Thermal ablation versus liver resection for small colorectal liver metastases (≤ 3 cm): a systematic review and meta-analysis of randomized and propensity score-matched studies.

BACKGROUND

The optimal local treatment for small colorectal liver metastases (CRLM) remains debated. We compared thermal ablation with liver resection for CRLM ≤ 3 cm using data from randomized and propensity score-matched studies.

METHODS

PubMed, Embase, and Web of Science were searched from inception to April 30, 2026. Eligible studies included randomized or propensity score-matched comparisons of thermal ablation with liver resection in patients with CRLM ≤ 3 cm and reported survival or complication outcomes. Hazard ratios (HRs) were pooled for overall survival (OS) and disease-free/progression-free survival (DFS/PFS). Risk ratios (RRs) were pooled for overall and major complications. Risk of bias was assessed using RoB 2 and ROBINS-I. Certainty of evidence was assessed using GRADE.

RESULTS

Seven studies were included: one randomized controlled trial and six propensity score-matched or target trial emulation studies. Thermal ablation was not associated with statistically significant differences in OS (HR 0.92, 95% CI 0.79-1.07; I2 = 25%) or DFS/PFS (HR 1.01, 95% CI 0.90-1.14; I2 = 34%) compared with liver resection. Leave-one-out analysis demonstrated stable survival estimates. Thermal ablation was associated with lower risks of overall complications (RR 0.38, 95% CI 0.28-0.52; I2 = 0%) and major complications (RR 0.35, 95% CI 0.22-0.55; I2 = 0%).

CONCLUSIONS

In selected patients with CRLM ≤ 3 cm, thermal ablation was not associated with statistically significant differences in OS or DFS/PFS compared with liver resection and was associated with lower complication rates. Treatment selection should remain individualized within multidisciplinary care.