2 The condition, current treatments and procedure
2.1 The most common primary liver cancers are hepatocellular carcinoma and cholangiocarcinoma.
2.2 Treatment for primary liver cancer depends on several factors, including the exact location and stage of the cancer, the patient's liver function and any patient-related comorbidities. For most patients, treatment with curative intent is not possible. The treatment options include surgical excision, chemotherapy (either systemic or local hepatic artery infusion), transarterial chemoembolisation, percutaneous ethanol injection, and thermal ablation techniques such as cryotherapy, radiofrequency and microwave ablation. Liver transplantation (with curative intent) may be appropriate for some patients.
2.3 The aim of irreversible electroporation (IRE) is to destroy cancerous cells by subjecting them to short pulses of high-voltage direct current. This creates multiple holes in the cell membrane, irreversibly damaging the cell's homeostasis mechanisms and leading to cell death.
2.4 IRE for primary liver cancer is done with the patient under general anaesthesia. A neuromuscular blocking agent is used to prevent muscle spasms. Needle-like electrodes are introduced percutaneously into the tumour under imaging guidance (either CT or, less commonly, ultrasound). The distance between the electrodes is confirmed by imaging. This is to ensure that the electrodes are correctly placed parallel to each other, and that enough current flow would be generated to ensure IRE. The procedure may also be done through an open surgical or laparoscopic approach, although the percutaneous route is the most common.
2.5 Electrodes are repositioned under imaging guidance to extend the zone of electroporation until the entire tumour and an appropriate margin have been ablated. The number of ablations is determined by the volume of the target tumour. When the ablation procedure is completed, further imaging may be done to confirm the extent of the ablation.