Brian Helfand, MD, PhD

Let’s say you have this patient, and you have a bone CTthat’s negative, and because of the low PSA [prostate-specific antigen], you have a next-generation imaging scan, whether it’s fluciclovine or PSMA [prostate-specific membrane antigen], that’s also negative. How would you follow this patient moving forward? Are you going to stick with the bone CT because it’s less expensive, it’s more available, and both scans were negative? What are you going to do on this guy?

 It’s one of those where it depends on the overall health and comorbidities of the patient. I don’t think that it’s unreasonable just to continue to follow the patient, especially if there are many comorbidities, and say “Hey, your PSA doubling time is very low. We’ll still follow your PSAs if you remain asymptomatic, if your PSAs remain at a very low doubling time, etc. We’ll continue to observe you.” Certainly, it’s very different in the younger, healthier patient where you want to be more aggressive. At this point, because he’s already had the radiation, it’s somewhat limiting.

On the other hand, to continue to follow the patient is certainly an option there. I do think that periodic scans are part of that observation with next-generation imaging. I certainly think, as Munir mentioned, as your PSA values get higher, the chance of you having positive scans increases. I don’t think it’s wrong to repeat those scans periodically. Alternatively, if that patient wants to be aggressive and keep things low, again, sometimes we’re treating more of a number at this point because we can’t identify where the disease is. Ultimately, you could offer hormone signaling inhibitor therapies. I’m more hesitant to do that, because sometimes changing that, until some PSA level, that becomes more uncomfortable more than anything else, but that’s still an ill-defined type space. I don’t know if that answers the question, but it’s a lot more observation.

I think Judd said it perfectly. We’re trying to figure out what this means. It’s sort of like the old M0 [no metastasis detected], we know M0’s going to go away, depending upon how these scans get approved and in what clinical scenario. I’m going to conclude here, but I’m going to ask each one of you a particular question. Dr Ghesani, we’ve talked about gallium PSMA, we’ve talked about fluciclovine, and we’ve talked about C-11 choline. You also mentioned obviously F-18 FDG [fluorodeoxyglucose]. From the PSMA side specifically, what else is in the pipeline that could we expect to see over the next year or two?

 There are more centers now getting access to gallium PSMA; no doubt that’ll continue to grow. Regarding several other agents, there are at least about 5 combinations, 2 gallium-based and 3 fluorine-based agents. Among all of them, the DCFPyL [fluorine F 18 DCFPyL] is farthest in the review process. It’s hard to tell with the FDA, but of all the available agents, the next one that very likely will be considered for approval, or at least in the FDA pipeline, is DCFPyL. However, there are many other agents…we participated in some of the trials and contributed close to about 50 patients. All those agents will in the very near future be considered by the FDA for approval. In the next 4 to 5 years, I wouldn’t be surprised to see 6 or 7 different molecular imaging agents available.

Judd and Brian, you each get 1 minute apiece with 2 questions. I’m going to go to Brian first because Dr Moul always needs to be the wrap-up, he’s the cleanup hitter. Comment on the greatest unmet need and the key take-home message when it comes to biochemical recurrence and detection.

 The greatest unmet need is the ability to localize the disease reliably at very low levels. I think the earlier we can identify patients who are having recurrence and [provide] potential intervention and/or modification of our plans to make it more precise for the patient is that need. I think that the scans out there right now have made a huge stride in answering that need. Ultimately, as Munir just said, if we have 6, is it going to be all 6 that are great? Do we have a combination of markers we mix together? There are many things coming in the pipeline. I’m excited about it, but I think they’re all in the pipeline because of that unmet need. We’ll see where it comes.

 I think we’re in an exciting time regarding this new imaging and potentially learning more about where the disease is. But I would make a comment that, as you and I have been in practice a long time, and I think I’ve been in practice longer than you, going on 30-some years. I think sometimes we must be careful not to be overly aggressive. I see second opinions where sometimes the urologist or the oncologist has scared the patient to death about a low-level PSA recurrence, and so we must step back. I think this imaging is great if used properly. I worry sometimes that if it’s used too early and we’re too aggressive with a patient, sometimes we’re potentially going to do more harm than good, especially in elderly patients. The take-home message is don’t forget to keep your doctor’s hat on and look at the patient, look at what’s in front of you, and put it in context. We don’t want to do any harm to these patients, and even though ADT [androgen deprivation therapy] and these new agents are great, sometimes we can overtreat these patients.

Judd, I think that’s a great concluding point. Again, it gets back to the old days, “Medicine continues. It’s a lot of science, but there’s a lot of art.” We still must practice the art of medicine. Thank you to Dr Helfand, Dr Ghesani and Dr Moul for joining tonight. I think it’s been a great discussion on a very timely topic. I also want to thank the folks over at 

®. Thanks to the viewing audience that took time out of your schedule, depending upon what part of the country you’re living in, it’s either going to be late afternoon or early to mid-evening. I hope everyone found this to be interactive and found it to be beneficial and impactful to how you will care for these patients moving forward. Thanks so much and have a great evening.

Videos

Dr Raoul Concepcion leads a multidisciplinary expert panel in a discussion about the challenges of long-term follow-up of prostate cancer in patients with negative bone/CT but positive molecular indicators of recurrence. 

Follow-Up After Negative Bone/CT in Prostate Cancer With Molecular Recurrence 

Brian, you mentioned this earlier. Let’s take the situation where this happens, and sometimes we’re trying to find disease in the patients we’re worried about. If the bone CT is negative, but let’s say you had a molecular scan that was positive, let’s say you got a fluciclovine that’s positive, and…remember, this was a patient who got external beam [radiation and] refused androgen deprivation therapy [ADT]. Let’s say it showed a 1.5-cm node above the field of radiotherapy and was seen on molecular imaging. How do you look at that patient now? What are the options that open up to you in that setting?

 I think it sounds like that would be a low-burden tumor recurrence, if indeed it’s 1 node that’s positive. I think some of the data are still somewhat emerging and still somewhat controversial, but it certainly depends on what level that node is, if it’s M0 [no metastasis detected] in the pelvis, or it’s M1, above the bifurcation. If it is M1, I think you can still go after it, or even M0 in the pelvis, [you can still] go after it. I think certainly the options in the pelvis these days are somewhat controversial, with data emerging, but whether it’s stereotactic guided radiation to that area, or we do offer salvage lymph node dissection if appropriate. If it’s M1, I think we’re more hesitant to be as aggressive with surgery. I still think there may be a role, although [the patient] may not fare as well if it is M1 disease.

Judd, what if it was an isolated lesion that they found on molecular imaging, say, L3 vertebral body?

 ADT, stereotactic radiation…I think what’s going to happen is as these scans get used more and more in this setting, these are the clinical scenarios that we’re going to start to see, which addresses the question in the queue, this concept of oligometastatic disease, and do you still put them on ADT? Regarding isolated bone lesion L3, what are your thoughts on that?

 I think No. 1, we’d present it to our tumor board, because obviously it’s very controversial, and there’s no level 1 evidence on what to do. He’s like an old-fashioned biochemical recurrence, but now he’s not really a biochemical recurrence because he has a positive novel imaging. I think we’re going to have to come up with a stage, and something to call it, like biochemical recurrence-plus, or biochemical recurrence molecular imaging. What I’d probably do in practice, and I know Dr Ghesani’s going to kick me, but I’d probably still get a regular imaging to see if that L3 lit up on a bone scan because if it least lit up on a regular scan, he would become eligible for some clinical trials that we have going on. What I don’t know, and I would ask Brian this, let’s say if you believe that’s a positive bone scan, then he becomes hormone-sensitive M1 disease.

That means you open the door for enzalutamide or abiraterone or docetaxel, not docetaxel because he’d be low volume, but you’d at least open the door for those 3 oral agents. So, is the insurance company going to approve an expensive drug like ENZA [enzalutamide] or APA [apalutamide] in the setting of a negative bone scan, but a positive Axumin scan? I’m asking more questions than I’m answering, and the honest answer is, I’d probably have to individualize, and chances are our Duke [Cancer Center] tumor board, if that was an oligometastatic site, they’d probably end up doing some spot radiation to that. I don’t know if our medical oncology team would push for ABI [abiraterone], ENZA [enzalutamide], or APA [apalutamide] in that case.

 This scenario is already playing out in our tumor boards. I see instances like these where, and Judd, you would not be wrong in ordering the bone scan, and I’ll tell you the reason why. When we look at these scans, and if we see that on CT there is a sufficiently large focus of sclerosis that lit up on the molecular imaging side, then it also gives you an idea that a bone scan may be positive given the size of the lesion. Then, if the patient’s going to the trial, you’re going to need that bone scan as a baseline so that you can compare it for treatment response in the future. So, it would be appropriate after the fact to consider doing a bone scan.

Dr Ghesani, this is a comment from the audience. Is it helpful, and should we be better about providing—especially because these scans now are so difficult to read—are we giving you enough clinical history to assist you in adequate interpretation when you read these scans?

: Yes, I can speak for my practice, and then I can relate to the other settings where there might be some difference. In our case, not only have we seen these cases being discussed at the tumor boards before the patients come in, but even if they were not presented yet and they are coming directly for imaging, we have the electronic medical record. Whenever we read the scans, we have multiple screens and I dedicate 1 screen for my Epic [medical record system] window, which is where all the records are always open.

Even nowadays, things are such that if you open up a case for dictation, not only does your dictation window open on one screen, your images open on the other, and your Epic window automatically pulls the patient’s data, so that everything is synchronized. In my practice, all the information that we need, it’s available at my fingertips. I can see that in a private practice setting, people may be wishing for more specific information that they need to make a clinical judgment about what the background of that patient is, like the 2 cases we discussed. Knowing all that information is critical when you interpret the images.



An expert panel discusses the challenges of detecting and managing biochemical recurrence in the context of oligometastatic prostate cancer. 

Molecular Recurrence in Oligometastatic Prostate Cancer  

Dr Ghesani, let’s make a hypothetical situation here. Assuming you had access to both fluciclovine and PSMA [prostate-specific membrane antigen], are there any data out there to suggest that at lower PSA [prostate-specific antigen] levels, one modality may be superior? Is it in general, or is one better than the other for soft tissue versus bone?

 First, there is significant published literature on the linearity of PSA levels correlating with the fluciclovine PET [positron emission tomography]/CT. As the PSA levels increase, the sensitivity of fluciclovine goes up. What is also interesting is that in some of those studies they looked at, even when the PSA level was less than 1 [ng/mL], there was still a significant number of cases where the Axumin [fluciclovine] picked up the disease. And in that subgroup of patients, CT and bone scans were completely negative.

To answer the question, no level of PSA is too low for these imaging modalities to show superiority with fluorine- or gallium-based PET scans [compared with] CT and bone scans. If at any point there is a concern, and it’s a clinical question, as Judd mentioned, that this patient does not meet the absolute definition, but the doubling time and then the nadir was not low enough, so there is a high degree of suspicion. In that case, if the insurance companies don’t give you pushback, then clearly the fluciclovine scan will be appropriate. Now, there are some emerging data that have shown, and it’s still early stage, that PSMA scans behave the same way, that as the PSA levels increase, their sensitivity starts to go up. There is at least 1 study that has looked at comparing the 2 and showing some superiority of gallium PSMA scans over the fluciclovine in the setting of very low PSA levels. Again, you must balance that with availability of the agents. Let’s say only fluciclovine PET is available, it still would be very appropriate to do that scan because studies have shown that it performs better than CT and bone scans in that setting.

Are there any data to suggest that the PSMA or the fluciclovine performs better in soft tissue? Does one perform better than the other, or vice versa in soft tissue versus bone? Or is it equal in terms of detection?

 There are still very early data, but they both do very well. What I have seen in my experience—these are not published data, and this has been referenced in some other ways—is that when you do the fluciclovine PET, you usually scan the patients about 3 to 5 minutes after injection. This means that the prostate bed is generally devoid of any urinary excretion, and that’s an advantage because in molecular imaging, you’re always looking at higher target and a lower background. If you lower your background in any specific way, then you are going to pick up things that are even subtle relative to a high background. In that case, the fluciclovine technically can have superiority when you’re looking at recurrence in the prostate bed. Many of the PSMA scans are done at a later stage, and there is invariably some degree of urinary excretion, so the bladder activity can obscure any small area of recurrence technically, that can be only in the prostate bed.

Dr Munir Ghesani reviews and comments on data regarding the sensitivity of imaging modalities in detecting biochemical recurrence in prostate cancer. 

Sensitivity of Imaging Modalities to Biochemical Recurrence in Prostate Cancer 

Let’s go to the second case, which is slightly different. We’re probably going to get into a discussion more to everybody’s point when we’re talking about a patient with much lower levels of PSA [prostate-specific antigen]. In this next case, in March 2016, a 64-year-old African American man presents to urology with a PSA of 5.8 ng/mL, and his DRE [digital rectal examination] is negative. The patient underwent multiparametric MRI of the prostate. He has a 66.3 volume gland and has a PI-RADS [prostate imaging reporting and data system] 4 lesion to the right peripheral zone measuring 1.5 cm. The patient undergoes mechanical fusion biopsy and 2 of 3 cores to the target area. Again, that is a PI-RADS 4 lesion, right peripheral zone, and he shows Gleason Group 3, 4+3, and then 3 of 12 systematic biopsies shows Gleason Group 4, 4+4, in the mid-left peripheral zone. He’s got a multifocal disease, not only in the right peripheral zone but also in the mid-left peripheral zone.

Staging work-up, bone scan and CT once again is negative. In this case, the patient opted for external beam radiation therapy, but he refused. As most of us know, patients with higher-risk prostate cancer should get 2 years of androgen deprivation therapy [ADT] along with their radiotherapy. However, the patient refused ADT because of the potential adverse-effect profile. He finishes his external beam therapy in 2016. These are the following PSAs dating from June 2017 and October 2017, and as you can see, he has this slow rise in PSA. For the first polling question, based on this PSA kinetics, would you restage the patient at this point? Yes or no? He finished radiotherapy in 2016. He had a PSA of 0.8 in June of 2017, and a PSA of 1.7 in June of 2018. On this PSA kinetics, would you restage the patient at this point? Yes or no? Looks like the polling is getting ready to conclude.

There is 1 question in the queue, which I’ll get to. According to the audience, basically 80%—the vast majority—say they would go ahead and restage as close to 90%. What imaging modality would you use to restage this patient? [The options are] technician bone scan and CT, whole-body MRI, Fluciclovine, gallium PSMA [prostate-specific membrane antigen], or C-11 choline, if you were going to restage? There is a question in the queue that somebody in the audience asked, just so we comment on this, the biochemical recurrence of 0.2 occurred 39 months after prostatectomy, and 6 years after prostatectomy the PSA is 0.62.

How can I balance the hope to get local treatment of oligometastatic tumors if found soon with the newest scans against the risk of more systemic metastases if I waited until all tumors can be seen? We’re probably going to answer this question with the role of imaging, so sit tight just for a second. The audience for this case—close to 60%—chose fluciclovine; 14% chose gallium PSMA, and 30% basically stuck with bone scan CT. I’m assuming that’s probably because of availability. Dr Moul, this is a patient whose PSA is low. He’s still below 2, but his doubling time looks to be under a year. How do you look at these patients? How do PSA values influence your choice of scans? Is it the value? Is it the doubling time? Is it the availability? How do you look at PSA relative? Does that impact your choice of scans?

 This is an interesting case, as you said. Technically, this gentleman does not meet the ASTRO [American Society for Therapeutic Radiology and Oncology] Phoenix definition of recurrence because his PSA is still below. If I walked in the exam room and he was in poor health, and if I perceive that his life expectancy is going to be less than 10 years, I might reassure him and say “Sir, your PSA is still below 2, so you haven’t met the definition of recurrence. We’re just going to keep an eye on things, and I’ll follow you closely and see you again in 6 months.” On the other hand, his nadir was poor.

We know from data way back with Frank Crights back in your neck of the woods, Raoul. He used to say that even with radiation, if the PSA didn’t nadir at 0.2 or less, then it was ultimately going to be a failure. You could argue this in 2 ways. If he’s in poor health, I would probably observe him. If he was in robust health or I perceived he had a greater than 10-year life expectancy, I would work him up. An Axumin fluciclovine scan would be an ideal imaging test. That’s what we would use at Duke because that’s what we have. If I got pushback from the insurance companies, I might have to order the bone scan and CT first.

Dr Raoul Concepcion leads a panel discussion on a case of a 64-year-old man with multifocal prostate cancer treated with IMRT who refused ADT. 

Brian Helfand, MD, PhD

Articles

Follow-Up After Negative Bone/CT in Prostate Cancer With Molecular Recurrence

Molecular Recurrence in Oligometastatic Prostate Cancer

Sensitivity of Imaging Modalities to Biochemical Recurrence in Prostate Cancer

Case 2: 64-Year-Old Man With Multifocal Prostate Cancer Post-IMRT

Brian Helfand, MD, PhD

Articles

Follow-Up After Negative Bone/CT in Prostate Cancer With Molecular Recurrence

Molecular Recurrence in Oligometastatic Prostate Cancer

Sensitivity of Imaging Modalities to Biochemical Recurrence in Prostate Cancer

Case 2: 64-Year-Old Man With Multifocal Prostate Cancer Post-IMRT

Follow-Up After Negative Bone/CT in Prostate Cancer With Molecular Recurrence 

Sensitivity of Imaging Modalities to Biochemical Recurrence in Prostate Cancer 