamentally from colorectal liver metastases where surgery is primary. 2, 3
• Combine with neoadjuvant and adjuvant chemotherapy plus hormonal therapy based on receptor status. 2, 3

For Non-Surgical Candidates or Small Lesions

• Radiofrequency ablation (RFA) or microwave ablation (MWA) are effective alternatives for tumors <4 cm, offering less invasive options with fewer contraindications and complications than surgery. 5, 6
• RFA achieves survival rates of 83% at 1 year, 49% at 3 years, and 35% at 5 years—superior to chemotherapy alone but inferior to surgical resection. 1
• Multi-probe stereotactic RFA with intraoperative image fusion can treat larger and multiple tumors in a single session. 5
• Consider hepatic arterial therapy (median survival 27.9 months) for liver-dominant disease not amenable to resection or ablation. 4

Critical Timing Considerations

The oncologist's tendency to continue chemotherapy until metastases disappear or stop responding must be abandoned for two essential reasons: 2

1. Surgeons need to visualize all metastases before chemotherapy makes them radiologically occult
2. Extended chemotherapy damages liver parenchyma, reducing the quality of residual liver after resection

Staging Laparoscopy Protocol

• Perform staging laparoscopy with intraoperative ultrasound (SL/IOUS) before definitive surgery to identify extensive or untreatable disease. 6
• SL/IOUS prevents unnecessary laparotomy in approximately 50% of patients initially considered surgical candidates. 6
• This should be considered standard of care before any surgical intervention for breast cancer liver metastases. 6

Role of Systemic Therapy

• Systemic chemotherapy and/or hormonal therapy remains the foundation of treatment for all metastatic breast cancer, with local therapies serving as adjuncts in selected patients. 3, 4
• HER2-positive patients should receive targeted therapy, which may improve outcomes even with metastatic disease. 3, 7
• Hormone receptor-positive patients require appropriate endocrine therapy. 3

Common Pitfalls to Avoid

• Delaying surgical referral until after chemotherapy initiation—this is the single most critical error, as it eliminates the window for optimal surgical planning. 2, 3
• Assuming all metastatic breast cancer is incurable and denying evaluation for local therapy—approximately 50% of stage IV patients develop liver metastases, and selected patients achieve long-term survival with resection. 3, 8
• Applying colorectal liver metastasis protocols directly to breast cancer—the treatment paradigm is reversed, with systemic therapy primary and surgery adjuvant. 2, 3
• Failing to obtain multidisciplinary input before treatment decisions, particularly in centers without high-volume hepatobiliary surgery experience. 2, 3

Expected Outcomes Without Intervention

• Median survival for untreated liver metastases ranges from 3-15 months depending on cancer subtype and performance status. 3, 7
• The presence of liver metastases significantly reduces survival compared to other single-site metastases. 3