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

BackgroundTumour 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.MethodsTen 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.ResultsThe 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.DiscussionMWA of liver tumours with tumour permittivity feedback control is feasible and appears effective for the treatment of small (<3 cm) liver tumours.