Guest: Dr. Harry Clarke – Urology
Host: Dr. Linda Austin – Psychiatry
Dr. Linda Austin: I’m Dr. Linda Austin. I’m talking, today, with Dr. Harry Clarke who is Professor of Urology and an expert in the treatment of prostate cancer here at MUSC. Dr. Clarke, in an earlier podcast we talked about some of the open surgical procedures for taking care of prostate cancer, where you do larger incisions, I suppose, one could say. I know, though, you are also an expert in the area of cryosurgery for prostate cancer. Can you describe what that is, please?
Dr. Harry Clarke: Certainly. Cryosurgery is a minimally invasive treatment where small needles, approximately 17-18 gauge needles, are passed through the skin, into the prostate, and under direct visualization with ultrasound, transrectal ultrasound, very similar to what we use when we do the initial prostate biopsies, we image the freezing of the prostate. A catheter is put in the urethra to warm that and a warming solution, in a closed system, is run through that to keep the urethra from freezing and to preserve the blood supply to the urethra. Then, 8-10 needles are placed into the prostate so that the entire prostate is completely frozen, and this is brought down to lethal temperatures, which is -40 degrees. Actually, cell culture lethality would be around -20. But, because there’s a blood supply to the prostate, we bring this down to about -40 degrees, and that destroys the tissue.
The question that’s often asked of me by patients is, what happens to it after that, if you freeze it and the tissue is dead, what happens to it? Basically, the tissue is replaced by collagen which is what scar tissue consists of, so it’s much like a scar or a scab that you would have on the surface of your arm, or if you skinned your knee. Over time, that is reabsorbed and the volume of the prostate, if you were to look at it with imaging, say, six months or a year later, would be reduced by about 30 percent. So, it would be about a third smaller.
The freezing, as I said, is stage-for-stage for every type of prostate cancer, just as effective as surgery or radiation. One of the drawbacks with freezing the prostate, and the reason that not everyone’s coming in to get their prostate frozen, is, when we freeze the prostate, we freeze the nerves, which are also on the side of the prostate, which support erectile function. So, patients concerned about maintaining erectile function would want to avoid to avoid this form of therapy. The classic patient that this is an invaluable treatment for is a patient who has already had prostate cancer treatment with the other minimally invasive treatment, that we can talk about in another podcast, brachytherapy, the implantation of radioactive seeds or, in fact, external beam radiation therapy.
In either of those cases, a patient may have a very good response to the radiation and then, some years later, the DSA may be going up and, on a biopsy, we find that there’s recurrent or persistent disease in the prosta