Julio Pow-Sang, MD, discusses the significance of assessing risk status, options for patients with prostate cancer whose risk status falls in a "grey-zone," and how technology is helping oncologists more accurately characterize risk.
Julio Pow-Sang, MD
Determining whether a patient with prostate cancer has low- or intermediate-risk disease is a significant distinction to make, as the 2 subsets are managed quite differently, explains Julio Pow-Sang, MD.
OncLive: Please provide an overview of your lecture on the options for patients with low- and intermediate-risk disease.
In a lecture at the 2016 OncLive State of the Science Summit on Genitourinary Cancers, Pow-Sang, MD, chair of Urological Oncology at Moffitt Cancer Center, discussed the significance of assessing risk status, options for patients whose risk status falls in a “grey-zone,” and how technology is helping oncologists more accurately characterize risk. He expanded on these topics in an interview with OncLive during the meeting.Pow-Sang: The goal is to clarify the distinction between risk groups with localized prostate cancer because that drives a lot of the decisions in management. One of the fortunate things happening is that, with better molecular testing and imaging, one is better able to characterize the tumors. Traditionally, cancers that were localized—specifically in prostate cancer—were divided into organ-confined cancer, localized cancer, and locally extensive cancer. That was the extent of the stratification, and it was very difficult to determine what treatment to give.
As we learned more and imaging [evolved], we were able to define better risk categories. The most traditional, modern one is the D’Amico Classification System, which divides localized cancer into low, intermediate, and high risk. When we are talking about low and intermediate risk, that classification blurs a little bit because there’s an overlap between low and intermediate groups.
More importantly, at present, one of the main options for low-risk patients is to do active surveillance. Initially, the sophistication of the testing to determine that a man was really truly a low-risk patient was very rudimentary. There was an approximate 30% chance that, with further testing, the patient was actually an intermediate-risk one. That was critical because intermediate-risk patients are more likely to have cancer spread and, eventually, die from their cancer. Therefore, they need treatment. That would be the general recommendation.
What are some of the key considerations for oncologists when treating patients?
We also recognize that there is a subset of men who have cancer and are never going to have problems for the rest of their life—and they start dying from something else. Newer tests and a better understanding of the behavior of the cancer have helped us determine who those men are versus the ones who might need treatment.One of the most important things is to define—as best as one can with the technology available—what risk that the man really falls into. That’s going to drive the discussion about potential management options—whether active surveillance is an option or not. If one defines that the man [has] very low-risk disease, one could feel very comfortable with watching that person and explaining the reasons why.
You mentioned the technology that’s available today. How can this technology be improved?
When dealing with an intermediate-risk patient, we start moving into the area of truly intermediate, high-intermediate, or even going into the high-risk territory—in which one might have to consider clinical trials because conventional treatments are not very good, or one might try to consider more aggressive local treatments, or a combination of treatments.We have very good technology [now] compared with what we had only 5 or 10 years ago, and it keeps improving. The big push now is to better characterize the tumors by molecular markers. There are several available. There are sets of genes that one can test for and then better determine the behavior of the cancer into the future. One big field is molecular markers of different types; they are tissue, urine, or blood-based markers.
What research questions do you think can or should still be answered?
The other big field is related to imaging. Until several years ago, we didn’t have a good way to assess for the cancer when it was very early. There is now technology with MRI that allows us to better define the tumors and, in many cases, help with the distinction between low and intermediate risk. We think the intermediate-risk [category] can be even better defined whether one is an intermediate “low,” “medium,” or “high.” There is more of a precision in characterizing the tumor so one could make better decisions with management.The main research question with localized prostate cancer is [determining how] to get a better definition of which men would be safe with active surveillance. Secondly, in men with intermediate-risk disease, there are a subset of men who are traditionally called intermediate; however, they have more probability of cancer progressing and not responding to local treatment. It is likely that upcoming improvements in technology and molecular testing are going to help define that.
The other big research question concerns the [role] of focal therapy. Within the armamentarium for local treatment, there is a treatment called focal therapy. Here, the cancer is only [in] one area of the prostate; an oncologist only treats that area. This is what one would compare with women—many years ago—with breast cancer in which one had the concept of radical mastectomy.
As the years went on and there was more knowledge, many of these women would be treated with a lumpectomy—with removal of part of the breast. The concept is similar, in which one may now characterize men who have what is called local disease. If I could use an expression, prostate cancer—in the majority of cases— is “peppered” throughout the prostate, so the whole prostate has to be treated.
In some cases, the cancer is localized to half of the prostate or a quarter of the area. There is technology, which is pretty reasonable, to determine if that is the case. In men who have intermediate-risk cancer—not the ones who are a candidate for active surveillance—we could treat that subset of men with focal treatments.
There is a technology called high-intensity focused ultrasound, and there is a lot of talk about it. It was just approved last year by the FDA to treat prostate conditions. Also, there is an old technology called cryosurgery; there is laser, and there are types of radiation therapy that can be used to focally treat the prostate if there is an indication that the cancer is in only one area of the prostate.