Dr. John Gore is a clinician, surgeon, researcher, and educator specializing in urologic oncology and general urology at the University of Washington.
Prostatepedia spoke with him about how Decipher changes the way doctors treat men with prostate cancer.
What is Decipher?
Dr. Gore: Decipher is from a family of genomic tests. In general, it tries to look at some of the alterations in people’s genes associated with cancer or its progression. Decipher attempts to create a panel of genes associated with the likelihood of a cancer coming back. It takes that panel of genes and integrates it with clinical information to calculate the risk of developing spread of cancer to sites that could be detected clinically, like the bones or the lymph nodes, within five years after prostate cancer surgery.
When is a man likely to encounter this test? After that initial biopsy when he is first diagnosed? After his prostatectomy?
Dr. Gore: The most common scenario would be after surgery. If a man has his prostate removed and the pathology shows that he has a cancer that by all accounts seems to have been successfully treated with the surgery, Decipher may not be the right test for him.
If he has some high-risk features— his cancer is potentially encroaching on the shell of his prostate, he has a positive surgical margin, or there is involvement of the seminal vesicles that sit behind the prostate—then he might benefit from Decipher.
That way we can ask if—in addition to knowing that he had some high-risk pathology features—he appears genomically to have a high-risk cancer?
What do the results look like? Do they change how a man is going to be treated post-surgery? How?
Dr. Gore: The actual report that a patient or doctor gets tells them the probability, or percent risk, that he will have clinical metastases within five years of having his prostate removed for prostate cancer. In general, those numbers tend to be in the single digits to low teens. It’s not a common event.
For most people, prostate cancer surgery successfully treats their cancer. That is why this is best used on higher-risk individuals.
In our study, we looked at a cadre of patients who were either found to have high-risk features at the time of their prostate cancer surgery, or now their PSA is subtly rising after going to zero after surgery. Those patients should potentially have more aggressive treatment.
We showed that if a patient had the Decipher test, physicians’ recommendations changed. If your Decipher results showed a lower risk score, your doctor was more likely to recommend observation.
Patients with a higher risk Decipher score were more aggressively treated. They were recommended to go ahead and get additional radiation to the area where their prostate was removed, rather than just active surveillance.
The bottom line is that Decipher changes how men are treated?
Dr. Gore: Yes. We have some follow-up data we just presented at the American Society of Clinical Oncology, Genitourinary meeting in February that showed that those treatment recommendations were actually followed 80% of the time.
You said only men who are high-risk should really be tested. Not everyone getting prostate cancer surgery needs a Decipher Test?
Dr. Gore: That’s right.
Is Decipher widely accepted in the medical community? If a man in rural Minnesota goes to his local urologist or local community oncologist, will he likely be offered the Decipher Test? If not, should he ask his doctor to order it?
Dr. Gore: I think it’s definitely worth requesting it. One thing that has come up is insurance payer coverage, not just for the Decipher Test, but also for other tests like it. The bar that some of these companies have to cross to get their test approved is fairly high.
Some insurance companies are asking if the test not only changes treatment for patients. The trial they’re looking for will compare patients who got the Decipher Test with patients who didn’t to see if the decisions that were made impacted cancer outcomes. If, for example, your Decipher results say you’re high-risk, and you get radiation based on that information, was that the correct decision? The challenge is that prostate cancer is immensely slow-growing. Even when it’s high-risk, even when it’s aggressive, we’re talking about clinical outcomes that take years and years to manifest. It imposes an irrationally onerous burden to prove that these tests are the right thing.
You could wait 10 years to find out if the treatment decisions were correct. Meanwhile, time is passing and these men need to make choices…
Dr. Gore: Absolutely.