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Hashim Ahmed: So, I'm chair of the National Cancer Research Institute, so I'm director of the research landscape in the UK. I've kept three slides. These are postdoc analyses of two studies where we compared MRI to template mapping biopsies. In template mapping biopsies, you take five-millimeter space biopsies—so 50/60 cores per patient on average—and they're as close to ground truth without removing the prostate, and that's quite important. As you can see, if you define an MRI negative or non-suspicious as PIRADS 1 or 2, as we used in these two studies, you do miss quite a lot of grade group 2 disease and a few GG1s as well. But once you start to apply a PSA density, you drop that missed grade group 2 disease to about 5% or less. So PSA density becomes really important in cleaning up those PIRADS 3 cases which are equivocal, that sort of widespread diffuse change that you see. Next slide.

When PROMIS came out in 2017, the UK pretty much within a year, almost wholesale—about 60-70% of units—switched to a pre-biopsy MRI paradigm, and the rapid pathway was government-funded to test out the reproducibility of this across our entire region. So it was across West London, and we piloted it. This is the pilot data at the moment. As you can see, using an MRI where we would not biopsy PIRADS 1s and 2s and not biopsy low PSA density or PIRADS 3s, we were avoiding biopsies in about 45% of cases that were coming through the door, and they were discharged. Rapid was all about getting the diagnosis quickly because that's what the UK wanted to do, and they were discharged almost the same day that we spoke, and the MRI had the report. "Mr. Smith, your MRI looks fine, off you go, and this is the PSA level that you should come back and get referred on," and we're getting about 5% of referrals.

So it's a very safe pathway, at least in the medium term, and you can see when we do that, for us, finding grade group 1 is a medical error. We treat it as such. We painstakingly go through who on earth made the decision to biopsy that man and we'll haul that person in front of the tumor board and ask them questions as to why they made that decision. We really will, and anybody who treats those are equally hauled through the coals. So, it's a big issue for us to find grade group 1 disease, and I jokingly once said to Chris Parker, who led the active surveillance paradigm in the UK, that with MRI we will almost eliminate active surveillance, and we're not too far off that. Of all of those cases that are GG1, 95% of them in the UK are on active surveillance.

So, I think there are some biological questions that the pathologists need to answer. Where is the validation of a lack of basement membrane against the biology and the behavior of the disease? Somebody cleverer than I needs to tell me where that basement membrane thing came from because you need to justify why you're using that as a criterion when the behavior of the entity that you're calling cancer is nowhere near like a cancer. But there are some ways we can find out a lot more information. When you have a template biopsy, you're sampling every five millimeters. There are quite a few centers in the US who are doing this. It's a great natural experiment. If there's fewer grade group 1 in template biopsy, you can follow these men up over time, maybe 10-15 years through national registries. You can start to say that prostates that haven't been removed [inaudible 00:04:46] don't lead to [inaudible 00:04:46], and something that do as an international endeavor. Similarly, in those men who do by mistake have a biopsy of a non-suspicious MRI something, there are plenty of you all to see in the UK who still do that. In some groups, they are found to have grade 1. What is the natural history of those? I think we've got plenty of follow-up now between Australasia and Europe, certainly, to be able to answer that question quite well. So very much welcome a consortium to.