Q&A Radiation Therapy for Prostate Cancer Treatment "Presentation" - Daniel Spratt

November 15, 2023

Daniel Spratt discusses using radiation therapy for prostate cancer treatment, including SBRT for oligometastatic disease and advanced techniques like spacers to reduce rectal toxicity. Audience members ask questions about managing total radiation dose with multiple therapies, treating lymph nodes, advising younger patients, and Medicare coverage of spacers.


Daniel Spratt, MD, Chair and Professor of Radiation Oncology, UH Cleveland Medical Center, Seidman Cancer Center, Case Western Reserve University, Cleveland, OH

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Audience Member 1: Just one quick one. In the context of those folks getting SBRT in the advanced setting, the mCRPC, et cetera, they're getting other, oftentimes multiple, RLT therapies, they may have alphas, they may have betas, they may have SBRT. Some of our limiting issues really tend to be toxicity from a dose perspective, so how do we account and monitor that total dose per patient throughout their course?

Daniel Spratt: Yeah, great question. There's a couple different concepts. A lot of patients will ask, if I gave them a course of radiation whatever to their prostate and they recur and we give another course, is there a lifetime exposure? Yes and no. There are limits to your total body exposure of radiation, but to specific areas or spots, we have dose constraints. And so, actually, on the VISION trial, which is the trial that got lutetium-PSMA approved, a pretty substantial number of those patients actually had external beam during the course of the trial. So I think that right now there hasn't been any signal. And there's trials ongoing, like Michael Zelefsky is running a trial with SBRT to oligo mets with lutetium-PSMA on top of it. So we'll learn more, but I would differentiate sort of the total body dose versus specific organs.

Audience Member 2: Really a great talk, some interesting things for sure. Specific question. How do you handle lymph nodes now in high risk patients, especially in the PSMA PET era? Are you kind of waiting for them to pop up and use SBRT versus treating them ahead? And then when you're done with that, just a quick, you alluded to SBRT for kidney lesions.

Daniel Spratt: Yeah, yeah. Okay. I'll quickly answer both those. I'll tell you my practice. Just like, I'm sure all of you, you guys have different practices, you talk to 10 red oncs, they'll tell you different things. For me, nodal radiation therapy, even with all the fancy techniques I just showed you, will increase, at least low-grade, if not moderate-grade, GI side effects. I mean, you're rating outing up to the common iliacs.

There is only one trial, and we're talking about intact, not post-op, intact setting, that has shown a potential benefit, and it's a very small trial out of India from Tata Memorial that showed a benefit called POP-RT. I fall in the camp on the quality of life side. So to me, actually, unless there's node-positive disease, I typically do not radiate the nodes. And I wait if they recur, sort of like this adjuvant for salvage debate. If they recur, it's actually very easy to radiate their pelvis. There are other people that would say no, and I would say that's the more the adjuvant camp, you should do everything all at once. It's a little different in the post-op setting, A, because the randomized trial is positive, but B, the patterns of failure are different in that setting.

Kidney, we do a lot. Lee Ponsky is the Chair of Urology at our center who's been a big pioneer of kidney SBRT, IROC is this big international consortium, and there's more trials coming out. It's about 98-98.5% that's published in Lancet Oncology. Local control, basically almost immeasurable effect in GFR. They have a whole series in single kidneys. So I do a ton of kidney SBRT in solitary kidneys or in patients that he doesn't think is the best surgical candidate. Otherwise, they do a partial nephrectomy. I don't have a big interest in treating tons of kidney cancer, but I think SBRT works very well. More advanced techniques have to be accounted for. When you're breathing, your kidneys move up and down, so the rad onc needs to know what they're doing.

Audience Member 3: Hi, there, great presentation and commend you on some of the data you've shown in terms of functional preservation for some of the patients. The question I have is relative to some of our younger men with newly diagnosed prostate cancer, because some of the data, I think, would show that younger men should really give serious consideration to radiation therapy as their primary treatment. One of the premises that you shared is that when folks get recurrent disease, that that's incompletely treated local disease. I think many of us in practice have seen a younger individual choosing radiation therapy and then getting a recurrence 10, 12 years later. Can you speak to what you say to patients that are coming to you for consultation given these good results and what their thoughts should be as far as their local therapy?

Daniel Spratt: Yeah. Young, I think you have to define what young is. I've seen 30-year-olds, I've seen 50-year-olds. So where you make that cutoff. I think as you start getting into the thirties and forties, I start citing almost testicular cancer data where you're talking about at least solid single-digit percentage points of secondary cancers in their lifetime. When you look at data in 60-year-olds, 55-year-olds from rectal cancer to gynecologic cancer and even prostate cancer from big studies, you're probably looking at 0.2-0.4% risk of secondary cancers. And so when you're in that population, I say there's a risk, but I also say, and I cite music data, it's a 0.2% in music of 30-day mortality after prostatectomy. These are both exceedingly rare events, and I think you could find data that's 0.1%.

But many of the younger patients, I think there's usually also other reasons they're having cancer in their forties, early fifties. So a lot of these guys, I think we naturally have these discussions and they do surgery, and if they need it, we can do radiation later. There'll be, of course, some patients that want radiation therapy. And I think that we are able, better now than before, to do re-radiation. But I think you have to have that very honest discussion with the patient. Ultimately, the functional outcomes from surgery are way better in a 40 or 50-year-old than they are in a 60 or 70-year-old. And so I think you need to make sure that they are hearing accurate estimates based on those types of patients.

Audience Member 4: Just one quick question. It's kind of easy about the spacers that are used in Medicare coverage. For our group up in Minnesota, we've been having a little issue trying to interpret Medicare coverage for higher grade diseases in getting the spacer in that criteria. Can you comment on that?

Daniel Spratt: I can't comment about Medicare in Minnesota. I will tell you, we do it in anyone that does not have, it's almost effectively T4 disease. They can have T3 disease. Usually ECE is near the neurovascular bundles, more posterior laterally. It should be in the plane behind Denonvilliers' fascia. So I think more and more people are doing it in high-risk disease. I haven't had any issues, both when I worked in the state of Michigan or in Ohio. I can't comment if they're looking at that. There has been other trials with other gels that have included higher risk patients. But, yeah. And there's rad oncs that'll say, "No, it has to be this exact more favorable population." But more and more, I think, do it with MRI, subtle T3 disease. Thank you. Really appreciate it.