Michael Greenberg: Thank you.
Daniel Welchons: Thanks for having me.
Zachary Klaassen: You guys both have extensive experience with prostate cancer rectal spacing. And so Mike, I just want to start with for our listeners as a background, why is it important to consider rectal spacing? What is the toxicity if we don't put a rectal spacing in? Just level set for our listeners why we even do this procedure.
Michael Greenberg: Well, being old enough where I practiced for many years without a spacer, we know what patients suffered from. Patients were cured from their cancer. However, sometimes they didn't want to leave the house. They'd have rectal bleeding, multiple bowel movements per day, irritability, urgency, mucus, and it became really intolerable for the patient. So it was really a quality-of-life measure, which improved their care dramatically.
Zachary Klaassen: So even in an era where we have really precise, you guys have great plans. We've changed from the '80s and '90s where we're just blasting the pelvis. We're still seeing toxicity in 2026, correct?
Michael Greenberg: We do. And again, some of it is because gas moving through the rectum during their treatment, which it can really change the position of the prostate or stool or filling of the bladder. All those things can make a dramatic difference.
Zachary Klaassen: Makes sense. Yeah. Dan, from a urologist perspective, you've been rectal spacing for several years now. Why is it important to get involved as a urologist and what got you into this field?
Daniel Welchons: I've always liked urology just because we are the quarterback for the patient's care. When it comes to their prostate cancer journey, we find out about it, diagnose them, recommend what they should do for treatment and either perform that treatment or send them to the radiation oncologist, and they always come back to us. So when they come back to us, we're the ones that are helping deal with the side effects from their prostate cancer treatments and helping them get through those side effects. And I think one of the blind spots we used to have was how to help them with their rectal side effects. We could always handle their ED and we could handle their urinary stuff, but all of a sudden you're trying to get a new doctor involved and it just gets overwhelming for the patient. So I think the idea behind this is how can we get ahead of it and how can we prevent this one particular side effect from occurring? And I think the data's pretty strong that by pushing ... And it's just intuitive. By pushing the rectum out of the way, people have less dose to the rectum and therefore less side effects. And the urologist is the one, I think, in general that really navigates that patient through their journey, including all the side effects that go with it.
Zachary Klaassen: Yeah, it makes sense. And I think, like you mentioned, as urologists, we see the genital urinary toxicity, the hematuria, the strictures. But when we start really thinking about it, if you don't get a rectal spacer historically from the literature, about 10 to 38% will have a grade-2-plus GI toxicity, whether that be rectal hemorrhage, as Mike mentioned, whether it'll be constipation, needing laxatives, enemas, et cetera. So it does come back to the urologist, and it's important, like you said, for us to be involved in that process. So Mike, I'd love for you to lay out for our listeners the available rectal spacers that are FDA-cleared that are on the market as we sit here today.
Michael Greenberg: Sure. So Boston Scientific led the journey. And back in 2016 when they came out with a pegylated SpaceOAR, the classic, we were so happy that we had something because we never had it before. So it's just called SpaceOAR and it's an accelerant and a pegylated material that in about eight to 15 seconds, it just gets hard quick. So that was the first one. We used to say spray and pray. You just had to push it really quickly, put the needle into the space at the base or seminal vesicles, and then just hope that you had pretty good distribution. And we know it was good, but we only got symmetry about 50, 49% of the time. And then they came out with a product called Vue, which they added an iodinated molecule to it, which helped for visualization on simulations for radiation as well as for cone-beam CT, which we use to verify the position every day. You can see it, very thick, even thicker. And again, when you have spacer, you're mixing two products together, so you really had to push hard. And thinking about it, it's a hard high-pressure system on the rectal mucosa. The next, BioProtect came out with a balloon, which looked good. Symmetry is probably pretty good, but you have to do a small cutdown and you have to use a very sharp trocar in an area that's probably very vascular. So the injuries and risks of safety are pretty high.
So the next is Barrigel, which is the hyaluronic acid, we call it NASHA, non-animal synthesized. And it's the same drug that's used in the face for plastic surgery for lips and cheeks and cosmetics. It's 98.5% water, and it's very safe. It's used as a different product in urology for pediatric, I think ureteral reflux. It's used in the anal sphincter itself, a product called Solaris for anal tone, for fecal incontinence. So we know it's safe. And the best thing is we all become artists. You can shape it, any length. So the BioProtect balloon, you can't cover the seminal vesicles on the prostate. And SpaceOAR, you don't have any control. With Barrigel, you shape it, you can do it in sagittal, you can do it in transverse. You really can get what you want, and it's a low-pressure system. And the nice thing is the next day patients don't call you and say, "Doc, I feel this ball. I feel this thickness." And it really allows us, it's the most flexible. It lets us do re-irradiation. It lets us basically build up areas where there's extracapsular extension and there's no reported fistulas. And we know now in the pegylated products that there are more and more fistulas being reported. And I think that's because it denudes the mucosa and devascularizes and they get an ulcer and then a fistula.
Zachary Klaassen: That's a great background, Mike. Thank you for that. Dan, when we look at from a urology perspective, is there certain aspects of a rectal spacer that are really key, really important to you? Working into your workflow, you're taking out kidneys, prostates, doing stones, BPH. What aspects of a rectal spacer are you looking for and is there one specific that encompasses all those?
Daniel Welchons: Although we say we're trying to help prevent all these rectal toxicities, the technology, the skill of the radiation oncologist has obviously come a long ways. Patients have had lots of radiation to their prostate under the skilled hand of the radiation oncologists and have done well, although they still have some rectal issues potentially. They've overall in general as a cohort done quite well. For me, the biggest thing is how do you get the patient some gains without potentially complicating their overall treatment course? And so we were early adopters of spacing at our practice and started with the pegylated spacer and just found that some of the complications were just unacceptable given that patients probably would've done okay just if they had radiation alone. So I think the safety profile is really the most important thing for us as urologists. We're also the ones that are doing the procedure on the patient a lot of times, at least in our practice. And so like any surgery you and I are doing, Zach, it's about safety.
How can I get you through this, get you off the table? I know you're a big real surgeon doing the big wax, but how do you get this patient through their care in the safest manner possible? So for my personal opinion is safety is by far the most important thing. How do you do a procedure that's going to render the best benefit with the very, very least amount of risk? And so for us, we've found that Barrigel provides that. It's just something that we feel confident that they will do well. Like Mike said, they're done with the procedure with almost any discomfort. I've never had a patient say they have discomfort afterwards. It's intuitive to the patient that pushing the rectum out of the way is a smart idea and the side-effect profile has been so low. It's to us the best choice for our patients at least.
Zachary Klaassen: That's great feedback. Mike, I want to ask you one more question just in terms of radiation planning. So you talked a little bit about symmetry in space. From a planning standpoint, and we have a lot of urologists and rad-oncs that listen to our discussions, but specifically for the urologist, why is it important to have that separation as well as have that symmetry when you're doing your planning phase?
Michael Greenberg: Well, obviously we want to protect the entire rectal surface circumferentially. I always say try to get a frown effect. And now with most radiation accelerators, there are arcs that are forming around the prostate and seminal vesicles and sometimes the lymph nodes as well. And so we really need good symmetry to cover both sides of the rectum. With the pegylated products, we would do it and say, well, okay, we're protecting half the rectum. But the studies are showing us now that dose escalation is everything. The higher we can push the dose to the target where the disease is particularly positive, the better the long-term control. And that was with 10-year data. And a lot of times that's extracapsular. And again, Barrigel is the only product that can really do that extracapsular, and it works very well. But again, with planning and with the simulation, we know that lowering those doses by 10, 15% to the anterior rectal wall makes a huge difference in symptomatology. And doing a lot of brachytherapy as well, I'll tell you that before where the rectum was right up against the high dose area, we almost always see the dose with Barrigel of zero, which is incredible. And also you can see it so well because real time it doesn't cause any problems with transillumination with the ultrasound, and we can put the needles right through it and there's no distortion. So again, another flexible issue, which makes it very easy.
Zachary Klaassen: That's awesome. Gentlemen, great discussion. I just want to give us a minute or two to wrap up. Dan, I'll start with you. Anything we haven't hit on? Any take-home messages for our listeners?
Daniel Welchons: No, I would say people that have not done any spacing or interested in it or hear some of the things about it, I would say it's been a big benefit to our practice, mainly because the patients have been so happy with the offering it. And I say all of the time, it's just very intuitive to the patients and they feel like you're really doing everything you can to get them through. And this is just an additional thing because when it comes to prostate cancer, if it's found early, we know cure rates are quite high. It's really all about how can you get the patient through their journey with the least amount of side effects. And this just adds to our armamentarium to help those patients, and they're very appreciative of it.
Zachary Klaassen: Yeah, it's well said. Mike, you've got the final word, my friend.
Michael Greenberg: Well, I think urologists and radiation oncologists are probably the greatest partnership of all specialties. We really work together so well, and you will make a difference. A lot of times you'll think, well, the technology will take care of it, but there's lots of things happening dynamically during the treatment. So this will help your patients. And talk to your urologist if they're the ones putting in the Barrigel, show them the issues, particular areas that you need a little more such as the apex and they'll help you. So work is a partnership and it works great. Really helps the patient.
Zachary Klaassen: Absolutely. Dan and Mike, thanks so much for your expertise and thanks for your time joining us on UroToday.
Michael Greenberg: Thank you. Great to see you. Thanks so much.
Daniel Welchons: Thanks, Zach. See you.