Irreversible electroporation (IRE), also known as non-thermal irreversible electroporation (NTIRE), is a non-invasive soft-tissue ablation technique used for tumor ablation in regions that require very high precision and preservation of surrounding collagenous structures (vessels and ducts) and a reduced susceptibility to heat sink effects.
In IRE electrodes are placed in tumor cells where they alter transmembrane potentials. This leads to permanent porous channels in the cell membranes causing irreversible damage and subsequently apoptosis. Apoptosis is a much more controlled way of cell death as opposed to necrosis. This is why the surrounding cells, vessels are spared 1,2.
IRE involves accurate parallel placement of at least two electrodes and is, therefore, more challenging than other ablation techniques. Other challenges include the potential need for general anesthesia due to the occurrence of whole-body muscle spasms and synchronisation with the cardiac refractory period to prevent cardiac arrhythmias, which have been described with IRE 3.
The major advantages of IRE are its applicability near structures that are susceptible to thermal injuries, such as bile ducts (hence its use in tumors in liver and pancreas) and vessels due to a decrease in the heat-sink effect. These advantages may provide a treatment option for tumors that would otherwise not have been candidates for ablation.
Follow up of IRE patient outcomes is an emerging topic of research within interventional oncology with hepatic tumors being the focus of many studies. Preliminary evidence suggests that IRE appears to mainly induce local tumor control rather than cure. A larger lesion size (> 2 cm) is associated with shorter time to progression. In addition the type of tumor is a significant factor in prognosis with HCC having better outcomes than metastatic colorectal carcinoma4.
- 1. Li D, Kang J, Golas BJ et-al. Minimally invasive local therapies for liver cancer. Cancer Biol Med. 2015;11 (4): 217-36. doi:10.7497/j.issn.2095-3941.2014.04.001 - Free text at pubmed - Pubmed citation
- 2. Rombouts SJ, Vogel JA, van Santvoort HC et-al. Systematic review of innovative ablative therapies for the treatment of locally advanced pancreatic cancer. Br J Surg. 2015;102 (3): 182-93. doi:10.1002/bjs.9716 - Pubmed citation
- 3. Deodhar A, Dickfeld T, Single GW et-al. Irreversible electroporation near the heart: ventricular arrhythmias can be prevented with ECG synchronization. AJR Am J Roentgenol. 2011;196 (3): W330-5. doi:10.2214/AJR.10.4490 - Free text at pubmed - Pubmed citation
- 4. Sebastian Mafeld, Jen Jou Wong, Nabil Kibriya, Ben Stenberg, Derek Manas, Paul Bassett, Tahira Aslam, Jonathan Evans, Peter Littler. Percutaneous Irreversible Electroporation (IRE) of Hepatic Malignancy: A Bi-institutional Analysis of Safety and Outcomes. (2019) CardioVascular and Interventional Radiology. 42 (4): 577.