Well, it's point-counterpoint, so let's hear the counterpoint by Dr. Amit Rastogi from the University of Kansas. Thank you. Thank you, Peter and Asma and to the ASG for giving me this opportunity to talk today. Before I start, this was supposed to be a debate, right, point and counterpoint? And my dear colleague and dear friend actually summarized my entire talk in his second to the last slide. So I think he got confused that this was a debate and he was just giving a regular talk as usual. So thank you, Charles. My job becomes easier now. So these are my disclosures. So when we do polypectomies, what is the aim of a good polypectomy? It is to remove the entire polyp in its entirety completely, safely, efficiently, and in the most ideal possible way so that the histopathologist can give you the most accurate histology or the histological interpretation, especially if advanced histology is present. Now what are the limitations of cold-snare polypectomy? The main limitation of cold-snare polypectomy, which actually is an advantage also, but it is the lack of cautery and heat, and this limits the amount of tissue that can be cut. This also makes the plane of resection very superficial. And also the snares that we use for cold-snare polypectomy, which are 9 to 10 millimeters in size, they limit the size of the polyp that can be removed on block and also limits the size of the large peduncleated polyps that can be removed. So all in all, because of these limitations, although cold-snare polypectomy is a good technique for certain polyps, it's not ideal for all polyps. Now let's look at the data of depth of resection. This is a study in which they resected polyps less than 10 millimeters and compared cold-snare polypectomy with hot-snare EMR. And they found that the submucosa was present in only 9% of the polyps that were resected by cold-snare compared to 92% resected by EMR. Another study compared cold-snare with hot-snare and underwater EMR. And look at this data here. Even when the endoscopist thought that they had resected the polyp on block and it was an endoscopic complete remission, histologic complete remission was only in two-thirds of the patients. Only 57% of the specimens contained muscularis mucosa with the cold-snare. And submucosa with cold-snare polypectomy was even seen in less than one-third of the polyps. The thickness of the submucosa was significantly lower with cold-snare compared to hot-snare and underwater EMR. Another study which looked at rectal polyps, rectal and rectosigmoid polyps, similar theme. Histologic complete remission less than 100%, significantly lower. Muscularis mucosa was present in majority of the specimen, although the submucosa was seen in only a quarter of the specimens. And the thickness of the submucosa was significantly lower with cold-snare compared to hot-snare. What about if we extend cold-snare to larger polyps? This is a prospective study in which they removed 10 to 14 millimeter polyps on block with cold-snare EMR. They removed 80 polyps. Failure rate, which was defined by the use of cautery, was 14%. On block resection was achieved in 83%, but histologic complete remission in only 64%. So you see it falls short of what an ideal polypectomy should be. So what does it all mean? Dr. Kahi will argue that what's the big deal in removing piecemeal or getting too much of submucosa, especially if the polyp is benign. But my argument is when there is suspicion of advanced histology, which is high-grade dysplasia, intermucosal cancer, superficially invasive cancer, even for polyps that are less than two centimeter, cold-snare polypectomy is not an ideal method. Because these are the situations where you need an on-block resection with as much submucosa as possible for clear vertical margins, and as much as normal mucosa around the polyp as possible for clear lateral margins for accurate risk stratification and prognostication. So for these polyps, on-block resection by either hot-snare polypectomy, EMR, underwater EMR, hybrid ESD, or ESD would be the preferred method, even for smaller lesions. Now whenever we're dealing with polyps, polypectomies, and EMRs, we should be very conversant with the terminology, because this helps us to decide what type of method to use. We should all be conversant with the Paris classification. We should all be conversant with the terms lateral spreading tumor granulotype, which have low risk of submucosal invasive cancer, versus a non-granulotype where the risk of invasive cancer is higher. We should be conversant with the NICE classification, where we have the NICE type 3, in which there is presence of the polyps that have these features, have invasive cancer. And also the JNET classification. The reason I like the JNET classification, it's further extrapolated the findings of NICE to high-grade dysplasia and superficially invasive cancer, which is seen when you have an irregular surface and vascular pattern on the polyp, compared to type 3, where there is loss of vascular pattern, which is deep invasive cancer. So here's some examples of relatively smaller polyps that had advanced histology, and where cold-snare polypectomy would not be ideal. Here's a polyp which can describe this as a Paris type 2C, because there's a depressed component. It's not very big. You get a closer look of the polyp, and this is a well-demarcated area in the center of the polyp in the depressed section, where under NICE, under NBI, you can see an irregular pattern. And I would classify this as JNET 2B. This should alert you that there's a high chance that this polyp might have advanced histology. Cold-snare polypectomy should not be done for this polyp. You have to remove this polyp on block, whether you do it by EMR, underwater EMR, or ESD, whatever your preferred method is, to get on-block resection with as much submucosa as possible. Another small polyp, central depressed area, well-demarcated. See the irregular vascular pattern. And this is another polyp that immediately should ring a bell that will have advanced histology. If you're not comfortable removing this, you have to refer it to a colleague or a regional expert who can do it. But these are the ones that should not be attempted with cold-snare because of the reasons we already discussed. In fact, this patient had superficially invasive cancer. But I could confidently tell the patient that the depth of invasion is less than 1,000 microns. There were no other poor prognostic features like lymphovascular invasion, poor differentiation or tumor budding, and that this is an endoscopic cure, which I would not have been able to say with conviction if I would have used cold-snare polypectomy in this patient. Another small polyp, superficially invasive features, JNA type 2B, removed on block. Margins were clear, and the depth of invasion was also less than 1,000 microns. But there was some lymphovascular invasion present. These are the patients. Sit down with them face-to-face, discuss the risk of lymph node metastasis. Patient was young, healthy, decided to go for surgery. There was no residual adenoma or cancer seen at the site, and all the draining lymph nodes were negative. So it was an endoscopic cure. But because of the presence of lymphovascular invasion seen in the specimen, patient decided to go for surgery. This is a quick video I wanted to show you. Patient referred to me with a relatively small polyp, at the most 15 millimeters, a tattoo mark. Another no-no, should not be so close underneath the polyp. That also should raise an alarm that there will be some submucosal fibrosis. Here I'm inspecting the polyp closely. If you see the central depressed area, it's a Paris type 2C lesion in the central portion, 2A plus 2C. This is irregular NBI pattern here in the center. This is very concerning. Is it JNA type 2B or almost creeping towards type 3? So I decided to do underwater EMR, submerge this area with water that lifts the polyp up. I've marked the margins of the polyp with cautery. I'm trying to ensnare it in one piece, taking my time. I'm torquing. I'm pushing the sheath of the snare down to engage as much tissue as I can. And then I remove it with heat, and we'll see what it shows. The base looks okay. There is some tattoo there. And then the histopathology showed that there was invasive cancer in this. There's a 1,500 micron invasion, but you can see the amount of submucosa I got. There's no way you could get this with cold snare. First of all, you could not even remove this on block with cold snare. And then there was some tumor budding. So we discussed with the patient. This patient decided to go for surgery also, but there were negative margins. There was no residual cancer, and there was no lymph node involvement either. Now moving on to polyps that are greater than two centimeters in size. So there was some emerging data saying that cold snare polypectomy is very good for them. But if you look at the studies, a lot of these studies have a large number of sessile serrated lesions. They showed that this was effective, less risk of bleeding, less recurrence rate. Then this study came out of Australia. There's a retrospective study, large number of polyps, showed that cold snare EMR was very effective. The recurrence rate was very low, very good safety profile. But the devil is in the detail. If you look at this study, they had very strict exclusion criteria. They excluded lesions that had suspicion of invasive cancer, submucosal invasion. They excluded lesions that had a greater than 10 millimeter sessile component, because on block resection of this may be difficult due to the thickness of the polyp base. They excluded peduncleated polyps, that's a no brainer. Two thirds of the polyp were sessile serrated lesions. And the conclusion of this study was that the high efficacy and the low recurrence rates achieved were due to appropriate lesion selection. There are certain polyps, which are more than 20 millimeters in size, that may be amenable to cold snare EMR, but not all. And the ones that you can do cold snare EMR are the ones that are lateral spreading tumor granular type, Paris type 2A, and sessile serrated lesions, because the risk of advanced histology in these is very, very low. Now more recently, there's a larger study that came out. Again, a retrospective study where they did not have these strict exclusion criterias like the Australian study. And look at the data in this study. Larger lesions, 29% were greater than three centimeters. Majority of, a high proportion of the lesions had advanced histology. They had fewer sessile serrated lesions. And the recurrence rate at first surveillance colonoscopy was 35%. In this day and age, with all the tools that we have, including snare tip soft coagulation of the margins when we are doing hot snare EMR, this recurrence rate is unacceptable. There were no procedural complications, so that is the hallmark of all the studies. Using cold snare polypectomy or EMR is the safety profile. But there were certain other drawbacks in this study, which we don't have time to discuss. But all in all, what it tells us is larger lesions may not be amenable to efficient cold snare EMR because of a high recurrence rate and larger the size. Look at this. At polyps greater than 50 millimeters, the recurrence rate was 75%. Now what about efficiency? I mean, we can sit there and remove these humongous polyps with a tiny cold snare and stay there for two hours in a person's colon. But reality is we have to be efficient. For large polyps like this, the time taken to remove these will be much more than what you can achieve by a quick hot snare EMR. And the number of pieces that you will be cutting these polyps out will be significantly higher in number. Now for the large polyps, you also have to consider this concept of covert submucosal invasive cancer, which means that when you look at a polyp, just by looking at it with NBI or any other chromoendoscopy technique that you have, you don't feel that there is evidence of invasive cancer. Yet when you remove them, there is evidence of submucosal invasive cancer. And the Australian group figured out the characteristics of such polyps. They have to be non-granular with a sessile component. They're larger in size. They are in rectosigmoid location. They can have a dominant sessile nodule. And they have genotype 2B or CUDO5I pattern. And these are the polyps where you should not embark upon cold snare polypectomy. You should try to do on-block resection, if possible, for the entire polyp or at least of the dominant sessile nodule by EMR, underwater EMR, hybrid ESD or ESD. And place the specimen firmly on a flat surface or a mold and pin the edges. So this is a short video of a rectal Paris type 2A, which initially I thought, okay, this is Paris type 2A lateral spreading tumor, granular type in the rectum. Maybe we can get away with cold snare EMR. Then I'm inspecting this polyp and you start seeing some concerning features right here. This is what a dominant nodule in a flat lesion looks like. And you look at closely with NBI, I don't see any pattern. So I started getting concerned that this could be NICE type 3 or JNET 3, could be 2B. So these are the ones I decided to do EMR, piecemeal EMR. But for this concerning area, which has a higher chance of harboring invasive cancer, you want to remove it on-block and send it separately. So you have to be very clear. You remove it on-block, retrieve it immediately, pin it on a wax mold and send it separately and describe what you did to the pathologist so that they can section it vertically and they can give you, if there is advanced histology, they can give you an accurate determination of all the features that we need, the depth of invasion, the lymphovascular invasion, the differentiation and tumor budding. So in conclusion, I hope I've convinced all of you that selecting polypectomy technique should be based on polyp characteristics. For polyps less than 10mm, with no endoscopic evidence of advanced histology, cold-snare polypectomy is very reasonable, should be done. For polyps 10-19mm in size, with no evidence of advanced histology, we could do either cold-snare or hot-snare. For polyps between 10-19mm with features of advanced histology, we should try to achieve on-block resection by either hot-snare or EMR, underwater EMR, hybrid ESD or ESD. Fessile serrated lesions, I would agree with Dr. Kahi, any size, doesn't matter, you should go with cold-snare. For large peduncleated lesions, especially more than 10mm, we should use hot-snare. Now for moving on to the larger polyps, for 20mm or more in size, the only time I would use cold-snare currently is for Paris type 2A lateral spreading granular type who have no features of advanced histology, they have a nice type 2 pattern. And if the large polyps don't have these features, are non-granular, have a fessile component, and I'm concerned about covert invasive cancer, then I would stay away from cold-snare polypectomy. Thank you for your attention.

cold-snare polypectomy

limitations

advanced histology

polyp removal

histological interpretation