Alicia Morgans: Hi, my name is Alicia Morgans and I'm a GU medical oncologist at Dana-Farber Cancer Institute in Boston, in the US. I'm so excited to have here with me today, Professor Silke Gillessen, who is the head of the Medical Oncology Department and the Medical and Scientific Director of the Oncology Institute of Southern Switzerland. Thank you so much for being here with me today, Professor Gillessen.

Silke Gillessen: Thank you very much. Very glad to meet everyone.

Alicia Morgans: Of course. So Professor, you have a very exciting upcoming event, the fall version of APCCC, 2021. Can you tell us a little bit about what we can expect at APCCC?

Silke Gillessen: Yes. So you are a member and you are a candidate, so you already know a bit how it works. As we said, it's a virtual form this time, because we didn't want or dared to do it face to face this time, but we will do one in April 2022. So stay tuned, but this time it will be a fully virtual. We have only four people, except obviously I will have you send me there. This is Professor Briganti, Professor Tombal, Professor James, and Professor Bossi. So they will come and we'll be in the studio. So we make it a bit more lively. And we have three sessions. The first one is, I think, very hot and very topical right now, management of newly diagnosed, metastatic hormone-sensitive prostate cancer. And as you know, now is the big question. Should we give triplets to everyone, to only the high risks, or high volume, high burden, whatever you want to call it. Or maybe to no one?

So it's, I think, a big question. Why now after the PEACE-1 data where we presented just now, three weeks ago at ESMO. And obviously we have also a lot of other questions, but I guess that one is really one of the most important one. And then the second session will be about PSMA in diagnostics and therapy. And here, obviously again, you've seen the questions. We will go really dive into the diagnostic part as well, because I think this is really something we see now, everyday in clinics. Patients, high risk prostate cancer, that you would conventionally stage in M0, N0. Now, at least in Switzerland, it's approved to do a PSMA PET/CT in these patients. And we see so many, as it was also described within the literature, patients with either N1 disease or even M1 disease.

So with this two little lesions in the bones that you don't see on the CT scan, like the CT scan that's together with the PSMA PET. And I guess this poses a lot of questions, right? So should we now treat these patients who would be in conventional imaging, M0, N0? And now let's say M1 with distant metastasis may be suspected, because you can't biopsy them because you don't see them in the CT scan. So you would do it, have the biopsy blind, but most people wouldn't do. So I think it's a lot of questions coming now. Should we really then leave the kind of curative approach that we would have done without the PSMA PET/CT? Or should we just add something on, but not leave the curative approach, what I think, but I mean, we don't really know because we don't have the data. Or should we really go and say, okay, we go completely palliative because we have this two, maybe not so clear lesions in the PSMA PET/CT in the bones.

So I think this is really a very important question. I don't know what you feel in the States, if you have the same problems, but I think that's really something we see a lot. Comment?

Alicia Morgans: Yeah, of course. I think that that is one of the burning questions, because that stage migration of patients can be very confusing and we don't want, or at least I don't want to lose the opportunity to cure patients who six months ago would have been treated with curative intent. Especially since we do have data from STAMPEDE suggesting a benefit in patients who have low-volume hormone-sensitive metastatic disease, that we can treat that primary tumor and hopefully shift to the survival curve. So I agree with you and at risk of saying where I voted, as you mentioned, I usually like to treat them with curative intent and then add something on. Whether that's SABR/SBRT to a distant metastatic site or intensified systemic therapy in addition, but every patient, I think it can be quite complicated. And every patient in my clinic, I think, at least deserves the conversation, "But this is what would have happened, and this is what we see now", what the right answer is. We'll have to get the consensus at APCCC.

Silke Gillessen: Yeah. I'm really excited to see what people will vote there. It's really, it would be a surprise right, because I think it's really kind of not clear. We don't have really data, it will take for years, probably, until we have the data. And for me, it's still unclear. I just had a, this question with my nuclear medicine specialist is a very, very good person. And it's also in reality, we should probably biopsy all these lesions, right? But obviously that's not possible. And so here, I think there stays that kind of difficulty, especially if you use the fluoride and not the gallium, what is done a lot now in Europe, that goes a little bit more to the bones and maybe also can do there more artifacts, but I'm not a specialist in that.

So, it's just kind of really interesting that we learn much more about which of these lesions, in the end, turned out to be real lesions. And what is maybe just unspecific, or a fragility fracture that takes some [00:06:23] form in the PSMA PET/CT. So I think it's, it's really, it would be very interesting to see. And very similarly is also what I'll be doing with the patients who are low-volume disease, metastatic, but low-volume disease in the conventional imaging and have the stage migration to high-volume disease in the PSMA PET/CT. Are we going to change our treatments there? In case you do different treatments, but as you know, we, at least I am believer in the STAMPEDE radiotherapy data. So, for low-volume, we would add local radiotherapy, so radiotherapy to the primary, whereas the high-volume we wouldn't.

So, again, there is a difference in treatment for us. A lot of people would probably not give Docetaxel in the low-volume patients. So it makes a difference, low-volume and high-volume, or burden, or however you want to call it. So, what are we doing now with these patients, right, that would be low-volume with conventional and or high volume. And obviously we have all the data with conventional imaging. So this will be all the questions, as you know, that we will have. And yeah, I'm really looking forward to see the results of the whole thing, I have to say.

Alicia Morgans: I am, too. And for some, perhaps that high-volume by that PSMA PET scan may suggest or may push that team into doing triplet therapy per PEACE-1. I don't agree with that, personally, because the data for PEACE-1, of course, was conventional imaging, but everyone may interpret things a little bit differently. And so the conversations, and the debates, and the voting, I think will be very, very exciting. And I really do look forward to it. So, what would your advice be to folks who are interested in virtually attending and coming to see what's going on at APCCC?

Silke Gillessen: Yeah. So, on the 9th of October, in ZST time, so in Zurich Swiss time, that would start at 1:00. So, in the afternoon. For you, it will be earlier in the morning, obviously. So it depends on your time zone, but so at ZST time it will be at 1:00 and it goes until 7:00. And maybe to make you a bit more excited, we've already discussed some of the panelist's results. So we will already see some of the results of the voting because this time, as you know, we have done the votings before, and we will now already have them really kind of cleaned up and made nice slides of it. So we will discuss what the panel has voted already on Saturday.

And then there is also some Challenge The Experts sessions in the end, two out of three are already booked out. So, but I guess everyone who is still interested should register, because especially even if you don't have time, Saturday was this on a weekend I realized, we can then hopefully put all the filmings on the website for everyone who's registered to look at about two weeks after the conference and until end of March. So, it's really worth registering, even if you don't have time on the Saturday, but then you can have a look afterwards.

Alicia Morgans: That's fantastic. Wonderful. Well, thank you again for putting this together. I really look forward to a lively APCCC because even if we are not physically together, we will be connecting across and around the globe. And I think it will be a phenomenal event. Thank you so much, professor Gillessen.

Silke Gillessen: Thank you so much for the invitation. As always, it was a pleasure.