Thermal ablation versus surgical resection for colorectal liver metastases: a Grading of Recommendations, Assessment, Development, and Evaluation (GRADE)-assessed systematic review, survival meta-analysis, and meta-regression.

[BACKGROUND] Colorectal cancer is a leading cause of cancer-related mortality worldwide, with liver metastases occurring in nearly 50% of patients during the disease course. This study aims to compare survival outcomes, including overall survival (OS) and disease-free survival (DFS), and tumor recurrence risks between thermal ablation and surgical resection for colorectal liver metastases (CRLMs), incorporating recent randomized trial data to provide updated recommendations.

[METHODS] Searches were performed across PubMed, Embase, and Web of Science to identify relevant studies comparing thermal ablation with surgical resection for CRLM. Meta-analyses were performed using random-effects models for pooled hazard ratios (HRs) and risk ratios (RRs) with corresponding 95% confidence intervals (CIs). Heterogeneity was assessed using I statistics, and publication bias was evaluated using funnel plot asymmetry and Egger's regression test.

[RESULTS] A total of 29 studies involving 5,719 patients were included in the analysis. Thermal ablation was associated with significantly worse OS compared to surgical resection (HR =1.56; 95% CI: 1.25-1.94). Subgroup analyses revealed that radiofrequency ablation (RFA) notably increased mortality risk (HR =1.63; 95% CI: 1.26-2.51), whereas microwave ablation (MWA) demonstrated non-inferiority to surgical resection. For tumors <3 cm, no significant survival difference was observed between the interventions, but for lesions ≥3 cm, surgical resection showed improved survival (HR =1.49; 95% CI: 1.16-1.91). DFS analysis showed a higher recurrence risk with thermal ablation (HR =1.93; 95% CI: 1.45-2.57). Local tumor recurrence was over three times more frequent following ablation compared to resection (RR =3.03; 95% CI: 1.99-4.61), while distal recurrence rates did not differ significantly. Heterogeneity was substantial for survival outcomes (I=68.0%) and recurrence outcomes (I=74.9%).

[CONCLUSIONS] Surgical resection remains superior to thermal ablation in terms of OS and DFS, particularly for larger lesions (>3 cm). While thermal ablation, especially MWA, offers a promising alternative for smaller lesions, its increased risk of local recurrence warrants careful patient selection and precise procedural execution. These findings underscore the need for personalized, lesion-specific approaches to CRLM management, integrating advancements in ablation technology and hybrid surgical-ablation strategies.