Redefining Advanced Prostate Cancer with Novel Imaging - Episode 6
Daniel George, MD: These patients have a positive CT bone scan. Typically, we’ll say, “Well, we’re done.” We’ve established metastatic disease. They’re stage M1, right? But is there a role for molecular imaging in that setting to really look to see if there is more extensive disease than we thought? Or is this the tip of the iceberg?
Raoul S. Concepcion, MD, FACS: Right, that was exactly what my next question was. And also, how do some of these scans perform, when looking at the primary tumor itself within the prostate?
Phillip Koo, MD: That’s a great question. Clearly, these novel next-generation imaging tools are disruptive. We’ve seen that they’ve performed much better, and it really forces us to think about how we think of low-volume disease versus high-volume disease and what we can do for primary disease as well. Neal brings up 2 great points. The biggest fact is that these tools have not been validated in those settings yet. It really is going to require efforts from a multidisciplinary approach to develop clinical trials that answer these questions.
In regard to lesion detection, all of the data show that on a per-patient basis, these tools detect more lesions in more patients. On a lesion-by-lesion analysis, all of these next-generation imaging tools detect more lesions than lesions seen in the past. Clearly, this idea of 1 lesion on a bone scan, tip of the iceberg, that’s real. There’s clearly going to be more. If there are not, it’s going to be reassuring that there are no more metastatic lesions. Then maybe treating that can lead to a “cure.”
The idea of primary lesion detection is a huge area that a lot of people are looking at. The group at Johns Hopkins has developed an F-18—based PSMA targeted agent that’s looking at this combined with PET MRI, which could actually help us determine which of the primary tumors are the bad actives. What are the ones that you could watch? What are the ones in which you need to intervene on? That’s another area that needs to be further developed, and we’ll see more data in regard to primary lesion characterization in the future.
With regard to primary disease, I think that’s probably the next area that we’re going to see more implementation of this next-generation imaging in. All of us have seen patients who present with an elevated prostate-specific antigen, high Gleason score, that have a negative bone scan on CT. And I don’t have to tell you that there is metastasis just waiting to be detected. So now, we have a tool that will detect these lesions. We see a lot of patients in that category who are pursuing next-generation imaging, whether it’s Axumin or PSMA. We’re seeing these metastatic lesions.
Raoul S. Concepcion, MD, FACS: One of the things, having grown up in an era of open prostatectomy as opposed to robotic, is that I always tried to be very aggressive in taking out the primary. I didn’t do so because I thought it was curative, I just knew that if you didn’t take out the primary, these people would have horrible local disease once they blew through hormonal therapy and those types of things. But I think there’s some pretty good next-generation sequencing data to suggest that you do have to be aggressive with the primary. This seeding and branching effect, and going back to reseeding the primary, is a little scary, actually.
Transcript Edited for Clarity