All right. Well, good afternoon. Thank you Darren. That was a great introduction. [BLANK_AUDIO] Not sure how to move on. There we go.
It's a little bit awkward over there, isn't it? All right. So, it's gonna be interesting because although I did a lot of RF ablation early in my career, about five years ago now I transitioned
completely to microwave and I haven't done an RF ablation in that time and I'll talk a little bit about why that transition has occurred and why I think that there are significant advantages to microwave over RF as we go through this discussion. There's a question mark next to the new aid medical because it is in the process of acquisition,
so I'm not sure if I actually hold shares in it anymore or not. Cellectar Biosciences is,
by the way, it's an unrelated company. So I've just started with cases. I thought I'd put some cases out here,
and we can talk about how you would go about doing these cases and specifically kinda touch on some of the basic things that we all think about as we approach cases and go through these cases on a day to day basis. So here's a nice, normal,
very typical example of a small HCC in the left hepatic lobe, and the first thing we all kind of encounter is what modality do we use. What is the most appropriate modality? How many RF users do we still have in here today?
So we've got a couple. What about microwave? More. What about cryo in the liver? I think saw a couple. Okay.
So, the answer, in my opinion, is number one, you should always use what you're most familiar with because your best results are gonna be with the equipment that you are comfortable with. That being said I really think that you ought to consider working towards identifying the best equipment and that's really a big
challenge. Because not only do we have numerous modalities any ethanol users by the way, any old school people? Every now and, yeah, so you have ethanol, so chemical ablation, you have heat and you have cold and amongst those, not only do you have the different modalities, the microwave, RF,
laser, etc. But you also have all the different companies and every company's system is a little bit different and you have to be very familiar with the system that you're gonna choose to use. And so I'm not gonna talk about any specific systems but I really encourage you when you do choose a system that you make sure that you
are comfortable with that system, and how it works and make sure you understand the physics behind how it works because that's very important. So I literally have two hour lectures based truly on what modalities to use.
There's not a straight forward answer. There is a paper we wrote in RadioGraphics, you can see there in October 2014 that goes over specifically all of the kind of underlying issues behind each modality, and where the advantages and disadvantages lie. And I encourage you to read that article or others if you have questions,
And I encourage you to read that article or others if you have questions, but the bottom line is as Darren indicated
is that the microwave really is rapidly replacing RF and there's really good reasons for that microwave has a lot of advantages on the physics side compared to RF. There's a lot of limitations to what you can accomplish in RF primarily because most of the heating is conductive heating which is a very inefficient mechanism of heating,
and so that limits the damage that you can do. With the microwave systems in the current day you really can do anything you can do with RF, if you want to run them at temperatures and powers that give you RF-like results you can do that.
But you can do a lot more as well and that's the biggest advantage of microwave and usually here I show a picture of a Yugo and Ferrari, and RF is the Yugo and yeah, it will get you there, but you can do a lot more with the Ferrari.
Doctor Claus/g kind of went over cryo a little bit,, and I will kind of reiterate what he said, which is, you have to be really careful with cryo, especially in a sclerotic patient.
We've down over a thousand liver ablations in our practice, and we've had only one patient fatality that was procedure related. And that was a PE. But if you look at cryo series out in the literature, you'll actually
find some significant death rates, procedural death rates associated with cryo shock particularly in sclerotic patients. So if you're gonna do that, you have to be really careful about it and you have to really think twice.
Because the reality is that heat is definitively in my opinion and in the literature's opinion a safer option. So I don't see a good argument for using cryo. And then don't forget about ethanol, even though it's kind of fallen out of favor and it's not as sexy as the heat based ablation modalities.
It's certainly has times when it can be very useful. So, I think in that case, I would use microwave. You would probably use whatever you use, but I think microwave is pretty straight forward.
So let's talk about targeting and Dr.
Klaus/g also kind of touched on this, which is how you target this. How many of you use CT as their primary targeting modality? How many use ultrasound?
That's very encouraging. Maybe I wouldn't have to argue as hard as I thought I might have to to convince you to use ultrasound. And the reason is right here. We all have kind of realized, at least in the liver non-contrast
CT is a very challenging modality to utilize for guidance. Sometimes almost impossible. You're essentially going off landmarks, you often don't have any real true indication of where that tumor is. So here we are in the non-contrast CT in the center pale, you could
hallucinate something, you could go based upon landmarks but you realistically can not see that tumor. So you either do something fancy like give a little contrast to give you an idea of where it is, and then do other things to try and make sure you're in the right
place. Create a bigger ablation zone than you have to in order to make sure that you cover it etc, etc. But the reality is these are almost always very visible on ultrasound.
So here's a nice example. This tumor is extremely exquisitely visible on ultrasound, very easy to identify and to target. So here we are during the ablation.
So here we are during the ablation. So now we've got our ablation antenna place.
You can see we put in a single microwave antenna, 65 watts, 5 minutes, and here's the post ablation. So how well does that gas cloud correlate with the zone of ablation? That's a good question, right? And there is a fair amount of data on RF looking specifically
at that issue and it turned out okay but not great correlation. Turns out that the correlation with microwave is probably quite a bit better. We just finished a postery that's gonna get published pretty soon, that shows that your ablation zone is probably two or three millimeters larger than the gas cloud.
So you can safely assume that if your target is within the cloud of gas, that it's completely ablated. And then you kind of assess your margin based upon that. So, let's see moving on here.
So here's our preempt post, and this is another thing I'll talk
a little bit about as we go through this, but we do an immediate post-ablation assessment while the patient's still on the cable. I know that there's some people that don't do that. How many people here do that? Either with ultrasound or with CT so it looks like about a third of you.
I really encourage you to consider that, you know some people will say well just bring him back but the reality is that's a whole another procedure, a whole another anesthesia whole other utilization of resources that probably wouldn't have been necessary if you had just accessed it at the moment and realize that you hadn't gotten a complete ablation. And so we do this and about 10% of the
time we go back and retreat mainly not because we didn't see residual tumor but we realize our margins are not quite where we want them to be. So you really should strongly consider that, I think it really helps. We actually studied guidance and we had twice the rate of
LTP when we use CT for guidance as compared to ultrasound. So once again ultrasound, if you are comfortable with it there's a great way to do it. So how big is the antenna? Does the ablation need to be in?
Dr. Klaus once again kinda touched on this briefly, but really this is getting at ablation zone margins, right? And margins are probably the best predictor of how well we're gonna
do. So you really need to think long and hard about your margins and how big they are, and the common teaching is half a centimeter for HCC and full centimeter for mets. So if I have a three centimeter tumor I really have to get, in the
case of [INAUDIBLE] a five centimeter ablation, that is a big ablation right? I mean that is really pretty significant and so if I kind of go through this, here is your adequate ablation zone of five centimeter with a nice big margin. Of course that way, it seems they are perfectly centered.
But the reality is that none of us are as perfect as we think we are. And we often a little off the center and then you end up even with a five centimeter ablation with a relatively narrow ablation margin. And the reality is we often get smaller ablations zones than we think we are going to as well.
And so add that in and then you get into the situation we actually have residual tumor. So you really have to be thoughtful in your planning about how you're gonna do these procedures, and how big your margins are gonna be and how big your ablations zone needs to be.
And then also remember that as Dr. Klaus/g mentioned as well, that your ablation zone is not spherical. It doesn't matter what system you use, there is no such thing as a spherical ablation zone no matter what some of the propaganda
out there says. So you really are actually having an oval [INAUDIBLE] ablation zone in some way shape or form. And remember that your adequate ablation margin is actually your shortest access dimension and so in order for this to adequate it has to be five centimeters in the short access dimension which means it's inevitably gonna
be larger in the long access division. And so once again this gives you wiggle room so that if you're not perfect, you can actually get it where often times we end up with situations like this. So realistically a lot of our LTPs actually result from poor planing where we just don't adequately plan for a large enough ablation zone.
So keep that in mind if you do this. I tell my residents and fellows all the time, one of the worst complications and in fact in [UNKNOWN] disease is pretty much guaranteed to be fatal is to leave tumor behind. This is, one chance at a cure a lot of times and if we don't get
an adequate ablation zone we take that away from them. So taking that into account, here we are a three centimeter tumor, how big of ablation zone do we need for an HTC ? We need a four centimeter minimum ablation zone. So then we have to think about how we're gonna do that, and how you're
gonna accomplish that depends upon the equipment that you use. I use the convenient system, well value lab convenient/g electronic system with RF for many years and a four centimeter ablation would be a challenge. You'd have to probably use three electrodes to get a short access dimension for a similar ablation and burn for at least 12 to 16
minutes. So that's a pretty big undertaking or if you just look at this you might think this would be easier I could do this with one or two electrodes, but the reality is this is really not true.
So in this case we need a four centimeter ablation so if we move through here we are. You can also see if there is complication of left hepatic vein is really close by. So Dr. Klaus also kind of briefly mentioned heat sinks and that's a
definition issue. You have to think about that particularly with RF but also with microwave and cryo. And take those into consideration. And so you are gonna put a little bit more power into this ablation than you might have otherwise.
So here we are, we decided to use two antennas, so we got one antenna along the medium margin, one antenna along the diateral margin/g. Here is our post ablation assessment monitoring with ultrasound. You can see that gas cloud is completely enveloped that tumor and so that looks like a good outcome.
Here is our immediate post ablation assessment and you can see that looks great. It looks like there's a nice ablation zone it's a little over 4 centimeters in both dimensions. One think I will mention, is with multi applicator microwave ablations, I have found that you can get
pretty close to spherical ablation actually although not perfectly spherical, but so nice result and adequate and we already talked
spherical, but so nice result and adequate and we already talked about the immediate assessment. So here is just an example, I'm just gonna run this movie. And this shows you one reason that we think the multiple applicators are so helpful.
The reality is that when you use a single applicator there is two issues that happen. So number one, your heat tends to be kind of misplaced in a way. All this circles aren't in the right spot. But the heat tends to be misplaced in a way because it's really in the center of the tumor whereas the biologically active part of the
tumor tends to around the periphery. In the case of a double or multi-applicator ablation, you tend to distribute that heat more at the periphery of the tumor so not only do you get bigger margins which are also applying the heat, in the more biologically active portion of the tumor, both of which
are critical to excellent results and so that's one of the big advantages of having multiple applicators over a single applicator no matter how big the single applicator ablation may be. So here's another case, this is a 57 year old female metastatic breast cancer to the liver and bones, she already had multiple interventions
over the years, surgeries and etc. But now she had this rapidly growing tumor right next to the IVC here. So is this safe? How many of you guys would try to give this a try? A safe ablation not too many are too excited about it.
[LAUGH] What about the heat sink, of the IVC, is that a problem? Are you worried about injuring the IVC is another thing to ask yourself, right. so those are definitely considerations.
I will start with the IVC injury, you can place an ablation antenna directly on to the IVC and ablate to your heart's content and you will never thrombose the IVC, it's just not possible. We've tried it in animals and it just doesn't happen.
Don't worry about injuring the IVC from that standpoint, you certainly don't wanna puncture it but I wouldn't worry about thrombosing it. As for the heat sink considerations, that's significant and you
really have to make sure you have a modality that's gonna give you an adequate ablation, in this case I need over a 5cm ablation So five and a half centimeters or right up against the CIVC so there is defiantly a challenge. Here is the intra-operative images. By the way the patient was my mum's best friend so the pressure
was on. But so here is the intra operative images and you can see that I have one of these antennas directly on the IVC essentially in attempt to overcome that heat sink effect. And in addition, I have placed three of these antennas which is a lot of power.
In here you can see afterwards is a 5.6 by 4.8 cm ablation, it's big enough. I wish it had been a little bit bigger and I wish their wasn't this one little dog near here, but I felt like it was adequate. Here she is, she is now four years out and everything looks great so, fortunately it
went really really well. So that brings me to the heat sink. Microwave really does overcome heat sink. This is where the chip downed in with a per fuse liver model. And you can see on the right side of this table here, the top is
microwave. And you can see even within very high perfusion rates, there is really no change in the size of the ablation zone. Whereas with RF it drops off over a different perfusion rate and
that just because RF's conducted heating gets overwhelmed by the perfusion of the tissues. So Microwave can be very advantageous here. What about the risk of thrombosis? Well this is the state that we did in our lab where we looked specifically at can we thrombose vessels?
And this are the hepatic arteries. You can see the hepatic arteries essentially do not thrombose, no matter how hard you try. Bigger vessels did not thrombose no matter how hard we try. What you can see is actually the portal vein was the most vulnerable structure, and you do have to be a little bit careful with the portal
vein and worrying about thrombosis. In our experience we've had a couple of these that happened and fortunately they often respond to inter-coagulation, and open back up. But obviously whether that's sclerotic, it can be an issue.
So you gotta be a little bit ablating close to large central portal veins.
Here is another one. This is an interesting case, they have a large hepatic hemangioma. It's progressed in size and it's giving him back pain.
A young man and he's kind of a little bit desperate at these point actually, so we were asked to take a look at him. So here is the tumor about 14 by 12 by 10 cm or so. We think this is a good case for ablation, how many would take this case on? Hands up , I see my colleague and maybe one or two others.
So the short answer is, I actually think that these kinda cases are probably the best cases we can have for ablation, benign tumors are an excellent target, both from the stent point,
it's an excellent option for the patient, and number two is an excellent growth opportunity for what we do. So, it is a completely untapped territory as far as I can tell. This is the procedure I did, I kinda split the tumor into two separate
portions, one is a superior margin and one is an inferior margin. And I took it and I did three burns in each location, placing the deep margin burns, pulled back burns, pull back burn and then pull them out.
In the end, let's see here, here's what it looked like, so you can tell by looking at it there's probably some enhancement around the periphery. So I probably didn't get a complete ablation, probably 90% of the
volume of the tumor, but that's more than adequate actually in this case. And the reason is this, if you look at this, this is a movie showing you tissue contraction especially with microwave,
tissue contraption is very dramatic, so if you watch this you can actually see the tissues getting pulled in, those green markers mark where those markers were at the start of the tumor during ablation, and you can see them getting sucked towards the center.
Almost all the contraction occurs in the short access which is one reason that our short access of ablation zone is shorter than the long access but, you can see, very significant tissue contraction. And the end result of that in this case, is you can see there is
my pre-ablation volume, and here is my post, and my arrow is not showing up. There it is, maybe. You can see,
so it's about half of the volume, immediately after the procedure and now I've had the patient gotten immediate pain relief, because he was getting pain from mass effect not from the tumor itself, other than the mass effect.
So this is a very important thing when it comes treating benign tumors. Remember, our goals of treatment are very different. We're trying to devascularize a tumor in the case of adenoma in particular, to decrease the risk of hemorrhage, we're trying to
decrease mass effect in this kind of malignant transformation risks associated with adenomas, but remember you don't have to get every single cell. So even if it's a big tumor like that it's not my goal to kill the entire tumor with a margin it's my goal to improve the patient's
symptoms, and quality of life. And they also seem to ablate easier than malignant tumors probably somewhat because the perfusion may be a little bit less. And so we can even target very large tumors. That's when the larger ones we've done, but we've done many tumors in similar size. So this really as a less invasive answer to a minor problem,
if you are a young person would you want a major liver surgery or would you want just a simple ablation? Hepatic adenomas are very easy to do too, here's a four and a half centimeter hepatic adenoma. You can see we kinda have nice ablation zoen.
These patients go back to work within days, versus the surgery where it tends to be long recovery. Here's kinda the cautionary tale. A young medical student, he wanted to be a surgeon and I think as
a result, he was kind of taking down the pathway of getting a hemihepatectomy. We wanted to do an embolization followed by ablation. And here is what happened to him. He actually needed a re-exploration for high grade bowel obstruction, and we all know that he's kind of headed fast in trouble to the
rest of his life probably related to adhesions and adhesive disease and bowel obstruction. So realistically, we could have done in a merry minimally invasive way and instead, he's got a major surgery. Works for hepatic cyst too. We place the antennas and we drain the cyst around the antennas
and then we do a relatively short burst of ablation, and we can get excellent result. Here is the cyst before and the cyst after. Six months later, you can see is about 10% of the volume of the cyst left.
The patient was completely asymptomatic. Here is another case.
Here is another case. Seems relatively straight forward. A little over 2 centimeter ablation HCC and you can see the one thing that you might think about, here is the pancreas right behind it.
Here is the stomach right over here. So we thought, okay, we'll put our antennas in and we'll see what we see. So here's our placement of our antenna. You can see it's relatively essentially positioned and that HCC
everything looks good. Here's our CT scan after placement before ablation. There's a couple of issues to get here. One is even though we used ultrasound for guidance we definitely utilize CT for the big picture. Some of it's a resource allocation issue,
but we're able to utilize CT and ultrasound for our procedures and if you can do that, it's a very strong powerful combination. So in this case, this was good because we saw not only are we close to the pancreas we don't wanna burn that,
but we're also very close to the stomach and we definitely don't wanna burn that. So what do we do at this point, we've already got the antenna in place. What would you guys do?
Anybody? >> [INAUDIBLE] >> [INAUDIBLE] And if you're gonna do ablation in this day and age you really need to be comfortable with the theories and the performance fighter deception. It's critical. In this case I just put a spinal needle through the left lobe,
inject a bunch of fluid into the kind of retrohepatic space here between the pancreas and the stomach and the tumor. And it gave me great separation, allowed me to do the procedure. Here's the intra-procedural monitoring see some of the saline here
kind of the hydrated section fluid/g. And here's afterwards, and you can see if I would have done the ablation without the hydrated section it would have gone like this. And that would have definitely incorporated both the pancreas and the stomach.
So definitely you have to be able to do [UNKNOWN] and be comfortable with it's performance. I recommend doping your saline or if in the case of RF make sure you use D5 because that allows you to differentiate it from soft tissue. If you just inject saline,
you expect it to be low attenuation that you can differentiate it from the liver and adjacent structures, but for whatever reason it does not turn out that way.
So Dr. Klaus also mentioned exophytic tumors. How many of you guys do exophytic tumors in your practice?
See only a couple of you. Yeah so I actually encourage you to take this on, they're actually not nearly as challenging as you may think they are and the reason is because there are techniques that you can utilize, where you don't
necessarily have to puncture directly into the tumor. Everybody is a little bit scared to puncture directly into the tumor for risk of bleeding and tumor seeding. So how do you approach this? Well actually we use the no touch or wedge technique fairly frequently
and what you do is you put your antenna as you have to have multi antenna system or multi applicator system to do this. But if you can put your antennas around the tumor like this without directly puncturing and here's the tumor, here's the antenna, here's the other antenna,
we haven't actually touched the tumor and so you have to, in that case you are being allowed that risk and yet you can get a good ablation. So here's a movie, a wedge ablation and what you'll see is the green is kind of complete ablation and even though we're not actually touching
the tumor in the center here. Let's say there's a tumor right here, you can see that the ablation zone's actually grow together in the center there because of the way that the synergy of the two antennas work. And so the way I do this is I do an ablation like this and then
I remove one of the antennas and replace it into the center of the tumor after it's already been devascularized and mostly killed and that works really, really well. There we are afterwards. Then here's this ablation and now I can see we're starting to
ablate deep into the tumor but over time it goes to grow up to incorporate the tumor. And here's the post-ablation assessment and it looks quite good. You're gonna get a little bit of a bigger ablation zone than you would normally, but it's usually adequate.
So here's another tough one, right. So and Dr. Klaus
showed a case almost exactly like this. You can see this HCC just right on top of the hepatic duct here, so this is one of the, I think it was the right hepatic duct, and so what do you do in that case? How can you manage that? What would you guys do, anybody?
>> [INAUDIBLE] >> Okay, so you can do biliary perfusion, essentially some people do that. There's the LA group I know does that quite a bit. Any other ideas? [BLANK_AUDIO]
How many of you would do intra arterial therapies for this? Maybe. Yeah, so intra-arterial therapies are definitely a consideration, you might think about a TACE or something like that in this case though I actually think that this is one of the places where ethanol
plays a role. You really are probably gonna make the patient worse off if you ablate their duct than they were to start with. So you really wanna you really wanna avoid that in any way shape or form, and I don't
think with either cryo or microwave you can safely say you can ablate this completely without possibly doing damage to the duct, but with ethanol, actually you can get a very nice treatment and you can ablate this tumor with minimal risk of damage to the the adjacent duct, interestingly when you use ethanol,
I don't know if you haven't used it, it actually kinda looks like a heat based ablation and causes this gas cloud and you can follow that quite well in ultrasound. Often we should almost already expect a come back and have to do
a re-treatment or two with ethanol. You almost never get it all in the first go around for whatever reason, it's just the way ethanol works and if you look at the historical kind of literature you'll see that most of them, if you look at the treatments, most of them take two to three sessions and you
should expect that to be the case. They're are inferior to heat based ablation as far as overall outcomes but they're still quite good. You can have local tumor progression rates in the 20% range which is actually pretty, it's not too bad considering a lot of time you're trying to bridge these patients to transplant.
>> Can you do intra arterial therapy followed by ethanol [INAUDIBLE] >> Sure, you can. If you're gonna do intra arterial therapy my approach would probably be to do the intra arterial therapy follow the patient and if in fact it shows evidence of local tumor progression, which they often
do over time, then at that point I would go back with the ethanol. But there's nothing to stop you from combination treatment and that's actually what this case is about so good segway. So in this case we have a patient with two HCCs.
>> Can you do intra arterial therapy followed by ethanol [INAUDIBLE] >> Sure, you can. If you're gonna do intra arterial therapy my approach would probably be to do the intra arterial therapy follow the patient and if in fact it shows evidence of local tumor progression, which they often
do over time, then at that point I would go back with the ethanol. But there's nothing to stop you from combination treatment and that's actually what this case is about so good segway. So in this case we have a patient with two HCCs. Here's one. It's a little under four centimeters right next to the gall bladder.
The gall bladder's kinda out of plane here but it's right underneath this tumor. So that brings the question of is it safe to ablate next to the gall bladder? And here's the other one. This one's a little bit higher.
You can see it's relatively indistinct. I can see there's a tumor there but but you can see the margin are distinct. Those measure out 3.6 centimeter but we weren't really sure how big it is. And so that brings up this concept of combination therapy. And I think combination therapy is not gonna be critical to our
success in the kinda intermediate sized tumors. With our microwave program we've actually shown that we can get complete ablation and tumors up to four centimeters so we kinda broken that magical three centimeter barrier and taken it to four centimeter but still you're going to have tumors like this that are kinda border line indistinct and are over four centimeters or what
do you do with them? Well we do believe in combination therapy and we do this frequently. So here's a nice example, nice TACE, you can see good up take in both these tumors, everything looks pretty good. We came back three weeks later and microwave ablated the one in the more superior tumor there
and you can see what looks like a nice response with good coverage, everybody was pretty happy. We decided to leave the one next to the gall bladder alone because we were a little bit worried about proximity to one of the bile ducts and such, but here's what it looks like
that one that we did the combination therapy. Everything looks good, you can see the [UNKNOWN] in the tumor itself and then you can see the margin of the ablation around the edge. So you can actually see the result quite well and that did great.
Unfortunately as often it happens with TACE alone as you know, the other one progressed over time, so here's that cuff of enhancing growing soft tissue around the rim of [UNKNOWN] that happened over the course next here and actually on this one you can really see how close
it is to the gall bladder. And so we reconsidered what we thought about the combination therapy, we decided we better go ahead and ablate this, so we put two PRs in this, the gall bladder and common duct were quite close, here is our ablation and here is our results. So here
is our ablation zone. After the gas starts to resolve you can actually see it a little bit better sometimes, so there is the ablation zone touching the gall bladder, the gall bladder wall itself got a little thicken, this patient had
some mild abdominal pain, but they never had any adverse outcome. [UNKNOWN] is published on that, there's been some other publications. It's actually very, very safe to ablate next to the gall bladder. >> [INAUDIBLE]
>> That's a perfect question with no good answer. The short answer is you could actually make arguments in both directions that you should actually do the ablation first followed by the intra-arterial therapies and vice versa. So the argument for doing the ablation first followed by the intra-arterial therapy is that you get that hyperemic rim around the margin of an
ablation zone. Which actually might in theory make your TACE more effective, better uptake, etc. We've taken the opposite tact which is we know that TACE is often not a complete treatment whereas we feel like ablation can be a
curative therapy. So we do it the way we think it will make the ablation more effective. So if you devascularize a tumor with TACE before hand you make your ablation more effective and therefore more likely to get a complete treatment. We usually separate them by a week,
in this case there is some logistical reason that we couldn't do it for three weeks, but the reality is any time within a month is probably adequate. All right so here's the gall bladder wall once again thickened, we've
done lots of these procedures, and we've never had anybody who's had a serious complication related to gall bladder. And I have a colleague who calls it the cockroach of the abdomen and I think that's a pretty accurate assessment, it really is pretty
hard to just hurt the gall bladder. So here's before and here's after and now this patient is several years out, everything looks good, no evidence of disease, so a good outcome.
no evidence of disease, so a good outcome. So here's our approach to combo therapy and you have to kinda take whatever approach you feel most comfortable with,
but this is what we do and we've actually incorporated this, not into only in our practice, but into the practice of our institution. So when we talk about these patients at Liver Tumor Board this is the approach that we always take.
If you're less than 3 cms we feel very, very comfortable and we can always, or nearly always, we have about a 7% local tumor progression rate but those are usually easily retreated, treat these with ablation alone.
If they're between 3 to 4 centimeters and they have have some worry, some characteristic. Infiltrated margins, location, things that makes it more challenging to ablate, things like that,
then we will consider doing a combination therapy. Anything over 4 centimeters and less than seven will almost always get a combination therapy but over 7 centimeters ablation kind of falls off the map. That's been our approach and we've had very good results with this and so I can say you guys have to do what you're comfortable with
but definitely a consideration.
So this case is used to illustrate some problem that we all have. So here's HCC in the right hepatic lobe. It's actually a cyst next to it which is a really good landmark. This is a 53 year old male and we got in and we do this ablation.
You can see we kinda undercut the tumor in this case. Rather than doing the wedge we actually kind of undercut it from one side but it works just as well, and here we are at the end of the ablation everything looks good. You'll see by the way that there's a very consistent theme in how I do my ablation, you'll see five minutes at 65 watts for almost every
patient. And there's a lot of reasons for that but probably the most important one is I'm kind of a simple guy and if I start messing around with a whole bunch of different settings and change in the way I do things then I find it difficult for me to predict what I'm gonna get. I just think the simple you keep it the more consistent you make
it the more likely you are to get consistent reproduce-able results. So we mess around a lot in the lab in the pigs, working on their livers and kidneys but when I'm working on a patient I wanna make sure I have a predictable consistent result that's gonna give them a great outcome. And so five minutes, 65 watts I use pretty routinely. The only alteration
I'll make to that, is number one, if I'm getting too big of an ablation I'm gonna injure something, I'll turn down the power or number two if I'm not quite covering as much as I want I'll continue the ablation for more time and that gives me a little bit larger ablation zone.
But once again it depends upon your equipment that you use. So here we are afterwards everything looks good on the ultrasound, and the question comes up do we have a complete ablation. I told you earlier that we should do immediate assessments and determine if we've got a complete ablation. So how do we know if we've got a complete ablation?
Well we usually do something like measure from a landmark and try to figure out if the tumor is centered there, things like that, how big our ablation zone is etc. This looks really good but are we sure that that's ablated and that's always a challenge for each and everyone of us as we go through these cases.
I wish it was simple and straightforward but it's often not. The good news is, is there's things coming to help and it's technology driven and every manufacturer pretty much has something like this in the works, this is one of the systems that I'm familiar with and as you can see what they allow you to do,
I don't know if you can tell, there's a little red circle in the center of that and that's the tumor pre-ablation and then the green is the overlaid ablation. And they do a registration technique to make sure that those line up and they make sure you've got a complete ablation.
So there's a lot of software coming down the pipe right now. Cryoablation has one that not only does this, but also shows you a planning before hand predictive of what they think the ablation zone would be. I haven't actually worked with it so I don't know how accurate it is but those kind of things are definitely gonna evolve and they are gonna make our jobs actually a lot easier to be honest with you.
are gonna make our jobs actually a lot easier to be honest with you.
So I have throw a cryo case in here just because we do do them every now and then so most of the time we are doing in kidneys these days and even then relatively rarely. But this is a patient who's had a left hepatectomy, too big tumor with lots of little daughters lesions. So you can kinda see these lesions are kinda scattered around it.
So we need a really big ablation here probably eight or nine centimeters and that's really challenging if not impossible to accomplish with current heat based modalities. But you can do it with cryo. And here's the cryoablation you can see this very large ablation zone that incorporates the entire tumor and a very large margin.
And so this is something that cryo is good at and there's a reason to use cryo in some cases. Unfortunately in this case there were other mets that developed down the line, this is a year later. You can see the ablation zone looks great but unfortunately they got another little tumor.
And that often happens in these patients obviously. So remember if you are going to use cryo there's no such thing as a single cryo probablation, it's just not effective. This is Peter Littrup's work when he looked at the thermal concentric, I'm blanking on the word but anyhow the temperature at different
levels out from the cryo probe based upon how many probes you have put in and you can see with a single probe you only have a very small zone of ablation around that probe. So a couple of things to remember, these are the two main rules people use, one cryoprobe per centimeter of tumor so if you have
a five centimeter tumor you need five cryoprobes, etc. And the two in one rule which essentially states that no more than two centimeters between the cryoprobes and no more than one centimeter from the edge of the tumor, and you'd figure the center of the tumor is gonna get incorporated because of the synergy of the ablation.
So if you do do cryo keep that in mind.
So here's another case, it's a little bit more of an advanced case maybe but this is something that comes out fairly frequently for us. Which is through the tumor, this is the one with metastatic
breast cancer. And she has four metastasis and two and three are right underneath the heart. So we actually had this referred to us from a fairly well know institution that said this was not safe. How many of you guys would try doing something right next to the
heart like that? So not a lot of excitement for it. So not only did we do this case but it kinda sparked our curiosity and we decided to do a study to figure out if it really was safe. So here is the case, I did this case about probably four or five
years ago now, and you can see these two were kind of ablated in combination with each other. This one, you can see this cryoprobe, this antenna is almost right underneath the heart and this one fairly close as well. Here is the afterwards and you can see this ablation zones technically release, this one
will incorporate a portion of the heart into the oblation zone. So it really made us start thinking well is this really safe? Or am I being kinda cowboy to go ahead and do this. So we did both a animal study and a clinical study and what we found was actually this is very safe. And probably the main reason is,
is because the heart is not a stationary object. It is moving constantly as you do this and when we do this in open situations where we're looking at the heart, we're looking at the lung, we actually did a clinical animal study in the lungs so we can get even closer to the heart.
And what you find is that if you're more than three millimeters away from the heart, your probably not gonna do any damage to the heart. And it probably has to do with its perfusion and its motion. So it's really very safe and we showed in our clinical practice
as well that it doesn't cause cardiac events. So don't be too concerned, obviously you don't wanna hit the heart but as far as ablating next to it.
So that brings me to the end of my cases.
My kinda conclusions you can see here really I think you had to strongly consider microwave over RF. I think you really can accomplish everything you can with RF and more. And I like to keep things simple, so I try to minimize how much
I go between different systems. Maybe you do enough cases and are comfortable enough with a bunch of systems that you can do that, but I don't feel comfortable doing that myself. I really think you shouldn't use ultrasound for guidance and
monitoring. I really think that the immediate assessment is important if you can do it. You can either use ultrasound or CT. You can do the contrast enhanced study. We use ultrasound particularly in patients with renal failure for
doing that assessment but most times we use CT. Becoming familiar with hydrodissection techniques is really critical if you're gonna do ablation. About a third of our cases that we do involve hydrodissection. We probably do a little bit more of a complex patient case load than most people but you really have to do it if you're
going to do it well. Ethanol for central tumors, or preductal tumors more accurately, I think is a good idea and really does, I think, still play a role even in this day and age.
You really should think about combining with intra-arterial therapy for larger or infiltrated tumors in HCC and remember the ablation near the gall bladder and heart is safe and the software packages that are gonna do both planning and post ablation assessment are gonna make our lives much easier. Thank you very much.
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