Intra-operative microwave ablation of liver malignancies with tumour permittivity feedback control: A prospective ablate and resect study

Abstract

Background Tumour permittivity feedback control is a novel method for microwave ablation (MWA) that theoretically allows for larger, more predictable ablations. This prospective case series evaluates the feasibility and efficacy of MWA of liver malignancies using a device with tumour permittivity feedback control. Methods Ten consecutive patients initially determined to be candidates for surgical resection of a liver malignancy underwent intra-operative MWA with tumour permittivity feedback control followed by a surgical resection. A 14-gauge Medwaves microwave antenna was used to deliver a single treatment according to the manufacturer's recommendations. Tumours were assessed grossly as well as by haematoxylin and eosin (H&E) and tetrazolium chloride staining. The primary end point was per cent tumour necrosis. Results The median maximum ablation diameter measured was 4.1 cm (range 3.0-6.8). The median ablation volume was 8.7 cm3 (range 4.84-17.55). Six of the 10 tumours demonstrated a pathological complete response (CR). Six of seven tumours ≤3 cm demonstrated a pathological CR. Zero of the three tumours ≥3 cm had a pathological CR, but all had ≥50% tumour necrosis. All patients survived and there were no ablation-related morbidities. Discussion MWA of liver tumours with tumour permittivity feedback control is feasible and appears effective for the treatment of small (<3 cm) liver tumours. © 2013 International Hepato-Pancreato-Biliary Association.