Liver cancer is the fifth most common malignant tumor in the world. The tumor can be removed through surgery or by utilizing thermal ablation techniques. If a treatment with conservative methods is no longer possible, there is an alternative: irreversible electroporation (IRE). The effectiveness of this method was now confirmed by a clinical study.
In this interview with MEDICA-tradefair.com, Dr. Philipp Wiggermann, who is responsible for the study discusses the results of the clinical trial, explains when IRE is used and what a future application will look like.
Dr. Wiggermann, what exactly is irreversible electroporation (IRE)? What happens in this case?
Dr. Philipp Wiggermann: IRE uses strong electromagnetic fields to disintegrate cell membranes. Cells are damaged when cell membranes are exposed to a strong magnetic field, causing nano-scale pores in the membrane. Usually, the cell is able to repair itself. This is the goal of reversible electroporation. However, if this method is used to generate too many pores, the cells are unable to self-repair and die. This is cell death by apoptosis and not necrosis. That is the fundamental difference between this method and other procedures.
When is irreversible electroporation used?
Wiggermann: The IRE procedure is traditionally used to treat various types of cancers and is most commonly used in hepatocellular carcinoma or liver cancer, respectively. Those patients whose liver we treat here at our Center have no other choice left. They have generally already undergone surgery but it no longer worked. Our approach is curative. Our objective is to completely remove all liver metastases in patients.
Why is IRE used as the last option once all conventional methods are no longer working?
Wiggermann: For one thing, medical science is very traditional. Generally speaking, that's a good thing since you don't try out a new method every day and don't follow the latest fashion trends in a manner of speaking. First, you use surgical procedures as well as radiofrequency ablation (RFA) and microwave ablation (MWA). They are typically performed by using a single probe, which is why they are a faster procedure than IRE. The IRE procedure takes at least twice as long as the RFA process. That’s also why IRE is likely not to become the primary method of treatment. Instead, it is used once the classic thermal procedures don’t achieve results.
Are there any risks with this intervention?
Wiggermann: Yes. Although it is a minimally invasive surgery, it requires general anesthesia. And any type of anesthesia entails a certain amount of risk. What's more, the liver has a number of functional segments where bleeding may occur. Plus you also have all the risks that ablation procedures entail. Having said that, you have to consider this in context because it is a very safe method compared to surgery.
You have conducted the largest clinical study on IRE to date. What did this study look like?
Wiggermann: We conducted a monocentric, single-arm study. We didn't change any processes in the Center. If there was a contraindication to surgery or thermal ablation, the patients were treated by using the IRE procedure. First, we charted the survival rates of patients. We subsequently also recorded long-term survival rates – and what the situation looks like after two or three years. That is the quintessence of the study. Based on its structural setup, you cannot compare it with complex oncology trials but that was also never our intention. It was important to us to first relate how this method also primarily fares in the long-term.
What was the result of the study?
Wiggermann: We were able to substantiate excellent efficiency rates after six weeks. And for the first time ever, we were also able to demonstrate the effects of IRE for a longer period of time – over five years. A significant percentage of patients no longer had any localized cancer. Having said that, we are unable to state how long these patients would have lived had they undergone systemic therapies. In collaboration with the departments of surgery and oncology, our next step is the development of a good study structure. This enables you to generate hard evidence and allows comparisons with other therapies.
IRE is so far not very widely used. Why is that?
Wiggermann: Percutaneous tumor ablations as such are still not very prevalent. Here in Regensburg, we have about 250 cases a year, which makes us one of the largest Centers in Germany. What's more, IRE requires a certain degree of technical knowledge and experience because it is more complex than thermal ablation. Last but not least, there are also monetary concerns. The device to perform IRE is significantly more expensive than a device for microwave ablation. Plus it has only been a few years since it has been adequately reimbursed.
Is this going to change in the future, also in light of the positive results of the study?
Wiggermann: Yes, things will change but you also have to put all this into perspective. Out of ten eligible tumor ablation patients, eight can be treated using thermal procedures. That means the majority of patients can be treated with methods that are technically easier to perform and are also less expensive. Having said that, there are many interested parties at the university level. And I think that shows a positive trend.