Erik P. Castle, MD
The prostate cancer paradigm continues to evolve with emerging treatment and imaging modalities, but risk stratification is the key to creating an appropriate management strategy—even between very low-risk and low-risk patients, explains Erik P. Castle, MD.
Various factors come into play when deciding whether such patients should undergo active surveillance or active treatment, he adds, including age, biomarkers, and family history.
“It is very important to keep the best interest of the patient at heart,” said Castle. “Take all of the factors into consideration, use that information that we can draw from in a very intelligent way, and educate our patients to give them the best treatment.”
In an interview during the 2018 OncLive®
State of the Science Summit™ on Genitourinary Cancers, Castle, consultant, Department of Urology, professor of urology, Mayo Clinic, spoke on the importance of risk stratifying low- and intermediate-risk localized prostate cancers.
OncLive: Please provide an overview of your presentation.
I spoke about risk stratification for both low- and intermediate-risk prostate cancer, primarily clinically localized cancer. This is the kind that one might be trying to decide whether you’re going to pursue active surveillance or some sort of definitive treatment. You can even sub-stratify low risk into very low-risk and low-risk disease.
The talk was an overview of the standard stratification techniques or approaches using different modeling and scores that are out there and available, but it focuses on the evolving use of biomarkers—and even imaging nowadays—when managing patients with newly diagnosed prostate cancer.
Active surveillance rates have increased in recent years. What can be done to further increase these rates?
It’s important to understand that there is a very big difference between very low and low risk. For very low risk, regardless of what the life expectancy is—unless it’s over 20 years—active surveillance is absolutely the preferred and recommended management. While active surveillance is recommended for low-risk disease, that’s also with the nuance of utilizing age, life expectancy, and patient factors to help make that decision. Therefore, we can do a lot more with active surveillance and increase the utilization of it if we do a better job of not only stratifying our patients, but knowing what their expectations are and educating them with what to expect with these low-risk and very low-risk cancers.
However, that is not to say that there isn’t a role for treatment, even in low-risk prostate cancer—particularly in a 50-year-old man who has a strong family history for prostate cancer-mortality or has good functional status, and we know that risk in his lifetime is developing significant cancer.
Have you ever a treated a patient in that particular scenario?
Absolutely. For young men with prostate cancer, I usually recommend treatment. The reason I say that is we use different terminology nowadays. We don’t say “prostate cancer screening,” we say, “the early detection of prostate cancer.” This means we are trying to identify patients who truly are at risk of death or suffering from their disease.
One of the biggest risk factors is young age and diagnosis. If a man is diagnosed at a very young age, we know that he is at a significant risk in the span in his life of having issues with the disease—so we tend to treat them more. While active surveillance is still appropriate, what it ends up being is delayed intervention. Therefore, we are trying to preserve a young man's functional status from an erectile function standpoint, but still balance that with the risk of monitoring this cancer. Utilizing these new biomarkers and newly developed imaging studies and approaches are very useful in these patients to help us decide how aggressive we need to be, and when to be aggressive.
What are some staging modalities for patients with high-risk prostate cancer?
High-risk prostate cancer, for the most part, is going to be treated unless the patient has a life expectancy that is less than 5 or 10 years. In those patients, there isn’t as much out there besides standard imaging, which would be a CT scan and some sort of bone imaging.
We are now moving away slightly from classic technetium-99 bone scan and using sodium fluoride and PET imaging. There ae some new PET imaging modalities such as PSMA-PET that has yet to be fully FDA approved. Choline C-11 PET scan is available at Mayo Clinic for patients who have been treated for high-risk prostate cancer and have had a biochemical recurrence. Then, there's 18F-Fluciclovine PET/CT.