We are extremely honored to have Dr. Michael Bourke join us from Sydney, Australia. Welcome Dr. Bourke, and we are looking forward to a very, very exciting session. So I'll hand it over to you, Michael. Thanks Asma. Yeah. So I think polypectomy is probably the most common therapeutic intervention undertaken by any gastroenterologist or endoscopist. It's a critical component of our day-to-day practice, and for a long time, it's been quite heuristic. You know, we just do things the way someone else did it, but now we have a large evidence base that informs us on how best to undertake polypectomy. And Professor Rastogi-Armit is going to take us through that, talking about basic and advanced polypectomy techniques, and then in a subsequent talk, talking about treating recurrence and other difficult lesions. Thanks, Armit. Thank you, Michael. Okay. So let's, over the next one hour or so, we'll discuss about basic and advanced polypectomy and the techniques. These are my disclosures. So first, before we go on to more advanced polypectomy techniques, I wanted to spend a few minutes discussing cold-snap polypectomy, which has seen a very rapid rise in practice over the last several years, and it's almost to the point that we call it the cold revolution. Cold-snap polypectomy is the preferred method for removing polyps less than equal to 10 millimeters because of a high complete resection rate and a very, very safe, very good safety profile. Cold-snap polypectomy is better than cold forceps for complete resection of polyps less than equal to 5 millimeters. If you compare cold-snap polypectomy with hot-snap polypectomy for polyps less than equal to 10 millimeters, the complete resection rates are similar. And the post-polypectomy bleeds, actually, although some studies have shown they're similar, they have more recent data showing that it's much less for cold-snap polypectomy. And cold-snap polypectomy is also more time efficient. Even for polyps greater than 10 millimeters, cold-snap polypectomy has been shown to be beneficial over compared to hot-snap polypectomy, mostly in terms of less post-polypectomy bleeding. Moreover, the treatment of SSLs, acyl serrated lesions, has changed more recently with the advent of cold-snap polypectomy, which has shown to be effective for SSLs of large sizes, as well as very safe and very low recurrence rate. And what is important in cold-snap polypectomy is the technique, and Dr. Berg's paper recently came out on this, that technique is more important than the type of snare you use removing polyps with cold-snap polypectomy technique. So going over a couple of quick videos. So the key here is you identify the polyp, good prep. You bring the polyp down to between 5 to 7 o'clock. You stay close to the polyp to have good control. You should have the scope in a stable position. And then you open your cold snare. So here I'm trying to open, and I try to hinge the tip of the snare at the mucosa proximal to the polyp. Then I get my sheath out. I actually dig in a little bit, maybe suction a little bit, and then close the snare to aim is to get a rim of normal mucosa around the polyp in my snare. So and then you flush water to open up the resected area and to look for any evidence of residual. But by ensuring, by making sure that you get a little rim of normal mucosa around the polyp, you almost always have complete resection. So that is the basic technique. This is a little bit of a larger polyp than the previous ones, about 5, 6 millimeters, same thing. Bring the polyp down to 5 to 6 o'clock position, open the snare. I try to wedge it beyond the tip, beyond the polyp, approximate to the polyp, then bring my sheath down. And I take my big dial away from me to push down and then try to suction a little bit, get a rim of normal mucosa around the polyp, get a nice clean resection, and thereby making sure that there is no residual adenomatous tissue remaining. So this is the basic technique which you should be implementing when you are performing cold snare polyp. Let me another quick example of polyp, bringing it, staying close to the polyp in a stable position, polyp in the lower quadrant, opening your snare, trying not to touch the polyp with your snare so that you have a rim of mucosa around the polyp that you can reset. Then turning your big dial away from you a little bit here, I'm falling a little further away, but I should get closer. Then take your big dial away so that you anchor your sheath distal to the polyp. And here you can see a normal rim of mucosa around the polyp. Sometimes if you grab too much tissue, it can get tough to cut through, but slightly open the snare, lift your snare up towards the center of the lumen. And then if you cut again, it should cut off. And this is the protrusion cord that we'll see, which is actually just heaped up a bunch of submucosal tissue and not a blood vessel as initially we would get concerned when we started doing this. So this is the basic technique of cold snare polypectomy, which everyone should practice, a very, very effective way of removing polyps at least less than equal to 10 millimeters. So I'll go over some data supporting this. This is a recent meta-analysis comparing cold snare polypectomy to biopsies for polyps less than equal to 5 millimeter. Significantly lower incomplete resection rate seen with cold snare polypectomy. If you compare cold snare polypectomy to hot snare polypectomy for polyps less than equal to 10 millimeters, similar incomplete resection rates. For bleeding, this was a meta-analysis that showed that the incidence of bleeding, rate of bleeding after cold snare polypectomy for polyps less than equal to 10 millimeters was 0%. Lower than what was seen with hot snare, although it did not reach statistical significance. And the other advantage of cold snare polypectomy was that the time was significantly shorter. It took longer with the hot snare. Obviously, that's understandable because you have to get the pad on the patient and use cautery. Now, a very recent study published last month in GIE from Japan showed that there was a significantly higher delayed bleeding with hot snare polypectomy compared to cold snare polypectomy for polyps less than equal to 10 millimeters. So all in all, excellent complete resection rate and very good safety profile with cold snare polypectomy. Now, this study is actually a very interesting study came out in the annals, where in patients who were on anticoagulation, they had randomized to two arms. We had patients who stopped their anticoagulation, got heparin bridging, and patients who continued their anticoagulation. And the patients who continued the anticoagulation underwent cold snare polypectomy of lesions less than equal to 10 millimeters. And the bleeding rate was actually lower numerically in the cold snare group in spite of the fact that these patients were taking their anticoagulations and had not stopped it. Plus, the time, procedure time was lower with cold snare polypectomy. The rate of hospitalization as well as the mean hospital stay was lower. So all in all, more beneficial for patients who are on anticoagulation and may not be able to stop it for a variety of reasons. For larger polyps, there's some data, a little bit of a gray zone, but there's some data for polyps between 10 to 20 millimeters. Safety profile, excellent for cold snare polypectomy with zero bleeding in this study, zero post polypectomy syndrome, and no cases of abdominal pain after the procedure. Now, what about extending these to bigger lesions? So especially for caesareated lesions that are greater than equal to 10 millimeter, cold snare polypectomy is a very, very useful tool. This last study in which 20% of the patients were actually greater than 20 millimeters, the safety profile was excellent. The adverse events were very, very uncommon. Abdominal pain less than 1%, intra-procedure bleeding requiring a clip was in one patient, delayed bleeding, zero. So this is, there's uniform evidence that it is very safe as far as bleeding is concerned. Moreover, the recurrence rate on follow-up was also pretty low, 7.8%, which is reasonable for caesareated lesions. And the factors for residual or recurrence seen at follow-up was proximal location and large polyp size, similar to what we see in adenomas. So this data, and then Dr. Berg's data from Australia compared cold snare polypectomy for large lesions greater than two centimeter with conventional EMR, not a randomized control study, but nevertheless, it was good historical controls. And what they found was that although on-block resection was more common with conventional EMR, understandably so, because the size of the snare which used for cold snares are smaller, the safety profile was excellent. Again, zero post-EMR bleeding, 0% deep muscle injury, and no delayed perforation. And the recurrence rate, which is always a thing that concerns us, was similar in the two. So overall, very, very effective and probably should be recommended for SSLs, which are even of larger sizes. So this is a couple of videos we'll go over of how we remove this. Now you can use, you can do this with and without injection. Studies have shown that without injection works out well too. But you have to define, as we talked about in the previous talk about advanced imaging, you have to define the extent of the lesion. So here, it's a very flat lesion. I defined it with NBI, and then we start removing it with cold snare. Now we use the same principle we use for the small snare, that we start with one side, from one side of the polyp. The key is to grab a little bit of normal mucosa surrounding the lesion and anchor the sheath, take your big dial down. So you're kind of digging the sheath into the mucosa compared to in hot snare, where you lift the snare up towards the lumen. Here, you do the opposite movement, which is trying to grab as much tissue as you can by turning your big dial away from you and kind of anchoring the sheath, so to speak, against the bowel wall or the colon wall. And here, you can see we're going around in a systematic fashion, trying to remove a little bit of extra mucosa around the polyp also, or around the lesion also. And as it is very safe, you can have some bleeding during the procedure, but this inadvertently will stop by the time you're done. So it can make visualization a little bit tricky, but you keep aggressive washing with the pump. And now you can see we're getting closer towards the end. What I do usually after I think I've removed it, I examine the edges with NBI or whatever electronic chromatoscopy platform you're using to look at the pattern, the pit pattern. And if you see normal surface pattern at the edges, that kind of ensures that you've removed the entire lesion and there is no residual. And if there is, if you suspect that there might be any residual anywhere, always err on the side of caution. Just try to remove a little bit of extra, even if it is normal mucosa, it's no big deal here because this is very safe. And as we discussed, no risk of perforation, no risk of post-polypectomy syndrome or abdominal pain and no risk of delayed bleeding. So here we're coming towards the end of the resection. It's usually very quick and very safe. And the key is to basically go about doing this in a systematic manner and making sure at the end that there is no residual lesion left by examining the edges carefully. The previous one was without injection. If there is a big lesion, we'll inject just to get a better sense. Injection gives a couple of advantages. Sometimes it'll highlight the borders or the margins of the lesion better. Obviously gives you a little more level of comfort, although the risk of damaging the muscular spapula is almost negligible here. Here we examine the lesion with NBI. We figured out what is the extent. I'm injecting a solution. We'll talk about what kind of solutions later on. But here, this is a solution which has blue dye in it. And you try to raise the lesion, basically separating the lesion from the deeper layers. You go around. In these 2, 2.5 up to 3 centimeter lesions, you can elevate the entire lesion and then start the resection. And again, starting the resection, you have to go systematically from one side and go over to the other side. So here I want to inject a little bit more because I want a little bit of normal muposa to be raised so that when I'm resecting it, I can get a little bit of 2 or 3 millimeters of normal muposa with my resection. So again, the same process that we discussed, you look down, get your snare around the lesion or around the portion of the polyp that you want to remove, turn your dial down and try to get some a little bit of normal muposa around the lesion and then systematically work your way towards the other side. Here we had mixed some epinephrine. So you see a little bit of less bleeding here, which I think is a reasonable practice. It just makes the procedure a little faster if you don't have too much of intraprocedural bleeding. But as I said, nothing to worry about. These invariably stop very quickly. So just moving along, you see we're getting closer to getting done. I'm trimming the margins. That is the key. I think one of the key takeaways here is make sure that there is no residual polypoly tissue left at the margins and are on the side of caution. And if you have to remove a little bit of normal muposa, go ahead and do it because that always ensures that you've removed the intelligence. So here I feel that there might be a little bit remaining here, a little bit of nodularity with abnormal patterns. So I go ahead, I get my snare down and I cut that area, just a little bit of trimming of the edges. And we are towards the end of our procedure. And obviously, again, here again, I'm looking at the margin. I saw a little bit, which we'll remove. But overall, big defect done very quickly and efficiently. No bleeding, as you can see, and very, very safe with regards to having any risk of perforation or delayed post-polypectomy bleeding or pain. So based on this, the U.S. Multisociety Task Force recommendations came out, which said that post-polypectomy should be a method of choice for diminutive and small lesions due to high complete resection rates and safety profile. And both cold snare or hot snare without some mucosal injection can be used for polyps between 10 to 19 millimeters and non-pedunculated. So these were the recent recommendations. So I highly encourage you guys to incorporate this in your practice if you've already not done it. Now, moving over to advanced polypectomy techniques is basically conventional hot EMR for polyps that are called as, quote unquote, complex polyps, larger than two centimeters. EMR has become the standard of care for large benign polyps. It's safer than surgical resection, which has a morbidity and mortality of 20% and 1%, actually. So our procedure is much safer with a very low perforation rate, very low bleeding rates. Mortality is less than 0.08%, and non-curative resection is also very low. Studies have shown that EMR is more cost effective than surgery. And the goal of endoscopic resection of polyps is to remove the entire lesion safely, efficiently, avoiding complications, and also ensuring that there is no residual or recurrence or minimal recurrence on follow-up. So first, let's look at certain principles. What are not to do things? So one of the major things that I always emphasize is, please, even if you don't remove large polyps in your practice, please do not refer benign lesions or benign appearing lesions to surgery. That is the biggest disservice you can do to a patient. Always have a go-to person either in your practice or in your area or a regional expert to whom you can refer large polyps to, especially if they are looking benign. Moreover, if you feel that you cannot remove a polyp, then you should not attempt removing it because that is also a big disservice you can do. If you remove a polyp partially, it will lead to scarring. And that scarring will make it very difficult or more difficult for the ensuing endoscopist in removing this polyp. So don't attempt to remove if you're not feeling competent to remove that entire lesion in one attempt. Also, please do not attempt to remove lesions which have features of deep invasive cancer, because those are the ones where you land up in trouble with complications. And these are the ones who need surgery. So again, if you're not sure whether the lesion has invasive cancer or not, you can always refer them to an expert. Now, if you feel competent that you can remove the lesion, but you don't have enough time on the schedule, it's your screening colonoscopy day, you have like 10, 12 procedures scheduled, please reschedule the procedure. Try not to remove it in a rush, because otherwise, what will happen is you will do a half-hearted job, quit midway and make subsequent procedures more difficult. So if you feel competent, then reschedule it, bring the patient back, maybe to the hospital setting where you can do a safe enough job and you have enough time on your schedule to do it. Also, please do not biopsy benign appearing lesions, because they serve no purpose. They just confirm your suspicion that it's a tubular adenoma, which you already knew by looking at it. They only cause scarring and can make subsequent resections difficult. Another thing that we always talk about is tattooing. You have sometimes tattoo lesions for future identification or for the surgeon. For benign lesions, if you tattoo, do not tattoo close to the lesion, because the ink or whatever carbon particle that you are injecting will diffuse to the submucosa. And if it reaches under the polyp, it will lead to submucosal fibrosis, making subsequent resections more difficult. And obviously, do not attempt to remove lesions with features of deep invasive cancers we discussed. Now, there are certain features of the polyp that will tell you whether or give you an idea whether this will be difficult to resect. And in this study, again from Australia, showed that a history of previous intervention is one such factor, involvement of the IC valve, where the access to the polyp is difficult is another factor, difficult position, larger lesion size, and previous use of APC. So based on these, you can assess a lesion, assess your competence in removing these lesions, and decide whether, OK, is this something that you want to tackle yourself or you want to refer to another colleague. Now, let's talk about the tools and the technique for EMR or endoscopic resection of large polyps. So you should have high definition scopes. All of us should be using them, should have the ability or the understanding and the knowledge to use electronic chromoendoscopy, just like we discussed in the previous talk. A cap or a distal attachment is a good accessory to have for a variety of regions, keeps the scope stable, keeps the mucosa away from the tip of the scope or the lens so you don't get read out, and is a useful adjunct for EMRs. Use CO2. That should be the standard. You should have injection needle. Variety of solutions are available. We can use saline mixed with dye or colloidal solutions like hydroxyethyl starch mixed with dye or hyaluronic acid. Then we have commercially available agents that are coming out. And I think every few months we see a new one out. But these have the color blue, they are colored blue, and they can be used. They have the advantage that they are more viscous, so they get absorbed less quickly compared to saline. And obviously, they produce a more prominent bulge, making the procedure maybe a little more efficient. And you can probably remove the lesion in less number of pieces than if you were to use just plain saline. But all these solutions are options. You should have snares of different shapes, round, oval, duckbill, hexagonal. Quadrasper forceps is a good equipment to have for controlling bleeding. We'll discuss that. You should have clips, and you should be using microprocessor-controlled electrosurgical generator in this day and age. Now, as far as the technique is concerned, the first order of business is lesion assessment and characterization. Look at the lesion, assess its extent, and characterize it. Make sure it doesn't have any features of invasive cancer. Then assess the resectability, and as I discussed, your own ability to resect the lesion, and if you have enough time on the schedule. Good bowel prep is a prerequisite. You don't want to be doing complex EMRs with poor bowel prep. You should have a stable scope position. You should have a short scope without loops, stable scope position. And the lesion position is also very important. We try to bring the lesion into anti-gravity position so that when you cut the lesion, or you push in water, or if there is bleeding, it does not pull over the lesion versus it goes away from the lesion because the lesion is high up and in anti-gravity. So that is very important, and you might have to turn the patient sometimes to accomplish this. A very useful tool for ascending colon lesions, especially if they're wrapped over folds, is retroflexion to get good assessment of the proximal aspect of the lesion, as well as to remove it. You should, after removing it, you should assess the base for any muscle injury, then examine the edges and treat any residual appropriately. After this, you should do treatment of the post-EMR edges. We'll talk about it with a snare tip soft coagulation, which has been shown to decrease the recurrence rates. More data has accumulated, and now the standard practice is to clip, close the lesion, or to close the post-EMR defect with clips for large polyps, especially if they are on the right side, to decrease the risk of post-polypectomy bleeding. You should be competent to manage complications. The two major complications that you deal with is bleeding during the procedure and perforation or muscle injury. Then you should have a plan for follow-up and surveillance colonoscopy. That's, in a nutshell, the tools and the technique needed for resection of large polyps. Talking about lesion assessment and characterization is very important before you start resection. You assess the extent of the lesion, whether it's accessible, what is the morphology, and here you should be conversant with the Paris classification, whether the surface is granular or non-granular. If you look at the surface, you should have a general evaluation. You should do a general evaluation and then focus on areas of concern, like we talked about with advanced imaging, to see if there's any demarcated areas or any areas of NICE type 3 or JNET type 3 that would be suggestive of invasive cancer. If there is evidence of invasive cancer, then the safe thing is to biopsy the lesion and tattoo the area, distill to it or what have you, and then send the patient to surgery after the biopsy confirms cancer. Now, if it looks like a benign lesion to you and you feel that it is removable in one attempt, then you should go ahead. Otherwise, then you should refer to an expert or your go-to person. Also, you should always assess, as I said, the time on your schedule. Never be rushed. These procedures do take time. You should have more time allotted to resecting these lesions compared to what you have for your regular routine screening colonoscopies. This is the PARIS classification. You have the pedunculated, semi-pedunculated, and sessile. It is the O1, and then the O2 are the flat lesions, superficially elevated, completely flat, and then the depressed. And we'll talk about why it is important to be conversant with the PARIS classification. The other term that we use is the granularity of the surface. If the lesion has a granular carpet-like surface, we describe this as lateral spreading tumor granular type. And if it is not granular and is smooth, then it is described as non-granular. The reason why it's important is if you have a granular lesion, the likelihood of invasive cancer is very, very low. And the way to remember is granular, G, G for good, non-granular, N for nasty. So non-granulars are nasty. Granulars are good. The risk of invasive cancers are low with granular lesions. The risk of invasive cancers or advanced histology is higher with the non-granular lesion. This meta-analysis showed that if you had a granular lesion like this, it's almost 0% chance that this has invasive cancer. If this granular lesion has a dominant nodule, then the risk is a little higher, but still it is around max 10%. Whereas for non-granular lesion, the risk is higher even if it's not depressed. For depressed, it's significantly higher, but for superficially elevated, it's still about 5%. So that is the reason why assessing the lesion not only for the pattern seen on electronic chromoendoscopy, but the gross morphology and the Paris classification is very important. Now, we talked about this in our previous study. There are certain features that tell us whether there is invasive cancer. These are the gross morphological features that we should assess. Then we can use chromoendoscopy with the KUDO type 5i and 5n patterns. We talked about the type 3 patterns. So I'm just going over this. I'm not going to repeat them. Type 3 pattern or the JNET type 3 pattern. And if you see any of these on the surface of the polyp, that should alert you that there is invasive cancer. So for example, this polyp has nice type 3 pattern. You do not remove, you biopsy and tattoo. Another polyp, which has a demarcated area in the center, which is irregular. It's almost like a JNET type 2b. And this had invasive cancer also. Another small lesion. You would think this is very small. But if you look at the surface, you can see that there's a well demarcated area of amorphous pattern. You see no vessels or no mucosal pattern in the central depressed area. This is nice type 3. And on surgical resection, it was found to have stage 2 and 0 staging. So based on this, let's go over some video examples of video demonstrations of EMR or endoscopic resection of large polyps. So this is the easiest type of polyp that we will encounter. Little large, but it's in the rectum, which is thick walled. It's a lateral spreading tumor, granular type. So the risk of invasive cancer is almost zero. It has nice type 2 pattern. So we spend a couple of minutes assessing it, and then we try to remove it. So usually what I'll try to do for these flat polyps is raise them with injecting a solution. So as I said, you can use saline mixed with a dye, or you can use a viscous solution, hydroxyethyl starch, or the commercial ones. The aim is to separate the lesion from the deeper layer, which is the muscularis propria. And you start from one edge of the lesion and gradually progress to the other side of the lesion. There are two ways of injecting. One is you push the needle into the wall and you start injecting. And if you don't see a bulge, then you pull the needle back out a little bit because you know you are beyond the submucosa. The other way is you start injecting and then you pierce. And as soon as you see the bulge, you stop because now you are in the submucosa plane. Once you inject the lesion safely, you can go ahead and get your snare around it. Try to get a little bit of normal mucosa around the edge and take the piece out. So the principle here is you get your snare around the portion of the lesion you want to dissect. Here I'm trying to wedge my snare to the edge of the previous defect so that I don't leave behind ridges. I get the lesion, after squeezing the snare I release the tension a little bit just as a safety measure that if in case the muscle is entrapped in the snare by releasing the tension or releasing the snare a little bit that muscle will muscle layer will pop out and I won't cause a perforation. So just it makes me feel better if nothing else. Here I release it so let the muscle if the muscle is entrapped in case it'll slip out and then you cut it. So now it's just a matter of doing the same sequence again and again. You inject, you get your snare around the lesion, try to get a little bit of normal mucosa around it, make sure you wedge your snare very completely adjacent or at the level of the previous polypectomy defect so that there are no ridges or islands of tissue left behind. You entrap the portion that you want to snare off, you close the snare then release the snare a little bit as a safety and then you cut through and I usually use endocut but a lot of folks use forced coagulation also and then you keep going over to the other side of the lesion and after you have completed completely resected you look for any evidence of bleeding any evidence of perforation and at the end you treat the edges with what Dr. Burke has described as snare tip soft coagulation which has been shown to decrease the risk of recurrence remarkably. So this is the tip of the snare and you go around the edges burning it with soft coagulation effect 580 watts and this has you get a rim it's a mount like a mount Fuji effect here and you get a nice rim of burn around it to complete the procedure. So this is another example of what I talked about a good technique is to to retroflex in the right colon for lesions that are wrapped over a fold to access the portion that is on the proximal side. So here you see a reasonably 3.5 centimeter lesion on the progonal side and here I'm retroflexed in the right colon and I'll do my resection of this portion of the polyp in the retroflex position. So it's easy to get your equipment out devices out even in the retroflex position I'm injecting the fluid of choice and raising the lesion so now I can safely resect this portion and after I've resected this portion which is not visible on the anti-grade view then I can reverse my retroflexion go to the anti-grade view and take care of the portion of the polyp which is visible on the forward view. So here you can see I'm getting the snare out same principle try to work start working from one side of the polyp try to ensnare this sometimes a little bit of maneuverability is a little difficult you have to be you have to have a little bit of practice of working in the retroflex position but it's not difficult and is strongly encouraged for these types of polyps to be able to do a complete resection. Again I'm getting my snare around it a little bit of normal mucosa here which is good because we have the safety of the of the fluid cushion and we release after closing the snare just release a little bit and then close it again you can see there's a big piece here it's always tempting to get big pieces out the other thing that I would want to caution is try not to remove more than two centimeter lesion on block on the right side and about 25 millimeters on the left side so that's my go-to sizes if you have lesions more than that size you can easily do piecemeal with better safety profile. So see you have removed it you see the nice base that is the other advantage of having the blue color is it helps you not only to assess the margins but the base for any muscle injury apart from the fact that it's just soothing to the eye. So here we've completed almost completed the the resection in the retroflex position and then we can finish the job by going into the forward view and removing the part of the polyp that was that is visible in the forward view. So once you have developed or gotten into the habit of doing these and taking care of polyps that are two to four centimeters in size you can then extend your gamut to even larger polyps. So this was a much larger polyp like a big humongous seven centimeter sessile lesion in the rectum but again once you have your principles in place you should not get daunted by these benign polyps because it's just a matter of repeating the same sequence of events or sequence of practice several times multiple times like in this polyp it took an hour and a half to remove this whole thing but it was just again the same thing as injection raising it working along the submucosal plane making sure you're not leaving behind bad islands or bridges of tissue between the resection pieces which become very difficult to remove at the end and then working our way from that here in this case in such a large polyp you work your way from the distal to proximal compared to what I showed in the previous video where you first resected the proximal part because you could not see it properly you had to retroflex. Here after removing so many pieces this is the first time we've seen some daylight here and now you just grab that opportunity you've got into the submucosal plane now you just work along that submucosal plane and continue your resection and after working on this for an hour and a half or an hour or so we are getting to the proximal edge of the lesion with a nice blue base which ensures that there is no bleeding there's no perforation there's no muscle injury and you're getting a safe resection. This was a lesion that had tubular villus adenoma with high grade dysplasia and we basically prevented a major resection in this patient because it was in the rectum he would have had to get a low anterior resection. So here we're coming towards the end after we get done you look at you spend some time looking at the base to make sure there are no islands of residual adenoma if there are you clean that up then you look for any visible vessels that might be potential source of bleeding and treat them and then treat the edges with a snare tip soft coagulation. Here we found some bleeding that was treated and then we treated the edges. Now this was conventional hot snare EMR what has come up recently is can we do the same thing with cold snare piecemeal EMR and initially there was some series that showed that this was very effective especially safe because there was hardly any post-polypectomy bleeding so everyone was encouraged and then this study also from Australia showed that the recurrence rate was also very low which is obviously important I mean you have to remove it safely and effectively and one of the things is that you should have a very low or a low recurrence rate when you go back and look at the site. Intra-procedural bleeding was very low post-EMR bleeding also low so all encouraging data however a recent study has kind of tempered this enthusiasm which also came out from one of the pioneering centers in Detroit and in this study the downside was that the recurrence rate on follow-up was very high 30 almost 35 percent and what the factors for presence of recurrent adenoma after cold snare EMR of lesions greater than two centimeters was age the size of the polyp and the polyp histology so as you see if you go over here on this table as the size increases the risk of having recurrent adenoma on follow-up was was increasing and goes up to like a almost 70 75 to 80 percent for lesions greater than 50 percent so we are in the process of actually in the middle of a large randomized controlled trial which has been led by Heiko Pol comparing cold snare polypectomy with hot snare EMR for lesions that are greater than equal to 20 millimeters and hopefully in the next couple of years we'll have some data with that but the the procedure is still or the concept of cold snare EMR of large adenomatous polyp is still the same this is a 2.5 centimeter benign appearing adenoma you you you raise it and usually I'll use some epinephrine with the solution to decrease the risk of intra-procedure bleeding you raise it nicely so that you you have not only the fluid separating lesion but also some epinephrine there to decrease the risk of bleeding and then once you've removed it once you've injected and raised it you start resecting it from one side again the same principles opening the snare getting your your your part of the polyp you have to push the snare down as opposed to taking it up like in hot snare and grab as much tissue as you can try to clean up the edges get some normal mucosa at the edges to to to to ensure that you're not missing any polyploid tissue and just keep doing the same sequence again and again till you get to the other side of the polyp and as you can see there's some intra-procedural bleeding but invariably as I mentioned this will stop at the end of the procedure then have a go around the edges with a electronic ondoscopy which can be a little tricky because of the bleeding so you have to use aggressive washing here to wash away the blood but ultimately you can see the pattern the mucosal pattern at the edges and you just have to compare it with the surrounding mucosa and as long as it's similar here there might be some suspicion of a little bit of a nub here which if you find then you just clean this up get your snare around it and clean up the the the margin so that there is very little chance of having and this is the key if you do this then I feel the chances of having recurrence at a follow-up will be significantly lower than otherwise so so here we are at the end of of this resection which was all performed with cold snare now another technique that has been described basically is underwater EMR this was described initially by Dr. Ben Moeller the whole concept here is instead of insufflating the lumen with air you inundate the lumen with water and what that does is it makes the mucosa and the submucosa float towards the lumen separating it from the muscularis propria and the polyp therefore because it's mucosal base is separated from the muscle muscle layer and thereby making resection safe without having the need to inject any any fluid now there are certain principles involved here you have to have a good prep if you don't then you won't be able to see the lesion you suck the air out bring the polyp to the dependent portion and then infuse water fill fill the the lumen with water as you can see just because of lack of air insufflation the entire polyp looks a little more shriveled and less expansive as compared to when you don't have when you insufflate with air so that is the whole principle is that this will shrink the polyp bring it towards the lumen separate it from the muscularis propria and then you can remove larger pieces on block or larger polyps on block here I'm trying to get my snare around the polyp having some difficulty because the size of the snare is a little bit shorter but with a little bit of trying you should be able to do that for polyps that are around 20 to 30 millimeters in size and once you you get your snare and the polyp entrapped in the snare then you can you can you can cut and remove it and I think one of the good technique here is also to mark the edges of the polyp prior to removal with APC because without any injection sometimes it's difficult to delineate the margins or the edges of the polyp and then once you've removed it you can examine the base for any muscle injury or bleeding it's basically a little faster and more efficient you use less accessories but does need a little bit of more experience and sense because you don't you lose that that the blue color that you're used to seeing and which helps you to delineate the margins as well as the base you don't see that because you're not injecting when you're doing the underwater EMR so some limitations because you can't do it in patients who have poor bowel prep or suboptimal prep if there are a lot of contractions if you are not able to remove it in one piece and you're doing a piecemeal underwater EMR and there's bleeding then that will make visualization more difficult and then you have to suction all the water and you have to do the whole thing again and again and obviously there's some risk of fecal peritonitis in case of perforation because there'll be a lot of fluid some mixed with stool which will leak out if there is a perforation and my main concern all I must confess I don't do this routinely I'll do it for polyps that are maybe 20 to 25 centimeter millimeters in size because I know I can remove them in one piece but I like the color or the dye color for making my margins clearer making the base of the EMR defect clearer to assess for any muscle injury and so on and so forth so but data shows that it's pretty effective this is a meta-analysis that showed that the complete resection rates with underwater EMR was very high and on block also very high recurrence rates pretty low less than nine percent post-procedural bleeding 2.85 very acceptable overall adverse events 3.31 also very acceptable now when you compare limited studies have compared conventional EMR and underwater EMR and even in those studies if you do the this meta-analysis showed that underwater EMR compared pretty favorably overall on block resection rate higher with underwater EMR on block resection rates for polyps greater than two centimeters significantly higher rates of recurrence and this was the surprising thing for me the rates of recurrence was lower with underwater EMR post-procedural bleeding was same perforation rate same and overall underwater EMR had shorter resection time because obviously you're not injecting and using less accessories and devices for the procedure now moving over to complications um bleeding is the main complication several risk factors have been identified they include the size uh right-sided lesions use of anticoagulants comorbidities uh in the patient peduncleated lesions now prophylactic therapy indiscriminate use of prophylactic therapy versus no therapy for all kinds of polyps whatever the size has not been shown to decrease delayed post-polypectomy bleeding certain risk factors have been identified and this is a score developed by Dr. Berg's group that showed that if the size is greater than 30 millimeters you give two points proximal location two points comorbidities one point and not using epinephrine one point and based on this if the score is five to six the risk of post-polypectomy bleeding or post-EMR bleeding is significantly higher or high so this happens now the the use very useful device here is the quadrasper forceps which is a forceps which flat uh cups uh the jaws are a flattish as opposed to the the the hot biopsy forceps so it's a little different here you can see i'm trying to grab the vessel and it exploded on me but it's no big deal these if you have the right equipment and you maintain your composure you'll be able to control this bleeding so i'm getting my quadrasper forceps around it and once i close it and the bleeding stops or decreases i know i am on the vessel i'll wash i've not completely stopped the bleeding but it's decreased significantly so i know i am on the vessel and then i'll use soft coagulation to burn it when i burn it i lift the forceps towards the lumen to to to prevent the heat from transmitting down towards the muscle although it's still soft coagulation so it's very safe and here we have been able to to control the bleeding pretty easily so this is a very useful tool now multiple studies have shown that clipping prevents bleeding but the meta-analysis has crystallized this down to large polyps in the proximal colon so that should be the standard of care that if you remove a large polyp in the proximal colon you should close the emr post emr defect with clips and this has been shown to decrease the risk of bleeding which was 3.8 percent with clipping versus 10 percent without clipping now how do we do that depends on how big the the the defect is some defects are very difficult to close based on the size but luckily we are getting clips or we have clips now with wider wider wingspan so what i do is i start from one edge of the post emr defect i try to anchor one jaw one jaw of the clip on one side then i torque my scope maybe suction a little bit turn my dials so that i can get to the other edge and then once i feel i have got there i'll close now i won't i will ask my nurse or tech not to deploy the clip till i'm sure that i've got both the edges and once i'm sure that i've got both the edges uh with the with the clip then i will ask them to deploy and that brings the two edges together then it's a matter of just working your way from this side to the opposite side in the same sequence get your clip anchor it at one edge torque your scope maybe push in a little bit suction turn your dials so that you can get the other jaw anchored at the other edge and then you close once you feel that you've got both the edges for sure then you ask your tech to deploy the clip and then you work so it's like a zipper effect that you create as you go along and basically you can you can completely close the defect or at least majority of the defect close in this manner the aim is to get these clips as close uh as possible and never try more than a centimeter gap between uh between uh the clips so obviously a little expensive but but very effective for right-sided polyps level one evidence showing that it decreases uh the risk of uh post polypectomy bleeding the other uh dreaded complication is perforation no one likes that the overall late rate luckily is low uh it's more for polyps that are greater than uh 20 millimeters in size or in the cecum transverse colon location other risk factors have been identified and also if you try to get too greedy and start removing bigger chunks like greater than 20 millimeters especially on the right side and the way you uh the the way you identify this is by uh inspecting the base uh for any evidence of muscle injury uh if you see muscle fibers and you don't see a target sign then that there's no injury but it's exposed if you see a white a ring cotri artificial cotri effect which at the base then it is suggestive of a target sign which is basically you've cut the muscle partially that has to be closed with clips and if you see a gaping hole then that means you have a full-blown uh muscle injury with frank perforation so this was a lesion several years ago when i didn't know better that i thought i'll remove but you can see it's a concerning lesion with some ulceration patient had anemia i thought this was the cause for the anemia we thought we'll remove it first raise it and this was in a difficult location in the hepatic flexure region so i started raising it and i thought that it raised well so that gave me more confidence that i should be able to to remove this uh and and so we we we thought that we'll go ahead and remove it although just by looking at it now i feel that i was not very smart in in trying to attempt removing this lesion and then uh we get our snare around it all in the retroflex position because it was very difficult to see this in the end on our uh forward view so i get my i get my snare nicely around it very feeling very happy and then we start uh cutting it and it didn't take too long to cut either and i'm pretty sure i used endocut so i'm moving it one thing that you can do is move the lesion and if you see the entire wall around it moving with you that's a bad sign so here i remove the lesion and you'll see in a second that there is a little bit of a gap here right here so so here is the full thickness perforation you can see a blue base here and you see darkness this darkness is never good here so so yeah this is a full thickness perforation which is obviously not very here you can see it again so it says check pc card but it should have said check the uh the pulse rate of the heart rate of the endoscopist which was very high at this time so but you have to maintain your composure you have tools to close this and avoid surgery now so as you can see i'm maintaining my position i'm not letting go of my retroflex position i'm getting clips out and i'm trying i'm going to clip it and once i can approximate i can get one clip the first clip is usually the most important one so i'm doing it in retroflexion i have to push the clip out to get the other wall into the clip and now i've approximated both the edges now it's just a matter of using your zipper technique to clip on either side of this and i was able to close this we admitted the patient for a couple of days did not even call surgery because if you call surgery before you know patient will be in the or you're sure that you've closed this colon is clean there is no risk of peritonitis you're using co2 and here we go we of course this defect in two days the patient went home without the need for surgery so so we have tools another tool is is is this this is a patient i had where i actually was resecting a residual adenoma upstream with a full thickness resection device and it's like very early on in my experience with full thickness resection device so for folks who have used this you know it's very bulky and this was a female patient very tight sigmoid turn i was able to negotiate the turn after some difficulty and i took care of the the lesion but when i came out and went back again to inspect we found this perforation in the rectal sigmoid region so again no reason to panic we use the ovesco clip or the over the scope clip here and as you can see i'm getting to the to the lesion you can see the perforation i'm trying to suction a little bit to make sure that the area of perforation comes into my cap of the over the scope clip so this is just a few trial just to make sure because you don't want to deploy the clip and not get the full perfection in here i'm seeing that the the the the the wall is pretty pliable it's not that stiff in spite of the fact and then i suction and i deploy the clip and once you deploy the clip it's it just closes it closes the perforation and again the same thing admitted the patient for a couple of days did not call surgery did not do a ct scan because i know what it will show there's no point doing it and uh and the patient did well and went home after a couple of days with no problem so so we when we are in this business of removing large polyps we should be able to take care of the complications because they will happen they happen in the best of hands they will happen to us and as long as we are competent in in taking care and managing the complications that avoids any adverse really adverse outcomes in the patients these are the electrocautery settings for your reference you can go over them for different types of techniques that we use now quick word about tattooing so we tattoo the lesions for a variety of aims one is to identify the site when we follow up or as a guide to the surgeon if you're sending them for surgery the aim is to tattoo a few centimeters away at least five centimeters maybe even sometimes more and try to tattoo two different walls so that if the surgeon opens up the abdomen the the they have a greater chance of uh visualizing the tattoo and uh the technique that i follow again described by dr burke is that you create a bleb with saline and then transfer uh the uh the tattoo particles into it or the carbon particles into it so that you don't soil the peritoneal cavity so here i'm in the submucosal space as you saw i injected saline to confirm that i was in the submucosal space and then change the saline syringe to my tattoo and injected it so this ensures that the the the spot or the carbon particle that you're using does not spill over into the peritoneal cavity which can make uh things difficult for the surgeon when they do surgery and there are certain areas where you don't need to tattoo which is the cecum or the ic valve or the distal rectum i mean cecum is cecum there's no there's everyone will recognize it so you don't need to tattoo in these areas but other areas uh you have to tattoo and then the other word of caution is if you tattoo very close to the post emr defect then obviously it can cause some uh fibrosis or if you're tattooing for before referring for resection always stay away from the lesion so that you don't cause submucosal fibrosis now quick word about on-block resection we talked about this in the previous study when you have suspicion of invasive cancer or superficial invasive cancer which is the presence of uh features that might predict that there's invasive cancer but superficial you may have to do on-block resection where you don't resect is when you have features of invasive cancer so anytime you see a lateral spreading tumor granular type with dominant nodule you should be concerned that this may have invasive cancer superficial invasive cancer or you have a non-granular lesion which is sessile or pseudo depressed or you have j j net type 2b size greater than two centimeter and you don't have features of nice type 3 or j-net type 3 if you don't have these and you have these then you are concerned that there may be some invasive cancer and this is the slide that we discussed again from dr berg's group where they defined the the the different uh criterias or the different features that predict covert submucosal invasive cancer and these are the ones where you want to remove the lesion either on block or if it's a lateral spreading tumor with a dominant nodule at least remove the dominant nodule on block and pin it on the flat surface and send it for vertical sectioning by histopathology and this will give you good accurate uh histological diagnosis if there is invasive cancer whether the lateral margins are clear vertical margins and what is the depth of invasion like we discussed earlier so in conclusion coarsen polypectomy should be the preferred method for polyps uh less than 10 millimeters as it is safe and effective and it is also safe and effective for polyps between 10 to 19 millimeters in size is very effective for sessile serrated lesions of all sizes either with or without submucosal injection uh for conventional emr follow the do's and don'ts that we discussed assess the lesion characterize it and decide the appropriate treatment follow proper technique do not refer benign lesions to surgery try not to remove it partially or half-heartedly and manage complications appropriately uh you should if you refer the patient or you want to identify the site for a future you can tattoo and schedule the appropriate follow-up other options are underwater emr and cold snare emr for large lesions you should identify lesions that may need on block resection or esd and refer them as necessary thank you

polypectomy

gastroenterology

therapeutic intervention

endoscopists

cold-snare polypectomy

hot-snare polypectomy

post-polypectomy bleeding

serrated lesions

conventional EMR

follow-up care