Expert Discusses Biomarker Development in Prostate Cancer

The field of prostate cancer has been transitioning with the identification of novel biomarkers. However, physicians are now facing a new challenge: which one is best appropriate for their patients?

Leonard Gomella, M.D., recommends that healthcare providers familiarize themselves with how each biomarker should be used and then decide which one to use — a more individualized approach in clinical practice.

In an interview with CURE, during the 10^th Annual Interdisciplinary Prostate Cancer Congress, Gomella, professor and chair, Department of Urology, and director, Kimmel Cancer Center Network, Thomas Jefferson University, discusses the future of biomarkers in prostate cancer.

Can you give an overview of your talk on biomarkers in prostate cancer?

Gomella: Biomarkers in prostate cancer is a very rapidly evolving field. We’re seeing new markers for prostate cancer almost on a weekly or monthly basis. Right now, biomarkers for prostate cancer fall into two general categories: biomarkers that are used for the biopsy and initial diagnosis of prostate cancer, and biomarkers that are used after the diagnosis of prostate cancer.

In the first case, we primarily have new blood and urine tests that are out there to help us decide who may or may not have prostate cancer and who may or may not need a biopsy. In the latter case, after we make a diagnosis we have genomic tissue markers that allow us to be more clear on what the best treatment might be for a patient, either active surveillance or active therapies, such as radical prostatectomy or radiation therapy. And lastly, for patients who have had radical prostatectomy, we have biomarkers to help us decide if those with adverse pathology need more treatment, such as radiation.

Right now in prostate cancer, a lot of it revolves around what we call the somatic markers in the tumor to help us guide treatment. We have a whole different class of biomarkers now, both genomic and basic tests, such as the SelectMDx, 4Kscore test, the PHI (Prostate Health Index) test and other blood and urine tests, to help us with the decision for the initial biopsy.

With so many new biomarkers available, what are the challenges?

With all the biomarkers, the challenge is which is the best one. There are so many out there, and I think it’s up to the individual provider to start to work with one or two of the biomarkers and decide if they work well in his or her hands.

There are not a lot of comparative trials out there right now with the different biomarkers, either the standard blood and urine test, or the newer genomic assays on the tumor. We don’t have head-to-head comparisons, but the ones that are approved by the Food and Drug Administration (FDA), such as the PHI test, which is approved for the screening of the initial determination if someone needs a biopsy, doctors just have to start using them and decide which one works best.

Since there are not a lot of clinical trials ongoing in this area, what do you envision for the future of biomarkers in prostate cancer?

The future of biomarkers is going to be tough in the absence of clinical trials. There are a few centers that are doing some head-to-head comparisons. The FDA has the burden on them right now to approve these markers, and once they get approved, it’s going to be in your hands to decide which one works the best. Absent of these clinical trials, I think it’s going to be very challenging going forward as more biomarkers become available.

Let’s face it, we’ve had many biomarkers over the last 10 to 15 years that have come and gone because, although they got FDA approval, when they got out to the real world of patient care, the providers did not find that they helped in their decision making. Each new biomarker is going to have to stand on its own and I think once they get FDA approval, the marketplace is going to decide if it’s a good test, or ‘you know what, when I use this it doesn’t help me that much’ — it’s like flipping a coin. So again, each biomarker is going to have to stand on its own. The papers are all based on clinical trials and very defined populations, so once they get out into the day-to-day practice of urology and screening and diagnosis of prostate cancer, that’s where they will either live or die.

How can urologists best decide which biomarkers to use?

You have to first look at what the biomarker is approved for. Some biomarkers are approved for that initial yes or no decision making for biopsy. Other biomarkers are approved after the diagnosis is made for deciding whether you follow this patient with a less aggressive approach, such as active surveillance, or if they need some type of active treatment. The decision making has to be put in the context of what you’re doing with the individual patient.

The important thing is that any provider, whether it be a urologist, radiation oncologist, or medical oncologist, should be familiar with the different assays that are out there and understand that it’s not one-size-fits-all. They often have very narrow FDA labels for how they should be used.