2023 News and Research in Prostate, Bladder, Kidney, and Testicular Cancer

Cancer.Net Podcast

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In this podcast, members of the Cancer.Net Editorial Board discuss the latest research, innovations, and discussions taking place across the field of genitourinary cancers, including prostate cancer, bladder cancer, kidney cancer, and testicular cancer.

This podcast is led by Cancer.Net Associate Editor for Genitourinary Cancers, Dr. Petros Grivas. Dr. Grivas is the clinical director of the Genitourinary Cancers Program at University of Washington Medicine and a professor in the clinical research division at the Fred Hutchinson Cancer Research Center. He is joined by Dr. Neeraj Agarwal, Dr. Shilpa Gupta, Dr. Tian Zhang, and Dr. Timothy Gilligan.

Dr. Agarwal is a Professor of Medicine, and a Presidential Endowed Chair of Cancer Research at the Huntsman Cancer Institute at the University of Utah. He directs the Genitourinary Oncology Program and Center of Investigational Therapeutics at the Huntsman Cancer Institute. He is also the Cancer.Net Specialty Editor for Prostate Cancer.

Dr. Gupta is the Director of the Genitourinary Medical Oncology Program at Taussig Cancer Institute and Co-Leader of the Genitourinary Oncology Program at Cleveland Clinic. She is also the Cancer.Net Specialty Editor for Bladder Cancer.

Dr. Zhang is an Associate Professor of Internal Medicine at UT Southwestern Medical Center and a medical oncologist at the Harold C. Simmons Comprehensive Cancer Center. She is also the Cancer.Net Specialty Editor for Kidney Cancer.

Dr. Gilligan is a Medical Oncologist, Associate Professor of Medicine, and Vice-Chair for Education at the Cleveland Clinic Taussig Cancer Institute. He is also the Cancer.Net Specialty Editor for Testicular Cancer.

View full disclosures for Dr. Grivas, Dr. Agarwal, Dr. Gupta, Dr. Zhang, and Dr. Gilligan at Cancer.Net.

Dr. Grivas: Hello. I'm Dr. Petros Grivas. I'm a medical oncologist in Seattle, a professor at the University of Washington and Fred Hutchinson Cancer Center. I'm really excited and thrilled today to host wonderful superstars in the field of GU Medical Oncology who will share insights about the highlights of kidney cancer, prostate cancer, and bladder, urothelial, urinary tract cancers that happened in 2023. And this highlight aims to inform our great audience about what are the clinically relevant insights, what patients should be aware, what patients should ask for when they go to the clinic, or overall, how they can be most well-informed and have the necessary tools to improve their care and feel well-supported in regards to education. So without further ado, we're going to cover in first prostate cancer, a very important update in this year. So all the people out there that are interested in hearing about prostate cancer will find this very, very useful and insightful. I'm very excited to host Professor, Dr. Neeraj Agarwal from University of Utah. Neeraj, do you want to introduce yourself?

Dr. Agarwal: Of course. It's such an honor to be here. My name is Dr. Neeraj Agarwal. I'm a professor of medicine and director of genitourinary oncology program at the University of Utah Huntsman Cancer Institute.

Dr. Grivas: Neeraj, thank you so much for accepting the invitation and being with us. I would like to ask you, what's your take on the current state of genetic testing in patients with prostate cancer? And when we say genetic testing, maybe you can clarify the distinction between germline and somatic and comment on both if you could. Thank you.

Dr. Agarwal: Of course, a very important topic. I must tell you that it is very clear from all the guidelines that in patients with advanced prostate cancer or metastatic prostate cancer, meaning when prostate cancer has spread to different parts of the body, both germline testing to look for hereditary mutations in the DNA repair genes and testing for the same genes inside the tumor tissue are considered standard of care. So, a patient with advanced prostate cancer should have germline testing and somatic tumor tissue testing to look for mutations that can predispose them to have prostate cancer, and if they have genes in the tumor which can be targeted by the current approved drugs, like drugs which are already approved right now or which are in clinical trials.

Unfortunately, less than 50% of patients in many areas of the country and in the world, less than 20% of patients are being tested. And even more, unfortunately, patients are less likely to be tested are those who are not well-resourced, who are not living in rich countries, if you will. They are poor- or low-resourced countries. Even with high-income countries, within those countries, patients who are living in relatively not-so-affluent neighborhoods, they are less likely to be tested. From racial perspective, patients who are Black or who are Hispanics are less likely to be tested. Based on how many drugs are out there in the clinic and emerging through clinical trials. And the fact that we can use many of these mutations for prognostication, to inform survival, to inform aggressiveness of the disease. It is not only to treat those patients, but also how to monitor the disease. The genetic testing is very important.

Dr. Grivas: Thank you so much, Neeraj. It's very insightful. And I think you did a great job outlining the clinical relevance for both the patient in terms of treatment decision-making and therapy options, especially for advanced prostate cancer, as well as the broader family and implications for cancer prevention and cancer screening for the broader family members. So definitely a very important topic.

Neeraj, the other question I have, if you could tell us more about this class of medications called PARP inhibitors. If you can comment on the currently approved PARP inhibitors, either as a single agent, what we call monotherapy or combination therapies for patients with prostate cancer in the United States, and who is eligible to receive those therapies?

Dr. Agarwal: And this is such a nice segue to talk about PARP inhibitors as we were just talking about genetic testing of prostate cancer. So, PARP inhibitors are a class of drug which are instrumental, critical in treatment of patients who harbor mutations in those DNA repair genes. And two monotherapies, meaning using these PARP inhibitors as single agents have been already approved in the United States and several other countries. These are olaparib or rucaparib. Olaparib is approved after patients have had disease progression on novel androgen-blocking therapies or androgen blockers such as enzalutamide or abiraterone or apalutamide. And these PARP inhibitors such as olaparib or rucaparib can be used for those patients as single agent if they have these DNA repair mutations. Now, last year, we saw several combinations of PARP inhibitors with these androgen or novel hormonal therapy, as we call them. And these include abiraterone plus olaparib, abiraterone plus niraparib, and talazoparib plus enzalutamide from various phase 3 trials. Now, I'd like to bring to your attention that these PARP inhibitor combinations are approved with different indications in the United States and in the European Union. And they continue to get approved in various other countries.

So the combination of abiraterone and a PARP inhibitor, whether it is olaparib or niraparib, they are approved for patients who have new metastatic castrate-resistant prostate cancer, and they have BRCA1 or BRCA2 mutations in the cancer cells or they have germline BRCA1 and BRCA2 mutations. Enzalutamide and talazoparib combination is approved in the United States for patients with metastatic castration-resistant prostate cancer with BRCA1 and BRCA2 mutations, but also several other DNA repair gene mutations. And that's a big difference as far as approval is concerned in the U.S. In the European Union, for our patients who are listening from European Union, the combination of abiraterone and olaparib and enzalutamide and talazoparib are approved for patients with metastatic castrate-resistant prostate cancer where chemotherapy is not clinically indicated, regardless of whether they have mutations in the DNA repair genes or not. And the combination of abiraterone and niraparib is only approved for patients with metastatic castrate-resistant prostate cancer with BRCA1 and BRCA2 mutation. So I just wanted to outline the different indications in the United States and in the Europe.

Dr. Grivas: Thank you so much, Neeraj. So eloquent and very relevant to multiple patients globally, as you pointed out, with some differences in terms of the regulatory approval and availability of those agents in different countries. So great insights. Maybe we'll ask you 1 more question again since we are doing the highlights of the year.

Another very important area of therapeutic development has to do with these novel agents that target the prostate cancer cells, and we call them theragnostics as a broader term. And I will let you explain what that means maybe in lay terms for our audience. And specifically, if you can comment on the recently presented PSMAforetrial at the ESMO meeting in Madrid with lutetium-177 PSMA. What are the implications of these results for our patients, and what is the role of lutetium therapy in this particular therapy setting?

Dr. Agarwal: Of course, very important and pertinent topic indeed. As our patients may know that lutetium-177 therapy, or simply speaking, lutetium therapy, has already been approved for patients with metastatic castrate-resistant prostate cancer who have had disease progression on this novel hormonal therapy and a chemotherapy with docetaxel or cabazitaxel. And this indication is already there in the U.S. and in various other countries. And patients are eligible to receive lutetium therapy as long as their disease has progressed on docetaxel or one of the taxane chemotherapy and a novel hormonal therapy.

Now, in the European Society of Medical Oncology meeting, Dr. Oliver Sartor presented the data on PSMAfore trial where lutetium therapy was used before chemotherapy. In this trial lutetium therapy was compared with another novel hormonal therapy after disease progression on 1 novel hormonal therapy. And there was approximately 6-month improvement in progression-free survival, meaning there was a delay in disease progression by 5 to 6 months in patients who were receiving lutetium therapy. And at the time of the report, there was no improvement in overall survival, with the caveat that 84% patients who were receiving novel hormonal therapy, actually, they switched over to lutetium therapy after disease progression. So, overall, survival data may not be met. Having said that, we already know that lutetium therapy is an effective therapy, and it has a definitive role in treatment of our patients with metastatic castrate-resistant prostate cancer.

Dr. Grivas: Thank you, Neeraj. That's very, very important data. And I'm so glad we have many more therapy options for our patients with prostate cancer. So involvement and accrual in clinical trials, I'm sure you will agree, is a very important and high priority. And I always encourage people with prostate cancer to ask about clinical trials that are relevant to their situation.

Dr. Agarwal: Yeah. I'd just like to add a point regarding lutetium therapy that there was a phase 2 trial in from Australia which compared lutetium therapy with cabazitaxel therapy after disease progression and docetaxel chemotherapy. And efficacy of both agents were not very different. So just wanted to make that point.

Dr. Grivas: Thank you, Neeraj. It's a very important point. And obviously, always want to think about pace and preference, convenience, distance from the cancer centers, all the relevant points, how we can individualize suggestions or recommendations for our patients. Thank you so much, Neeraj, for your wonderful input, insights, and all the work you do in the field.

Dr. Agarwal: Thank you very much for having me.

Dr. Grivas: Of course, of course. And now we're going to transition to a different cancer type. We're going to talk about bladder cancer and urothelial cancer in general, urinary tract cancer. And we're delighted and excited to have Dr. Shilpa Gupta from Cleveland Clinic, who's a professor there of oncology. Shilpa, I want to introduce yourself?

Dr. Gupta: I'm Shilpa Gupta. I'm a genitourinary medical oncologist and the director of the GU Program at Cleveland Clinic. I'm really excited to be doing this podcast with you all.

Dr. Grivas: Thank you, Shilpa. You have done amazing work in the field, pushing the field forward. You are part of those transformative studies. I will ask you in the beginning where I'm going to focus my first question for people who have advanced or metastatic bladder cancer or urinary tract cancer or upper or lower tract. And we saw really exciting, impressive data at the recent ESMO Congress in Madrid a couple of months ago. And I know you were there and were enjoying to see the improvement in patient outcomes that comes with better quality of life for patients in the last several years. And the question I have for you, if you want to summarize the key data in the first-line treatment, patients who have no prior treatment for metastatic urothelial cancer, what are the key data we showed at the ESMO meeting?

Dr. Gupta: Thank you, Petros. As you said, this is a really exciting time for both patients as well as the physicians treating bladder cancer because of all the new developments which we've seen after decades. So at ESMO 2023, we saw the key data from the EV-302 trial, which was a phase 3 trial, which randomized patients to the standard of care, platinum-based chemotherapy, gemcitabine-cisplatin or gemcitabine-carboplatin, versus a novel drug, which is an antibody-drug conjugate called enfortumab vedotin and the immunotherapy pembrolizumab. And the primary endpoint was to see if patients lived longer and this delayed progression. And we saw that in this the progression-free survival, we saw that it was 12.5 months with enfortumab vedotin and pembrolizumab compared to 6.3 months, which means that the risk of progression or death was decreased by 55% with this new combination. And the benefit was seen across all the various factors, especially patients with liver metastases, visceral metastases, whether or not they had contraindications to receiving cisplatin or not or PD-L1 expression. So this is the first time we saw such a remarkable benefit with any treatment that beat platinums. And the overall survival was also doubled: 16 months in chemotherapy versus 31.5 months with this combination. So the risk of death was reduced by 53%. And we also saw that the overall response rates were 68% with this compared to 44% with chemo. And 29% of patients had complete responses. And this was really remarkable because we have not seen such data before.

And in the same session, we also saw another phase 3 trial that was presented, which was the Checkmate 901 trial, in which the investigators tested whether the addition of immunotherapy called nivolumab to the standard of care, gemcitabine and cisplatin was better than gemcitabine and cisplatin alone. So this was a study only looking for patients who can receive cisplatin.

So patients were randomized to 6 cycles of gemcitabine cisplatin versus nivolumab, gemcitabine cisplatin for up to 6 cycles. And after that, they continued nivolumab maintenance every month for up to 2 years. And in this, the primary endpoint of overall survival was also met, although the difference was not as huge as the other study. It was 18.9 months with chemotherapy versus 21.7 months with the combination. And progression-free survival was also improved by just 0.3 months with the combination. And the objective response rates were higher with the combination, 57% versus 43%, and there were 21% complete responses.

So the bottom line is that both these trials showed us that the frontline treatment is not going to be just platinums anymore moving forward. We will have the option of the enfortumab vedotin and pembrolizumab for all comers, patients who can get platinums, and nivolumab and gemcitabine cisplatin for patients who are cisplatin eligible.

Dr. Grivas: Thank you, Shilpa. Wonderful summary. Really, really exciting time to see the field moving forward and translate those results to longer life for our patients. In that context, I will also ask you—I asked Neeraj before about genetic testing in prostate cancer. I will ask you a similar question about genetic testing in bladder cancer. Again, reminding the audience about the distinction between germline testing, which is the DNA we are born with, and somatic testing, which is the cancer-specific genomic changes. Could you comment on the importance of genetic testing in bladder cancer?

Dr. Gupta: Yes. Absolutely, Petros. Genetic testing in urothelial cancer is very important because for the first time a few years ago, we saw a drug targeting the fibroblastic growth factor receptor or FGFR alterations. This drug is called erdafitinib. It is the first targeted therapy to be approved in urothelial cancer. It is only seen in up to 20% of patients who harbor these alterations for whom this option may be viable. And we saw initially that erdafitinib was approved in patients who harbor these alterations in the phase 2 BLC2001 trial where it showed response rates of 40% and encouraging progression-free survival, and overall survival. And then we also saw in a phase 3 trial called the THOR trial where patients who harbored these alterations by genetic testing, erdafitinib was much better than chemotherapy, prolonged survival by almost 4.2 months compared to chemotherapy. So unless we are testing, we won't find this. So it is really important to test all our advanced disease patients so we are not depriving them of this additional targeted therapy.

Dr. Grivas: Thank you, Shilpa. Very important message for our patients to definitely discuss the value of genetic testing. And if we think about therapy implications, specifically genomic changes, DNA changes in these FGFR-2 and FGFR-3 genes are very relevant and important for potential therapy with this agent called erdafitinib. Shilpa, a quick comment. We saw data from THOR cohort 2 comparing erdafitinib with this inhibitor of this FGFR that we just talked about compared to pembrolizumab, which is an immunotherapy drug inhibiting a checkpoint of the immune system. Could you quickly comment on that? And I think both options are available for our patients and sometimes just comes down to the sequence based on a particular patient case.

Dr. Gupta: So Petros, as we had thought that patients who harbor these alterations in their tumors, they may benefit from using targeted therapy before immunotherapy. That was the premise of the cohort 2 of the THOR trial, that patients will do better if they received erdafitinib first after progressing on 1 prior line of therapy, which is not an immunotherapy. So patients were randomized to erdafitinib versus pembrolizumab. Of course, all of them had to have the FGFR alterations. The primary endpoint was overall survival. Initially, like I said, the study assumed that there'll be 46% improvement in overall survival with erdafitinib over pembrolizumab. However, the study was a negative study. There was no difference in the overall survival. And what that means for our patients is that erdafitinib right now is positioned for patients who've had prior platinums and immunotherapies. So erdafitinib should not be used before immunotherapy. So I think this is the first study that really settles the question of sequencing for our patients. And I think the message is that in a patient's journey, they should be getting all these therapies. We just now know that it's better to use pembrolizumab before erdafitinib and not vice versa.

Dr. Grivas: Thanks, Shilpa. And then really, really interesting to see these trials being reported. And as you said, individual discussion with the patients and the response rate may be another factor to consider. If someone wants to have a more rapid control of the cancer of the disease, we may potentially think about an agent with high response rate and vice versa. So I think to your point, individual decisions. And I think patients asking those questions is very important in the clinic to help select the right patient for the right treatment for the right patient.

Dr. Gupta: Yeah. Absolutely, Petros. They did see that the response rates were 40% with the erdafitinib versus 21% with the immunotherapy. So using that information can sometimes guide us if a patient has high disease burden.

Dr. Grivas: Thank you, Shilpa. That was very insightful. And thank you for all you are doing for the patients and the field in general. You really, really have helped the field move forward. So congratulations and thank you. And we're going to transition to another superstar in the field of GU cancers. Very excited to host Dr. Tian Zhang. Dr. Zhang is in UT Southwestern in Dallas. Tian, you want to introduce yourself?

Dr. Zhang: Hi, Petros. Thank you so much. Tian Zhang, I'm a GU medical oncologist and associate professor at UT Southwestern Medical Center in Dallas.

Dr. Grivas: Wonderful. Thanks, Tian. Again, the same comments. All the work you're doing in the field is tremendous. Thanks for joining us today. Tian, we saw some very interesting data at the ESMO meeting. And since we're doing the highlights of the year, I think the predominance of the data we saw at the ESMO meeting was about this drug called belzutifan, where I will ask you to enlighten us what exactly this is. And particularly, we saw 3 different trials. I would probably ask you to focus more on the LITESPARK-005. What was the trial design and what was the primary goal of the study? When patients go on this drug, what they should be aware in terms of side effects? And what was all this discussion that the take-home message at the end of ESMO regarding belzutifan? Thank you.

Dr. Zhang: Sure. We’ll parse that one at a time. Belzutifan, I hope many of our audience knows is a small molecule inhibitor of the HIF complex, a hypoxia-inducible factor complex, which is implicated in the development of kidney cancers. And this biology actually contributed to the Nobel Prize in 2019. Understanding the structure of the HIF complex and how to target it. For a long time, HIF was thought to be un-targetable. And so the fact that there were small molecules identified actually here in Dallas at UT Southwestern that inhibits the dimerization of the HIF complex is really novel and shows us the bench-to-bedside translatability of these preclinical discoveries.

And so there were a couple of molecules that were discovered here on campus and they paved the way for what became molecules that have now made it to clinic, in particular belzutifan. And so we've had belzutifan now approved for Von Hippel-Lindau Syndrome over the last 2 years or so. So many of us are familiar with using this drug in the clinic. It's an oral agent that's able to target the HIF complex and block it and really control the spread of clear cell kidney cancers, in particular in Von Hippel-Lindau disease.

LITESPARK-005, the trial that you're alluding to, there was a registrational trial for belzutifan across other kidney cancer populations. And this trial was the 1 that made, I think, the biggest impact of the 3 trials that were presented at ESMO this year. LITESPARK-005 was a phase 3 trial of patients who had metastatic or locally advanced clear cell kidney cancer who had progressed after prior systemic therapies, not more than 3 prior lines. And they were randomized to either belzutifan at the 120 milligrams daily dose or everolimus at the 10 milligrams daily dose. And the primary endpoint was delay of progression. So progression-free survival as well as overall survival. So we saw the primary endpoint of these was met for progression-free survival.

There was about a 26% risk reduction for progression for patients treated with belzutifan versus those that were treated with everolimus. The objective response rate I would highlight is also significant for the patients treated with belzutifan. There was actually a 3.5% complete response rate and objective responses. So including partial responders was about 23%.

I would say that patients who are treated with belzutifan need to be aware of the side effects of anemia and also hypoxia [low levels of oxygen in the body]. And in fact, higher grades of anemia can occur in up to a third of patients and higher rates of hypoxia. So low oxygen saturations can occur in up to 10% or so of patients. And so that's really important when we're thinking about those toxicities and how we might hold or support the side effects with growth factors, for example, for the anemia. Otherwise, it's quite well tolerated as a single agent.

As you alluded to, there was 1 controversial aspect of this particular trial because the control cohort was treated with everolimus. And everolimus as a single agent may not be what people use at this point in the refractory setting. But it is an acceptable approved treatment option for patients in the refractory kidney cancer setting, and therefore, it was chosen as the control cohort. And belzutifan did improve compared to a known standard of treatment. So I think that's really important to add to our armamentarium in refractory disease.

Dr. Grivas: Wonderful, Tian. Thank you so much for a really, really comprehensive and detailed review. We'll have to see whether it will be available for patients with advanced clear-cell kidney cancer. To your point, it's already available for patients with this condition that you mentioned, the Von Hippel-Lindau genetic condition. So it's great to see more options available for our patients.

Maybe I'll ask you another quick trial to comment on Tian, and I'll ask you individual questions to make it easier, to your point, for the audience to follow. And I'm referring to the RENOTORCH trial. This was conducted in China, and I think it was practice-changing there. Could you tell us the study design?

Dr. Zhang: RENOTORCH was another phase 3 randomized trial. It was conducted all in China of patients with unresectable metastatic clear cell kidney cancer, no systemic prior therapy, and also intermediate- and poor-risk disease by IMDC criteria. So these were all first-line metastatic disease, and patients were randomized to either toripalimab, which is their PD-1 inhibitor, plus axitinib versus sunitinib. So this is a trial design that mirrors many of our prior trials in the first-line metastatic setting that have led to approvals of VEGF IO [immunotherapy] combinations. But this is the first one that was carried out purely in the Chinese population and important for the Chinese population to gain access to these types of combinations.

Dr. Grivas: Thank you, Tian. Very important to see this global approach, as you mentioned, oncology and see trials from different countries. What were the main findings of this trial?

Dr. Zhang: Sure. The primary endpoint was progression-free survival of the 2 cohorts. And they randomized about 420 patients. About 80% per cohort had intermediate-risk disease. And the combination of axitinib with toripalimab did improve progression-free survival. So it had a 35% risk reduction for progression over time. So it did meet its primary endpoint.

Dr. Grivas: Thank you, Tian. It's great to see progress in the field. As I mentioned, new agents, positive trials. Could you comment a little bit on the side effect profile and the significance of this trial for our patients worldwide?

Dr. Zhang: Sure. When we're talking about VEGF IO combinations very similarly as to the prior trials that we've seen in the toxicity profiles, we're thinking a lot about the immunotherapy toxicities of rashes and colitis [inflammation of the colon], endocrinopathies [hormone problems], as well as the rare inflammatory reactions of the liver, lungs, or kidney, but also added in the small molecule effects of hypertension, hand-foot syndrome, and mucositis [mouth sores] and taste changes. So very important to think through those side effect profiles as our patients are being treated with these combinations.

Dr. Grivas: Thank you so much, Tian. Great to see, again, this progress made worldwide. And I think it speaks to the idea of how we can have equitable healthcare delivery across the globe, right, and have agents accessible in different parts of the world.

Dr. Zhang: Absolutely. In fact, I would just add that the Chinese population haven't actually had access to drugs like cabozantinib. And this is their first phase 3 grade 1 evidence for a combination of VEGF with IO combination. So it's really important that these trials are carried out in the populations where we try to find the effect and see that the consistent benefit is there so that those patients have access to all of these treatment options.

Dr. Grivas: Thank you, Tian. I appreciate your wonderful insights and all your amazing contributions in the field and your research. It's really, really inspiring to see. And I'm going to transition now. Last but not least, we're having the honor of hosting professor, Dr. Tim Gilligan, who is in Cleveland Clinic, and Tim is a world-known expert in urinary cancers, including testicular cancer. Tim, would you like to introduce yourself?

Dr. Gilligan: Yes. Hi. So I think you just did. Tim Gilligan, an oncologist at Cleveland Clinic. I chaired the NCCN panel on testis cancer and edit the UpToDate sections on testis cancer with their help.

Dr. Grivas: Fantastic. Thanks, Tim, for being with us today. And all the work you have done for our patients with GU cancers, testicular cancer, and a lot of work is being done with the NCCN and other guidelines. And you are co-chairing the NCCN guidelines, to your point. Tim, a lot of discussion is happening nowadays across cancer types regarding the role of what we call biomarkers, which are potential features that can help us select patients for the right treatment or help us estimate the prognosis, how long people live. Could you comment a little bit on this biomarker called microRNA in patients with testis cancer? How do you envision this being developed in the future? Is it ready for prime time or not yet?

Dr. Gilligan: And that's an important question. It's not ready for prime time yet, but we are making progress. There are a couple of areas where it could be very useful. So for example, in stage I testicular cancer, we tell patients to go on surveillance because they're usually cured with orchiectomy [surgical removal of the tumor and testicle], but there is a risk of relapse, and that risk of relapse is highly variable. And our current risk stratification systems for predicting who's going to relapse, who has stage 1 disease, are helpful, but they're far from perfect. And so there was data presented this year that mRNA may be more accurate at predicting for men with stage I non-seminomas who's destined to relapse. And so the implication of that would be if you are positive for mRNA, this particular mRNA for non-seminoma and you have stage I disease, normal scans, normal markers, you could identify a high-risk group of patients who maybe should get a cycle of BEP chemotherapy rather than waiting. If you know they're going to relapse, you're going to have to get them 3 cycles of BEP, why not just treat them right away? Or maybe RPLND [retroperitoneal lymph node dissection] could be helpful in that setting. We don't know. But we would need to do studies validating that approach.

There is data showing that it does predict relapse, but it's not at the point of saying, "Are the patients really going to do better with immediate treatment and which treatment is going to be best for them?" But I thought that was an important finding and really an example of how we think we're going to use it, which is to find relapse a lot earlier and so that we can give a less toxic treatment. And the benefit of that is that we know more and more that chemotherapy is toxic and resulted in second cancers. For men who get multiple cycles of cisplatin-based chemotherapy, or if they get radiation therapy, they're at higher risk of dying of other cancers than the general population. So if this could help us find early relapses, treat it more gently, less aggressively, have late, less toxicity, and the same cure rate. That would be great. So we're not there yet, but I think we're going to get there.

Dr. Grivas: Thanks, Tim. Very, very helpful to know. So this microRNA 371 that we talk about is not ready for prime time, but you definitely see promise for the future, and more trials, more studies are being done. Again, illustrating the importance of clinical trials that can help us evaluate the added value of a particular biomarker, including this particular microRNA that we talked about.

Dr. Gilligan: Before you change the subject on getting to crude biomarkers, there was also an interesting abstract showing that for stage I seminoma. If we actually use our current markers, we may be able to predict much more accurately. And it'll be interesting to see if that changes. They looked at the variables of lymphovascular invasion, invasion of the hilum of the testis, whether or not preoperative markers were elevated, LDH, and beta HCG. What was interesting to me about that paper was that this is about 900 patients. It was pretty large. That if you had all 4 risk factors, the relapse rate was about 64%. Whereas your average relapse risk for stage I seminoma is about 15%. We put everyone on surveillance. If we started if that model is persuasive to the community and starts getting used, then maybe patients with those 4 risk markers who most of whom are going to relapse, according to this data, maybe you want to treat those people and not put them on surveillance. So that'll be interesting to follow up on too.

Dr. Grivas: Thanks, Tim. And you are referring to currently available blood tests, right, that can be used, and we use them in clinical practice. So we just put them together, try to get a sense of the chance of cancer coming back, what we call recurrence, and how long people may live. That can help us make a therapy decision. Thank you, Tim. This is very, very interesting. And I'm glad to see the progress in the field.

I think you alluded to that before, but there is a trend discussing when we have a removal of the testicle for a patient with testis cancer, what to do next, depending on the stage, those markers that the blood tests you told us about. What about the role of surgery for removal of lymph nodes, for example? And do you see a trend going forward that in many selective cases, certain scenarios, we may potentially select surgery as opposed to chemotherapy or radiation to avoid these potential complications down the road? And if so, which are those patients who may benefit from surgery?

Dr. Gilligan: Yeah, an important question. I think surgery, there's been a growing interest in using surgery rather than chemotherapy in order to avoid late effects. So retroperitoneal lymph node dissection (RPLND) is the most obvious example of that. There is data now showing that most patients with stage II seminoma can be cured with retroperitoneal lymph node dissection. We used to treat those patients with chemotherapy or radiation, but as I've noted, both of those are associated with an increased risk of second cancers down the line. So there are papers on both sides of the Atlantic showing that you can cure most people. However, it is important to note that the relapse rate after surgery is significantly higher than the relapse rate after chemotherapy or radiation. If you take a stage II patient and treat them with chemotherapy or radiation, you're going to cure well over 90% of them. Whereas the relapse risk with surgery, depending on what you find at surgery, is going to be higher. So on average, it's going to be in the realm of 20%, maybe as high as 30%, depending on which paper you look at. And if you take patients who have PN2 disease, so a lymph node is 2 centimeters or bigger, 25% or more of those patients are relapsing after surgery.

So it's important for patients to understand that this treatment has the benefit of avoiding chemotherapy for most patients, but it also has a higher risk of relapse than the old treatments. We still think it's attractive because if you can avoid chemotherapy in 3 out of 4 patients or 4 out of 5 patients, that's a benefit to those patients. And also, if you go in and find a significant amount of cancer at surgery, you can give 2 cycles of chemotherapy right away and almost eliminate the risk of relapse, which is less chemo than they would be getting upfront, which would be 3 or 4 cycles. So one of the emphasis now is really trying to avoid late toxicities if we can. You sometimes see that even in the metastatic setting in terms of resecting residual masses and situations where we maybe in the past would have thought about second-line chemotherapy. I think people are more thinking about opportunities to use surgery instead to try to limit the quantity of chemo that we're giving. Those are much trickier decisions than the stage II decisions, but definitely a growing interest in surgery rather than chemo.

Dr. Grivas: Thank you so much. It's really, really exciting to see that testis cancer was really transformed in the past with developments of therapies like chemotherapy, radiation therapy, and surgery. And it's great to see this evolving down the road.

And I think all of the above that you mentioned evolves through the conduction of clinical trials. And as I mentioned before, I think it's so important to give the opportunity for patients and families to review clinical trial options. I think it's critical to try to help them, but also help other patients, the community, the society in general. So I always try to underline the importance of clinical trials across the board.

And on that note, I think we had such a successful year, 2023 across GU cancers. It's so great to see the progress being made. All of us are looking forward for more exciting research being done in 2024 and beyond. And on that note, I want to thank so much Dr. Agarwal, Dr. Gupta, Dr. Zhang, and Dr. Gilligan for wonderful insights and all the great work they're doing in the field of GU cancers.

As the editor for the GU Cancers for the wonderful Cancer.Net, I'm so proud of this team and really, really looking forward to further podcasts like this and how we can better serve the educational mission for ASCO, working with the wonderful staff at Cancer.Net. Thank you so much, all of you, for your time today and all you are doing.

Dr. Gupta: Thank you, Petros.

Dr. Zhang: Thank you, Petros.

ASCO: Thank you, Dr. Grivas, Dr. Agarwal, Dr. Gupta, Dr. Zhang, and Dr. Gilligan. You can learn more about new research in genitourinary cancers at www.cancer.net.

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