So, EOS ablation, are we there yet? So I have nothing to disclose. The ablation technique includes injection, alcohol injection, and radiofrequency ablation, and this can be used for solid and cystic tumors. My talk today will cover EOS injection of PNAT, EOS RFA of PNAT, as well as RFA of pancreatic adenocarcinoma, so I will cover solid tumors. Starting with EOS-guided ethanol injection, the indications for it is that we can do it in functional neuroendocrine tumor or insulinoma, or non-functional neuroendocrine tumor that's larger than two centimeters, however, these patients should be patients that are not fit for surgery, or the patient refused surgery, or un-receptable, because, you know, usually with these two categories, the patients deserve surgery if they are candidates. For non-functional PNAT that's less than two centimeters, a low-grade or G1, we can offer the ablation therapy as well in some selected cases. So here are the three main indications for now. What about technique? There are several steps in doing EOS alcohol injection. So the first step is that generally we recommend doing contrast-enhanced EOS to confirm that the lesion is hypervascular, then we use either a 25 or 22-gauge needle, advance the needle into the tumor a few millimeters away from the deep part of the tumor, then inject about 0.1 ml, then wait a little while to observe the hypoechoic cloudiness, which extends to the margin of the tumor, but make sure it doesn't go outside the tumor, otherwise it's going to create pancreatitis. Then you want to pull back the needle slowly, and then you may want to inject a little bit more of the alcohol, if required, until you can see that the tumor is filled with the alcohol, so you're going to see the changes, which I will show you in the video in a second. And you can actually aim the needle at multiple directions where you feel that you need to inject more alcohol. However, if you start seeing that the alcohol leaks outside the tumor, you should stop. Before removing the needle, make sure that you want to keep the, wait for about a minute also to minimize tracking of the alcohol into the adjacent structure. Finally, after you finish, you can check with the cloud truss again to evaluate the efficacy of the injection. So here is a video demonstrating a case of neuroendocrine tumor at the pancreatic head. The size of the tumor is very small right there, and the needle is being advanced, a 25-gauge needle is being advanced, and now you can see, once the alcohol is being injected, you can see that the cloudiness inside the lesion, and you can actually, if the lesion is big enough, then you can move the needle to different areas of the lesion, just like doing fanning technique. After that, you can use contrast enhance to assess the efficacy of tumor ablation. Generally, with the neuroendocrine tumor, you're going to see the enhancement after you inject sunaview, but if your technique is very good, you might not see any enhancement at all. Like in this case, you can see a little bit of enhancement right here, but I think this is quite good. Well, what about data? Well, there have been some studies reporting the efficacy of the ethanol injection, and most of these are being reported with insulinoma. The tumor location can be anywhere from head to tail, and the size of the tumor is ranging between 10 to 20, while the concentration and the volume varies. Most of the reports show 100% response, adverse event though. Some of these have hematoma. Some of them have abdominal pain, necrotizing pancreatitis, and PD stricture. So just recently this year, this is probably the best study that we could find, which is reporting the efficacy of EOS-guided RFA and ethanol ablation for PNET is a systematic review and meta-analysis. So the pool success rate of the ethanol ablation, the clinical success is about 80%, whereas technical success is more than 95%. Adverse event is about 11%, and that being acute pancreatitis and PD stricture. So this technique is actually quite easy to perform, and the clinical success is quite good. Well, as I mentioned, adverse events of 11% is acceptable, but it can be less. So what can we do to avoid these complications? For acute pancreatitis, I think we should make sure as we're injecting that the alcohol doesn't leak outside the tumor. So once you see that, you should stop injection. What about PD stricture? I think it's very important before we do this type of procedure to assess the proximity of the pancreatic duct and the lesion. If the lesion is really close to the pancreatic duct, then a PD stent can be placed before you do the ablation. What about bleeding? We can use smaller size needle and make sure you use Doppler before we puncture the lesion. Well, but you know, the ethanol injection still has some issues. Number one, we don't know what the adequate volume is. Number two, the method is not standardized. And number three, when the remnant viable tissue is very minimal, we really don't know yet what to do with them. Should we repeat the ethanol injection or should we just follow? So here are the issues. Well, then another technique that we can offer to the patient is RFA. The indications for RFA as of now is locally advanced pancreatic tumor, neuroendocrine tumor and PDEC. Let's look at the detail of the RFA. So there, there are a few steps to set up the RFA machine and the device actually includes the generator here, ground pads and water pump and also tubing, the white and the blue tubing to cool the system. I'm going to show you the technique for RFA. So there are several steps to be taken when we do RFA. So step one is to again, check the lesion with contrast enhanced EOS for NET if available. But if you don't have contrast, it's still okay to do it without contrast. Number two, check Doppler, advance the RFA needle into the tumor. Again, keep the tip of the needle a few millimeters away from the deepest part of the tumor and then activate the energy. Now as you're starting to deliver the energy, you're going to start seeing bubbles coming through the needle. And as you see, if the bubble expands until it covers the whole area, that's when you can stop. And it's kind of like similar to the injection therapy. When you start, you start at the almost deepest part of the lesion and then you can slowly pull back the needle and deliver the energy more until you can see that the tumor is being occupied by all the bubbles. So here is some video to demonstrate how we prepare the equipment. So here, I want to highlight here, this RFA needle has two compartments, sheath and then the needle. I want you to see the needle right here. So the active part of the needle is this part right here, and it's one centimeter and the rest is the sheath to protect the heat to damage the tissue. So that one centimeter is at the active area. So we're showing you here, this is a pig's liver, we're showing you here how this works. Once you advance the needle into the lesion, you can see the needle is coming through right here. You see the tip right there, the one centimeter tip right here. And once you start doing this, make sure that you put this on continuous mode. And we can do 50 watts is what people recommend. Some people use 30 and slowly go up if 30 doesn't show any effect. Here, this is a bubble. This is a bubble that I was mentioning. So it comes, it comes. Now, if you keep an eye here, you can start seeing this bubble and you can withdraw the needle a little bit and you can see this bubble coming. Okay. All right. So here's a real case. This patient has a pancreatic net and this is a lesion right here. That's the needle. You can see the active portion right here. And now you start delivering the RFA and you start seeing the bubble. You can slowly pull back the needle a little bit as you're trying to ablate more. See that? So this part is white, right? And then you can move to the other part. Here we go. And now this part, you put the needle right here towards the other edge of the tumor and deliver the ablation. And after that, we can do contrast enhance. So as you can see here, the contrast is coming. A little bit of enhancement. So once you see that a little bit of enhancement that's left, you can actually aim right there. The needle goes there and then deliver more ablation to the area with enhancement. And you complete ablation using contrast enhancement guided. The number of sessions really depends on how well you can ablate. What about adverse event? Obviously, pancreatitis, pancreatic duct structure, bleeding, gut wall necrosis, or vascular thrombosis. So for pancreatitis, very similar to the alcohol injection, want to avoid ablating outside the tumor. For pancreatic duct structure, it's very important before we do this to assess the proximity between the tumor and the main pancreatic duct. If the distance between the tumor and the main pancreatic duct is less than five millimeters, then prophylactic PD stent is recommended. Bleeding, make sure you shake Doppler. Gut wall necrosis, make sure you don't burn the wall. So make sure that the needle is already inside the tumor before you step your foot on the pedal. And vascular thrombosis, this may occur if the tip of the catheter hit the vessel. So make sure that you avoid that. As far as follow-up protocol, so we generally reassess with cross-sectional imaging three months after the ablation. If complete ablation is achieved, then we follow cross-sectional imaging at six months and 12 months. If it's incomplete, we repeat the ablation therapy and follow it up again with contrast enhanced CT or EUS as well as clinical follow-up. What about data? The data on RFA is actually quite good. For PNET, clinical success is about 85% with a technical success of 94%. 14% adverse events and 8% being acute pancreatitis. This is based on systematic review. What about RFA in PDAG? I think this is the new area here because based on the old data, it doesn't seem to have worked well for pancreatic adenocarcinoma. But here we have a new, over a year ago, actually two years now, systematic review and meta-analysis for RFA in pancreatic tumor. And the patients in these studies were those who had unrespectable locally advanced pancreatic cancer, 27%, PNET, 40%, and metastasis for about 3%, ablation is about 30%. Technical success is 100%, clinical success 91% with an adverse event being 15%, almost 10% have abdominal pain. So I think this tells you that this technique is not that difficult to do with a pretty good clinical success. So if you have a patient with unrespectable locally advanced pancreatic cancer, or PNET, this technique can be offered to this type of patients. Now here, I just want to share with you a study that comes out of Thailand. Dr. Konkan, he evaluated the effect of RFA on patients with unrespectable pancreatic cancer of more than four centimeters undergoing chemotherapy. What he wanted to see was the additional survival effect that the RFA has on top of the chemotherapy. And based on the results, well, first of all, this is a preliminary data that he allowed me to share with you guys. So based on this preliminary data, it seems that when you add RFA to the chemotherapy, the patients live longer with a higher survival rate. So I think how true that is, we're going to have to wait and see the final version of this study. Finally, I'd like to conclude that EUS guided ablation therapy is having high technical and clinical success with an acceptable adverse event. It can be effective in selected cases, especially PNET. The techniques of injection therapy with ethanol needs to be standardized. And we're still going to need more data on the efficacy and the effect of this type of treatment in patients with unrespectable pancreatic tumors. With that, I'd like to thank you very much, and I'll be happy to answer the questions.

endoscopic ultrasound

ablation therapy

ethanol injection

radiofrequency ablation

pancreatic tumors