Seungtaek L. Choi, MD
Researchers have long debated whether surgery or radiation therapy (RT) is a more beneficial treatment method for locally advanced prostate cancer. Seungtaek L. Choi, MD, says both are good options, but that there are definitely some patients who are more likely to benefit from RT, and researchers are exploring new approaches to enhance the benefit of the treatment.
“We are trying to figure out how to give RT better,” says Choi, an assistant professor in the Department of Radiation Oncology, and clinical Medical Director, Department of Genitourinary Medical Oncology, Division of Radiation Oncology, The University of Texas MD Anderson Cancer Center. “More and more physicians are giving stereotactic body radiation therapy (SBRT) in the high-risk and maybe the locally advanced prostate cancer population, although that’s difficult because as soon as you need to treat more outside the prostate with these high doses, you might be increasing the risk of side effects, too.”
Combination approaches are also being explored to enhance the impact of RT, including regimens adding RT to chemotherapy, targeted therapy, and immunotherapy.
In an interview during the 2017 OncLive®
State of the Science Summit on Genitourinary Cancers, Choi discussed the latest developments with RT in prostate cancer.OncLive: What were the highlights of your discussion on RT in prostate cancer?Choi:
The main points would be that RT is an effective method for treatment for these locally advanced cancers. These patients tend to have poorer outcomes. When you look at RT, we are getting better in terms of improving the treatments with better techniques as well as a lower risk of side effects. We still have a ways to go, but we are definitely trying to improve things by improving our treatment. How have you seen RT evolve over the years and make a mark in this disease?
The biggest change I have seen is that the treatments have evolved to have more doses to the prostate or to the cancer. There is definitely less dose to the rectum and the bladder and I’m seeing a decreased risk of side effects.
That is what we see first. Unfortunately, with prostate cancer, it takes us a long time to see the actual cure rate. For RT, we have to wait at least 5 to 7 years to make sure we really cured the patients. However, the side effects often occur in the first 2 to 5 years, so you sort of see the side effects first and then you see the effect on the cure rate.
We have seen less rectal and bladder irritation. The risk of urinary incontinence with RT is very low—it’s usually less than 1%.
Overall, the patients have done very well. Now, we are beginning to see the patients are also cured of their cancer with very low prostate-specific antigen (PSA). When I started doing this almost 11 years ago, the PSA almost never went to 0 with RT. With surgery, you see the PSA goes to 0. With RT, it comes near baseline, but now with the higher-dose and more accurate RT delivery, the PSA is going to 0. We are doing a good job of eradicating the cancer in the prostate. What are the considering factors for patients to receive RT for their prostate cancer?
I get that a lot. Patients often ask me, “Which treatment should I get?” Unfortunately, a lot of the patients have multiple choices. In fact, I always tell patients, “I have good news and bad news. The good news is that you have a lot of good options; the bad news is that you have to pick which one.”
However, for most patients, both surgery and RT are good options with a very high chance for cure and low risk for side effects. However, there are definitely some patients who are more likely to benefit from RT. These are the ones who have medical problems—so patients with heart disease or risk over anesthesia or surgery itself. Some other patients who might benefit better are the ones who have very aggressive disease that they might undergo RT anyway even if they had surgery. It is controversial whether RT by itself is [less effective] than RT plus surgery.
We are getting into an era of when we start talking about multimodality therapy— where we need surgery followed by RT to get the best cure rate. I am not completely sure that you need that surgery; RT by itself might be fine. In the end, in some patients, RT might be better to cover the area outside of the prostate without needing surgery.
There are some side effects that some patients want to avoid. Urinary incontinence is a risk factor with surgery and is not with RT. People say RT can cause incontinence, too, but in modern day it is very uncommon. In my practice, it is less than 1%, which means that it’s not really an issue. If that is the side effect they most want to avoid, than RT is better than surgery. Are there any combinations with RT being explored currently?