Updated: Mar 10, 2019
When treating unresectable HCC with Y90 radioembolization, pressure directed devices may have distinct technical advantages over end-hole catheters in some clinical scenarios. Dr. Charles Nutting and Dr. Nainesh Parikh discuss and debate their use of devices like the Surefire Infusion System, and the current state of clinical data backing these devices on the BackTable podcast.
The BackTable Brief
Pressure directed therapy may have distinct technical advantages in some clinical scenarios.
A hypovascular tumor with low-capacitance vessels and low visibility on angiography can indicate that a pressure directed device may help to deliver more of the intended dose to the tumor.
Atypical hepatic anatomy or risk of reflux may also warrant the use of a pressure directed device for its antireflux profile.
Some studies suggest that pressure directed devices, such as the Surefire Infusion System, increase tumor uptake and decrease non-target embolization, but these technical advantages have not been tied to greater survival benefit or an incremental cost benefit.
Learn more about the fundamentals of pressure directed therapy in our last article.
Disclaimer: The opinions expressed by the participants of the BackTable Podcast belong solely to the participants, and do not necessarily reflect the views of BackTable.
Clear Indications for Pressure Directed Therapy with Y90 Radioembolization in HCC
"...I would think about [the Surefire Infusion System] as both as an antireflux and as a pressure directed therapy device. And I probably wouldn't get too caught up in the details except to say: if you feel like you have a patient [and you] can't see the mass very well on angiography, or it's a small vessel or something like that, and you're going to have trouble getting in all of your dose, you might try pressure directed therapy to see if you can actually get all of your intended dose in. I think that might be an option for where you might try to use this device."
"Yeah, I agree, Nain. I think that probably low-capacitant vessels, when you inject and you really don't see the tumor very well, that may be a good indication to use an antireflux catheter to drive more of the therapy deeper into the tumor itself. Perhaps aberrant hepatic anatomy, or you have a gastrohepatic trunk and you want to make sure that you're not gonna reflux into any of the gastric branches, you could place that out in segments two and three, and drive the dose deeper without that concern for reflux into the stomach."
The Current State of Data Supporting Pressure Directed Therapy in HCC
"Sure, so I think that if we can improve delivery to the tumor and decrease inadvertent embolization, the patients are going to have better outcomes. And if we look at the retrospective data out of Georgetown, they saw improved results in the patients who had Hepatocellular Carcinoma, the imaging studies afterwards, there were better response rates in patients who were treated with a pressure-directed therapy. And I think that this was also mimicked in the Piedmont data, which shows that there was improved outcomes with decreased recurrence rates in patients who were treated with a Surefire device, or catheter-directed therapy, versus an end-hole catheter alone…."
"...what Charlie's talking about with the data, we're trying to bear out. So I will say that first of all, for us, I think there's a trade-off between how selective you get for each of the tumors that you're treating, versus the amount of normal liver parenchyma that you are going to treat with your either [arterial therapy].
When we look at how we're going to treat these patients, we're going to, of course, get it as selective as possible, based on the various distribution of the tumor. And what I mean by that is if segments five and six are spared and we can only look at segments seven and eight, we will. Similarly, if segments two and three are spared, and four is involved, then we'll try to get out and only treat segment four.
We at Moffitt actually only use end-hole catheters, and it's not to say we're necessarily biased, so to speak, but what I would say is that we're not necessarily convinced, particularly because our patient population tends to start with the radioembolization.
Charlie, you seem to know the data a little bit better than me, but if I recall, the Georgetown data and the Piedmont data were solely for chemoembolization. It'd be interesting to know how that changes for radioembolization…. I haven't dug into the data of each of their patients, but it's almost as if you want to know if you've parked your catheter in the main right, or in segment two of the left, call it, and then you compare that way how the outcomes look, because I do think that there are several different variables for how you can compare these pieces of data.
But I think one of the big things for us is that our patient population, our institution, tends to start with radioembolization, we don't end up using the Surefire device quite as much, based on the data that's out there."
"I would agree with that, Nain. I think that there is some data that came out of the University of Tennessee with Doctor Pasciak et al, and they showed that when they were using Surefire catheter with the infusion of the MAA and radioembolization, that there was actually improved dosing to the tumor, with decreased inadvertent embolization or non-target embolization. So you're right, I think that there is more work that needs to be done in this area, but some of the initial data is fairly compelling."
Improved dosing and decreased inadvertent embolization with pressure directed therapy has not yet been tied to survival benefit
"So with these patients, all of the discussion we're having is that this is palliative and not curative. The holy grail of any therapy is that it's curative. If you think of the continuum of doing nothing versus doing a therapy that's curative, then where do we fall? Well we know that survival data, when we do liver-directed therapy, is on the order of twelve to twenty-four months - for HCC - of life extension. And so then, within that data, I think the question is how do you look at improved survival, and what's statistically significant, and what makes the most sense?
I agree with Charlie completely that therapy and patient outcomes are paramount, and costs shouldn't factor in, in that sense. I could tell you that at our institution, because we are, number one, a conservative place, but number two, all of our purchasing is centralized, and goes through the AT Committee, these discussions are held every day, about what the data shows, how much the cost of the catheter is, things like that.
And I think what we'd like to see, what I'd honestly love to see, is that there is a clear benefit. Because once the data bears out that there's a clear benefit, I think then you can start to say, okay, there's an obvious indication here, we need to do more work to prove other indications. But as Charlie said, the cost is not really something that is gonna be prohibited because the patients are going to benefit significantly from this.
So, Anish, in my - in our practice, and at our institution, I think, for us, that's why we're probably waiting, so to speak, to hear more data, because, given our practice patterns, we'd love to see a more concise situation. And I know Charlie and I have talked about it, but as an example, one of those indications might be for the guy that's in Tennessee, or even for us, doing two or three of these a day, hypovascular tumors that you otherwise feel are helpless when you're trying to do liver-directed therapy.
I'm very excited by the aspect of the thought around therapy for pressure-directed hypovascular tumors, I think it's something that could be great. But I do think that our institution, and for us, and for me, personally, I think about that equation by saying, okay, what's a clear indication, what's a questionable indication, and what do we think we're really gaining here?"
Dr. Charles Nutting is a practicing interventional radiologist with RIA Endovascular in Denver, Colorado.
Dr. Nainesh Parikh is a practicing interventional radiologist with Moffitt Cancer Center in Tampa, Florida.
Cite this podcast:
BackTable, LLC (Producer). (2017, November 5). Ep 16 – Pressure-Directed Therapy in Y90 [Audio podcast]. Retrieved from https://www.backtable.com/podcasts
The Materials available on the BackTable Blog are for informational and educational purposes only and are not a substitute for the professional judgment of a healthcare professional in diagnosing and treating patients.
The podcast referenced in this article was sponsored by Surefire Medical.