Saturday, January 27, 2007

An encouraging article

"The PSA disease-free survival after salvage radiation for all patients is approximately 25-40% at five-to-ten years after radiation.7,8 Favorable patients (PSA less than 2.0, Gleason score less than 8, positive surgical margins) may experience PSA diseasefree survivals of 60-70%.8"
Sailer, Scott L. "Radiation Therapy for Prostate Cancer: External Beam, Brachytherapy, and Salvage" North Carolina Medical Journal. March-April 2006, p. 152.

Since I'm in the "favorable patients" category (PSA 0.7, Gleason 7, positive margins) I'm in the 60-70% 5-10 year disease-free survival group. I'll take those odds. Before meeting with my oncologists, I had thought my margins were negative and my odds were much worse. (To clarify this--usually you would think negative margins are a good thing, because it means there was no cancer found at the cut edge of the removed tissue. However, when you are trying to figure out whether your recurrence is localized or not, it can turn things in your favor to have positive margins. Why? It provides a logical explanation for the increased PSA. It means there was an increased chance cancerous cells were left behind in the prostate bed, and if that's where your PSA is coming from, rather than distant sites, your PCa may still be curable.)

Sailer also says:
If a patient’s PSA does not initially decline to zero, he likely had occult metastatic disease at diagnosis and would not benefit from localized radiation, unless the source of the residual PSA is a positive margin and the Gleason score less than 8.

Well, my PSA was below 0.1 initially, but who knows what it would have been on an ultrasensitive test? .06? .07? I would say that it's likely my PSA did NOT decline to zero initially, and I would have likely had metastatic disease (or maybe more properly "systemic"), BUT I have positive margins--which gives a possible explanation for the PSA--and my Gleason was less than 8. Sailer is restating my earlier pessimism--when I thought I had negative margins, I figured the cancer was out of the barn. With negative margins, where would my PSA be coming from? Distant sites? Very possible. As I wrote above, normally positive margins=bad and negative=good..except when you're evaluating a rising PSA after surgery and trying to figure out whether or not salvage will work. With positive margins, it increases the probability that my problem is still local. Again, no guarantees. But I'm much happier to be in the 60-70% likely to have durable benefit or cure rather than in the 10-20% probability of durable benefit.

And remember, if you're having a recurrence after surgery--you're a unique human being, not a statistic. These are probabilities only. An acquaintance of mine had similar circumstances--PSA rising rapidly after prostatectomy--but he had negative margins. Nevertheless, he seems to have received a benefit from radiation--his PSA dropped from 0.5 before radiation to 0.01 afterwards. That's very encouraging--and against the known probabilities. Hopefully he's cured. He didn't have IMRT, like me, but proton beam therapy at Loma Linda University Medical Center.

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