SSLs on the ASGE SuTab tip of the week. In the past several weeks we've talked about ways to avoid complications in lesions removed with electrocautery but the most effective way to avoid complications is to avoid electrocautery entirely. That underlies the so-called cold revolution where we now remove almost everything under one centimeter in size without electrocautery and there's tremendous interest in whether the cold revolution can be expanded into larger lesions and the most convincing body of evidence that we can do that is now for the sessile serrated lesions or SSLs. That's now the preferred term it's replaced sessile serrated adenoma and sessile serrated polyp. I often ask people if you had your choice between an SSL and a conventional adenoma of equal size in your colon which would you choose and people are often afraid of the SSL because we hear that it contributes disproportionately to interval cancer and that's true but not because individual SSLs are more dangerous in fact compared to conventional adenomas of equal size they're seven to ten times less likely to have invasive cancer. No it's because they're missed more often because of their subtle and often flat appearance and I think another factor is that many patients who develop interval cancer through the serrated pathway have unrecognized SPS serrated polyposis syndrome and this is why it's so important to count the lesions and to count them by size and recognize SPS because we bring SPS patients back at least initially annually and that gives us a greater chance to detect lesions that we missed and get them out before they become malignant. It's hard to know the true or actual prevalence of SSLs in screening populations first because of different histologic definitions of what an SSL is relative or compared to a hyperplastic polyp. Second because of variation among pathologists in identifying and interpreting SSL elements histologically and third because of all the variation between endoscopists in finding the lesions. I think the highest quality studies suggest the true prevalence is at least eight to nine percent but we have plenty of studies showing detection rates that are less than fifty percent of that and you can see why looking at this lesion. This lesion is probably a true Paris 2b lesion that is this essentially flat. I think most of the 2b lesions that I see are actually SSLs and not conventional adenomas. It has a very thin mucus cap on it probably best to not only keep an eye out for these but once you find them keep an eye on them not wash the mucus cap off until you've started the resection or injected them so you don't lose track of it. You can see how we see the edge better after injection. Importantly unless you think there's cancer in an SSL don't biopsy it. Don't biopsy the middle or the edge or any part of it before it's resected. If you're gonna refer it or if for some reason you're gonna remove it later yourself don't take a biopsy of any part because the biopsy will produce semicostal fibrosis that will impair the lifting and tend to make the snare slide over the fibrotic part. Here's an almost real-time demonstration of cold EMR on an SSL. This is the same very flat SSL that we saw earlier and injected and this method can be done two ways. One is inject and then piecemeal resect and the other one is to remove it cold piecemeal without injection. There's no randomized control trial comparing the two but observational data on both methods indicate that both have a very low recurrence rate at follow-up in the range of 1 to 8 percent and of course the huge advantage of this is that it's devoid of complications. Personally I've performed many hundreds of cold piecemeal resections on SSLs never had a significant complication. I like the injection method because it gives such nice delineation of the border of the lesion. Now this process is cold from beginning to end there's no aspect of it that utilizes electrocautery so we're not going to perform STSC at the end rather we're going to rely on resecting a margin of normal tissue around the edge in order to get that complete resection and there's really no limit on how big that margin can be. We're using here a diminutive snare this is 10 millimeters it's a specialty snare so the wire braid is reduced in diameter by about a third compared to a standard diminutive snare which gives us better cutting action. Notice that sometimes the parts that we're going to remove already seem to be separated from the underlying submucosa that's one of the features of SSLs that makes them so nice for cold resection and which will be disrupted if previous biopsies or attempts at resection have been made. I like to use a standard scope to do this I find that you can suck back the pieces around the snare into the trap very well compared to a pediatric scope when you're doing this. In terms of efficiency because we're removing smaller pieces here we're taking some normal material off the edge again no limit to that because we're taking smaller pieces the snaring is not quite as efficient but no need to perform STSC or clipping so overall still a very efficient process at the end we'll inspect the edge carefully and then we're done. Here's a larger SSL that we're going to do cold EMR on in terms of the size range to perform cold EMR I usually start at a lower threshold of around 10 to 12 millimeters diameter and then there's no upper limit on what you can use cold EMR on SSLs tend to not be as big as granular lateral spreading tumors conventional adenomas most of them are in the 10 to 40 millimeter size range and only occasional ones get bigger than that doesn't matter they are candidates for cold EMR almost any injection fluid of any viscosity will work well to raise these lesions because they have so little semicostal fibrosis in terms of where to inject usually best to start as we did in this lesion on the anatomic proximal side so that you turn the lesion toward you and then go over to the distal edge and inject some in order to be able to see that margin I like the contrast and I think nice to include epinephrine typically at a dilution of about one to two hundred thousand if there are a lot of these to perform as in an SPS patient I may dilute it to one in four hundred or five hundred thousand a lot of epinephrine injected will give some people a bellyache for an hour or two after the procedure but overall no size limit the strategy is the same inject use your small snare to move from one side to the other until the process is complete finally we should note that while available evidence suggests that most SSLs regardless of size can be resected effectively and certainly very safely with cold techniques these recommendations are based on observational data and no randomized trials have yet compared hot EMR to cold EMR or cold EMR to piecemeal cold resection without injection next week perhaps not every SSL is a good candidate for cold resection on the ASGE SuTab tip of the week

Submucosal Injection

Cold EMR

Sessile Serrated Lesions

Colon

Cold Revolution