Ready, Aim, Ablate: Liver Ablation Procedure Techniques

[Dr. Christopher Beck]
Got it. And how about resources for some interventional radiologists out there? Are there any papers or sites that you've looked at that, as you were kind of getting your ablation practice off the ground that you thought these were good foundational papers that either help you participate in tumor boards or help educate referring docs?

[Dr. Driss Raissi]
I think one of the things that I've tried to do when dealing with through my referring colleagues is radiofrequency ablation is rather what's trusted out there. And people now know that radiofrequency ablation works so when you talk to surgeons and hepatologists, radiofrequency ablation is something that instills trust in them like, "Oh, okay. Yeah, we know about it. We know it's being compared to surgical resection. We know it's rather comparable up to 3.5 centimeter lesions." It's something that they now feel comfortable with. So your first step is to know the literature that compares microwave ablation to radiofrequency ablation. So you can sell microwave ablation as equivalent or non-inferior to radiofrequency ablation.

[Dr. Christopher Beck]
Sure.

[Dr. Driss Raissi]
So there is a paper that I like which is in the International Journal of Hyperthermia and it's a rather recent one from 2019, which compares micro ablation to radiofrequency ablation in hepatocellular carcinoma. It's a systematic review and meta-analysis comparing both modalities. I think they looked at 14 studies, a combination of retrospective studies and control cohort studies for lesions specifically larger than three centimeters and it found no significant difference. You're not going to find papers out there comparing five centimeter radiofrequency ablation because it would inherently have its limitations and the local control starts to drop after 3.5.

Also, one of my favorite articles actually, recently actually, was in 2019 by de Jong et al, which was a systematic review of microwave ablation itself published in 2019 European Journal of Radiology. I think it was called, microwave ablation systematic review of various FDA approved devices. Why do I like that article and I use it in a lot of my presentations? Because you would learn a lot of the physical properties of microwave ablation. You'll learn that not all microwave ablation devices are made the same. Some have different properties than others. Some may be better than others.

And you will also see something very important. You will see how the performance in ex vivo models has nothing to do with in vivo models, which if you're a fellow, you're going to see all these excited numbers in ex vivo model so I'm like, "Oh gee, I can ablate at six centimeter lesion with one probe and be done." No, you won't.

[Dr. Christopher Beck]
I know we've been talking a lot about HCC, and this could still be HCC, it can be multifocal HCC. Do you have a limit as to the number of lesions that you want to ablate before you start thinking about another treatment modality?

[Dr. Driss Raissi]
That's a good question, right Chris? Because it doesn't seem like there is anything written in the letters where people just kind of mention things here and there. You want to go by Milan criteria and say, "No more than three." I mean, we're going to lose a lot of patients.

[Dr. Christopher Beck]
Yeah. Seems conservative, right?

[Dr. Driss Raissi]
Yeah, we're going to lose a lot of patients. Then somebody told me once, "Oh, four." And I'm like, "Based on what? Why four? Because it's one more than three?"

[Dr. Driss Raissi]
Yeah. I mean obviously, you can do more. My surgical colleagues, when they start doing their burns, they're like, "Oh yeah, I burned eight lesions." Yeah. I mean, you have the benefit of doing an intraop. So they don't seem to have a limit of how many lesions they Zap intraoperatively. So should we have a limit? Well, maybe. I mean, sometimes it's very tedious and if you ablate eight lesions in the same session knowing that you are ablating let's say, I don't know, 30, 40, CC's of liver, that adds up to potentially sending the patient into liver failure. So we have to be smart about it.

So I usually take up to six lesions. But what do I do? I try to do what I think makes sense. Why do they have the same sessions? So if I have them in the right maybe, and if I feel like, you know what? The left will take care of the patient so I can freely maneuver in his right lobe now when he has a healthy left, okay. And vice versa, but if I'm going to try to target left and right, a total of three lesions, three lesions here, especially in a patient with HCC, it could be dicey.

So what I do is, I actually divide my sessions. I'm like, "Come to me. Right lobe will give you three or four lesions in that right lobe and then we'll take care of the other one, two, three lesions, whatever you have in the left lobe." The test of time, within two to three weeks. And look at his life, it seems like he has tolerated it. There's no reason to rush. Why are we rushing? We might be dealing with dire consequences.