Purpose: To compare the ablation area produced by a single application of a microwave ablation (MWA) system, equipped with a miniaturized device on the tip of the antenna entrapping reflected microwaves, with that produced by an internally cooled radiofrequency ablation (RFA) system.
Materials and methods: Forty patients with primary or secondary inoperable liver tumors, selected to undergo percutaneous thermal ablation, were randomly assigned to MWA or RFA procedure. The ablation areas produced by a single application of MWA (ablation time 10 min) or RFA (ablation time 12 min) energy were assessed by contrast-enhanced ultrasonography immediately after the end of the procedure. The long- and short-axis diameters of the ablation areas were measured and compared using Student t test.
Results: Long- and short-axis diameters of the ablation areas produced by MWA were significantly greater than those produced by RFA: 48.5 ± 6.7 versus 30.9 ± 1.1 mm (p < 0.0001) and 38.5 ± 4.6 versus 26.8 ± 2.9 mm (p < 0.0001), respectively.
Conclusion: The MWA system can achieve significantly larger ablation areas than the internally cooled RFA system. Broader randomized trials are strongly warranted to investigate whether such superiority can translate into better long-term outcome of the ablation procedure.