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 (VE-T) and the expected ablation volume of the stand-alone MWA (VT). 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. VE-T as final ablation volume induced by the combined treatment (TAE-MWA), VN as initial nodule volume, VT 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 cm3 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 cm3 − 210 cm3) (p < 0.05). The VE-T mean was four times the VN mean, while the VT mean was about twice the VN 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.