Betsy Post 0:00
So welcome everyone to tonight’s event, our DocTalk: Hasta La Vista baby, how ablation can be a cancer Terminator. We are so excited you could join us, and even more excited that we have a wonderful speaker this evening with many years experience. So with us this evening, we have Dr Ronald Arellano, and he is an interventional radiologist at Mass Gen hospital. He has a long, illustrious background with lots of expertise on ablation and other things in interventional radiology. He has been published many times. I was looking today, well over 100 maybe I didn’t find them all. That’s not my area of expertise, but I looked and you have some great publications out there as well. So thank you so much for taking your time, your energy, your effort to be with our patients and caregivers in COLONTOWN to talk about ablation this evening, and as it relates to liver lung, also for everyone that is listening, please know that there were questions that were given to me in advance by patients and caregivers in various groups. So I did send those in advance, and he is prepared to talk about the questions that were sent in advance at the end of his presentation. We will also hopefully have time for some live Q and A at the end, as he’s presenting, we don’t want to interrupt the presentation, so please put questions in chat. So there is a zoom chat, so please put questions in there, and we will take questions live at the end, as long as we have time. But all the questions that were posed in advance were given to him, and he is prepared to talk about those as well. So without further ado, I will actually have Julie stop sharing my slides so you can share yours, and I’m going to turn it over to you. And again, thank you so much for being here to help us this evening.

Dr. Arellano 2:20
Thank you, Ms post for that very kind introduction and for the invitation to be part of this very important group that you run. So thank you very much. Can you everybody hear me okay? And you can see my slides? Okay, again. Thank you for the invitation, and thank you for those kind words at the beginning. What I’d like to do for the next hour or so is to kind of go through some of the basics of the ablation. And the way I’ve approached this, what is as though we were meeting together in my clinic, and as though you were referred to me for an ablation. And most of what I’m going to talk about are sort of the talking points that I discussed with all of my patients regarding ablation. And then, as this post mentioned, I saved some questions for the end and happy to take live questions as well. So with that, we’ll get underway. So what I’d like to do this evening, or at this time, is to describe some of the ablation devices that we use to treat liver and lung metastases. We’ll discuss some of the indications for treatment, some of the potential complications of liver directed ablation, and then describe some literature, not too much, literature, that supports the use of ablation for treating liver and or lung metastases. And I will say that most of this talk will be focused on liver, but there’s a lot of overlap between liver and lung disease, and so much of what I say is going to apply to the lung as well, with some exceptions.

Dr. Arellano 3:52
So we’ll start off with the discussion of the different types of ablation devices. I feel very, well, fortunate in that when I arrived at the Mass General in 1998 that was pretty near the very beginning of the world of ablation as we know it now, to treat liver and renal and other and lung tumors. And so over the years, I’ve been fortunate to acquire experience with many of the different ablation devices. And so that’s what we’re going to go over here. Now most of the ablation devices that are currently used to treat liver and lung tumors are radio frequency ablation, microwave ablation, cryoablation and irreversible electroporation, which is commonly referred to as nano knife, or abbreviated as IRE of these four, I would say that radio frequency and microwave are the two most commonly used ablation devices. The first three, as are indicated by the asterisks, there are thermal based ablation devices with radio frequency ablation and microwave ablation. We kill tumors by burning them with cryoablation. We kill tumors by freezing them. Irreversible electroporation is non thermal, and the way I think about it ire is that, well, I’ll go into those details in a little bit, but basically it’s a non thermal technology.

Dr. Arellano 5:26
This is just a slide demonstrating that we use the power of the electromagnetic spectrum. Maybe some of us remember these things from our chemistry class, our physics class or science classes in high school or college or graduate school, but what we do is harness the power of electromagnetic energy and use that power and translate that power into heat with RFA and microwave and we use that heat to kill tumors. So in contrast to surgery, where a surgeon will go in and she will resect a tumor from the liver or remove something from a part of the body. In contrast to that, ablation kills tumor “insitu” or in place. We don’t physically remove tumors from the body, but we burn them in place. With radio frequency ablation, we basically put a patient into an electrical circuit. We place grounding pads on their thighs, and those grounding pads are connected to a power generator. That power generator has a radio frequency electrode attached to it, and we place that electrode into the tumor. Now, the mechanism by which this works, once the patient is set up for treatment and we turn on the switch for an ablation that generator sends High Frequency radio waves between the generator and the electrode that’s embedded within the tumor through the order of several 100,000 times per second. And what happens by putting this the patient in the electrical circuit, for the ions that we have in our tissues, things like sodium, potassium chloride, magnesium, those ions around the needle device, they begin to try to align themselves in the direction of the electrical current. And remember, that’s oscillating very rapidly. So as those ions move back and forth, they’re generating friction, and that friction is generating heat. The analogy is taking two sticks and rubbing them together, and that friction that generates a fire. We use that same principle at an electron level to generate heat, and it’s a heat then that is used to kill, to destroy, ablate tumors. Those terms are all used synonymously.

Dr. Arellano 7:54
And this is a diagram which represents what I just said. You can see a power generator. These are grounding pads that are placed on the skin. Now, when you think about this, you know what radio frequency really is, the physics behind this is the same as what is used in the operating room with the electrocautery. Again, when a surgeon makes an incision and to control the bleeding at the incision site, she’ll take a cautery device and press a button and zap that bleed, and it will control the bleeding. And it’s that heat that kills or it destroys the blood vessel to control the bleeding. We’re using that same principle to burn and to kill tumors within the liver. So these are the grounding pads that connect the patient to the power generator, the electrode that’s placed with either CAT scan or ultrasound guidance into the tumor. Again, this is a diagrammatic representation of what I described. As those electrical currents are going back and forth at very high frequency, the ions, the positive and negatively charged ions, are bumping up against each other, rubbing against each other and generating frictional heat to kill tumors. And this is an example of what we try to achieve. This is the frequency with which radio frequency is used, and this is just another diagrammatic representation of an electrode going into a tumor for treatment. Now, what we aim for our temperatures greater than 60 degrees Celsius. Now this is sort of a table, if you will, that shows what happens as we go from normal temperatures to slightly elevated temperatures to even higher temperatures. If we subject tissues, for example, to 46 to 48 degrees Celsius for at least 45 minutes, we cause irreversible cell damage. Now 50 to 52 degrees Celsius, we can cause coagulation necrosis, again, synonymous with ablation, with ablated tissue, in about four to six minutes. But in most cases, with radio frequency ablation, we rapidly achieve temperatures that are approaching 100 degrees Celsius. And so at that temperature, we have very close to near instantaneous, coagulative necrosis or cell death, and greater than 110 degrees we cause tissue vaporization, in which the tissue is basically vaporized. But most of the time we are working in the near 100 degrees Celsius range with radio frequency ablation. This is a slide that shows the histologic changes that we aim to see or that are seen after an ablation. On the left here is normal liver tissue, and after subjecting tissue to radio frequency ablation, we have areas of n, which is represents tissue necrosis. And then there’s a rim of hyperemia, which is increased blood flow along the margin of the zone of the ablation. And then, we transition into normal liver. So this is what we want to achieve. And when we say necrosis, what we’re really talking at a histologic level, when a pathologist looks under a microscope at ablated tissue, what they see is total Wipeout. Hasta la vista, gone, in that all the organelles, all the structures that allow a cell to replicate, to divide and to grow are completely destroyed, and so that tissue is is wiped out and completely ablated.

Dr. Arellano 11:51
Go to the next slide. Now, one of the principles that underlies successful ablation is that of a surgical an ablative margin, going back to the surgical analogy, if a surgeon were to cut this out, he or she would, if this were a lesion on the surface of the liver, the surgeon wouldn’t spend a lot of time teasing away visibly normal from abnormal tissue to enucleate the tumor. Really, what the surgeon would do is remove the tumor in addition to a little bit of the surrounding liver tissue to ensure that the resected margin, is free of tumor. In general, with ablation of colorectal metastasis, we’re aiming for a minimal margin of five millimeters, ideally 10 millimeters. I think more and more literature is now showing that for colorectal metastasis, as opposed to somebody with primary liver cancer, say, from cirrhosis, the best outcomes are achieved when we can create a margin around the tumor, an ablative margin around the tumor of at least one centimeter. So if we have a three centimeter tumor, really what we want to do is achieve a zone of ablation that’s five centimeters, a one centimeter circumferential rind or rim around this tumor, and that’s what we’re trying to achieve with ablation. In that margin, we take that into account as we prepare for ablations, as we analyze ablation, our approach, the location of the tumor its relation to critical structures, etc. And we’ll talk a little bit more about that later on. That’s radio frequency ablation.

Dr. Arellano 13:42
Microwave ablation is similar. The physics behind microwave ablation are very similar to radio frequency ablation. Again, we harness the the energy of microwaves, which within that electromagnetic spectrum in this range here, and we use that energy to generate heat and to ablate tissue. In contrast to radio frequency ablation, instead of agitating the ions within tissues, with microwave ablation, we are agitating water within tissues, and that’s the mechanism by which we use it in our in our kitchens, when we heat it’s the water within tissues that are agitated and generate the heat. We use that same technology to treat tumors, similar to radio frequency ablation, but again, in contrast to agitation of ions, we’re agitating the water within tissues and generating a very high, what are called dipole moments, or rotations of water within the water molecules within tissues. And then that friction and agitation generates heat, and that heat similar to radio frequency ablation, similar to that table that I showed, a few slides back. We can generate tissue temperatures up into the 100 degrees Celsius range. Now, between the two the end game between radio frequency ablation and microwave ablation, as well as the other ablation devices, it’s important to remember that the end game is necrotic tissue. Whether you heat it or you freeze it, or you electrocute it with ire what we aim for is dead tissue. There are little nuances, procedural nuances between the two, which don’t necessarily make one better than the other, because the end game is necrotic tissue.

Dr. Arellano 15:37
And so with radio frequency and microwave ablation. It’s based on heat, and this is the device that we use with the microwave. There are at least three microwave and more emerging now in the market, but this is the device that we use at the Massachusetts General Hospital. And really it’s a power generator, similar to radio frequency ablation, in contrast to RFA, we do not need to put a patient into an electrical circuit. Therefore, we do not need grounding pads. So the setup is a little bit easier, but this is the basic setup. This is our our microwave antenna and the power generator that’s used to place into the tumor. Now there are maybe some some minor advantages to microwave ablation versus radio frequency ablation, but not much. Again, the end game is necrotic tissue. We started out using radio frequency ablation at the Mass General Hospital in 1998 and then after about 10 years, there was one iteration of a microwave device that was very clunky and not easy to use. And then the physicists and engineers went back to the drawing board, and a few years later, they all came back with a much better, refined and user friendly device. Comparing the two, microwave might be a little bit quicker, because we’re able to achieve rapid temperatures in a quicker, shorter amount of time. We can ablate a similar sized tumor in less time than radio frequency ablation or cryo ablation or ire. And less burn or ablation time translates into less procedure time, less anesthesia time.

Dr. Arellano 17:22
So I’ve been using microwave ablation now for the last 10 years or so, for most of the livers that I trea. But it’s important to keep in mind that they all work. RFA, microwave, cryo ablation, ire all of them work. And it may be at your local institution, at your local hospital, it may be that the interventional radiologists there only have a radio frequency ablation device. Don’t be dismayed. It’s effective. It’s very powerful. It’s very useful. Most of the literature that’s out there, because RFA has been around longer, is centered on RFA, but there’s more and more and more emerging with microwave ablation. Let me go on to the next slide. So the next ablation device that’s not heat based, but is thermal ablation nonetheless, is cryoablation. With cryoablation, it’s also a needle based system. So with a radio frequency ablation, microwave and cryoablation, we place needles, electrodes, microwaved antennas, into the liver or lung, into the tumor, and once it’s there, we use that device to ablate with cryoablation. It’s a different physics behind this. Basically, the cryo needle is connected to a cryoblation device that is connected to gasses. Argon and helium are the two most common gases used now. Those gasses are pushed through the shaft of the needle and then near the tip of the needle, the diameter of that shaft downsizes, referred to as a choke, and as the gasses emerge from that choke or that downsize, and those gasses expand through the magic of physics, that expansion of gasses results in a drop in temperatures.

Dr. Arellano 19:18
With cryo ablation, we’re able to achieve temperatures of minus 40 degrees Celsius, and at that temperatures, we cause necrosis of tissue, different mechanism compared to microwave and radio frequency ablation. With cryo ablation, we subject tumors to a freeze thaw freeze cycle, meaning once our needle is in place, or needles are in place with cryo ablation, we hit the switch, and the gasses start going through the needles, not in the patient, but through the needles. And as over time, an ice ball is generated. During the freezing cycle, as this diagram illustrates cell shrinkage, dehydration. You have extra cellular ice crystals form, intracellular ice– so we kind of hit the cells with with basically ice, ice chips, if you will, and then we partially thaw that ice ball that we’ve created for about eight minutes, and during that thaw phase, there is some cellular swelling and bursting. The melted ice causes damage to the blood vessels within the tumor. And so it’s a second hit, if you will, to the tumors. And then we re subject those tumors to an additional cycle, 10 minute cycle of freezing. And once the 10 plus eight and then 10=28 minutes of treatment are completed, we thaw the tissues to allow removal of the cryoprobes. And then over time, those cells undergo cell death, what’s referred to as apoptosis, another diagrammatic representation of what I just told you. But the interesting thing about cryoablation is that it, in contrast, as far as we know now, to radio frequency ablation and microwave ablation, that this may activate the immune system and may have a role in immunomodulation and one of the the active areas of research now is combining ablation with immunotherapies to see if hand in hand in combination is working synergistically that they may have improved outcomes, including in treating patients with metastatic disease,

Dr. Arellano 21:40
Moving on now to irreversible electroporation or ire or nano knife. The simplistic way that I think about nano knife or ire is that we are electrocuting cells. So this is non thermal, replace needles in and around a tumor, and between those needles, we send high electrical current. We sent high electrical voltage between those needle pairs. So for example, if there are four needles centered around a tumor, there are up to 1, 2, 3, 4, 5, 6, electrode pairs with which we deliver electrical pulses. And these are high voltage electrical pulses. If we all think back to high school biology class or college biology class, we were taught about the cellular membrane, the phospholipid bilayer of the cell membrane. Basically, these are fat molecules that surround the cell. And what irreversible electroporation does is by subjecting cells to very high voltages, the cellular phospholipid membrane creates little tiny holes. For low voltages, you can have temporary openings of that cell membrane, and then the membrane repairs and closes itself. When subjecting the membrane to very high pulses, openings develop on that cell membrane, and the cell it cannot recover from that, there are permanent holes on that membrane. And so when you again thinking back to high school biology, that semipermeable membrane the cell contents inside the cell move out, and liquid and other contents outside the cell move in, it causes total disruption of the cell, leading to cell death, a term that is referred to apoptosis. So in contrast to burning with radio frequency and microwave or freezing with cryo ablation, we are creating openings, pores. That’s why it’s referred to as the Nano knife. Nano pores, which are tiny, less than a micron size, openings on the cell membrane that cause the cell to undergo disruption and ultimately cell death.

Dr. Arellano 24:00
This is the Nano knife. There’s only one currently available in the market now. And this diagram here just represents the different configurations of needle placement that we can use depending on the size of the ablated volume that we aim to create. Most tumors require at least two probes. And of all the ablation devices, this one is the most meticulous in terms of performing the procedure. These probes cannot be placed more than two centimeters apart. They could be as parallel as we can to place them, to make sure there are no gaps of untreated tissue as a result of the treatment. Now, again, in contrast to the other ablation devices that I’ve described, because we are using high voltage electrical current, patients heartbeat can go into dyrsrhythmia as a result. And so Nano Knife or IRE requires the use of general anesthesia, so that means intubation, whereas the other procedures, most of them can be easily performed with monitored anesthesia care or intra procedural conscious sedation. But with IRE, we need very close cardiac monitoring. Patients need to be connected to a cardiac monitor with our device, as well as with with an EKG monitoring and anesthesia evaluation. And patients need to be completely paralyzed, similar to patients who undergo electroconvulsive therapy. Because of the high voltage, they can result in very severe muscular contractions if patients are not completely paralyzed. So IRE requires cardiac monitoring as well as general anesthesia and complete paralysis to minimize severe muscle contractions.

Dr. Arellano 25:54
Now here’s an example of a patient, not colorectal cancer, but liver cancer from cirrhosis. There is a tumor here, and this represents a location where I defer to IRE as opposed to the other ablation devices. This tumor, which is depicted by the arrow and I’m outlining on my cursor here, is what we call a centrally located lesion. Here’s one of the large veins that supply blood to the liver. The arteries that supply the liver are these white lines here. The bile ducts are all this area here. Using a heat based device, remember, to treat this tumor and thinking about that margin, what we need to do is create a zone of ablation that is about this size here, and that size is going to encroach primarily on the bile ducts and possibly result in bile duct injury. And so therefore, for centrally located tumors such as this, I tend to use irreversible electroporation because it’s non thermal, and therefore it has less of a risk of causing biliary stricture, vascular injury as a result. This is what we call a coronal view. So now we’re looking at the patient as though this patient is standing in front of us, and we’re looking front to back. These dots represent the electrodes within the tumor. And again, those when I talk about electrode pairs, those high voltages go for about 90 cardiac pulses. There’s pulses going here, here, here, here, and then across here and across here. So it takes about 12 to 15 minutes to complete an ablation cycle with irreversible electroporation. The device delivers a pulse between a specific cardiac cycle. It’ll deliver 10 pulses, based on the cardiac beat, 5 second rest another 10 pulses. It’ll do 70 pulses between each pair, then switch to another pair and do another and deliver another 70 pulses. So add it up. That’s about 10 to 15 minutes or so of ablation.

Dr. Arellano 28:05
This is what we look for after an ablation. This is immediately after the IRE. Remember that that white tumor is here. This represents that zone of ablation that we achieved after that irreversible electroporation device. Now procedure. This is an example of pre what it looked like. This was immediately after the procedure, and this is about six months after the treatment. What was initially bright is dark. This little rim here is just some residual hyperemia. This is not active tumor as a result. And you can appreciate that the tumor has diminished in size as well as no longer enhancing. Okay, so those are at least the four different ablation devices that are currently available that most people use now to treat liver as well as lung tumors. Now, when you know, how do we screen patients? How do we qualify patients for this, for treatment? This is an example of someone that I would not accept for ablation, that for whom I would not recommend ablation. I don’t think anybody would recommend for ablation. This patient has large tumors scattered throughout most of the right hepatic lobe. I didn’t include an example of a left hepatic lobe, though. This probably bridges part of the left hepatic lobe. The size of the tumor as well as the extent of the tumor. You can imagine, to achieve a zone of ablation that exceeds the margin of this tumor, we would be ablating for about two weeks to get all that treatment, which is just not feasible. So this is a gross example of someone who would not qualify for ablation. In contrast to this patient here, this patient has two liver lesions, one in the left hepatic lobe here, and the second one in the right hepatic lobe, which is here. This is a patient who is appropriate for ablation in general. There’s no hard and fast rules in terms of number or size, but there are general guidelines that most surgeons as well as interventional radiologists consider and abide by with with minor variations, depending on clinical experience, judgment, etc. But in general, up to three tumors, each being less than three centimeters or up to three centimeters in size that and tumors in a safe location, and most areas in the liver are going to be relatively safe, I would say that patient would qualify for an ablation without question.

Dr. Arellano 30:46
Is that a hard and fast rule? No, a three and a half centimeter tumor, I would definitely consider it for an ablation. A four centimeter tumor? I would if it were a solitary tumor. I also would consider for an ablation, understanding that I need to generate a six centimeter ablation zone with microwave ablation that can easily be done in about 15 minutes. It would take a longer time to do with radio frequency ablation, and and standard time with cryo ablation. But up to two centimeters, up to three. Now, somebody came to me with two centimeters today, I would treat. If nine months from now, they came back with another one or two centimeters that were in favorable locations within that size range, I would definitely consider for treatment. So keep in mind, there’s no hard and fast rules, but in general, anywhere between three maybe up to five centimeters, pushing the limits at five but three centimeter tumors, up to three tumors at any given time, I think would be appropriate for ablation.

Dr. Arellano 31:47
Now this is an imaging example of what I showed. This is a post ablation scan. This is three and a half years after the initial ablation, and you can see that within this area of unenhanced, ablated tissue. there’s what I refer to as the ghost of the tumor. If you look closely, you can see, I’m going to try and convince you that what I’m outlining here is a ovoid area that’s a little bit darker than here. That’s the the ablated tissue. And this is the margin around that tissue, and this is what we’re trying to achieve. And we use imaging as our primary tool to assess treatment response. So we’re looking for the size of the ablation zone that exceeds the size of the tumor. And this is an example of the same on the left lobe lesion. Within this zone of ablation is this ghost or dead tumor, and this is the margin of ablation. They’ll have a pre procedure, usually contrast enhanced CT and or MRI, sometimes a PET CT. If we can get a PET CT ahead of time, we can use that also to localize the tumor. But also equally important is to use that PET CT post procedure looking for absence of hot spots on the FDG avidity, or the hot spots on a PET CT scan. Sometimes, depending on the state, insurance companies will balk at doing two PET scans in a short amount of time. In a perfect world, we would have a baseline PET CT do the ablation, and then a month later, get a post, or month to six weeks later, get a post CT scan to look for absence of enhancement, absence of FDG, avidity on a PET scan, if we have it. So this is the general gist of what I had prepared. I’m happy to take any questions now from the chat or transition over to some of the prepared questions that were sent in earlier.

Betsy Post 33:57
I think if you want to do the questions that were sent earlier, I think a lot of the questions in the chat probably are very similar, so why don’t we start with those, and then we can move to the ones in the chat.

Dr. Arellano 34:08
Okay, so for these commonly asked questions, I’ve included some, I’ve written down some comments, and others. I’m just going to kind of freeform it as we go along. Let’s see. “Why would you use one type of ablation versus another?” Well, again, it’s important to keep in mind that whether it’s cryo ablation or microwave or RFA or irreversible electroporation, the end game is dead tissue. It’s ablated tissue, whether you’ve frozen it or burned it or electrocuted it. So, you know, we at MGH are fortunate in that we have these devices available to us that we’ve acquired over time, and so we have a little bit of flexibility there. I will say that for the last 10 years or so, we’ve transitioned away from RFA knowing that it’s good. It, but into into microwave ablation, and that’s primarily because, for a three centimeter tumor, let’s say, with microwave ablation, I can create a five centimeter zone of ablation in about 10 or 15 minutes, depending on how much power and time that I adjust on the machine. For a similar sized lesion with radio frequency ablation, depending on the device that can take anywhere from, you know, maybe up to 15 minutes, but sometimes up to 20 depending on the device that you use. What we used to use, we used a device that would generate about a 1.75 length by 1.25 diameter. So a cylinder of burn tissue. So to achieve a zone of ablation around a three centimeter tumor, we’d have to complete a 12 minute burn cycle, readjust the needle in a different location of the tumor, do an overlapping ablation, and to do that three or four times to achieve the goal of burning the tumor and generating that zone of ablation. Nothing wrong with that. I did that for 15 years, and it works just fine, but you can achieve the same volume of ablated tissue with microwave ablation, which is why I use it. Some don’t have a microwave device, and they use ablation, RFA, which is just fine. Others won’t have neither and have only a cryoablation device. Cryo would be fine. The general rule for cryoablation is that you place one needle per every two centimeters. So for a three centimeter tumor, you might need three, maybe up to four needles. So there’s time to place those needles in again with ultrasound or CT guidance, and then the 28 minute freeze, thaw free cycle, and then the treatment is done. So of the three, they’re all effective. But I get the job done easier, quicker with with a single needle, with microwave. That’s what I do. But depending on where you are, the local ablation devices at your local facilities or hospital would be just fine. So that’s my rationale for choosing ablation a microwave over RFA. But I’ve used all three, and I advocate for all three because they’re all very, very effective. I hope that answers that question

Dr. Arellano 37:19
“Is there a limit on the number of metastases that can be ablated?” Where I alluded to this earlier during the presentation, again, this is variable. If somebody has six or seven lesions in the liver, even though they may be all three centimeters or less, I think that’s really pushing the limits of anesthesia time to try to treat all at once. And you have to worry. I worry. And I think my colleagues in medical oncology and surgical oncology, we worry that if somebody has that many tumors, that that tumor biology is is going to be on the aggressive side, and so that even if we try to pick off seven in one setting, it may be that in very short order, many more will develop. So again, anywhere from three, ideally three, maybe four, maybe five tumors I would consider but definitely three, most tumors, three centimeters in size or less. Again, 3.5 maybe four, I would treat a solitary tumor up to five. If the patient was not a surgical candidate, and the tumor was stable after chemotherapy, I would consider it. But I would also advise that, because of that size, you may have to come back for touch up work, repeat ablation in that the first go around, I may get 80 or 90% of the tumor, but on the follow up imaging, if that shows a little bit of incompletely treated tumor, I’d bring you back and extend the size of the ablation to generate a larger margin, and then, Yeah. So these are the points that I may put up here. Maybe I’ve treated up to three lesions at a time, and I think that’s fine. Again, with microwave it usually goes pretty quick, but with cryo, it’s going to be a long, a longer procedure time, maybe even so with microwave ablation, we always have whenever we do an ablation, even though we’re focusing on killing the tumor, equally important is considering the location of that tumor and the adjacent structures, and the risk of what we call non target organ injury in the liver. Those non target risks can be the bile ducts, as I mentioned earlier. If it’s in the dome of the liver, which is the top part of the liver, we have to think about the lung, the heart, if it’s on the inside surface of the liver, bowel, stomach, sometimes the pancreas, especially the patient is a very thin patient. So all these things we have to take into consideration when we evaluate patients tumors for treatment. So I hope that answers that question

Dr. Arellano 40:05
“What’s the ideal size of colorectal mets that I would consider for an ablation, and why are larger metastases not eligible for ablation?” Well, again, I think I’ve addressed some of this on previous questions, and in the talk. It’s really about the margin. Again, for a three centimeter tumor, we’re talking about a five centimeter margin, a four centimeter tumor, a six centimeter zone of ablation, So one centimeter, two centimeter, three centimeter. For five centimeter tumors, we’re talking about a seven centimeter margin of ablation. That’s a lot of ablated tissue, and it may not be feasible to get that size of an ablation at one setting. So that may require repeat ablations. Again, even if a lesion is situated well within the liver, surrounded by a lot of normal liver, as that size of ablation enlarges, we might begin to encroach on the bile ducts. So I think most people who do ablation would consider tumors that hover around that three to three and a half, maybe up to four centimeter range. And the literature would reflect that the best outcomes when comparing ablation with surgery are going to be best in that three centimeter range. So those are the general guidelines that we use as we consider ablation. So larger tumors harder to achieve complete tumor ablation and margin because of the size, at least in one setting.

Dr. Arellano 41:44
“Anatomic limitations to ablations”. Well, again, I’ve mentioned a little bit of this before, non target organ injury. When we consider it a tumor, we had to consider it in terms of its neighborhood. What are the neighbors adjacent to the tumor? And when we think about the size of the ablation as we’re evaluating tumor is that zone of ablation going to approach structures? Now we have a lot of experience at the MGH, and over the years, we’ve developed and adopted techniques to help mitigate some of these limitations, these anatomic limitations, to allow us to achieve tumors that may otherwise would have been considered unablatable. I have an example. I think I have it coming up. I’ll show an example, lesions that are in the top of the liver, what we refer to as the dome of the liver. To target those lesions, there are several factors that come into play for non target considerations. Number one is the lung. It may be that in order to get our device into that tumor, we have to go through lung tissue, and that puts the patient at risk for a collapsed lung, pneumothorax. In reality, when we see a small pneumothorax, it’s of no clinical consequences. For patients who have severe underlying lung disease where collapsed lung or pneumothorax or air in the chest cavity, which is technically what that is, can change respiratory dynamics, but nevertheless, I try to avoid that whenever possible. So one of the techniques that we use quite a bit is for lesions that are in the top of the liver, or lesions that are on the outer edge of the liver, what we call sub capsular tumors that are near the lining of the abdominal wall. We put a needle into the abdominal cavity and put a needle right over the left lobe of the liver, and through that needle, we put fluid into the abdominal cavity, creating what’s called ascites, which is fluid accumulation in the abdominal cavity. And what that ascites does is pushes the liver away from the diaphragm. If my left hand here is the diaphragm, the lung is up here, it pushes the liver away from the diaphragm, and therefore it allows us to take a path to the liver, avoiding the lung tissue.

Dr. Arellano 43:59
A diaphragm is innervated by what’s called the phrenic nerve. The phrenic nerve, if it’s irritated, can cause about a week to 10 days worth of sharp shoulder & neck pain. Patients describe it as a sensation of somebody taking an ice pick and just kind of jabbing their shoulder blade constantly for a week or so. And so I try to avoid irritating that phrenic nerve as much as possible for that reason. And so this technique of creating artificial ascites, we can oftentimes move the liver away from the heart, from the lung, from the diaphragm. And similarly, I, over the years, have come to respect the peritoneum, which is that inner lining of the abdominal cavity. There are a lot of nerve cells on that peritoneum, and for tumors that are right on the surface of the liver, again, thinking about that zone of ablation, if there was no separation, would extend to that peritoneal lining and burn that and that can be another source of a week or 10 days of discomfort for patients. So when for subcapsular lesions, dome lesions, I place fluid in the abdominal cavity to protect the lung, the phrenic nerve and the peritoneum, and it therefore allows me to be as aggressive as I can on treating the tumor while minimizing non target injury. So centrally near the bile ducts, as I mentioned earlier, I would not use a temperature based device. I would probably use the Nano knife or the IRE device, because it’s non thermal and it has more of a protective effect on the bile ducts, and low chance of causing biliary stricture, which, over time, can lead to loss of liver tissue. So those are the maneuvers that I’ve mentioned here. I hope that answers that question,

Dr. Arellano 45:55
“How often is too often to have an ablation, and how frequently can ablation be used? Or the downsides to multiple ablations?” Well, again, if somebody came to me with two or three liver lesions today, and I treated them, and they were tumor free in the liver for a year or six months, then they popped up another one, as long as that tumor is in a location and it’s of a size that’s a minimal to ablation, I think they’re a candidate for repeat treatment. I think these questions allude to preservation of liver tissue, which is a very legitimate concern and legitimate question. Most patients that I treat with liver metastases do not have underlying cirrhosis, and when patients have underlying cirrhosis, you have less wiggle room, because when you think about that margin of quote, unquote, normal liver you’re going to treat, you’re taking out normally functioning liver. So with patients with cirrhosis and decompensation, they may be at higher risk of liver dysfunction after an ablation. So I have to be careful about those patients, but I will say, I think those patients are in the minority, most patients who have tissue that is normal or relatively normal, ablations can be repeated multiple times. So you know, as far as downsides, again, it’s just a matter I think, if there’s no cirrhosis, the risk of tipping somebody into liver failure as a result of multiple ablations, I think, is very low. But with somebody with cirrhosis and compromised liver function, most definitely have to take that into consideration, and that might be a limitation to how aggressive we can be to treat colorectal metastases in the liver.

Dr. Arellano 47:43
“The timing of ablation with chemotherapy and or surgery?”. Well, this is very variable. The reason I left this blank is because it’s very variable. There are some cases, instances in my institution where the surgeon will go in and remove a right lobe full of liver tumors and leave behind one left lobe liver lesion and after a month or so, after recovery, the patient will be referred to me for ablation of the left lobe liver disease using imaging guidance. Another variation is they’re going to resect liver lesions on the right side, multiple liver lesions on the right but intraoperatively, they may call me to bring the ablation device into the operating room, and using ultrasound guidance, will target that in the operating room to treat at that time. I’ve done that from my perspective, it’s not ideal, only because we have a very busy schedule, and we have many patients scheduled at a time, and so to break away and do that, usually it’s unannounced. In other words, they don’t, they haven’t always let us know that this is what they’re doing, but they encounter something in the operating room, and they’ll call me and say, Is it possible to come up? And I oblige. So, you know, I think if you’re going to have surgery, first sufficient time to recover from surgery, three to four weeks and then come in for an ablation, would probably be just fine. Chemotherapy. Again. This is a big variable. Most patients that are referred to me have undergone chemotherapy already, at least, or are in the midst of chemotherapy. They may be in a chemotherapy holiday, and it may be that chemotherapy has treated most of the lesions, and there’s one recalcitrant lesion that just won’t budge. And so, either during chemotherapy or off chemotherapy, I can, I can treat patients. So there’s no hard and fast rules with regard to the timing of chemotherapy.

Dr. Arellano 49:42
“How long do you need to be off?” I’ve treated patients while they’ll get a dose of chemotherapy last week, and their next dose is two weeks from now. I can treat them in that window, that interval window, or once they’ve completed their chemotherapy. I can also treat it as well. So it’s variable. Yeah. This is an example of that artificial ascites that I mentioned. Here’s a tumor high in the dome of the liver. Here’s the heart here. And what this gray crescent here represents is the fluid that I’ve placed in that cavity. And you can see here, this line here is that diaphragm right up against the edge of the liver. So to treat here, to generate that zone of ablation that exceeds the size of the tumor that most definitely I’m going to irritate or burn that diaphragm. Now there have been reports of diaphragmatic rupture, phrenic nerve injury and burning a hole in the diaphragm and bowel loops migrating through that hole into the chest cavity and causing strangulation and other problems, all the more reason why I like to protect the diaphragm whenever I’m doing an ablation, whenever it’s possible. This is that example of creating artificial acsites. Here’s the heart, and here’s that fluid, and here’s our needle, demonstrating that our needles in place, the edge of the liver is here. So even if my zone of ablation goes out to the edge of the liver, no chance of irritating the diaphragm or injuring the heart during the ablation. So this is an example of what I spoke to a few minutes ago of artificial ascites. Same example here.

Dr. Arellano 51:20
“What are the possible complications of ablation?” Well, I mentioned some of them already. The literature talks about phrenic nerve injury, bowel injury, for sure, bile duct injury, as a result of stricture, narrowing scar tissue on the bile ducts, bile cannot leave the liver, and if it goes untreated, then over time that you lose volume of liver that’s affected by the dilated bile ducts. But overall, the complication rate is relatively low. It hovers between five to 8%. Bleeding. Obviously, whenever we puncture the liver with any sharp device, there’s a risk of bleeding. But for somebody who has normal coagulation profiles, who’s not on blood thinners, that bleeding risk is really three to 5%. One of the techniques that many people utilize when they’re doing ablation is, once they’ve completed, bring the tumor on their way out of the liver, you can ablate the path of a needle, thereby further minimizing the risk of ablation. Infection is a reported risk. I usually give antibiotics for patients who undergo liver ablation, certainly patients who have pancreatic cancer who undergo liver ablation for pancreatic metastases. Usually those patients, if they had a Whipples procedure where they’ve removed the tumor from the pancreas and redirected flow and into the bowel and reattach loops of bowel to the stomach, those patients are a definitely higher risk for liver abscesses. And those patients, I don’t treat very many of them, but those that I’ve treated, I do usually do a week course of antibiotics before the ablation, followed by another week after the ablation to minimize that risk of infection. The lung injury, which I’ve alluded to, which I try to avoid by putting the fluid into the abdominal cavity. And the bile duct injury that I’ve mentioned already.

Dr. Arellano 53:21
“Am I able to ablate the same area more than once? If there’s a recurrence?” Most definitely, yes, if a recurrence or if something that’s incompletely treated, which is not technically a recurrence, for example, if I do an ablation today, I usually get follow up imaging a month later, and if that shows incompletely treated tumor, I’ll schedule the patient to come back for, as I say, touch up work and extend that zone of ablation. If I treated a tumor today and a new tumor developed six months from now, most definitely, I can treat that tumor as long as it’s in a favorable location. So yes, repeat ablations are feasible. I’d always say that repeat ablations are much easier than repeat surgical resections. After surgery, there’s scar tissue, to gain exposure and access to the liver and mobilizing the liver for resection, I’ve never done it, but I’ve heard from enough surgeons over time that it’s a very difficult task for them to repeat resection, it is seldom done. But repeat ablations, as long as the location is favorable and the size is favorable, most definitely feasible.

Dr. Arellano 54:30
“Why IRE versus ablation?” I think I’ve addressed this already, really for centrally located tumors, those near the bile ducts, I’ll use IRE. Anything else that I can safely target for an ablation, RFA, cryo or microwave. I’ll use ablation first because it’s quicker and easier. We don’t need general anesthesia. We don’t need general or complete neuromuscular paralysis for any of the other devices. So, and I will say, most of the ablations that I perform are done with an anesthesiologist administering medications. But seldom do we use general anesthesia. Most of the procedures are performed using monitored Anesthesia Care. The same types of medications patients receive who undergo colonoscopies, so through an IV, a combination of medications that make you sleepy and drowsy and for the most part, forgetful, for most of the procedure.

Dr. Arellano 56:11
“SBRT versus ablation”. You know, I think they’re equally competitive, sometimes in challenging locations, or for larger tumors, SBRT is more favorable than ablation, but for for a similarly sized lesion, a three centimeter lesion in a favorable location, sbrt or ablation, I think are equally effective, both achieve and the end game of destroyed or killed tissue. I don’t want to sound biased, so I’ll leave it at that lung mets, I think lung mets are certainly feasible. I personally do not perform lung mets. We do lung ablations at the Mass General, most of the principles that I’ve discussed here, the zone of the ablation, a favorable location, diaphragm in the lungs. Certainly, we’re dealing with the heart, much more tumors that are near the heart, near the central airway, the trachea, the bronchi. You have to take all those factors into consideration when considering what type of device and the zone of ablation that you want to create. I know my colleague at the Mass General uses primarily cryoablation for his liver tumors. But others have reported the use of microwave ablation and radio frequency ablation, as well as IRE for lung tumors.

Dr. Arellano 56:49
“Ablation versus resection”. This is a paper that was published in 2020 we looked at almost 2400 patients who were treated with RFA or microwave versus an R0 resection. It was very difficult for me to tease out from this paper what an R0 resection meant. Was it a complete resection of the a lobe of the liver versus partial resection? And that wasn’t very clear, easily delineated. But this is an example of something that would not be ablated based on its size, but resected, they would not ablate this, they would resect this. I would argue at our institution, we would consider ablation even though we’re close to the stomach again, there are maneuvers that we can use to push the stomach away and to move away from the diaphragm. Again in a patient like this, who they considered was an ablation patient, as well as a potential resection of patient. I think a resection would be a right hepatectomy versus localized tumor ablation. And the reason why that difference is important is because local tumor recurrence, if you do a right hepatectomy, there’s no chance of tumor recurring on the right lobe, because it’s gone versus an ablation. If you’re taking out just the tumors and leaving behind other liver, normal liver, there’s always the potential of local recurrence, and it’s important to delineate that local recurrence, is it local recurrence of the ablated zone, versus a new tumor in a different part of the liver, which it qualifies for local recurrence? Let me stop here, because I think we’re approaching eight o’clock. I’m happy to go on a little bit more, or if there are other questions that I can address for anybody.

Betsy Post 58:25
So there are some questions in the chat,

Betsy Post 58:30
I think a lot of them, though, you’ve addressed, let me just kind of gloss over some that I think you’ve already talked about. Someone was talking about recurrence rate for different types of ablation. So if there is information on recurrence rates for,

Dr. Arellano 58:46
yeah, I think a general statement that I’ll say is for, let’s say this ideal lesion of three centimeters or so in this paper that I refer to here, what this paper showed that at 1, 3, 5, and eight year survival, resection versus ablation with RFA or cryo ablation were equal for tumors less than three centimeters in size. For larger tumors, maybe resection had a slight advantage, but again, it’s hard to know what was resected was a complete global resection, lobar resection, or a right hepatectomy versus wedge resection or partial hepatectomy. That’s not very clearly delineated in that paper, but I think for three centimeter sized tumors, I think the local recurrence rate, if you’re doing only a wedge resection, I think the recurrence rates are comparable, which are going to be low, probably, well, certainly in the one to three, at the five year range, they’re going to be very low. These numbers, I didn’t type in the numbers. We’re talking about 97 versus 80s, versus the 70s, versus the 40% survival rates for 1, 3, 5, and eight years here. So I. Within five years, resection versus ablation are pretty equal for ablation. .

Betsy Post 1:00:08
Great. We do have a question about a patient with lung mets. So if there’s a patient with mets in both lungs approximately maybe 10, is that something that’s considered, if you did ablation in multiple procedures, is that something that could be considered or is 10 plus too many?

Dr. Arellano 1:00:31
Unfortunately, I think most, most interventionalists, oncologists and surgeons, would probably say 10 is is too many, because each puncture for each tumor is going to be a collapsed lung risk. And so even if you, even if you spread that out over time, let’s say you targeted three or four today, and then you let the patient recover, and you brought them back three or four weeks later and did another round of another three or four, etc, you’re extending treatment over multiple months for 10 on either side, we’re talking probably close to a year. And then during that interval, there’s always the risk of new tumors developing. And so there’s a lot of talk in medical circles about tumor biology. Some tumors tend to be less aggressive than others. And so for someone with 10 tumors, some would give chemotherapy, I think, and then and wait it out for a time interval to assess what’s called a test of time. If you’ve maxed out or treated aggressively with chemotherapy, maybe treated a couple or two or two or three at once, and then waited, and if new tumors develop in a short interval, then it’s best to back off. But if things are stable over time, I think 10 on either side is still too much, but three to five maybe depending on the local interventionalist, the surgeon, the oncologist. I will say in all these scenarios, I think the best care is through a multi disciplinary approach. So you want to have a medical oncologist, a surgical oncologist, an interventional radiologist or interventional oncologist on your team, you want them to be part of your team, caring after you, so that, the more minds together, I think the better outcomes there are, but 10, I’m afraid, is probably too many.

Betsy Post 1:02:26
And some of the questions I think were answered, so I’m just kind of skimming. One of them about lung mets. Are the side effects or efficacy of cryoablation and RFA, MWA similar to what you address with liver?

Dr. Arellano 1:02:44
Yeah, I think so. We did a study several years ago comparing patients who had liver biopsies or kidney biopsies with those who had liver and renal ablations. And we know that when we do embolization of tumors, will we kill tumors by cutting off their blood supply, patients experience what’s called a post embolization syndrome. Usually it’s fatigue, it’s muscle achiness, maybe a low grade temperature. Early on in our game with ablation, I asked the question, well, if we ablate a patient, do they have a similar experience? And what we found was that, yes, indeed, they do, but it’s very minor. I’ve always been impressed when I do an embolization procedure on a patient, they can, they can take a loop. They can get hit with that post embolization syndrome for a good solid week, they’re feeling like they have a bad case of the flu. In contrast with an ablation procedure, they experience those symptoms, but to a much less degree, most patients say they begin to feel a day or two after the ablation, as though they’re going to come down with the flu. They’re tired. They have their minor muscle achiness, doesn’t limit their quality of life. It just kind of they know that they’re waiting for the other shoe to drop, as they say. But after three or four days, those symptoms resolve and they’re back at their baseline. So most patients, I would say, 99% of the patients, have this post ablation syndrome. But for the most part, it’s a minor nuisance. And most patients say, like, yes, I I remember you telling me about it, and then I had it, but it was nothing major,

Betsy Post 1:04:18
Great. And if you could just take a couple more, that would be amazing. Hopefully that’s okay with you.

Dr. Arellano 1:04:26
Absolutely.

Betsy Post 1:04:26
Some of these are really good. And I think one of them that we didn’t talk about is the size, the smallest size you would have ablated?

Dr. Arellano 1:04:40
Yeah, that’s a very good question. You know, I recently treated a patient who had tumors that were hovering in the nine to 10 millimeter or one centimeter range. And the challenge with– the good news is that the tumors are very small. The challenge, though, is I see the tumors by imaging. Most of the places I do are going to be done with CT guidance, sometimes with ultrasound guidance. Most of these tumors, as I mentioned earlier, or patients will have a pre procedure, CAT scan, MRI scan or a PET scan. We don’t do PET guided CTs, but some institutions do, and so they can administer a dose of the pet agent, look for it lighting up, and target that area of enhancement. For the ablation, we don’t have that capability at the moment. And so for tumors that are small, when I do an ablation, most of the time they’re done without CT scans. Doesn’t mean so even though I may not see the tumor very well, I can still do the ablation using anatomic landmarks. I didn’t go into this on the talk. But basically, when I do ablation for small tumors in that range of one centimeter, let’s say I will have, if they have had an MR. I’ll have the MR up and a monitor next to my CT scan and I’ll relate the location of the tumor relative to landmarks within the liver, branches of the hepatic vein, branches of the portal vein, and measure, you know, it’s like a like a sailor navigating the seas, and they, they plot their course. I use a similar approach, where I even though I don’t see the tumor, when I measure its distance relative to intra live liver anatomy, even though I don’t see it, I know it’s there, and I target that area with an ablation, and so even though I don’t see it, I use educated, what I like to think is educated guesswork to guide my needle placement and do the treatment. We did that approach for biopsies that were poorly seen or not visible and with without giving contrast to confirm our needle position, we got an answer 92% of the time when we gave contrast to confirm we were on target to the lesion, it was actually 92% at the time, a little bit less. So using that same technique, I’ll target lesions, I’ll place my needle where the lesion is based on other imaging, contrast enhanced MR or CT scan, and I’ll tell my trainees that even though we don’t see the lesion, we know it’s there, and this is what we’re going to target, and this is how we’re going to approach the lesion. So the smallest lesion. So for lesions that that that hover at about seven to nine or so, sometimes I can see them, and it’s easy to target. When I don’t see them, that’s the technique that I use.

Betsy Post 1:07:44
That’s great. Do any of these ablative procedures impact the eligibility for liver surgery and does ablation impact the regeneration capability of the liver?

Dr. Arellano 1:07:58
To answer the first question, does ablating a tumor preclude you from surgery later on? No, if I treat a solitary tumor today, and you’re tumor free for X amount of time, and then over time, a couple of other lesions develop. I think the options at that point, can you repeat ablation? Possibly. If there are many tumors and they’re confined to the same lobe, then I think, if the argument can be made to resect that lobe of the liver, then by all means, I think it can be done. There might be a little bit of scar tissue on the edge of the liver, but not to the degree of as an open abdomen from prior surgery. I will say, just to parenthetically, you know, patients who have had bowel resections. And going back to the question of complications, you know, sometimes, especially with RF, even though I may be treating a liver lesion, there have been a couple of reports of a bowel injury, a burn injury to the bowel, even though the bowel is physically removed by several centimeters away. And some have postulated that adhesions that can develop in the abdomen after surgery and act as a thermal arc, and then that is sort of a theoretical explanation for why that happened. But that’s only because we’re talking about surgery here. But I think if surgery is an option, ablation does not preclude surgery. The second question was regeneration. If a patient has not had surgery, the amount of normal liver that I ablate is really a small amount of liver such that the liver will not hypertrophy as a result of that ablation. As I mentioned earlier, most patients will not have underlying liver disease, such as cirrhosis. With a cirrhotic liver, when you do a resection that whatever was removed from the liver, or if you do an ablation, whatever was killed, that area does not regrow. The surrounding liver hypertrophy, that kind of bulks up like as though being on steroids, it kind of bulks up and tries to pick up the slack for what was either cut out or ablated. So having an ablation, per se, does not necessarily affect the liver’s ability to hypertrophy,

Betsy Post 1:10:23
Great. And then there are two questions about CEA. Will the CEA drop after ablation? And if so, is it immediate?

Dr. Arellano 1:10:32
Yeah, another good question. Oftentimes, in conjunction with developing metastases within the liver, the CEA levels will elevate. And in addition to imaging as our metric to assess treatment response, looking for that zone of ablation, no enhancement in the tumor, absence of FDG avidity, oftentimes, CEA levels do drop. How immediate it’s a hard question to answer, because it’s nothing that we studied. I don’t know if the literature shows any reports on that and what I mean by that. If I did an ablation today, I wouldn’t trend the CEA levels daily for a month. Usually, what I’ll do is get a CEA at the time of their follow up imaging, when they start an IV and they’re going to do a blood draw anyway, we’ll send a CEA level at that time. And in most cases, it drops. If it doesn’t drop, then it prompts a question, could there be tumors that we’re not detecting, either in the liver or elsewhere, and that may then prompt a PET scan to look for a cold tumor or tumors that may be outside the liver.

Betsy Post 1:11:47
Great. I think we’re almost done. Thank you so much for being so generous with your time. Someone just I think they’re only like one one more that we didn’t get to. How common is needle track seeding? My IR, who did my cryoablation for my lung met said it’s pretty rare.

Dr. Arellano 1:12:04
Yeah, I would agree. I think it’s pretty rare. And when you think about it, many of our trainees and patients will ask that question. And fortunately, it’s very rare. It’s been described before, but it’s very rare. And the reason I think it’s very rare is because, remember, when we put our needle in, we’re burning not only the tumor, but the adjacent tissue. And so if seeding is to occur when the needle or the probe or the device is removed, in my mind, that’s another way of saying the ablation was ineffective. By even though we’ve subjected a tissue to 100 degrees Celsius for 10 or 15 minutes, or frozen for 30 minutes, we’re saying that despite that nuclear bomb, if you will, on that tumor that a cell survived, or cells survived and and they were able to make their way, be deposited along the liver track on the way out. I think it’s very rare. I think when seeding has occurred, it may have occurred as a result of multiple punctures or a direct puncture of the tumor. For those tumors that are on the edge of the liver, even though the shortest path to the tumor may be a direct puncture of the liver, I avoid direct punctures because if that tumor bleeds, you could potentially seed along that track or deposit tumor if blood migrates into the abdominal cavity, tumors can be spread that way. So the shortest distance isn’t always the best distance. In most of the cases, I go through a little bit of normal liver and route to a tumor to minimize if there is bleeding, there should be minimal risk of seeding, but I think the risk of needle track seeding is very low. As I say, some people will ablate the track. They’ll subject the pathway of the needle to a little bit of heat, enough heat to kind of cause coagulation, to minimize that risk of bleeding, and therefore the theoretically seeding. But to me, it’s more of a theoretical argument. A lot of people had a lot of time to sit around and drink coffee and talk about theory. That’s one of the topics that comes up. But I think it’s, it’s an interesting question, but not a practical one.

Betsy Post 1:14:33
Thank you. And I think just, I think this might be the last one. Could you talk a little bit about why a surgeon would use resection and ablation at the same time to address liver tumors. So when you hear about a liver surgeon who’s saying, I’m going to resect this and ablate that, and also, could you speak to would an IR be involved in that? Or is it something a surgeon would do?

Dr. Arellano 1:14:55
Yeah, you know there are some surgeons who do intraoperative ablations. There are some who will call the interventional radiologist to do it. Again, it all depends on the local institution and the local practices. If a surgeon is going to, I think part of the rationale is, if I’m going to subject my patient to anesthesia, open them up to a major liver re section and be there. And if I’m going to take out the right level the liver and there’s one easily targeted lesion in the left, why not just take care of everything then and there. Close them up, close up the patient and let them recover. Which is fine from my perspective, if it’s planned out ahead of time. It just makes everyone’s life easier. But sometimes even if they call me if I’m free, and I’ll go up to the OR and do that, because it’s in the best interest of the patient. Is there anything wrong with doing the liver resection, closing them up, and then a month later, bringing them to me to do the ablation? Not necessarily. So I think you know what goes into that decision making? I think it’s local factors, local preferences, the local IR team, the how busy things are, the feasibility, the availability of people, et cetera, et cetera. One is not necessarily better than the other. They’re both very good options,

Betsy Post 1:16:13
Great. And I think someone said, is ablation outpatient, I think you said yes.

Dr. Arellano 1:16:18
Yeah for the most part, all with very few exceptions, ablation procedures are outpatient procedures. And I’ll say, over the years, at least at our institutions, the anesthesiologists have been fantastic in terms of being part of this team, this multidisciplinary team. They’ve developed protocols to facilitate recovery. All our ablations now they do a nerve block to which has had a tremendous impact in terms of comfort level, inter procedural as well as recovery. In the early days of ablation, when after an ablation, we recovered patients for four hours now with with anesthesia, nerve block and their protocol that they use, every ablation will take about an hour and a half to do. And by two hours post ablation, patients are sitting up, they’re eating a sandwich, and they’re getting ready to go home. So most patients, by two hours post ablation, are ready to be discharged from the hospital.

Betsy Post 1:17:20
Great. And the last one, and you’ve been so generous of your time, this the last one, I promise. Someone was saying, if there’s a bad liver bleed after an ablation, does that make you more susceptible to a recurrence?

Dr. Arellano 1:17:34
Not necessarily. The bleed may be if a tumor is five centimeters away from the capsule of the liver, if that area is ablated. Remember, this is we’re coagulating tissue, similar to what the surgeons use to control bleeding when they’re making incisions and using electrocautery so the tumor itself is not likely to bleed. The bleed can occur nevertheless, at the site of the puncture which is separate from the tumor. And so I think the risk of bleeding after an ablation, or the risk of seeding after an ablation, is low. Again, as I mentioned earlier, if it’s a direct puncture of the tumor and there’s bleeding that occurs before you start ablating then there could be a risk of seeding. But, and that’s the reason why I always go through whenever possible, and this is most of the time, plan a course, a trajectory from the skin into the liver, through normal liver, and then into the tumor, even though that may be 10 centimeters as opposed to a five centimeter direct puncture of the liver, shorter is not necessarily better or easier or safer. So a bleed could be if it’s from the capsule. I don’t think there’s a higher chance of seeding if it’s a direct puncture and there’s bleeding before you start turning on the switch and ablting, there’s a potential risk of seeding for sure.

Betsy Post 1:18:58
Thank you. So I just want to thank you so much for being here. I think this Doc Talk has been phenomenal. You made it so easy to understand. I know that I learned a lot, and I’ve been doing this for years, and educating patients. So I just want to thank you on behalf of COLONTOWN, all of our patients and caregivers, you did an incredible job. We’re going to use this for years to come, because it’s been recorded. Your slides were amazing, and your time and your attention, I just cannot thank you enough. I think it was phenomenal. So we will have this recorded for patients. And if you have any parting words, we’d love to hear those.

Dr. Arellano 1:19:36
Well, again, I want to thank you for the invitation to speak to COLONTOWN and thank you for the questions you submitted and the questions that were brought up here. I hope this has been helpful. And I have one of these slides. I have my email at the very end here, but if anyone wants to reach out to me, I’m happy to, field questions. So thank you very much for your attention.

Betsy Post 1:20:03
Thank you, and I have to give you a little love, because someone said, Thank you so much. I’m a proud patient of MGH, so

Dr. Arellano 1:20:13
Thank you. Thank you very much.

Betsy Post 1:20:15
Thank you so much. And I’ll be in touch, and I’ll definitely make sure that everyone has that information. Okay,

Dr. Arellano 1:20:22
Well, thank you very much. Okay, good luck. Everyone. Take care. Bye, bye, bye.