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    Prostate MRI has value, but results are not ‘gospel’



    Let’s talk about active surveillance. How do you use MRI there?

    There are two separate scenarios with active surveillance. The data are strong that in men who are considering active surveillance, MRI prior to the restaging biopsy helps better identify areas with higher grade cancers while effectively providing more information on whether surveillance is a smart idea. That’s done fairly routinely at our center and many others.

    Also see: Factors in prostate Ca decision-making vary by race

    However, once men are on active surveillance, it is not standard of care to routinely obtain MRIs as part of their surveillance, and the NCCN guidelines specifically state that. However, emerging data from a few centers such as Memorial Sloan Kettering Cancer Center, the National Cancer Institute, and UCLA suggest that, while a man is on surveillance, an MRI periodically is very helpful in identifying whether he is “progressing.”


    At our center, we use it in a patient who is on active surveillance, has low-volume Gleason 6 disease, and PSA below 10.0 ng/mL. Instead of doing an immediate 3-month re-confirmation biopsy, we do the MRI then. Does that sound reasonable?

    That’s very similar to the practice pattern at our place, except we also routinely add the re-staging biopsy.


    When do you use MRI in a patient with previous negative biopsies whose PSAs are going up?

    In many ways, I think that’s the sweet spot of prostate MRI. There is a large amount of supporting data in that setting. A consensus statement was published in 2016 by the Society of Abdominal Radiology in conjunction with the American Urological Association. The key take-home points are to talk to your team about having a quality MRI and what it takes to get there, and to have experienced people interpreting them. But if the patient has a PI-RADS 3 to 5 lesion, it should be sampled a minimum of two times per lesion, sometimes more, depending on its size. There are many different ways of getting a needle into that lesion, but the data on whether one technique is better than the other are not great.

    There are three main techniques for conducting an MRI-guided prostate biopsy. First is called cognitive registration, which is basically seeing an abnormality in a particular region on MRI and conducting an ultrasound-guided biopsy to take extra samples from that area. Second is an in-bore MRI biopsy, which is very time-consuming but is probably the best way to confirm that your needle is inserted into the region of interest. Third, which seems to be the most commonly used and what we use, is done in the urology clinic using a platform that fuses the MRI image with the ultrasound image to take extra samples.


    Talk a little about what a urologist needs to do to get up to speed in fusion biopsy. Would you agree it’s not just one in-service program?

    I absolutely agree. There are courses and training sessions, but like most things we do, it takes time and thoughtful insight into looking at your own outcomes. At our center, we decided that one urologist would do all of the fusion biopsies. We’ve looked back at the biopsy data and have regular communication with our radiology team where we’ve correlated data with prostatectomy specimens. We think of it as an iterative process.


    Early on, we had multiple radiologists who happened to be covering the MRI room, and that didn’t work out well for us. Would you agree that that team of a dedicated reader (radiologist) and dedicated surgeon (urologist) probably makes for the best systematic review of the MRIs, the best biopsy, and the best results overall?

    Absolutely. There’s even published research confirming that. Memorial Sloan Kettering showed the same MRI images to three separate GU radiologists, and the accuracy varied among those three. Whether you’re in an academic practice or a community practice, it’s incredibly important to identify people who have a specific interest and skill set.

    Next: What do you do with PI-RADS 3 or 2 lesions?

    J. Brantley Thrasher, MD
    Dr. Thrasher, a Urology Times editorial consultant, is professor and chair of urology at the University of Kansas Medical Center, Kansas ...

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    • UBM User
      I am a medical oncologist specializing in prostate cancer (PC) since 1983, and have had an extended experience with prostate MRI for over 2 decades. The discussion above by Eggener and Thrasher is very reasonable but a few points are worth mentioning. 1. I would not want any patient under my guidance studied with a 1.5T MRI. At the very least 3T should be routine. In the near future we will likely see 7T being used given the more discrete anatomy revealed. 2. There should be OBJECTIFIED data and less emphasis on "narrative", the latter of which tends to encourage a CYA approach. I want to know the index lesions, where they are, their size, the findings on T2WI (T2-weighted imaging), DWI (diffusion weighted imaging) with the apparent diffusion coefficient (ADC) values given, and 3. When contrast is used I want to know which Gadolinium (Gd)-based contrast agent (GBCA) is intended & to be sure it is one in the cyclic & ideally non-ionic category (e.g., Gadovist, ProHance) to minimize toxicity. 4. Of course I want a PI-RADS v2 score rendered. 5. In the best of worlds I would like to see snapshots of the area(s) of concern and have the radiologist label pathologic findings so that I and other medical oncologists become more educated about imaging in PC patients. 6. Lastly, urologists should always defer prostate biopsies until at least 6 weeks after or during the mp-MRI since hemorrhage invariably occurs and results in a more problematic interpretation. These are some issues important to me in my care of PC patients. Stephen B. Strum, MD, FACP