I'll talk a little bit about hybrid EMR, some ESD concepts that we can bring into our EMR practice. These are my disclosures. So as we already know, and it's been talked about, EMR should be the first-line treatment for most non-malignant colorectal polyps, and the reason for that is because technical success is very good, right? So we are generally able to take most of these polyps out, and as Jennifer mentioned, the adverse event rate is fairly low. It's got a good safety profile, and it has several advantages over surgery that most of us are aware of. But in spite of that, there are potential limitations. We've seen these with difficult cases that were presented yesterday, and some of these include that it's associated with a low rate of emblock resection when dealing with larger lesions. This inevitably is going to require piecemeal resection, which is fine. It's associated with a higher recurrence, but there are adjunct techniques nowadays that have shown to be effective and potentially reduce that risk. Having said that, EMR can still be extremely challenging in the setting of submucosal fibrosis, such as the presence of a tattoo prior and completely resected lesions. Some non-granular lesions can be quite fibrotic, and certainly in the present invasive cancer. So in the scopic submucosal dissection, the advantages that obviously allows us to resect a lesion and block irrespective of size, thereby provides the optimal pathological specimen, not only for staging, but in the setting of certain cases, it can be curative for cancer, and thereby also associated with a lower risk of recurrence, given that it's resected in one piece. And this is particularly important when we're dealing with anything that we suspect that has cancer. As you see from the NCN guidelines, when you remove a lesion in a single piece, an accurate histopathological assessment can be performed. It tells you that the lesion has been completely removed. It can assess for lymphovascular invasion, other prognosticators, then no further treatment is necessary. On the other hand, you can have the same specimen, even though it's been cured endoscopically, if it cannot be accurately assessed histopathologically, you inevitably commit the patient to surgery. So that's where the concept of end block resection is important. So for those of you who like food, like myself, you can all agree that that steak on the left is not the same as what you have on that pan on the right. Same thing with your pathologist. He's going to tell you that ESD specimen is superior than the piecemeal resection. So our main job as endoscopists, when it comes to advanced resection, as many of the speakers already highlighted previously, is to risk stratify lesions. So we need to understand what lesions are optimal for what type of technique. And that is going to play into the need for end block resection. There's multiple classification systems, as you guys have already heard. Nice classification, the KUDO, the JANET, and so forth. I try to dumb it down for myself a little bit more into three categories. So you can have a regular tuberoid pattern. This is your NICE2. This is your JANET type 2A, where everything just looks kind of similar in terms of the width of those tubular patterns. That's going to be your low-grade dysplasia. This is going to be the lesion that you can adequately remove piecemeal without major consequences. The middle lesion is the one that you still have that conserved tubular pattern, but now you start seeing some variability. There's variability in the width, in the vessels, in the pit pattern. And this is where you start thinking about advanced neoplasia. Advanced neoplasia meaning early cancer or high-grade dysplasia. These are the lesions that, if possible, you should probably try to remove in one single piece. And then the lesions on the far right are certainly those that are deeply invasive, when you can no longer see any pattern at all. These are the type of lesions that are better referred to surgery. And then it comes to LST morphology, as we kind of briefly touched upon yesterday. The risk of cancer in these lesions also increases, particularly in the left colon as well as in the rectum, and thereby some of these lesions are better removed and blocked in that area. So I'm just going to give an example of a lesion. This was a lesion that was diagnosed as high-grade dysplasia on biopsy and referred to me. And then I'll kind of pause it as we look at it and tell me what you guys think. Any comments from the audience on that vascular or pit pattern? So people are saying cancer. Do you think it's deeply invasive or superficially invasive? Deep. So I guess I'm deep. Okay. So, yeah. So in the middle, it's quite amorphous. You start suspecting deep cancer. So this is a lesion that I did an endoscopic ultrasound on, and there was a nice interface between the lesion and the muscularis propria. So I knew it was submucosally invasive. It's really hard to tell. Is it going to be less than 1,000 microns? I just kind of care whether it's invasive to a point that I cannot resect, or is it possibly resectable? So I know what's your next step. Some people will say full thickness resection, EFTR. And this is probably the right lesion for that, right? It's not that large. It's probably just about maybe a centimeter and a half. So this could have been a good case for EFTR. Unfortunately, I generally leave EFTR as my last resort, so I decided to do ESD for this lesion. Here's the lesion on MBI. And you see some of that, what I call chicken skin around the lesion. This is kind of another telltale sign that there may be cancer already involved. So I'll just kind of fast forward this. But basically, there's the ESD. At the end, we removed the pieces. One area, there was a little bit of a muscle injury, so I put a clip, removed it. And this is the histopathology of the patient. It was invasive cancer, margins negative. Is this it? Should we stop here, or should we ask more questions at this point? What? Right, right, right. So this is where you want to talk to your pathologist, right? So you shouldn't stop here. You should ask them about the depth of invasion. Is there lymphovascular involvement and so forth? Thankfully, this patient, it was a superficial cancer. There was no lymphovascular involvement, so he was cured. So then the question is, why don't we just do ESD for all, right? Why are we still doing EMR? And the reason is because it's a technically complex procedure. It's associated with longer procedural time, steep learning curve, and higher rate for serious adverse events. So we started thinking about what other strategies can we adopt that may potentially still allow us to resect lesions and block. And that's where the concepts of pre-cut EMR or hybrid ESD come into play. These terms are often used interchangeably, but there are some subtle differences. With pre-cut EMR, what you do is you do like a mucosal incision around the lesion, but you don't really dissect into the submucosa. So that's pre-cut EMR. Hybrid ESD, you do circumferential mucosal incision, and you do some extent of submucosal dissection. And how much submucosal dissection you do at that point varies. So again, these are just some images of what pre-cut EMR would be. You see they'll do like a circumferential mucosal incision and then put the snare around it. You can do that with the tip of the snare of an ESD knife, and I'll kind of touch upon that a little bit later as well. So what is the data for pre-cut EMR? This is a study by Dr. Saito's group, and what they demonstrated in this small study was that the end-block resection rate, if you look at there, it's not very impressive, right? It's relatively modest at only 67%, with complete resection noted in only 17% of four specimens. That's actually quite low. So when they look into the subgroups, you can see that the end-block resection rate is high for lesions between 2 to 3 centimeters and decreases exponentially once the lesion gets above 3 centimeters, right? And this makes sense. If you think about pre-cut EMR, all you're doing is you're making a mucosal incision. By not dissecting into the submucosa, you're not really shrinking the size of where your snare goes around. So if you have a big lesion, even if you make a mucosal incision, you're not really reducing the size of the lesion. So because of that, I don't think it's that effective for lesions larger than 3 centimeters because your snare is still not going to be able to adequately capture it. But the advantage of a pre-cut EMR is that it creates a ledge where you can anchor your snare that can be quite helpful for fibrotic lesions like some of the videos that Raj demonstrated yesterday. So here's a case, just kind of an example. This was an LSTNG that recurred. They had partially removed it times two, so it came to us. And as you can see, the residual amount is not too big. But as you start injecting it, it forms this kind of crescent shape. So you know that your snare is not going to be adequately going to trap this lesion. It's going to slip, right? So what are your choices here? Do you want to do piecemeal resection, cold avulsion, pre-cut, full thickness? Any votes for anything? All of the above. All right. So I decided to do pre-cut. So again, what I would do is I lift the normal mucosa around the lesion. I do it a little bit further from the lesion. And then I dissect a little bit with the tip of the snare to isolate that fibrotic portion of my lesion, which is there. And then you can really anchor your snare to remove it. So here's a video. I think this was just from a couple weeks ago. There's a lift there, but the dark stuff is also tattoo. So this was a lesion that was referred that was tattooed. And you can see it was biopsied as well. Any comments on the pit pattern or vascular pattern? Sorry. So yeah, so the middle portion of the lesion made me a little bit concerned. It doesn't look that tubular. It's got some loss of pattern. And then, you know, it didn't lift that well, but that could have been from the tattoo. But the bottom line is I was not very sure if we were going to be dealing with invasive cancer in the setting of tattoo or not. So again, in these type of cases, the lesion is not too big. It's probably right around 2 centimeters. You could argue maybe you can do EFTR. We ended up doing the pre-cut EMR, as you'll see here. So again, here we're just using an ESD knife, similar to the same knife that you guys were playing the hands-on lab yesterday and just going around the lesion to open up the mucosa. And then once we've separated the entire margin, I used a captivator snare and put it around it. Any dissection at all? No, I just, yeah. You'll see something here, which I want to highlight. So I felt pretty good that I had the entire lesion there. I went ahead and I resected it. And you see tattoo all over the base. This is all black, but then there's a little piece of tissue here. So I wasn't sure, well, did I miss it? Is this something within the lesion? It seems like to be within the borders of my resection. Anyways, I took that off, but just to highlight some of the limitations of these techniques, right? Because it's still blind, you're still not seeing the base. You think you're getting unblocked, but there's a little bit of tissue there. I took it out, I still sent a pathology to make sure, closed it up, and the pathology just came back as a tubular adenoma. So again, it just tells us sometimes we're not as good as we think at visualizing lesions or being able to tell whether there's cancer or not. And thereby, the importance of sometimes considering and block irrespectively. So hybrid ESD, again, the difference between hybrid ESD and pre-cut EMR is that you're going to be doing some submucosal dissection in addition to the mucosal incision itself. What is the data on hybrid ESD? So this was a systematic review meta-analysis of 16 studies. It was published just within the past two years by Hero's Group. And what they noticed is that hybrid ESD is associated with a significant shorter procedural time. Again, not surprisingly, adverse events were lower with hybrid ESD. Now, the downside is that when they look at outcomes such as MBLOC resectional rate, it was also significantly lower when compared to conventional ESD. So the problem with this data is that there's a lot of limitations with the current evidence. Number one, 14 out of the 16 studies, including this meta-analysis, are observational studies. So there's significant selection bias. You can think of it as, you know, people are doing ESD. They get to a point that they cannot remove the lesion because it's, for whatever reason, it's difficult. And then they switch to hybrid ESD, right? So potentially, the worst outcomes are associated to that. There's lack of control for endoscopous experience, lesion size, prior interventions, and so forth. So there's just a lot of limitations regarding whether hybrid ESD is better, worse, or equivalent to conventional ESD. So as part of that, we're currently doing a multi-center randomized study looking at hybrid versus non-hybrid ESD for colorectal polyps, in which our primary outcomes include procedural time, resection outcomes, adverse events, recurrence, and endoscopous grading of procedural difficulty. So this is a patient that we did as part of our research protocol. Again, this is not a lesion that you necessarily have to do ESD. I just want to clarify that. This is an LSTG in the cecum, so you can perfectly take this out as part of EMR. But this is part of our research study, and I'm just including it in this video to show you the technique. So again, we're going around the lesion, doing some dissection. As you can see in this technique, we're going to actually be doing some mucosal dissection. We're not just opening it up, the mucosal incision. There we are between the lesion. You have the lesion on the left, the muscles on the right, and we're going to keep dissecting. And the idea is you want to dissect enough the lesion off the muscle so when you actually put the snare around the lesion, you feel good about it, that you're going to have a high chance of in-block resection. So I think I resected about half of the lesion or so. That's where I felt comfortable. It's about 4 centimeters, 3.5 centimeters. Put the snare around it at that point as part of the randomized study, and then this final part, you just take it off with the snare. But again, unlike conventional ESD, this is always the nerve-wrecking part because you don't know after a snare goes off if you've left a piece behind or not. So then you're always in suspense, see if the work paid off. In this case, it did, so in-block resection. Thank you. There's still some mucosa in the area, right? It's just, you basically shrank the lesion. So yes, there's exposed muscle, but we still inject in that portion before I put the snare down. So I have another lesion here. So this is a lesion that was in the descending colon. Any thoughts about pit pattern? Any thoughts? Let's say, 2J, not 2B. J, not 2B. So advanced neoplasia, right? So high-grade dysplasia, maybe cancer. So this was in the left colon. Again, not a large lesion. This is, you know, one-ish, one and a half. There is a scar to the left. There is a big tattoo there. I just saw how you dressed this lesion. Yes. Just look for the depression in the middle. If you take a closer look, you can see the edge here. And you can see the edge elevated. So 2C plus 2A. So, yeah, let's come back here. They cancer, high-grade dysplasia. Right. So again, this is a lesion that you wanna remove and block. Now, again, size-wise, you can remove this and block with EMR, but it's got a tattoo, it's got the scar. I have my doubts of how well I can remove this and block with EMR. So, you know, I decided to actually, for this case, I said, you know, let me go with EFTR. Now, the problem is, with this patient, the sycmoid colon was very, very challenging. And I actually was not able to pass the EFTR device, which I show here. I actually, it was so tough, I put a wire, I tried to go over the wire, and I just couldn't do it. And I said, okay, well, I'm giving up on the EFTR. So I went with ESD. So again, if you see the injection, it lifts nicely in the normal mucosal side. So you kinda wanna start injecting further away from the lesion. But if you see at 12 o'clock, it doesn't lift at all. And again, it's because of the scar tissue. And as we expose to some mucosa, getting closer to the lesion, you're gonna see that it's very fibrotic. There's a lot of tattoo in that area, which impeded adequate removal. So this side was still lifting relatively okay. But as I go to the other side, which I'll show later, it's pretty much just fibrotic tattoo. And then you can already see the strands of muscle. It was, it was. So at that point, you're in a bad position for ESD because I'm having a really hard time getting parallel to underneath the lesion. So my knife is constantly perpendicular. I have no sub-mucosal space. So the risk of perforation is quite high. So, but I felt good that I had gotten to the point where, again, I can probably put the snare around it and get it in block. What's the problem is that you have a lot of... Exactly. So there's the, after the resection, you can just see it's all black, but we got it all in one piece. It came back with high-grade dysplasia. Unfortunately, no cancer. Yeah, I try, yeah, to give it an extra lift as I put the snare around it. So when it comes to doing like the mucosal incision, kind of doing the hyper knife technique, I always tell there are two, three very important concepts. Number one, you wanna get a very, very good lift before you make that mucosal incision. And the reason for that is that the direction of your knife has to be almost perpendicular to the mucosa. This particular true in areas like the stomach where the mucosa is very thick. If not, you're not really gonna be able to cut into the sub-mucosa. So you wanna get a knife lift, puncture through the mucosa into the sub-mucosa, and then start dissecting laterally. The other important thing is, like I was saying in the lab, you wanna dissect a little bit, check your work, make sure that you're cutting those sub-mucosal fibers by tracing your initial mucosal incision to open things up, or else if you just make the mucosal incision, things do not separate. If they don't separate, you're actually making things worse because you already made a mucosal incision. When you inject fluid, it's just gonna leak out now, and you have not separated the lesion enough. Now, once you've done the sub-mucosal dissection, you kinda wanna stay a little bit closer to the muscle side rather than the mucosal side, because on the mucosal side, that's where the vessel branches out, so you actually get more oozing by cutting very superficially. So these are just some concepts to keep in mind. Different ESD knives that you guys may have had a chance to play with a few of them. You know, you have needle-type knives that you think of as you cut by pushing, insulated-tip knives you cut by pulling, and then you have certain scissor-type of knives nowadays that are very useful as well. So just to end, another application for ESD, you know, especially if you're not an expert in maneuvering the end of the loop like Rajesh, you know, I definitely can't, is when you deal with some of these pedunculated polyps, and the head of the polyp is just very large, and then the lumen is just very small, and then you got this very long stalk. So it just, it makes it very, you wanna resect these lesions and block, but sometimes it can just be very difficult to manipulate the snare and the end of the loop and whatnot. So these are the kind of situations where doing ESD techniques is safer in the setting that the risk of perforation is gonna be low, right, because you're dealing at the stalk. The word of caution, though, is these things bleed, and they'll bleed a lot if you don't control it adequately. For this particular lesion, I used that scissor-type of knife that I demonstrated on the previous image. I think I did decide to inject a little bit of epinephrine. And you'll see the scissor-type of knife, it's insulated on the outside, so only cuts what it touches. And then the other nice thing is that once you close it, you don't have to cut until you step on the pedal, right? So that's another advantage of the scissor-type knife. The other advantage is you can almost use it like a quag rasper if bleeding were to occur, which I think it does at the very end. Or I think I just cauterized a couple vessels at the base of the stalk right there. And I think I decided to put a clip at the base of the stalk. So just some final words on pre-cut EMR and hybrid ESD. So people often say, well, why are you bringing out a knife? Why don't you just use the tip of the snare to do this? I would definitely put a word of caution. If you're just starting to do this or you wanna start incorporating it into practice and you've never done this before, don't use the tip of the snare. The tip of the snare, you think it's small, it's not that small. Look at the ESD knives. These are like 1.5, 2-millimeter knives. It's much smaller than the tip of the snare. It's extremely easy to perforate. I would definitely advise against doing hybrid ESD with the tip of the snare if you don't have experience. Pre-cut EMR, you could use the tip of the snare. I do it sometimes as well. These techniques, I look at them as almost like a stepwise approach towards ESD. It's a learning step towards ESD. It may potentially provide that happy medium of not being as difficult as conventional ESD, but still provide some benefits in terms of M-block resection for certain type of lesions. It's not gonna be able to M-block resect every type of lesion. Now, I put the question mark when it comes to invasive component because we still don't have data on whether it can achieve the same rate of M-block and R0 resection standard ESD. Is this technique appropriate for cancer? I don't know. And when you look at some of the data with snare resection, the incomplete resection a lot of times is from the cautery at the deep margin. So is this the appropriate technique for cancer? We still need more data. So those are my main take-home points. Pre-cut EMR hybrid ESD can increase the rate of M-block resection, particularly lesions two to three, probably not larger than five. It can be used for fibrotic lesions, need for M-block resection for invasive cancer. It could be a modified technique towards learning conventional ESD. And then since I have two minutes to spare, I just wanna show you this video again. And this is just to highlight some of the points that the previous speakers have done, which is the effect of the tattoo. Sometimes when you see just a black base after a snare, you don't really appreciate how bad is a tattoo when coming to dissection. But that's what the India ink does. And that's what it looks like when you're trying to peel off a lesion and you're pretty much just have no submucose and you're peeling it off the muscle itself and the colon. So you wanna inject several centimeters away from the lesion, because even if you feel like you're far away, when that blep forms and it starts flattening out, that tattoo it's gonna spread, right? So even though you say, well, I'm two centimeters away and you inject the 10 cc's of India ink, that's gonna spread towards the lesion. And this is just to demonstrate, there are certain type of lesions we cannot do with hybrid ESD. You cannot do with full thickness resection and so forth, because the lesion is just a little bit larger. So in these type of scenarios, you just have to do conventional ESD. But in the West, we're still trying to primarily do lesions in the left colon and reserve lesions in the right colon when there's a clear invasive cancer, or obviously in a place that do high volume, these type of procedures. I think that's pretty much all I have. All right. Thank you.

hybrid EMR

endoscopic mucosal resection

ESD

colorectal polyps

pathological specimens

risk stratification