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Real-World Experience With the Expanded Access Program for 89Zr-Girentuximab PET in Small Renal Masses - R. Jonathan Henderson

November 18, 2025

Zachary Klaassen hosts Jonathan Henderson to discuss his experience with the Expanded Access Program for [89Zr]Zr-girentuximab PET imaging for small renal masses. Dr. Henderson shares insights from implementing this technology in his high-volume Arkansas practice, noting that the ZIRCON trial demonstrated approximately 90% sensitivity and specificity for identifying clear cell renal cell carcinoma. Dr. Henderson emphasizes that patients respond enthusiastically to having PET scan options for renal masses, a technology they already associate with advanced cancer detection. The imaging serves as a valuable decision-making tool for patients on the fence between observation and intervention, particularly benefiting elderly patients or poor surgical candidates. He envisions future applications in post-ablation surveillance and metastatic disease detection beyond current small renal mass evaluation.

Biographies:

R. Jonathan Henderson, MD, Urologist, Arkansas, Urology, Little Rock, AR

Zachary Klaassen, MD, MSc, Urologic Oncologist, Assistant Professor of Surgery/Urology at the Medical College of Georgia at Augusta University, Wellstar MCG, Georgia Cancer Center, Augusta, GA



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Girentuximab Imaging in Renal Cancer: Diamond in the Rough or Just ZIRCON? - Beyond the Abstract

Phase II Trial Compares PET Imaging to Conventional Scans Post-Nephrectomy - Brian Shuch

Results from the Phase 3 Study of 89Zr-DFO-Girentuximab for PET/CT Imaging of Clear Cell Renal Cell Carcinoma (ZIRCON) - Brian Shuch

Advancing the Management of Indeterminate Renal Masses: The Emerging Role of Molecular Imaging - Alexander Kutikov

Study Examines CAIX-PET Imaging for Small Renal Mass Characterization - Timothy McClure

SNMMI 2023: 89Zr-DFO-Girentuximab PET/CT Imaging Can Accurately Detect Clear Cell Renal Cell Carcinoma Primary and Secondary Lesions in Patients with Renal Masses at Conventional Imaging, Results from ZIRCON Phase 3 Study
Read the Full Video Transcript

Zachary Klaassen: Hi, my name is Zach Klaassen, Urologic Oncologist at the Georgia Cancer Center in Augusta, Georgia. I'm delighted to be joined on UroToday by Dr. John Henderson, who's Urologist at Arkansas Urology in Little Rock, Arkansas. Today we're going to be talking about John's experience with the Expanded Access Program for 89-zirconium girentuximab PET imaging for small renal masses. John, thanks for joining us on UroToday.

Jonathan Henderson: My pleasure. Thanks for having me.

Zachary Klaassen: Absolutely. We're excited to hear about your experience with the Expanded Access Program. Before we get into that, let's just think generally how we're working up small renal masses. How are you doing that in your clinic currently?

Jonathan Henderson: Pretty much the same way we've been doing it for the past 20 years, right?

Zachary Klaassen: Right.

Jonathan  Henderson: Ultrasound has a limited utility in my practice, but for the most part, a CT scan is preferred. It's funny because radiologists will oftentimes recommend an MRI, and I'm like, you know, that's not going to give me any more information than a CT. So for the most part, CT scan.

Zachary Klaassen: Yeah, absolutely. How frequently would you say you're doing renal mass biopsies? Just off the top of your head?

Jonathan Henderson: Probably less than 10% of renal masses that we are sent. We have a pretty high volume practice, so even 10% of that we're probably, you know, I'd say practice-wide we probably have 70 renal biopsies a year.

Zachary Klaassen: Yeah. Would you be able to maybe pinpoint sort of who those patients would be? What would be the nickname for the biopsies?

Jonathan Henderson: Yeah, yeah, because when I send somebody for renal biopsy, it's usually somebody who I don't want to operate on, and I'm hoping it's going to be some oncocytic neoplasm and something I can convince them not to, this sounds funny, force me to take them to the OR.

Zachary Klaassen: Yes. No, absolutely. I think we all have those patients at our practice for sure. I want to jump into our discussion about this new imaging modality. Before we do that, the ZIRCON trial came out a couple of years ago looking at zirconium-89 girentuximab PET imaging for renal masses. Just give our listeners a high-level overview of those results and why we're having this discussion today.

Jonathan Henderson: Yeah. Well, it is pretty simple, right? So it is zirconium-89 and 89, 90 is pretty much what the sensitivity and specificity was in the trial. That's the thing to remember is that 90% are expressing. So there is a 10% gap there. It's not 100%, and I think that's an important thing that you really have to remember.

Zachary Klaassen: Yeah, no, absolutely. I think that's a great way of remembering it too. We mentioned you have access to the program where we can get this into the patients. Maybe just walk us through how you implemented this early access program, some factors for patient identification, coordination and workflow in your practice with the ACCESS program.

Jonathan Henderson: Yeah, well, it was honestly very simple. Once we had access, all we had to do is say to the partners, we've got this access. We have small renal masses. We don't want any big giant guys, and we were flooded with two, three centimeter masses. And working it in we had to do some initial camera calibration, and I think anytime you add a new isotope that that's going to have to be done wherever your PET center is. We have it in-house, so that made adoption easy for us, and honestly, we were only limited by the amount of tracer we could get. I don't know exactly how many patients we had, I think somewhere around 60 or 70, and it was a very smooth implementation. Some you get into an issue where a patient traveling, there's a little logistic problem because you're giving them tracer and then having them come back a few days later for their scan and so sometimes that can be an issue. It's not like a CT where you come in and you get it all done at once, but that's pretty common with most of the PET tracers, right?

Zachary Klaassen: Yeah, absolutely. No, that's a great answer. I think when you look at, just from a logistical standpoint, did your team learn anything along the way, maybe about communicating with other specialists, NucMed, radiology, et cetera?

Jonathan Henderson: So the only standout there is the radiologist. The radiologist was a little resistant to learning a new imaging modality, if you will, because ... And you know, right, I'm a urologist, so I don't get this. To me, I'm like, well, look at the picture and if it glows, it's a positive. But apparently everyone is different, and the radiologist really felt like there's a lot of training that goes into learning a new modality, and I appreciate that, they're right for taking it seriously. But it does take communication and they have to understand the value that it brings. Otherwise, they're not going to invest that time in making it work.

Zachary Klaassen: No, absolutely. My last question is kind of a two-part question, just what are your thoughts on real-world utilization and impact as things maybe roll out after an FDA approval, and what has the patient experience been when you take this data with them and you sit down with them in the clinic?

Jonathan Henderson: Yeah, let me answer that second one first because to me that really stood out. The patients are excited. And here's the deal. Most people have heard of PET scans. Most people know that PET scan is the most advanced imaging modality for cancer. And so for years, I've had patients ask, "Why can't they get a PET scan from a renal mass?" So then you have to talk to them about the photopenic aspects on traditional FDG PET and how of all the cancer types, this is the one we don't use it on, all that stuff. And so being able to say, yeah, we've got this brand new PET we can sign you up for. It was a real positive aspect for the patients. So translate that further into the fact that the patient population that you're employed in are the patients that you really want to either convince, do nothing, observation, or even forget about it, or the patients that don't want intervention, and you're trying to nudge them that direction, right?

Zachary Klaassen: Yeah.

Jonathan Henderson: So to me, this is a good discriminatory test to either get you off the fence in the observation or off the fence in the intervention category, and so it is nice to have that tool.

Zachary Klaassen: Yeah, no, that's well said. As sort of part one of that question, what's your thoughts on the impact if this starts to roll out after an FDA approval? I mean, the uptake to you sounds like it'll be massive.

Jonathan Henderson: Yeah, well, yes and no. I mean, there are certainly a lot of patients that you don't need ancillary imaging for. You got to get to the OR. And honestly I think to me, the real attractive feature is the future applications that we don't have yet. So somebody who's had ablative therapy, I think this is going to be golden to know if you have recurrence or even metastatic disease, but that's down the road right now though, small renal masses, I've had a number of patients who didn't trust the technology, and so we had a negative scan and we went ahead with a biopsy and then got a benign neoplasm afterwards. That gives me the confidence to trust it in the future, the small renal mass. Now, given that it's only accurate 90% of the time, am I going to completely say you don't have to come back at all? Not unless it's a 90-year-old patient or something like that, but that's an area that I see a ton of patients over 80 who aren't great surgical candidates to begin with, and I can get this scan for them, show them that it's negative, pretty much put it to bed. So yeah, I think it's pretty impactful across a large number of patients, and again, for those patients who are clearly headed to the OR, it's not necessary.

Zachary Klaassen: Yeah, it's great perspective, and I think if you look at, you're in a LUGPA, there's a lot of LUGPA in the country. You guys are seeing a lot of these small renal masses in the community, so I think having this tool, like you said, would be awesome. John, fantastic conversation. Really enjoyed it. Any take home messages or concluding statements, anything we haven't hit on you want to share with our listeners?

Jonathan Henderson: No, not really. I think you've covered it all pretty well. I'm excited for this to be able to come to the market when it does, and I hope that those FDA hurdles won't be in the way too long.

Zachary Klaassen: Yeah, absolutely. Well said. John, thanks so much for joining us on the road today.

Jonathan Henderson: Great. Thank you, Zach.