Percutaneous microwave ablation for liver tumours adjacent to the marginal angle

This study was designed to describe the technical essentials of microwave ablation (MWA) for tumours adjacent to the liver marginal angle (LMA) and to determine the feasibility, safety and efficacy of this approach.

A total of 22 patients with primary or metastatic liver tumours adjacent to the LMA were enrolled. There were 19 small tumours (≤3 cm) and three larger tumours (>3 cm) with maximum diameters ranging from 0.7-2.7 cm (mean 1.7 ± 0.6 cm) and 4.7-6.6 cm (mean 5.4 ± 1.0 cm), respectively. For small tumours the entire acute angle was segmentally blocked utilising MWA. For larger tumours, the feeding arteries were initially blocked with ethanol before conformal ablation. Artificial ascites, real-time monitoring, small ethanol doses, colour Doppler flow imaging or contrast enhanced ultrasound guidance was used as an additional technique to assist with ablation. Contrast imaging was performed to evaluate the ablative efficacy. Treatment responses, local tumour progression (LTP) and complications were recorded.

All patients achieved a complete response. LTP was identified in two cases (9.1%) during the 4.5 month median follow-up period (range 2-29 months). A total of five additional sessions were performed, and secondary effectiveness was achieved in patients with LTP. No major complications were observed.

Percutaneous MWA is a new promising technique for tumours adjacent to the LMA, especially in cases with small tumours. Technical improvements to this procedure are expected to improve the results for large tumours abutting the LMA.