In today’s podcast, Dr. Sumanta Kumar Pal will discuss three studies highlighted at the 2017 Genitourinary Cancers Symposium, including two studies on metastatic kidney cancer and one study on metastatic prostate cancer.
ASCO: You’re listening to a podcast from Lineagotica. This cancer information website is produced by the American Society of Clinical Oncology, known as ASCO, the world’s leading professional organization for doctors who care for people with cancer.
In today’s podcast, Dr. Sumanta Kumar Pal will discuss three studies highlighted at the 2017 Genitourinary Cancers Symposium, including two studies on metastatic kidney cancer and one study on metastatic prostate cancer. The Genitourinary Cancers Symposium, held February 16th through the 18th, is co-sponsored by ASCO and offers presentations on the latest multidisciplinary research for genitourinary cancers.
Dr. Pal is a medical oncologist and Co-Director of the Kidney Cancer Program at City of Hope, as well as Assistant Professor in the Department of Medical Oncology and Therapeutics Research. He is also a member of ASCO’s Cancer Communications Committee.
ASCO would like to thank Dr. Pal for discussing this research.
Dr. Pal: Hi. My name is Monty Pal and I'm a medical oncologist at the City of Hope Comprehensive Cancer Center. I'll be discussing a couple of abstracts that are of interest from the 2017 Genitourinary Cancer Symposium. The first abstract is from Dr. Rana McKay who's now at the University of California, San Diego. And her abstract pertains to discontinuation of novel immune-based treatments for advanced kidney cancer. Now what's interesting is there's been a lot of interest around immunotherapy for kidney cancer as there has been for other diseases such as melanoma, and bladder cancer, and so on. And really, a part of the intrigue is that these treatments have been sold to us as being relatively innocuous. In truth, what we see is that there are some toxicities that can merge with these treatments. But one interesting caveat is what happens to patients after they develop these toxicities.
Now in this series, Dr. McKay identified nine patients with advanced kidney cancer who received some of these novel immune-based treatments. These patients all had significant side effects associated with treatment. One of the unique observations in this study is that she observed that patients actually had clinical benefit with the drug that continued despite discontinuation for some immune related adverse events. The types of adverse events or side effects that were incurred in this study included eye-related side effects, joint pains, issues with the thyroid gland, muscle pain, and so on. It was a relatively diverse array of side effects, but one thing that really resonated is that in many cases, continuation of the drug despite the incurrence of these side effects was not necessary in order to maintain clinical benefit.
Now, the second abstract that I thought was of interest from the 2017 Genitourinary Cancers Symposium was from Dr. Derosa from the Institut Gustave Roussy in Paris, France. There's also been a lot of interest recently and I've seen this on the covers of The Economist, Time Magazine, etc. regarding the microbiome, in the context of various cancer sub types. The microbiome refers to the bacterial composition of the gut, of the oral flora, etc. And what we're finding more and more is that the various bacteria that comprise one's stool, that comprise one's saliva, etc. can really play a key role in terms of defining responses to immune-based treatments. What Dr. Derosa did is she assessed patients that receiving immune-based therapies—in this case for kidney cancer—and what she was able to do is discern those patients that have received antibiotics versus those patients who did not.
The hypothesis was the patients who received antibiotics therapy would have clearance of the bacteria in their gut and so forth. And by virtue of this, they may potentially benefit less from immune-based therapies. And she in fact confirmed this hypothesis demonstrating in a cohort of 80 patients that have kidney cancer that received of antibiotics therapy, was associated with decreased benefit in association with immune-based treatments. Now, it's really important to note here that she didn't look specifically of the presence or absence of gut bacteria and that's an important missing step, but her group is working on that currently.
Finally, we're going to shift gears a little bit away from immune-based therapy and discuss some really interesting diagnostic tests that are being introduced at the ASCO 2017 Genitourinary Cancer Symposium. In particular, I wanted to reflect on a circulating tumor DNA test that's reported by Dr. Guru Sonpavde from the University of Alabama at Birmingham. This test is one that actually looks at a patient's blood. You might be familiar with this modality from pregnancy in which setting we are able to actually the circulating fetal DNA from a mother's DNA. The principle here is very similar. We're actually using this diagnostic test to discern tumor DNA versus the patient's own DNA.
In a series of 514 patients with metastatic prostate cancer, what was quite remarkable is that circulating tumor DNA could be detected in nearly 95% of patients. It was a really interesting array of different mutations that were identified in this study. And one thing that resonated with me as a practicing clinician is that many of the mutations that patients had detected in their blood from advanced prostate cancer were actually targetable using drugs that we have now in the clinic. These aren't conventional therapies. For instance, in the context of certain mutations, drugs that are relevant to kidney cancer or melanoma could be applied. Having said that, they offer unique hope to this very advanced population of patients with advanced prostate cancer.
So in summary, I think that circulating tumor DNA is a test that's really on the horizon for patients with metastatic or advanced prostate cancer and clearly the data from Dr. Sonpavde as has been shown in other diseases shows that there may be some promise in terms of using this test to direct at therapy.
ASCO: Thank you, Dr. Pal. To learn more about the topics discussed in this podcast, please visit lineagotica.info. And for more expert interviews and stories from people living with cancer, visit the Lineagotica Blog at lineagotica.info/blog.
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