Understanding the Decipher Prostate test and its role in cancer care
Having an understanding of the unique biology of your prostate cancer can help you and your care team make more informed treatment decisions. Genomic tests like Decipher provide deeper insights by analyzing the expression of certain genes within the tumor.
We asked Dr. Atish Choudhury at Dana-Farber Cancer Institute and Dr. Hardeep Phull at Palomar Health during recent “Ask the Expert” webinars to share how they incorporate these tools into their own clinical practice. See their answers below.
The following questions and responses have been lightly edited for grammatical purposes.
1) What is the Decipher Prostate test?
Dr. Atish Choudhury: There are three approved gene expression tests for prostate cancer. One is called Decipher, one is called Oncotype DX, and one is called Prolaris. Basically, these are molecular tests to look at the gene expression within the cancers because it turns out that the pathology is very good at telling us how aggressive the cancer has the potential to be. These molecular tests can provide some additional information. More aggressive kinds of cancers will express certain kinds of proteins in what we call the cell cycle, cell growth, and cell spread, things along those lines, and less aggressive cancers will express fewer of those genes.
Dr. Hardeep Phull: Decipher is a wonderful genomic test that basically determines what’s the risk of prostate cancer spreading? What’s the risk of death from prostate cancer? It measures about 22 genes to calculate a score and the score is usually used to help people go into three categories: low, intermediate, or high. So, how does that help me if I get a Decipher? What does it do? It helps me look at the risk of this prostate cancer. What is it doing molecularly? I don’t care about the PSA and the absolute number. What is it doing on a genomic cellular level? What are the risks of metastases, death, and survival from it?
2) How do you interpret Decipher test results and how do they guide treatment decisions?
Dr. Atish Choudhury: How do we use these scores clinically? It’s a little bit challenging because we don’t have a lot of clinical trials to tell us that changing our management based on these gene expression scores actually improves patient outcomes. What we basically consider these to be are adjunct pieces of information that suggest within a particular Gleason score, is this a more or less aggressive version of that kind of cancer? Clinically, I use it for certain kinds of decisions. For example, if somebody has what we would call a favorable intermediate risk cancer and a patient is deciding between watching it or getting treatment on the sooner side, sometimes I will order a test like that to get a better sense of whether this is an aggressive kind of favorable intermediate cancer. In that case, we might recommend sooner treatment, but if you send that kind of test and there’s a low score, I might say, “Okay, well, this is something that we might reasonably watch.”
So the difficulty is when there’s some sort of disconnect. For example, if there’s a Gleason 6 cancer, but there’s a high Decipher score, should we then change our recommendation from surveillance to treatment? That really hasn’t been demonstrated in clinical trials, so I would say that a higher Decipher score might suggest that the patient might transition to a higher grade cancer somewhat sooner than patients with a low Decipher score. It wouldn’t necessarily exclude them from surveillance completely just based on that specific score.
The other side is what if there’s a high Gleason score but the Decipher score is somewhat low? Again, the Gleason score is a very good prognosticator of outcomes from prostate cancer. For example, if you’re going to do radiation and hormonal treatments for at least a 9 or 10 cancer, the common recommendation is to treat with the hormonal drugs for about 18 to 36 months. I probably wouldn’t change that recommendation based on a low Decipher score. If somebody did have a low Decipher score, I might lean more towards the 18-month side rather than the 36-month side. So it’s a tool, it’s an adjunct, but it probably shouldn’t change our management based on the absence of clinical trial data that suggests that changing our clinical management actually benefits patients.
Dr. Hardeep Phull: For me and other doctors like radiation doctors and neurologists, it helps us assess risk level. Would this patient in front of me benefit from androgen deprivation? What is the risk after taking out the prostate if we did a prostatectomy? What is the risk with radiation? Could we just do surveillance alone? It’s a little more sophisticated way of stratifying patients and doing a little more digging and thinking about what the risk level is.
I’ll tell every patient this. A risk level on a piece of paper is not the same as the risk tolerance level of the individual in front of you. It is so important to advocate for the person in front of you. So if someone in front of you is very scared of surgery or says to you, “I want to monitor this. I’m okay with some risk.” Well, you take on that risk with the patient. You lift them up and say, “I’ve got you. I’ll help you with that goal.” Whereas if someone, even low risk, says, “I am scared. I want this prostate out. I understand the risks of that. Can you please get me through that so I feel better at night and sleep better about it?” Absolutely. That’s my goal. We have these tools, but it’s important to realize they’re just tools or guides. You still have to help reflect what the individual wants.
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