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When Should Patients Get Radiation Therapy for Prostate Cancer?

Common practice has been for prostate cancer patients to delay radiation therapy after having their prostate removed.

However, new research from a UVA radiation oncologist is upending this commonly held belief.

When Should Patients Get Radiation Therapy for Prostate Cancer?
Featured Speaker:
Timothy Showalter, MD
Dr. Timothy Showalter is a board-certified radiation oncologist whose specialties include prostate cancer.

Learn more about UVA Cancer Center 


 
Transcription:
When Should Patients Get Radiation Therapy for Prostate Cancer?

Melanie Cole (Host):  Common practice has been for prostate cancer patients to delay radiation therapy after having their prostate removed. However, new research is upending this commonly held belief. My guest today is Dr. Timothy Showalter. He’s board-certified radiation oncologist whose specialties include prostate cancer. Welcome to the show, Dr. Showalter. Tell us a little bit about this. If they’re delaying receiving radiation therapy after having their prostate removed, why is that and what’s changed? 

Dr. Timothy Showalter (Guest):  Well, first of all, thanks for having me. It’s great to be here. The area of postoperative radiation therapy for prostate cancer is an interesting and very challenging one. There were years ago clinical trials that showed that there was a survival advantage to adding radiation therapy for men with advanced prostate cancer after surgery. Those studies were conducted before we had the PSA blood test, which really changed the way we treat prostate cancer patients. Over time, a lot of clinicians have opted to not offer immediate radiation therapy after prostatectomy with a few goals in mind. One is that some of the patients can be followed with the PSA blood test over time and may end up never having their prostate cancer return. It’s kind of nice to avoid radiation therapy in those patients. The other reason is that there has been a long-held fear in the urology community and in the radiation oncology community that earlier radiation has a higher rate of side effects or complications for urinary function and for sexual function as well compared to delayed radiation. What we found in our recent research is that the latter point about the effect of radiation timing on ultimate complications from radiation therapy just isn’t true. 

Melanie:  Wow, that’s really good news for men. I mean, because so many men, Dr. Showalter, worry that due to radiation and any other treatments. When they hear prostate cancer, they think of sexual dysfunction, they think of incontinence and these side effects. What do you want them to know about the findings of these studies and what they can look forward to in the future?

Dr. Showalter:  I think if you’re a man in that situation and your urologist or radiation oncologist has talked to you about the option of doing radiation therapy, I would say first off that if you have more favorable features, for example, a low Gleason score or very low PSA, I think it’s perfectly fine to not rush in to radiation treatment. If, on the other hand, you got a high Gleason score and your urologist has mentioned that you are high risk for progression, I think for those men, it’s pretty clear that timing does matter in terms of cure rate. That earlier radiation therapy is more effective. The recent research is reassuring to men like that, because the research is basically saying, “Hey, if the radiation therapy is offered early when it’s most effective, it’s not going to increase your risk of complications,” because ultimately, these men will need radiation anyways. 

Melanie:  The question I asked you at the beginning, Dr. Showalter, was for patients receiving radiation therapy, after having their prostate removed. What about those who opt not to have it removed? Is that changing in the landscape of prostate cancer today?

Dr. Showalter:  Well, the technology has really changed prostate cancer radiation therapy for men with intact prostates who have not opted for surgery. There are a number of new options for those men as well. In the past 15 to 20 years, we’ve seen a number of incremental gains in the way we line patients up and track the prostate gland during radiation treatment and in the way we deliver radiation therapy, and they’ve culminated in giving more focused radiation that’s safer for patients and causes less collateral damage, having better cure rates by giving a higher radiation dose. Then more recently, offering radiation treatment over a shorter time schedule, for instance, a stereotactic body radiation therapy has been one advanced and external beam radiation therapy, where we’re now treating men with radiation schedules as short as five treatments. That’s opposed to the traditional approach of eight to nine weeks of treatment. 

Melanie:  If patients opt not to have their prostate removed and they do have these radiation treatments, maybe hormone treatments, any of the other treatments out there, how do you keep track for them? How do they know it’s not going to recur? Because having their prostate removed feels like it would be a safer bet but less and less men are choosing that now, so how do you tell them “We’re going to keep track, we’re going to keep a watch”? 

Dr. Showalter:  Well, first off, it’s helpful to sit down with patients and run through the actual numbers for available clinical trials and, of course, as you know, there’s a ton of prostate cancer research that comes out every day. It’s a herculean task to keep up with all of the new clinical research that comes out each month in the medical journals. The first thing I do is sit down and run the numbers and the reason why the national guidelines recommend either radiation or surgery is that both actually have the same cure rates and similar quality of life outcomes as well. It’s important that the patient realize that it really is a choice. Then in the follow-up period, it takes time to see the full response from radiation and for us to see the PSA blood test go as low as it’s going to go. It often takes a year and a half to two years of just following blood test. The number one way for us to check on patients over time is to continue to follow how their PSA blood test responds. The PSA blood test is a really good marker of radiation response and monitoring patients to make sure the prostate cancer doesn’t return. 

Melanie:  Give some numbers, Dr. Showalter. What do you want men to know about their PSA numbers? 

Dr. Showalter:  Well, there’s a lot of uncertainty and lack of clarity for the PSA blood test in the screening situation. In terms of diagnosing them with prostate cancer, there’s a whole lot of literature about what sort of PSA value should prompt the biopsy for example. The PSA test has been recognized to be not a great test in that situation, but it’s quite good in the after-radiation treatment. We generally see the PSA blood test go down to less than one or less than 0.5 within two years after receiving radiation treatment. That’s generally considered a good number and predict the patients will do well long term. For some of our high-dose radiation treatments including when part of our radiation is delivered with implanted radiation like brachytherapy or seed implants, we see PSA values go all the way down to undetectable, so below the sensitivity of the test. It’s just important to follow those numbers over time, keep an eye on the trend, and as we proceed, patients are generally reassured by those numbers.

Melanie:  That’s great information. In just the last few minutes, give a bit of a summary about the studies that upend these common views we’ve been discussing and why patients with prostate cancer should come to UVA Cancer Center for their care. 

Dr. Showalter:  First off, for the studies that we looked at, there were actually two reports that we published recently and this was in collaboration with some of my colleagues from Thomas Jefferson University as well. We looked at a total of 10,000 men between the United States and a separate cohort of men in a region of Italy as well and evaluated how men did in terms of major complications from treatment in terms of urinary, sexual, and gastrointestinal function. We did observe, as predicted, some increased risk of complications related to receiving radiation at all. But interestingly, the main hypothesis of the paper is that we did identify that earlier radiation did not increase risk of side effects. It’s highly reassuring for men who are contemplating jumping in with radiation. In fact, for some of the domains, earlier radiation actually had lower risk of complications than delayed radiation. Here at UVA, I think one of the benefits to being at a teaching hospital like the University of Virginia is that we have focused urologists and radiation oncologists who are very familiar with the latest literature and, for example, are aware of a research like this and can counsel patients in a detailed fashion about the latest research that may affect their treatment decisions such as the influence of treatment timing. 

Melanie:  It’s great information and we applaud you on all of your research studies. Keep up the great work. You are listening to UVA Health Systems Radio. For more information, you can go to uvahealth.com. That’s uvahealth.com. This is Melanie Cole. Thanks so much for listening.