Dr. Michael S. Cookson, MD, MMHC, presented “MRI in the Management of Prostate Cancer: What Urologists Need to Know” at the 26th Annual Perspectives in Urology: Point-Counterpoint, November 12, 2017 in Scottsdale, AZ
How to cite: Cookson, Michael S. “MRI in the Management of Prostate Cancer: What Urologists Need to Know” November 12, 2017. Accessed Apr 2020. https://grandroundsinurology.com/MRI-in-the-Management-of-Prostate-Cancer/
Dr. Michael S. Cookson, MD, MMHC, discusses the advantages of using MRI for the enhanced detection of prostate cancer, as opposed to traditional biopsy.
MRI in the Management of Prostate Cancer: What Urologists Need to Know
I don’t have any disclosures relevant to this, although I do have a bias that MRIs are very helpful as a management tool and I certainly use it a lot in my practice. This ARS question, and I’m going to kind of go over some of the AUA position statements, the joint consensus with the society of radiology. They recommend prostate MRI in the setting of:
- Initial screening, B. Prior negative biopsy, C. Elevated PSA, D. History of ASAP. And the votes are in and so the first lecture is set that one up or they just already know the answer, very true. So, these are some options for how it can be used, prostate MRI in your practice. We’re going to sort of focus on the biopsy, naïve, prior negative biopsy and active surveillance cohort in the interest of time today. So, that will be where we spend our time. Many of you may know, some of you may not know there are two policy statements that have been published now by the AUA. The first one was a couple of years ago and was a joint statement combining the urologist and the radiologist’s point of view. I think this one got published this month in the Journal of Urology and it’s available online and it’s more of a policy statement on the state of where we are in terms of evidence for using the MRI, so again, we’ll focus on the top categories first.
So, when we talk about the biopsy naïve patient, we know that the majority of initial prostate biopsies are negative, right, 75% of those will come back negative. Many clinically significant cancers get missed on round one, an extended templates and saturation biopsies and all those additional attempts are really to find these missed tumors, but they have their own pitfalls. So, just give you a clinical scenario, 50 year old African American male, PSA was 8.6. He had a family history. He undergoes an MRI and this was before his biopsy which thank God got set up. We already know the PI-RAD lesion 4s are potentially cancerous. He undergoes the standard as well as a targeted biopsy and the standard biopsies, the 12 core missed the cancer, but the targeted one found it. You would say well, looking at the lesion how could you miss that, but it happens all the time. So, the policy statement for biopsy naïve patients says that these can detect more clinically significant cancers when you combine them and Robert just showed that evidence as well. Targeted biopsies alone, though, can miss some small cancers like the 0.5 or lower volume type tumors and so it’s still recommended to do systematic biopsies with the targeted biopsies and then they do state that there is just not enough information, though for this to be the standard for all patients up front. There is lots of issues and the issues surround the quality of the MRI, the magnet that you use, the experience of the radiologist. Maybe in Europe the cost is lower, but in the United States, the cost is still quite high for an MRI. And the availability of other biomarkers also has to be played in. They realize that there could be certain circumstances. We do get occasionally recommended patients who have difficulty accessing their rectum or they may have had prior surgery where you can’t do a transrectal assessment, large calcifications that can obscure the visualization, et cetera, et cetera, so there are exceptional times when certainly you could justify an MRI regardless of whether you believe it should be done in all patients and again, the caveat in the policy statement is that it’s just not ready for prime time for all patients and so when you order these, you may sometimes get a block from the insurance company. I don’t know if any of you have figured that out, but the peer to peer thing is usually peer to schmuck and whoever you’re talking too is usually not very intelligent. What we found is if we ask for an oncology peer, we get to talk our language and we get approval. So, I don’t know if that’s, if you run into that, but that’s the way we’ve worked around that.
Evaluation of the biopsy naïve patients, we need to continue to do further studies on these patients. We just talked about the PROMISE study and I’ll just briefly highlight the differences in what we do today versus what they did and there’s also a more modern day study called the PRECISION study that is looking at the PRECISION study that is looking at the specific area to give us the high-level evidence. The PROMISE study, which was the U.K. study that was presented earlier, again biopsy naïve patients who came in elevated PSA abnormal DRE, all of them were able to undergo MRI. Key difference is we don’t use this 1.5 Tesla magnet. If you do use it, you are probably using an endorectal coil. Otherwise it is like fuzzy math, you just don’t get good pictures, and then this was a stretch right because they didn’t go and do the nice targeting biopsies that we’re talking about, what they did was a traditional ultrasound and a templated biopsy but they weren’t guiding their biopsies based on the MRI, they simply looked at the mapping of the MRI, compared it to where the templated trans peroneal biopsies hit and then made their conclusions, the definitions for significant cancer were there, but Gleeson 7s and longer 6mm cores. They did find at least using that kind of logic that the MRI would have if you would have guided your biopsies towards it detected more cancers, more clinically significant cancers, and you would have missed them if you just did it, so at least a third or more cancers would have been detected if you would have used that MRI but again 1.5 magnet not a 3, not guided image guided techniques, so it’s an interesting study. It has added some support to the biopsy naïve category, but it requires additional studies, and this, the orange and the reds are if you had PIRAD lesions 1, 2, through 5, what are the chances you would find cancer, and clearly there’s a nice correlation between increasing PIRAD score, version 2 and the ability to detect cancer and of course the higher grade cancers are detected more on the 4s and 5s.
So it has made its way into the NCCN guidelines now, so again if you are talking to that peer-to-peer, you should see that there is consideration for this in there and use that to your advantage if you can, and hopefully you can get that approved in your patient population. So the next group is the prior negative biopsy that was the ARS question, it sounds like most of you understand that this is a move forward, and this is the AUA statement, they say well blood, urine, tissue, biomarkers improve patient selection for repeat biopsy they don’t improve the diagnostic yield of the biopsy itself, you don’t know where to go, so in comparison imaging has both the potential to improve on your ability to select the right patient and to yield a better biopsy and actually detect the cancer that you are so worried about. So I think that is a key importance of the MRI, it is really kind of a biomarker but it also tells you where to go.
Another just example, 62-year-old gentleman, an elevated PSA, was about 18, he did five prior negative biopsies, he has an MRI, and you can—I don’t know how that projects from where I’m sitting it’s hard to see but there is a big anterior lesion that just never got sampled on all of these transrectal ultrasounds so he undergoes a biopsy of that. These are the visualizations of it, and it was PIRADs 5, and a Gleeson 9 anterior tumor, and when you have the imaging and you know where to go it’s pretty easy to get there, but if you don’t you’re guessing, and if you just keep sampling the peripheral zone and you’re going to miss some of these cancers, so what does the policy statement say? Current primary application for this in men with a rising PSA for whom there is suspicion for prostate cancer in a previous negative biopsy so that is its best application. When it is available, high-quality MRI should be strongly considered in any patient with a prior negative biopsy who has persistent suspicion so again that is good fuel for the fire when you’re talking to insurance companies about why you are doing this in this setting.
The decision whether to perform MRI in this setting also must take into account the other things that we’ve already talked about over the course of the last two days that include the ability to obtain biomarkers. You’ve got to have a good radiologist and if you’re doing fusion guided or cognitive biopsies you have to have some experience with it because there is a learning curve, and they go on to say that the 3 to 5 PIRADs are the ones that warrant further suspicion, and while these targeting, the fusion and the targeting may be reliable, the absence of visualization of tumor as you just saw in the earlier talk does not mean the absence of tumor, so you don’t get off the hook usually by the MRI being negative, it just tells you you are not missing a big lesion, so you can use other factors. You know if you go to biopsy them on a repeat biopsy you might still get a 20%, 25%, positive biopsy rate, so a negative MRI you have to counsel them because a lot of people say well my MRI is negative I don’t need another biopsy. That may or may not be true, so you still have to counsel them about it. But I think nobody is at the stage where we think targeting alone is the way to go. You still need to include the systematic biopsies, and you also do the targeted biopsies, and by the way when you do the targeted biopsies, it is recommended to take at least two cores from that target. Some people take three. Let’s see, they said in patients with negative or low suspicion then other ancillary tests may be identified to kind of talk to them about re=biopsy and if a repeat biopsy is deferred because the MRI was thought to be negative and the patient was comfortable knowing that he doesn’t have a large high-grade lesion then you still have to continue follow him, it’s not like you tell them, you know, come back in five years. What about active surveillance?
Many of us are putting patients on active surveillance. We want to use the tools that we have available, including MRI in our practice, and imaging alone may as we know detect tumors previously missed on biopsy. MRI can provide a non-invasive way to monitor so you don’t always have to undergo a punitive annual biopsy and lesion location may influence the monitoring and the treatment. This was a study out of UCSF. They just had great ultrasonographers. They biopsied patients but were on active surveillance, and then they started to look at what if they threw in the MRI to see if that would help and what they found was that on repeat biopsy, which is recommended in men undergoing active surveillance 40% were upgraded and somewhere around a third of them or more were only found based on the targeting. So it did add value in entry into your active surveillance if you inherit somebody from another program or if they’re referred from another center or if you just did a regular biopsy and now you have the MRI available to you.
Another example is a 57-year-old gentleman he had an elevated PSA. He had a low-risk Gleason 6 biopsy, undergoes surveillance, so part of his surveillance is to do an MRI at our shop and he undergoes that. He has a PIRADs three lesion. He gets a biopsy, systematic plus that, and it confirms the 6, he continues on active surveillance. The lesion remains stable for a couple of years. Year 3 the lesion started changing, it had progressed at least by radiologic criteria. He underwent a biopsy, and the biopsy showed disease progression as well.
So it can be used in a way to sort of trigger when to do those biopsies, and you have to individualize that, whether you do believe everyone should have a biopsy every year or not is up to you. We have a lot of men though who have normal imaging, have been biopsied several times, and now they are simply followed by annual imaging, PSA testing, and symptoms. So what does the policy statement say, multiparametric MRI has demonstrated improved diagnosis in the intermediate and high-risk patients on targeted biopsies, which could be beneficial in identifying patients for active surveillance protocols. However, current information about MRI is not sufficient to support the role of repeat MRI without a biopsy in monitoring men, so they are kind of cautioning you not to just rely solely on your MRI as your only tool in the follow-up.
MRI, fusion biopsy and in-bore I thought maybe Robert was going to talk about that when I saw the topic of MRI guided biopsy because there are some centers that do MRI machine in-bore guided biopsies but that is not very common for urologists to do, and it’s not that often that we rely on our radiologists to do that either. But they realize that not everybody has the image-guided technology and so if you could do these image guided it’s probably preferred but cognitive fusion or knowing where it’s at and using the MRI and then guiding your transperoneal biopsies for example into that location is a reasonable alternative if you don’t have that available to you.
So in conclusion, significant addition of traditional imaging for the management has the potential to improve the timely identification of significant cancer. Enhancing targeting approaches have the potential to reduce cost as you saw in the last talk through reduction of necessary and inaccurate biopsies. Current evidence supports the performance of this MRI in men who have had an initial negative standard biopsy but still concerned for cancer, and targeted biopsies combining MRI, TRUS, and trans-peroneal biopsy will likely become the preferred method of initial biopsy and biopsy naïve men although the data is not there. So in the future multiparametric may be beneficial in men with presumed clinically localized before selecting therapy. It offers useful information for surgical planning.
I saw his talk about whether it can predict. I can tell you that an MRI on a high-risk prostate cancer patient can certainly help guide the way we approach the surgical attack, whether there is large extracapsular extension to go wide. It’s better to know that ahead of time than at the time of surgery. Currently enthusiasm for the benefit suggests more evidence will be forthcoming. They’re going to do more and more of these trials to try and add some value to what we already believe to be true and currently the use of MRI in many of the areas that we are trying to do it in are still considered investigational due to the lack of high-level evidence. Increasingly we’re going to be using MRI in our practice to help guide treatment. These consensus statements recommended for prior negative biopsy, NCCN guidelines has now included it for initial biopsy as an option and then cost is our major problem in the U.S. It’s an expensive test, and it needs to come down. In Australia, it is the most common test done, and they don’t charge very much for it at all, and the quality of imaging and the experience of the radiologist and the urologist on both ends are really important in helping to guide therapy so thank you for your attention, and thanks for having me at the meeting.