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Daniel Spratt: All right. Thanks. I'm Dan Spratt. So none of my comments today reflect any of my roles on the NCCN or the FDA, although they are my personal beliefs. Can we kill the bone scan? None of this is relevant. I don't get funded for bone scans.

So what’s the role of diagnostic tests in medicine? So there’s diagnostic imaging, there’s prognostic imaging at its core. Other than for diagnosis, we do imaging to do TNM staging. And there’s, of course, monitoring response criteria. But to put this ultra simple, the simplistic goal of cancer imaging is to detect cancer.

So if the goal of cancer imaging—sorry—the goal of cancer imaging is not itself, though, to improve quality or quantity of life. That’s the goal of our therapeutic interventions that may be based upon the diagnosis or prognostication that imaging provides us. So what is the role of the bone scan? So this is not even the controversial part at all. So bone scan has zero role in the diagnosis of prostate cancer.

Prognosis—it does not do T-staging. It does not do N-staging. It does not do M1a staging or M1c staging. So this is the current state. Even if you love bone scans, this is what it can possibly fit into. And within this landscape, where does it have a role? It has no role in low risk, intermediate risk—and I’ll discuss it in high risk. It has no role for most of what we see in recurrent prostate cancer, and it has a historical role in metastatic prostate cancer.

But let’s take a look at this. So there are many studies out. A lot of the studies with bone scans are in the 1990s and 2000s. But when you look at PSAs under 20, almost no patients will have a positive bone scan. Remember, we’re not talking about conventional imaging. We’re not talking about CT scans. We’re talking about a pure bone scan. The sensitivity is under 50%. That is worthless.

When you get into higher PSAs for skeletal metastases—so we’re only, again, talking about the bone—it’s about 90% compared to the PSMA PET. However, these are patients, and so we do care about seminal vesicle invasion. Do they have lymph node involvement, visceral organ involvement? And the PSMA—sorry—the sensitivity for bone scan compared to PSMA PET drops again back to about 50%.

You can look at this wonderful study from the prior speaker. In this cohort of mainly high-risk prostate cancer, you can see the sensitivity. Look at any of the blue forest plot hazard ratios, their confidence intervals—very low sensitivity, 50% or less. So in localized prostate cancer, bone scan has a poor performance to detect cancer. It fails to meet the core purpose of cancer imaging.

What about recurrent prostate cancer? Now, I don’t think I have seen a patient with non-metastatic prostate cancer with a PSA over 20 in quite some time. Most of our patients, we’re talking about giving postoperative radiation PSAs of 0.2, 0.5, 1.0.

This was a study from now over five years ago, but just to show how ridiculous—and people say bone scans are cheap. Well, they are not free. And in the VA system, one in five men who had surgery in the VA had a bone scan post-operatively at a PSA of 0.2, which, of course, it will detect absolutely nothing. And these studies over decades—you can see in this one study, in the very large study over multiple decades, they found basically there was no utility in a bone scan until the PSA after surgery was 40. This other study said it’s probably not useful till over 20. So again, in most of our patients, there’s probably minimal to no role.

This is a study—rather than just by PSA, this is by the high-risk BCR criteria published by people who have organized this meeting—is that in high-risk BCR that are CT bone scan negative—so this includes the CT—and so a negative CT and bone scan, 84% of them have disease detected on PSMA PET CT. About half of them were metastatic disease. So once again, bone scan in the recurrent setting, maybe you could argue in these ultra, ultra, ultra high-PSA patients, fails to meet the core purpose of cancer imaging.

And in metastatic disease, I’m going to argue here in disease at least—and there’s many studies you can pull on this—is that there is quite a distribution in patients that have low-volume metastatic disease by CT and bone scan, some of which, which I’m not really showing here, may not even have metastatic disease, so they’re downstaged from M1 to M0. But you can also find patients with what we would consider a pretty high volume of metastatic disease. PET upstaged patients, about 40% of these.

Once again, I would say at least in the low-volume setting, this is inadequate. Especially in low-volume disease, we are doing right now, for those familiar, STAMPEDE2. We’re radiating up to 10 sites of metastatic disease. So this trial, if you were just to use CT bone scan, you’re going to underestimate a massive amount of the burden of cancer the patient has.

So bone scans largely fail to meet this goal. Doing back-of-the-envelope calculations of what is the remaining population of our patients that we would say bone scan has a role, it’s about 15%. And the majority of those lesions identified you would see on the CT. So I’m going to be nice and say maybe 3% of patients that bone scan is going to be something useful for a patient.

And even within this—and this goes very relevant to the last talk—if you had a PSA of 100 and Gleason 9 and T3b disease, do you even need the bone scan to tell you if there’s bone mets or there’s not bone mets? And I say this because let’s look at abiraterone. We have level 1 data that giving it to patients with STAMPEDE’s very high-risk or node-positive or low-volume or high-volume disease, there’s a survival benefit. That bone scan would not augment that therapeutic benefit.

RT to the primary—in high-risk, localized disease, in low-volume metastatic disease, if your interpretation of the PEACE-1 trial, some would even say in high-volume metastatic disease—that bone scan would not change your therapeutic decision. Amongst great, phenomenal expert nuclear medicine physicians, they are terrible at agreeing with one another with an inter-reader agreement of 0.51. So they can’t even agree on what the bone scan even showed, and these are amongst experts.

So can we kill the bone scan? Well, it already died, so this really isn’t much of a talk. And that’s in early adopters. You look at late adopters. This is from Northwell Health. So this is 2021, quarter 1. Many of us in the US were using it before then. But you can see here that in just two and a half years, they’re down to 25% of the scans they perform are bone scans. And if you just plot this out, probably by today, they’re using almost no bone scans unless it plateaued.

So can we kill it? It’s already dead, and hence why I am not speaking at the Bone Scan Conference. Thank you.