Electrocuting Liver Cancer -- In-Depth Doctor's Interview

How does this new technique work?

Dr. Raj Narayanan: The new technology that we brought into the University of Miami is called the NanoKnife. It’s a device that is used to treat tumors but works in a principle that’s different than the technology that we’re used to so far, which is radio frequency ablation and cryoablation. In radio frequency ablation, we use heat to kill the tumors, and in cryoablation, we freeze the tumor, but with the NanoKnife, or irreversible electrophoresis – I-R-E – the probes generate very high voltage electricity. What that does is create multiple holes in the cell membrane and kills the cell organelles, but leaves the cell membrane intact. The body removes the dead cell membranes like it’s a part of a dead cell in the body, so when the healing process takes place, it almost looks like the tumor was not there in the place where there used to be a tumor. With radio frequency ablation and cryoablation, you have a scar, fibrosis happens, and then it slowly starts shrinking but the scar tissue is there, whereas with this, the body removes the tumor cells that were killed.

How is it that these are flushed out, whereas a scar remains with the other procedures?

Dr. Narayanan: You’re using very high temperatures or you’re freezing it to a very low temperature, so pretty much killing the whole thing, the whole cell, so that’s why you have the fibrosis and the scarring, whereas with this, you’re just making multiple holes in the cell membrane – almost like a neutron bomb where you kill everything inside, but the structure remains. Since the structure is still there, the body thinks that it’s a dead cell and it cleans it and it removes it.

Does it only target the cancer cells?

Dr. Narayanan: Yes, because this is where we’re going to place it, right in the tumor. There is a slight difference where we place the probes compared to radio frequency ablation and cryoablation where we used to put them in the center of the tumor. Here, you kind of are at the margin of the tumor and you kind of either triangulate it if you use three probes or use four, depending on the size of the tumor.

Are you essentially surrounding the tumor?

Dr. Narayanan: With these probes, yes, and the electrodes are then connected to a generator. Once we turn it on, it fires the electrical pulse, and once it does that, it attacks the tumor at the cellular level.

How do you accessing the tumors?

Dr. Narayanan: That’s one of the best parts of this technology is that you don’t have to make any incision. This is done with CT scan guidance or ultrasound guidance, and it’s performed by an interventional radiologist. Part of our training involves targeting tumors with imaging guidance in a very precise fashion, so we use either CT guidance or ultrasound guidance to place these probes without any incision on the patient. It’s a very small skin nick that we make. Once we make the nick – it’s about two to three millimeters – we can place the probe through that. As we’re advancing the probe, we watch the trajectory with the CAT scan guidance to make sure that we’re going in the right direction, and then once we’re satisfied with the first probe, then you put the next one, and then so forth.

Is the probe about two or three millimeters?

Dr. Narayanan: In thickness, yes, and they are about 15 centimeters long. They’re pretty thin probes and you just advance them with the imaging guidance. The wire is connected once we have the probes in place and we’re satisfied with the location – that’s when the wires are connected to the generator.

What was the concept behind this procedure?

Dr. Narayanan: The primary concept has been around for awhile now when they used this in cells to deliver chemotherapeutic agents. At that time, it was called reversible electrophoresis because the change that happened to the membrane potential in this cell was not permanent – they just altered it with the voltage so that it would allow the drug to permeate the cell but then the membrane closes again. What they did was they went up higher on the voltage and then instead of causing reversible electrophoresis, now they cause irreversible electrophoresis.

Is it like electrocution?

Dr. Narayanan: Pretty much.

What kinds of cancers does this treat?

Dr. Narayanan: Right now, we’ve started with the liver, but we intend to use it in lung, kidneys, and actually, the first case of pancreas has been done a few days ago, so those are the areas we’re looking at, but for now, we have now started using it in the liver.

What kind of success rates have you seen so far?

Dr. Narayanan: It is a little too early to say. The person with the most experience with this technology is Professor Ken Thompson at the Alfred Hospital in Melbourne who did the Phase I study for this technology. He’s done close to about 50 to 60 patients, where he has used them in various types of tumors and locations, and has proved the safety of the technology. He has also shown us in a couple of meetings his preliminary results, and some of the patients that he has a follow up are over a year now, depending on the size of the tumor. It looks like the success rate varies based on the size of the tumor. Some of the patients that he treated were much bigger in size, close to ten centimeters, so the success was not that great, but at least it proved the safety of the technology. In well selected patients, the success was very good.

Are there any therapies that are needed alongside this technology?

Dr. Narayanan: No, you don’t need any kind of additional therapy. Once we finish the procedure we have a follow up protocol for these patients. We now intend to bring them in about one month to do a repeat imaging study to look at the area that we treated to see how it has responded to the treatment, which is what we do with radio frequency ablation also, so if we started out with the CAT scan prior to the procedure, we repeat the same modality so you have a comparison.

How long is a patient’s recovery time?

Dr. Narayanan: Most of these patients, once they recover from their anesthesia, they should be okay because there’s no incision and there’s just a little band-aid that we have over the site. We have kept all our ablation patients overnight, and we intend to do that with the NanoKnife also so that we can monitor them to make sure that there are no complications. Once the patients wake up from the anesthesia, in about a couple of hours, they’re able to take some liquids and hopefully, by later in the evening, they can have their dinner and then watch them and then in the next morning, we discharge them.

What are some of the complications that can occur?

Dr. Narayanan: Any time you put a needle into the body, there’s always a risk factor involved with bleeding. If the tumor is very high in the liver and it’s close to the lung, you have a chance of causing what we call a pneumothorax, or a partial collapse of the lung. Those are the two things. Infection, technically, is also a possibility, but I would think that would be more in a bigger lesion that injury to vessels or ducts can theoretically happen. One of the advantages of the NanoKnife is that it does not cause injury to a bioduct or a blood vessel when you’re treating a tumor, as opposed to radio frequency ablation. It does not affect the blood vessels or the bioducts because of the cellular composition of those.

Who would be a candidate for this procedure?

Dr. Narayanan: The ideal candidate for this procedure would be liver cancer patients who are first of all, non-surgical candidates, or those we are trying to downstage for a transplant. Also, those with tumor sizes less than five centimeters, patients who do not have multiple lesions, and patients who do not have a significant cardiac history. Those who have a pacemaker, at this point, would not be able to have this procedure because of the theoretical possibility of cardiac arrhythmia when the probe delivers the electrical energy. The ideal person would be someone with a tumor size between three to four centimeters.

What type of patient is not a good candidate for the procedure?

Dr. Narayanan: The patient who, at this point, we do not consider to be an ideal candidate would be those with multiple lesions in the liver, say, more than four or five lesions which are greater than five centimeters or more, and those who have other co-morbidities – actually, those with a significant cardiac history. If they have any cardiac problems or if they have a pacemaker, they would not be a candidate for this treatment.

What do you hope this technology will lead to, in the future?

Dr. Narayanan: This technology holds a lot of promise, but we are definitely in the beginning of this implementation of this. We are actually the fourth center in the United States and within the first ten in the world to start using this technology, so a lot of work needs to be done as far as gauging the actual success of this treatment modality, the follow-ups and how the patients respond. Based on the preliminary studies, it does hold a lot of promise, and in well-chosen or patients who are ideal candidates for this procedure, it brings in a whole new way of treating these tumors with the technology that did not exist before. It’s safe, it eliminates a problem which we have traditionally faced with radio frequency ablation where if a tumor is close to a blood vessel or a major blood vessel, we do not get good ablation because of the loss of heat because of the blood flow in the vessel that’s close to the tumor, the part of the tumor that’s close to the blood vessel does not get treated properly. With the NanoKnife you will not have that problem, so that’s a significant advantage. The other advantage is also the time it takes to treat the tumor. Traditionally, with an ablation, it can take anywhere from 15 minutes to sometimes even 30 minutes to treat the tumor. With the NanoKnife, each activation is about 40 to 45 seconds, so you’re able to treat the tumors in a much shorter period of time. It varies by case because of the size and the number of probes that you’re going to place. The placement of the probes actually takes the time – that’s the part of the procedure where more time is spent; the actual ablation time is a lot quicker.

Could the patient come in the morning of the procedure and be out of the hospital the next morning?

Dr. Narayanan: Absolutely. The patient just has a very short hospital stay, and as we get more comfortable and we have more data and experience, we intend to send patients home the same day.

END OF INTERVIEW

This information is intended for additional research purposes only. It is not to be used as a prescription or advice from Ivanhoe Broadcast News, Inc. or any medical professional interviewed. Ivanhoe Broadcast News, Inc. assumes no responsibility for the depth or accuracy of physician statements. Procedures or medicines apply to different people and medical factors; always consult your physician on medical matters.

If you would like more information, please contact:

Lisa Worley

Media Relations

University of Miami Miller School of Medicine

(305) 243-5184

Sign up for a free weekly e-mail on Medical Breakthroughs called

First to Know by clicking here.

Read the full report, Electrocuting Liver Cancer.