Varun Sundaram: Thanks for having me, Zach.
Zachary Klaassen: So just tell us a little about your experience with Barrigel™ and why it's been incorporated into your practice. Why does it make sense to you? Why is it good for the patients?
Varun Sundaram: Well, it's kind of a no-brainer. It's there to protect the patients, reduce risks, and it does so in a safe way. So when Barrigel™ came out, we incorporate it pretty quickly into the practice. And after about five or six of them, we didn't look back. It was 100% Barrigel™ all the way.
Zachary Klaassen: That's awesome. Can you just run through the safety data, because I know there's some other options on the market, but the safety data for Barrigel™ is pretty important.
Varun Sundaram: It's pretty convincing. So there's always an option for reversal. So say something goes wrong, the gel goes in the wrong place, you can completely reverse it. And the patient can go on with radiation without having to skip a beat. And that was really important for us because Barrigel™ is actually the only one that's been studied in high-risk patients with ADT. And so we have a lot of those patients. And they're not the type of people you want to say, "Oh, let's delay this. Let's do radiation in six months." So that allowed us to get people treated as we needed to and safely. The most important part about that is we've never had to do it.
Zachary Klaassen: Yeah.
Varun Sundaram: Yeah. So you can reverse it, but you'll hardly ever have to because when you're placing Barrigel™, you actually have better visualization once the gel goes in. And you can see pretty clearly when it's going into the rectum or the prostate, and adjust so that you don't ever have to reverse. And it's so minimal, sometimes even the MRI can't pick it up.
Zachary Klaassen: Yeah, absolutely right.
Varun Sundaram: There have been no theories events in the mod database for Barrigel™. There have been a couple of minor complaints, but nothing that events in a fistula, severe pain, delaying radiation. So it's a safe product for safety. It's there to prevent side effects. And so if it causes side effects, it's not really worth it to us because our patients are there for an experience, or therefore treatment of their cancer, they're not there for additional complications. And Barrigel allows us to help them and help them safely.
Zachary Klaassen: And I think from a urologist perspective or both the urologists, we're doing a service for the patient but also for the radiation oncologist. And so the last thing we want is to be thinking about possible complications when we know we're going to get those with radical prostatectomies and cystectomies and everything else.
Varun Sundaram: Absolutely.
Zachary Klaassen: I think we've learned a little bit more about the technique. And you've been a pioneer of the apical space. And just before we get into the technique, just tell us how that secondary analysis of the Barrigel™ trial came about, what that data showed.
Varun Sundaram: Yeah. The King data looked back at the pivotal trial. And they looked at what characteristics of the Barrigel™ placement portended the best protection of rectal side effects. And they found that it wasn't symmetry, it wasn't space at the base. It was space at the apex. Particularly one centimeter of space at the apex lowered the rectal dose of radiation across a variety of radiation protocols. I wouldn't say it gave us the idea, but it gave credence to the idea that if you focus on the apex, you do better to that patient. And that just makes sense as well because as a urologist when we're doing prostatectomies, that's the area that's stuck to the prostate. There's millimeters of tissue, there's no fat, there's nothing there to protect the rectum. And so the fact that you can get Barrigel™ there and get it safely there just made sense.
And the King data really just slammed that home that aside from pre-radiation bowel function, apical spacing is the only thing that held out on multivariate analysis to predict lower side effects.
Zachary Klaassen: And one centimeter space, regardless of where anywhere else is being spaced, that's the key at the apex, right?
Varun Sundaram: Correct. One centimeter at the apex. So it reinforced my idea to just stick with the apex and then worry about everything else later. Because you have so much gel, you have so much time. And so if you get that space at the apex, very often the rest of the prostate will kind of take care of itself. You won't even have to worry about it.
Zachary Klaassen: Let's go through a little more of the technique and I wish you have some great videos which we can maybe tag to this conversation, but you've been a pioneer in doing it. Just walk our listeners through how you do... I know you do it in the clinic. Just walk through the whole process.
Varun Sundaram: Just the traditional setup for Barrigel™, you want the patient square, you want their legs down a little bit, so not high lithotomy that raises the rectal hump the higher the legs are. And you want them very even on the table so that you're able to find your needle. Once you've numbed them up enough and I do a pudendal nerve block, you want to start the Barrigel™ in the middle or even the apical segment of the prostate. If you go too far past to the base or seminal vessels, then you puncture Denonvilliers' fascia. And that allows the gel to leak out and you waste gel where there's already space.
If you focus on the apex, you can get a nice big gel ball that's very symmetric because it's within the boundaries of Denonvilliers' and the vascular bundles on the side and you get that one centimeter space of the apex. And then it pushes back towards the mid and the base and spaces that as well. So you get more bang for your buck. It's easier to see on CT. And this is what's been shown to reduce clinically significant decline in bowel function.
Zachary Klaassen: A great summary from the apical space. And this is not an advanced technique, but maybe just walk our listeners through the initial maybe 10 cases before you get into the apical space.
Varun Sundaram: Yeah, I wouldn't call it an advanced technique. I would call it just a slightly different approach. And I actually think it's really important that people start learning it to start. As opposed to learning it one way and then trying to switch because it's hard to learn a new thing. And then once you've learned it's even harder to switch it because you finally feel comfortable with something. So if people are learning Barrigel™ or rectal spacing for the first time, they need to start with the apical technique. So starting with going as apical as possible, where you feel comfortable, where you feel that fat plane, the more experience you get, the more comfortable you'll get going where there's no fat plane, which I wouldn't tell the first time user to do that. But even in your first five cases, if you follow these techniques, if you follow this advice, you can reproduce what an expert can do. Maybe not as fast, but just as good. And that patient gets just the same quality of treatment that an expert could give them.
I think that's really important is that this is reproducible, but you got to learn it the right way. And I think this is where I make a chug for coming out to Austin, and learning from our immersion program. Because you see what's important for me, the placer, you see what's important for the dosimetrist, what's important for the radiation oncologist. And it's really important that you see all of these different points of care to really understand why we do rectal spacing.
Zachary Klaassen: Yeah, great point. I think your guys' program has really got people in to see both within 24 hours they get the whole package. The last question I want to ask you just about apical spacing is somebody may be listening say, "Hey, you put 12 millimeters or 13 millimeters at the apex, are these patients going into retention?" Is this something you've seen? Is it in the clinical trial?
Varun Sundaram: So I've never seen that and in the clinical trial, no patients had any issues with urinary retention.
Zachary Klaassen: Excellent.
Varun Sundaram: It's a soft dynamic substance. And once you remove the probe, however much it's diverting the prostate up will then be equally divided by pushing the prostate up, pushing the rectum down. So even two centimeter space ends up being one centimeter of adjustment to the prostate. So people won't go into retention from that.
Zachary Klaassen: Excellent. Anything we haven't hit on? Any take-home points for our listeners?
Varun Sundaram: No, I think that's it.
Zachary Klaassen: Awesome. Thanks Varun.
Varun Sundaram: Thanks for having me.