Hello, everyone, and thank you for inviting me to talk on my favorite topic, cold snare resection. So the title is provocative, cold snare revolution in polypectomy. So revolution, a dramatic and wide reaching change. If I look back at my career, 20 years ago, my attending used to say, every poly needs to be removed using electrocautery. Why? First, to ensure complete and soft resection. And second, to reduce the risk of bleeding. You can see how we used to do it, engaging the snare, tenting away from the wall. And then afterwards, enjoying the view of a nice clean base and a cauterized margin that perhaps falsely assured us that the poly was completely removed. So almost 10 years ago, we published this paper, a care study that showed that a hot snare resection of five to 20 million polyps actually had an incomplete resection rate of about 10% and increased with polyp size, but also varied across endoscopies and probably related to some marginal tissue that was not recognized after hot snare resection and could not be cauterized just by using electrocautery. So we have now learned that cold snare resection of small polyps seems to be safe. The immediate bleeding risk of most studies is about 2%. No delayed bleeding risk has been reported for those very small polyps, or it's a rare event. The typical approach to cold snare resection is trying to push the tip of the catheter towards the wall to engage a healthy tissue margin. So let's look at studies related to cold snare resection and bleeding risk. Here is a matched controlled study, cold snare polypectomy versus hot snare polypectomy. Very large study that matched for other risk factors. And the bottom line is that the risk of delayed bleeding was about six fold, an odds ratio of about six. So two bleeding events in the cold snare group, 12 bleeding events in the hot snare group. And that is for polyps that are small, up to 10 millimeter in size. So clearly, cold snare resection seemed to be safer for this type of polyp. So there are numerous studies related to the completeness of resection, cold versus hot snare polypectomy, and the results are pretty similar for both outcomes. This randomized trial looked at complete resection of four to nine millimeter polyps, hot versus cold, and with a non-inferiority design. And they found that the cold snare resection was non-inferior to hot snare resection. The incomplete resection rate was about 7% after cold snare resection and 11% after hot snare resection. Pretty similar to what we've seen in the CARE study. So not surprisingly, the societies have picked up on this and now recommend cold snare resection as a standard approach for all polyps up to 10 millimeter in size, and as a possible approach for polyps up to 90 millimeter in size. So but there remain a number of questions. What's the size cutoff for polyps? Is there any morphology that should not be removed with the cold snare? What's the histology? Does that inform us what to do? Are there special snares we should use? Should we inject or not inject before resection? And how should we handle antithrombotics? I'd like to use the rest of the time to go through some of these questions. So let's first talk about dedicated cold snares. This early study found a greater incomplete resection rate using the standard snare and lower with the dedicated cold snare. But surprisingly, the overall incomplete resection rate was pretty high. So this randomized trial looked at dedicated or thin cold snare versus standard snare and found no significant difference. The number of incompletely removed polyps up to 10 millimeter in size was three in the dedicated cold snare group and seven in the standard snare group. So what about larger polyps? So let's look about size as the determinant for choosing cold snare resection versus hot snare resection. Again, there have been a number of studies published over recent years. This meta-analysis summarized eight studies and found an overall delayed bleeding rate that's close, less than 1%. Even for 20 millimeter larger polyps, there was no report delayed bleeding rate, no perforation. There's some intra-procedural bleeding and the recurrence rate overall is somewhat comparable to traditional incomplete resection rates that we know from hot snare resection, but it seems to be far greater for adenomas compared to cell-cell serrated polyps and much greater for larger polyps, 10 millimeter in size compared to those that are less than 20 millimeter in size. So interestingly, a couple of more recent studies found that there is some delayed bleeding associated with cold snare resection. So we were all kind of thinking, you know, cold snare resection is completely safe. There's hardly any bleeding, no perforation, but there are some reports of delayed bleeding. In this study, he had a 4% delayed bleeding rate following resection of 20 millimeter larger polyps, adenomas and cell-cell serrated polyps. What about histology? So in this study that used historical hot EMR as a control group, found that cold EMR of polyps that are of cell-cell serrated polyps, 20 millimeter larger in size, had the same recurrence rate or a similar recurrence rate. So no difference here. But the complication rate was zero in the cold snare EMR group. And the typical, what we expect in the hot snare EMR group, 5% delayed bleeding after hot snare EMR and close to 3% perforation or target signs in the hot snare EMR. So suggesting that cold resection of 20 millimeter or larger cell-cell serrated polyps is at least as effective as hot snare EMR, but safer. Now here are some studies that looked at adenoma recurrence as opposed to cell-cell serrated polyp recurrence. In gray, the results of the meta-analysis that we just looked at. And in yellow, the most recent one, 310 polyps, 20 millimeter larger in size. And recurrence rate overall was 35% in that group. And 40% for adenomas, 12% for cell-cell serrated polyps. So that is somewhat sobering. And here are some of the details of that study. So overall, 35% recurrence, a high more than 50% recurrence rate for polyps that are TVAs, have high greatest plasia, 61%, or larger than 30 millimeters. So that holds true for other, you know, in additional studies, it's unlikely that cold snare resection will be the approach or a chosen approach for resection of non-cell-cell serrated lesions. So why is there such a high incomplete or could there be a high incomplete resection rate? We know from hot snare resection that's related to the margin because margin ablation reduces the risk of recurrence by at least 75% to even down to 2% in this observational study that was recently published. So what are potential issues and what can we do? So here's a non-granulomavirus lesion in the sigmoid colon, and you can see that the proximal margin is not clearly seen, and there might be even a CUDO5 pit pattern. So what was done here is the lesion was marked with a forceps. So small forceps bites were taken, and that allows to anchor the tip of the snare to be anchored in the defects of the forceps bites and thereby having a better push down of the snare onto the wall and making sure that the first cut or the first couple of cuts are really in the right plane. Different to hot snare resection, it seems more likely that the problem of recurrence is not in the margin, but more likely in the base and that we are not in the right plane for some polyps, particularly those that were mentioned, tubulobulus adenomas and hygrosplasia. So here, for instance, you will see that we try to engage the tissue with the snare and then we close, but we kind of shave off the tip of the mucosa. And if you don't, if you don't try to remove what's beneath it, you might have the source of recurrence in that area. So what can you do? Well, you can attempt a suction technique, making sure like suctioning the tissue into the cap that is used here. And as you can see, we're trying with the dedicated cold snare to resect it, but it doesn't work. So you're stuck. The snare is then being released and we changed to a different dedicated cold snare here with nitinol that then again, well, then again, trying to engage that same area that we couldn't transect with the dedicated steel snare. And here it seems to go much easier. And if you look at the defect afterwards, it's clearly deeper than the surrounding resection base that was removed with a standard or with a dedicated cold snare that's made of steel. Now here again, that white stuff here is probably, white tissue is probably still residual poly tissue that again, we're trying to remove with that snare. And what might happen if you cut deeper, you might hit bigger submucosal vessels. And here we had some bleeding that need to be controlled with cold placement. So what about submucosal injection? Should we use submucosal injection for cold snare resection? Well, we don't really know it for hot snare resection. So, but this study looked at six to 15 millimeter polyps in four groups, cold without resection, cold with submucosal injection, hot with and without submucosal injection. And the first really interesting thing is that the incomplete resection rate was really low across all four groups. There were a couple of incomplete resection with hot snare resection, none in the cold snare group. And the severe adversity range rate was also extremely, was very low in across all groups. So if anything, cold snare resection without submucosal injection seemed to dominated the groups in the comparison and was clearly not inferior to any of the other groups. So this is suggesting that if you remove a polyp up to 15 millimeter in size, you do not need to use submucosal injection. So this study here removed sessile serrated polyps that were 10 millimeter in size and a larger proportion also more than 20 millimeter in size. And they did not use any submucosal injection recently published in CGH. And the incomplete resection rate was phenomenal. Only one polyp was incomplete removed based on marginal biopsies. Again, no submucosal injection, almost perfect complete resection rate. The caveat is here that the authors say that it's essential to completely delineate or see the margin. And if they were not able to see the margin clearly as seen in the picture here, they used chromoendoscopy to make sure the margins are being seen before resecting it. So we're not as used to using chromoendoscopy, but clearly if the margins are seen that seems to support cold snare resection of those polyps without any submucosal injection. Now, I'd love to talk more about antithrombotic management, however, based on the time we can do that during the live case demonstration or discussion. The bottom line is there's increasing evidence that cold snare resection can be considered a low risk procedure. So in summary, cold snare resection should be the standard for all polyps up to 10 millimeter in size, and probably it's likely the standard for all polyps up to 50 millimeter in size, maybe up to 90 millimeter. It should probably also be the standard for all sessile serrated polyps, and it may, it's still a revolutionary consideration for non-sessile serrated polyps that are 20 millimeter larger in size. And we need to wait for the study to understand whether there's a subset of polyps that should not be removed by cold snare or should be removed by cold snare. There doesn't seem to be a role for submucosal injection for polyps that are 50 millimeters or smaller in size, and cold snare resection may be considered a low risk procedure. Thank you for your attention.

cold snare resection

polypectomy procedures

complete resection

risk of bleeding

safe and effective