Mark Emberton, BSc, MBBS, FRSC (Urol), MD, FMedSci describes his approach to diagnosing patients with prostate cancer, highlighting prostate-specific antigen (PSA) testing and magnetic resonance imaging (MRI) as critical to cancer detection.
Mark Emberton, BSc, MBBS, FRSC (Urol), MD, FMedSci: So my name is Mark Emberton. I'm a urologist working in London. I'm also a professor of interventional oncology at UCL, which is one of the large universities within London, and Dean of the Faculty of Medical Sciences at UCL.
So this is about the diagnosis of a man at risk. Most men will present with an elevated PSA. These days we go straight to MRI, the evidence to support this is now overwhelming, and largely as a result of the studies that we published in 2017 PROMISE and 2017- 2018 PRECISION. Which- and that caused NICE and other organizations to recommend MRI in all men prior to biopsy. That recommendation from the National Institute of Clinical Excellence was available in April, 2019. And since then, I think most of the world have adopted this. What MRI does, it allows us to adjust for the inherent errors in PSA. So in other words, the false positives and the false negatives, and allows us to contextualize the PSA and to determine the PSA density, because MRI gives us volume. MRI also allows us to avoid biopsies in a large number of men. Just like if you are a woman worried about breast cancer and you have a negative mammogram, you're reassured by that. I think that a negative MRI of the prostate is also very, very reassuring in that it's associated with a very, very low risk of clinically significant disease. I don't biopsy men that have a normal MRI and I really only biopsy men that have lesions. So MRI has transformed our diagnostic processes by allowing us to target an area of high cancer probability. In other words, an abnormality that we see on MRI, rather than the random spread of needles into areas of low probability. And that has increased the diagnostic yield, has increased the proportion of patients with clinically significant disease that we identify, and has reduced significantly the amount of the patients that are overdiagnosed. So in other words, diagnosed with low volume Gleason 3 + 3 which doesn't impact on life expectancy. So in summary, there's a triage test, which is currently PSA. We then move to MRI, which then informs whether or not to biopsy and also the conduct of the biopsy. These days, the biopsy is often done with image fusion, and there are many platforms that help you guide the needle straight onto the air of abnormality so that you can maximize the opportunity. I think the prostate biopsy is similar to a brain biopsy. It's possibly the most important event in the whole journey of a man at risk of prostate cancer, right through to treatment, as it determines everything. And so it's gone from a relatively imprecise procedure to a procedure that needs to be taken very seriously and done with extraordinary precision.
So the diffusion of MRI has occurred at different rates throughout the world. And some of that has been a resource issue, some of that has been a reimbursement issue in terms of healthcare systems. In Europe, the adoption of MRI was very quick, in the UK particularly, but in Europe. In the United States, it took a while. The reasons aren't entirely clear. Reimbursement was difficult, and of course it was European agencies that made these strong recommendation to include it in the diagnostic workup. The American agencies lagged a little bit behind on that. And so the adoption was slightly slower. I think it's fair to say now that most men diagnose in the United States, and I'm speaking in the summer of 2022 would be offered an MRI scan. In fact, if you're not offered an MRI scan, I would walk away as a patient and seek another urologist to guide me through the diagnostic process, as I think your- the risk of missing a diagnosis or over diagnosis without an MRI is really unacceptably high at present. The other thing that is different about the USA compared to the rest of the world is the degree to which we use the perineum to access the prostate. In Europe now it's almost impossible to get a transrectal biopsy as we've moved to transperineal in order to avoid infection and also rectal bleeding. And so it's a harm reduction strategy. And I think in the USA, it's fair to say that most biopsies are still done transrectally, but that transition toward a transperineal approach is happening, and I presume will be complete over the next few years.