Combined trans-arterial embolisation and microwave ablation for the treatment of large unresectable hepatic metastases (>3 cm in maximal diameter).

Purpose: To assess the safety and efficacy of a two-step single-session procedure, combining transarterial embolization (TAE) and percutaneous microwave ablation (MWA), in the treatment of > 3 cm unresectable liver metastases. We also compared the final volume obtained by the two techniques (V _E-T ) and the expected ablation volume of the stand-alone MWA (V _T ).
Methods: From January 2015 to December 2017, 22 consecutive patients, with a total of 24 unresectable hepatic metastases >3 cm in diameter underwent a two-step single-session combined treatment of TAE and MWA. Follow-up computed tomography scans were performed at 1-, 3-, 6-, 12, and 24 months post-procedure. V _E-T as final ablation volume induced by the combined treatment (TAE-MWA), V _N as initial nodule volume, V _T as expected ablation volume of MWA treatment alone were evaluated and compared.
Results: Tumor dimensions ranged from 32 to 73 mm. Technical success was achieved in all treated tumors with no local tumor recurrence. Final ablation volumes ranged from 50 to 450 cm ³ and the short-axis diameter of the ablation zone ranged from 12 to 48 mm. The mean ΔV increment in the final ablation volume with respect to the stand-alone MWA was 196% (ranging from 25 cm ³ - 210 cm ³ ) ( p  < 0.05). The V _E-T mean was four times the V _N mean, while the V _T mean was about twice the V _N mean. No recurrence and only one case of post-embolization bleeding were observed.
Conclusions: This study demonstrated the safety and efficacy of a combined two-step single-session TAE-MWA treatment of unresectable hepatic metastases > 3 cm in diameter.