Abstract

Percutaneous radiofrequency ablation (RFA) is widely used in colorectal liver metastases (CRLM) when surgical resection is not feasible. Computed tomography (CT) and ultrasound (US) are the two main guidance modalities. Comparative data are limited. This review compared their reported outcomes. Four databases were searched (PubMed, Ovid MEDLINE and Embase, Web of Science, and Google Scholar) following PRISMA 2020. The Newcastle-Ottawa Scale was used for risk of bias. GRADE was used for certainty of evidence. Twenty studies met inclusion criteria. Of these, 8 were CT-guided, 11 were US-guided, and 1 was comparative. All were observational. Technical success was 86.7% to 100% (CT) and 63% to 98.9% (US). Most studies exceeded 90%. Local tumor progression (LTP) was 12.8% to 50.7% (CT) and 7.0% to 39.1% (US). Five-year overall survival was 27% to 41.8% (CT) and 24% to 74.8% (US). The higher upper US range reflected studies of small solitary lesions only. The single propensity-matched comparison reported lower 1-year LTP with US guidance (15.9% vs. 24.2%, p = 0.039). Overall survival did not differ between arms. Complications were low in both groups. Certainty of evidence was very low across all outcomes. CT and US guidance produce overlapping outcomes in percutaneous RFA for CRLM. The available evidence does not establish the superiority of either modality. Prospective comparative trials are needed.

Key words: Radiofrequency ablation, colorectal liver metastases, computed tomography, ultrasound guidance, systematic review, percutaneous ablation