TULSA Procuedre for Prostate Cancer: A Practical Guide

[Dr. Aditya Bagrodia]
Then for the actual urethral applicator placement, is that a cysto wire over a wire, or is that just placed like a catheter?

[Dr. Xiaosong Meng]
We do a council tip catheter first, empty out the bladder, put a little bit of fluid back into the bladder, super stiff wire, and then we put the urethral applicator over the super stiff wire. If it's a rigid urethral applicator, so like putting in a rigid cystoscope, it usually goes in no problem over the wire.

[Dr. Aditya Bagrodia]
Perfect. The rectal cooling device, that's roughly what diameter? Are you doing anything on the front end? I'll tell you why I asked this, is I had a colleague of mine doing a HIFU case and post-radiation, and the patient had fairly significant anal stenosis. Suffice it to say that that was a deal breaker day of surgery. Any kind of assessment of that going into this?

[Dr. Xiaosong Meng]
It's a decent diameter. I don't know the exact dimensions of it. I would say it's probably at least 2 centimeters across. Certainly, if you have trouble getting your finger in the rectum for a DRE, probably not a good candidate for this. I know Dr. Lotan had treated a patient post-radiation with pretty tight anus, and he did have a little bit of struggle getting it in.

[Dr. Aditya Bagrodia]
If you had, I guess, a fairly uneventful prostate biopsy with a transrectal probe, is that usually going to be okay?

[Dr. Xiaosong Meng]
Yes, I think that's actually a good benchmark.

[Dr. Aditya Bagrodia]
Great. I hope these details aren't boring for you guys. I just want to make this some of the practical consideration that I've thought about and maybe others have thought about. We've just gotten to placing our urethral applicator and our rectal cooling device and now we're taking our sequences, making sure that things are in the appropriate position and drawing out our treatment plans.

[Dr. Daniel Costa]
That's right. When deciding what to treat, we normally already had that conversation with the patient and urology and radiology already extending information. We already go into the treatment day knowing what we plan to do. When we get those images, then it's a matter of putting that in practice. We will find where the cancer is. Let's suppose it's as focal as can be treatment. We find the cancer, we try to have at least a one-centimeter safety margin in as many directions as possible so that almost invariably results in a minimum of, as Xiaosong was saying, a quadrant ablation.

It's very uncommon that you'd have such a small lesion that you'd be able to get away with blast in that the way the system works is you have different elements in the urethra probe. Each element, you can think of it as a five-millimeter slab in the transverse direction of the prostate. You can turn on or off those different slabs and that's how the treatment operates. You choose which elements you're going to use and what is the transverse section of each of those elements that you want to the ablation to happen. Then you choose if you think of the prostate as a clock face, you will choose where you want to start, let's say at twelve o'clock or at three o'clock.

Then in which direction, clockwise or counterclockwise since the probe sweeps in one of those two directions. Usually, what we want to do is to start treating where the cancer is because if something happens, if we have to abort or if there is swelling as we are treating the area that is the most critical region to be covered has already been covered. Once we do that first sweep, we normally do at least a second sweep where the MRI visible lesion is, and we tend to do that in the opposite direction of the first suite.

What we noticed is in some men that have tiny classifications or that have some tissue properties that we can't recognize but result in a suboptimal heat distribution, sometimes we have a much better heat distribution when we are coming in a different direction. This is something that hasn't been studied, but it's a consistent anecdotal observation at our center and in other centers as well.

[Dr. Aditya Bagrodia]
It certainly sounds like this is where the battle for a good cancer procedure is going to be won and lost, which is going to be careful contouring really being dialed in on temperature maximums at various different time points. Some of it sounds like a repeat freeze-thaw cycle of cryoablation with the multi-pass that you're describing here, but this is where I'm guessing it's going to be a little bit more technologically involved and ostensibly, you're going to get fairly heavy support at least early on from your local representative. Is that true?

[Dr. Daniel Costa]
Absolutely, yes. It is easy to watch a video of what a TULSA Procedure looks like and think that it's a plug-and-play technology, that you just push a button and you are there waiting for the procedure to be done before you say goodbye to the patient but that's not true. It requires close monitoring during the treatment as Xiaosong alluded to, and that's something that we learned after maybe 10, 15 patients that we had treated, it's very common for the gland to swell in response to the heating.

If you're dealing with a very peripheral lesion, especially postural lateral lesions, it's very easy to go unnoticed that the lesion with the swelling now falls outside of the originally drawn area and that can be easily a source of undertreatment and cancer and repeat biopsy. It's important to monitor, and that's one of the strengths of TULSA, is the ability to do so. You can see that the gland swelling or that the bladder is getting fuller and therefore this result in a little bit of a change in some displacement at the base of the prostate, so recognizing that and responding to it is a critical step in order to have adequate treatment.

[Dr. Aditya Bagrodia]
How often are you running your MRI sequences? Forgive my ignorance, you're obviously on a-- If it's an ultrasound and it's HIFU, you can look at cavitation or if it's cryo, you're looking at the ice ball. We don't have any real-time monitoring here, so is it just, let's run the T2 again, and how long does that take and how often are you doing it?

[Dr. Daniel Costa]
It's throughout the procedure. It never stops from beginning to end, the scanner is running and so you are getting that feedback every five, six seconds. You get a new frame that shows you what the temperature is and what the anatomy looks like. Now, I should disclose that the anatomic depiction that we get every five, six seconds is not that phenomenal T2 that you can see everything very clearly. These are images used for the temperature monitoring that allow you to get a sense of where those interfaces are, where the interface between the prostate and the periprostatic fat is. It's nuanced. You really have to be looking for this.

It's not something that pops out and it's so obvious that the gland is swelling and that's one of the reasons why there is a learning curve and it requires constant monitoring.

[Dr. Xiaosong Meng]
Going back to your question earlier, Aditya, about the support from the company. There is always someone from the company there for their treatment and even now, 120 cases in, someone still comes, they record data, they do a lot of granular data in terms of how long are you taking to prep the room, put the devices in, do your planning, your treatment, any issues. That's one nice thing about it is that you'll have an expert from the company there to at least help you. Then sometimes it's like the MRI machine's not working, and they'll help you kind of troubleshoot some things like that with the MRI techs, which is helpful.

[Dr. Aditya Bagrodia]
I guess so in addition to the urologist radiologist, anesthesiologist, you would need an MRI technician as well, is that correct?

[Dr. Xiaosong Meng]
Yes, there's usually at least two or three around [chuckles] coming from the OR is nice, there's so many people around to help out. Going back to one of your earlier questions about the different areas, so we do it obviously in the hospital. They do have free-standing imaging centers where urologists can bring patients to treat. There's a mobile van now or a mobile truck that they can treat, and some of these are done in the OR, like the OR at St. Louis University, they're doing theirs in their MRI suite in the OR. It's a whole variety of different areas of where people are getting treated.

[Dr. Aditya Bagrodia]
Then like a typical straightforward quarter or hemi-gland, that's going to be three hours. My understanding is that your experience as well of course there's going to be patient-specific variability. Is that typical?

[Dr. Daniel Costa]
Yes, so the ablation time, which is one of several steps in the entire treatment time is directly dependent on the volume of ablation and the number of sweeps that we choose to do. The quickest ablation we can do is 20 to 30 minutes, but the average ablation time is around one hour. Now, when you add the other steps, so general anesthesia, patient positioning, device placement, in many instances, the devices need to be repositioned or there is an annoying air bubble that needs to be addressed. Then removing the devices, putting the Foley catheter and waking up, it's usually a three-hour procedure time.