In a patient with colorectal cancer and multiple liver metastases, should hepatic artery chemo‑infusion, Y‑90 radioembolization (transarterial radioembolization), or percutaneous ablation be used as the primary locoregional therapy?

Treatment Selection for Multiple Colorectal Liver Metastases

For patients with multiple unresectable colorectal liver metastases, systemic chemotherapy remains the vital first-line therapy, with percutaneous ablation combined with systemic therapy offering survival benefit when feasible, while hepatic artery infusion chemotherapy should be considered for conversion to resectability, and TARE reserved specifically as salvage therapy after failure of multiple systemic chemotherapy lines. 1

Treatment Algorithm Based on Clinical Scenario

First-Line Approach: Systemic Therapy Foundation

Systemic chemotherapy is the cornerstone for multifocal disease and must be initiated first. 1 The evidence clearly establishes FOLFOXIRI as superior to FOLFIRI, particularly when combined with biologics like bevacizumab or cetuximab (for RAS-wild-type, left-sided primaries). 1, 2 This approach can convert 9-40% of initially unresectable metastases to resectable status. 3

When to Add Locoregional Therapy

Percutaneous ablation combined with systemic therapy should be your primary locoregional choice when technically feasible. The CLOCC phase II trial demonstrated clear survival benefit: median overall survival of 45.6 months versus 40.5 months for systemic therapy alone, with progression-free survival of 16.8 months versus 9.9 months. 1 This applies to:

• Limited number of lesions (<5 metastases ideally)
• Smaller tumors (<3 cm optimal, up to 5 cm with combination approaches)
• Adequate ablation margin >5 mm achievable 1

Hepatic Artery Infusion Chemotherapy: The Conversion Strategy

Use HAI when conversion to resectability is the goal in patients with liver-dominant or liver-only disease who have not achieved adequate response to systemic therapy. 1 The evidence shows:

• Can convert unresectable disease to resectable (possibly improving survival) 1
• Achieves higher drug concentration within the liver 1
• The OPTILIV phase II study demonstrated 29.7% conversion to R0-R1 resection in heavily pre-treated patients with median of 10 metastases 2

Critical caveat: HAI involves procedural complexity and potential liver toxicity, and should be performed before TARE if both are being considered, as HAI becomes technically difficult post-TARE. 4

TARE: Reserve for Salvage Only

TARE should be reserved exclusively for chemo-refractory disease that has failed multiple prior systemic chemotherapy options. 1 The evidence is definitive:

• Provides no additional survival benefit when added to first-line systemic chemotherapy 1
• Three randomized studies with >1000 patients failed to show overall survival benefit when added to best systemic treatment 2
• However, TARE has demonstrated survival benefit specifically in salvage settings after multiple chemotherapy failures 1

One exception: Subgroup analysis suggests potential benefit for right-sided colon primary tumors (22 versus 17.1 months survival) when combined with systemic therapy. 1

Combination Locoregional Therapy

For larger lesions (3-5 cm), combine TACE/TAE with ablation for excellent local tumor control. 1 One prospective study demonstrated good tumor control with chemoembolization plus RFA. 1

Key Decision Points

Assess resectability first: If ≤5 metastases with adequate liver remnant, pursue conversion strategy with aggressive systemic therapy ± HAI. 1

For truly unresectable multifocal disease:

1. Start FOLFOXIRI + biologic (bevacizumab for right-sided/RAS-mutant; cetuximab for left-sided RAS-wild-type) 2
2. Add ablation if limited lesions become technically feasible 1
3. Consider HAI if liver-dominant and inadequate systemic response 1
4. Reserve TARE only after multiple chemotherapy line failures 1

Common Pitfalls to Avoid

• Do not use TARE as first-line locoregional therapy – the evidence shows no benefit and it may preclude subsequent HAI 1, 4
• Do not use HAI for solitary disease – it's not conventionally indicated 1
• Do not delay systemic therapy to pursue locoregional options first in multifocal disease 1
• Do not assume all locoregional therapies are equivalent – ablation has the strongest survival data when combined with systemic therapy 1

The 2022 ACR Appropriateness Criteria 1 and 2023 ESMO guidelines 2 provide the most current framework, with the CLOCC trial 1 offering the highest-quality evidence for survival benefit with early aggressive local treatment using ablation plus systemic therapy in the unresectable setting.