Targeting FGFR Mutations in Metastatic Urothelial Cancer - Episode 6
The significance of using broad genomic profiling tests to help detect promising biomarkers in metastatic urothelial cancer.
Arlene O. Siefker-Radtke, MD: What I’m hearing, Scott, is, "Use all the resources at hand, our APNs, [advanced practice nurses] are fantastic at getting things done, and keeping the process moving forward," and, I might even argue, are our urologic oncology colleagues because getting that tissue is important. And as you mentioned, there are sites that may be more challenging than others. I agree with you. We can get good core needle biopsies from lymph nodes, from liver, from the bladder, etc. A good transurethral resection by our urologist can yield a very nice, and sometimes the most robust, piece of tissue. We are more challenged, though, when we start talking about lung metastases, where perhaps due to location or concomitant emphysema, we end up with smaller tissue specimens. And then the bone is particularly challenging because the process of decalcifying the bone often leads to reduction in RNA and DNA. So once bone is decalcified, we have destruction of what we're trying to look for. Getting that optimal tissue from the bladder, lymph nodes, liver, and well-located lung nodules in a patient without emphysema can be most helpful in achieving the diagnosis. Additionally, it can make a difference based on where the tumor is and how easily we can detect the mutation. I know we've talked about FGFR3 since we have FGFR3-targeted therapy. We've talked about PD-L1 expression levels, how they may fluctuate, and how they're sometimes used in urothelial cancer, but not really used in most patients with urothelial cancer. Are there any other biomarkers that you feel look promising for our patients with urothelial cancer?
Scott T. Tagawa, MD, MS, FACP: Yes, I would say that there are additional, mostly genomic, biomarkers. Some of them will be grouped, for instance, if you look at TCGA [The Cancer Genome Atlas] subsets to put them into categories, and some of them are more specific; they may not be quite prime-time today, but they may be helpful in the future. Some of them are taking a drug that may be already approved in another cancer, and then we're studying it in urothelial cancer. There's a lot of back and forth, for instance, between lung cancer and urothelial cancer. It's one of the reasons I will always advocate for panel testing when it’s available, rather than single gene testing. However, I don't really know of a case, at least in our country, where panel testing is not available if the single gene test is available. I realize there may be some issues in terms of insurance coverage. Luckily, what I have found, at least here in New York, is that sometimes, some of the platforms don't go after we do in-house testing. But, if I'm sending out, many of the platforms don't go after copays, at least. But in diseases, such as urothelial carcinoma, where there is a validated biomarker, such as FGFR3 alterations, billing for that test in the overall panel basically pays for the panel itself. And we first identified this in lung cancer, so if we're looking for EGFR, or RAS, or ALK, just obtaining the financial money from those testing. The rest of it comes for free. Different commercial panels are going to do it differently, but overall, it's not that much more expensive to do a panel than it is a single gene.
Transcript edited for clarity.