COMMENTARY

Salvage Radiation Post-Prostatectomy: Where's the Evidence?

Gerald Chodak, MD

Disclosures

May 26, 2011

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Hello. I am Dr. Gerald Chodak from Medscape. Recently Cotter and associates[1] published a paper looking at the effect of salvage radiation in men who failed radical prostatectomy with a rising prostate-specific antigen (PSA). They have long-term data that showed a significant improvement in survival. The question is whether that information is reliable enough to make recommendations.

First let's look at the study design and then the results. These patients were enrolled from Duke University and underwent surgery between 1988 and 2008. Of the more than 4000 men who had surgery, about 520 had a rising PSA. The radical prostatectomy also included a negative lymph node dissection. All the men who were enrolled had a PSA nadir of 0.2 ng/mL and at least 2 increases in their PSA levels.

The treatment for a rising PSA consisted of the following:

  • Some men received no treatment while others received radiation therapy alone (usually 66 Gy);

  • Some men received radiation simultaneously with androgen deprivation therapy or eventual androgen deprivation therapy if the PSA increased again; and

  • Some men received androgen deprivation therapy by itself.

The hormone therapy consisted of medical or surgical castration alone, antiandrogen therapy, or a combination of the two. There was no standardized approach.

What did the study show? First, salvage radiation was associated with a higher overall survival. The benefit occurred for men whose PSA doubling time was less than 6 months or greater than 6 months and in men who also had cardiac morbidity at the time of their treatment.

Let's talk about the strengths and weaknesses that were associated with this study because there were several limitations. They are shown on the following slide. First, it was a retrospective analysis. Second, hormone therapy was variable in how it was administered, its duration, and what were chosen as the starting and stopping points. The investigators only considered 1 major comorbid illness, which was cardiac disease, but other comorbid illnesses could have been present that might have greatly affected the results. Furthermore, 17% were missing comorbidity data and 25% of the men were excluded because of missing information at the time the study was done.

So, where does this leave us? Does the information provide enough data or support to recommend to our patients that they receive hormone therapy? The investigators point out that this is only a retrospective analysis and can only generate hypotheses, but they also claim that it's the best follow-up information we have to date. So, the question then becomes: can we make recommendations on the basis of this trial? I think the answer is no, not really. It's interesting information that can be discussed with patients but it is by no means strong enough information that would allow us to say all men would benefit by getting salvage radiation. Only a prospective randomized trial will allow us to determine that, and so far it's not clear that any such study is in progress. We are left with the information we have from a randomized trial that some men do benefit by getting immediate or adjuvant radiation if they have high risk factors. For those who don't choose radiation but their PSA goes up later, I don't believe that this study provides good enough support to make strong recommendations for patients to get salvage radiation going forward.

I look forward to your comments. Thank you.

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