I have decided (much like the New Years resolution…good luck!) to try and write a somewhat longer post each Friday for the amusement of my 4 readers. So this week, I will take on the issue of “what is best” for eliminating the prostate gland. If you are pressed for time, the bottom line here is that there are lots of techniques that work but the side effects differ. Also, for those with time crunch who want to jump to the “best data”, I recommend this article written a few years back by Dr. Martin Sanda. It is the best current article I know regarding side effects of the most commonly employed treatments: surgery, external beam radiotherapy and brachytherapy.
If you think about it, the idea of getting rid of tissue in your body is relatively simple. Cut it out, or use some energy source to cook or freeze the tissue. That said, I like to point out the old aphorism, “if it wasn’t for bleeding, we’d all be surgeons.” For that matter, one could just inject a very caustic chemical, like clorox, into the tissue. The problem then becomes restricting the approach to the targeted tissue while sparing surrounding tissue. As with any other organ, the prostate lies next to some pretty important normal structures, and this is where the challenge begins. Take a look at this picture series to orient yourself to the nearby critical structures like bladder, rectum, nerves, and bone. Now look at the real thing in this video. Finally, if you want to consider getting rid of the prostate with a radiation beam, look at this image and draw a beam through the prostate from any direction you want, remembering that the radiation will affect every thing in its path.
Since you are probably already very familiar with the standard surgical approaches to losing the prostate (robotic or open surgery) as well as the standard radiation approaches (external beam versus seeds), I will turn to the evaluation of “new techniques” for the remainder of this discussion. I was prompted to do this by several patients who asked about proton beam treatment and one who asked about HIFU this week. One clue: new is not always better.
Proton beam therapy has been around for a long time starting in the 1950’s. The physics of protons are different from photons (light, x-ray, gamma ray, etc) in that they deposit their energy after being “captured” by an atom deep in the tissue. Thus, higher doses of energy can be delivered more accurately to the prostate or other targeted tissue. However, the cost of setting up a cyclotron to generate protons for therapy is huge. There are places in the body (like the neck or brain perhaps) where the better “focus” ability of protons may make a difference. However, since prostate cancer is so prevalent, the centers that are being put in place do everything they can to use proton treatments as a marketing tool. Read this WSJ article for an honest look at what is going on. Just as you are likely reading this blog on a machine with much greater computing power than the one you had 10 years ago, the computers that control “standard” radiation therapy machines have improved to the point that it is not at all clear proton beam therapy offers any advantages. There are no randomized trials suggesting improved outcomes comparing the two techniques. Expert reviews agree with my viewpoint. My bottom line: I would not travel to a proton center to receive proton therapy and I would oppose my university purchasing a proton machine unless it was tied to a huge (expensive) research program devoid of the plan to market our prostate cancer treatment center. In the era of our need to contain costs, this is one issue that the American public should join in opposing. I say restrict these expensive machines to research institutes with proven ability to do outstanding translational radiation physics research.
What about High Intensity Focused Ultrasound (HIFU)? First, it is just another way of delivering energy to the prostate gland. Second, just as 99% of prostate biopsies are done with ultrasound guidance in a urology office, the urologist is the one who might purchase and use this machine. Now suppose you are a patient who has heart disease or other medical problems that might make you not a good surgical candidate. You have a small tumor that may not need to be treated at all. But you want some sort of treatment. What gets set up with this scenario is that a patient might logically believe HIFU is “new and better”, while a urologist or urology center in the U.S. or elsewhere can do something other than “watch and wait” or refer a patient with more aggressive disease to a radiation center. Marketing forces could easily take over medical judgment. In one review article, the authors state, “In conclusion, HIFU as primary therapy for prostate cancer is indicated in older patients (>or=70 years) with T1-T2 N0M0 disease, a Gleason score of <7, a PSA level of <15 ng/mL and a prostate volume of <40 mL. In these patients HIFU achieves short-term cancer control, as shown by a high percentage of negative biopsies and significantly reduced PSA levels.” To which I would say, “did these patients really need any treatment at all?” Although HIFU, like cryotherapy may have an interesting role in salvage treatment after radiation failure, I would not want HIFU if I had a prostate cancer that needed treatment. The standard treatments you already know about have much more data to support them in terms of side effects and long term outcomes. I regard HIFU as another area I would restrict to research only use. (Publish or perish – do not use a fancy machine for marketing).
Lastly for today: Cryotherapy. I guess you could properly think of this as a way of removing energy from the prostate to the point the cells can survive. More simply, if you form ice crystals in a cell, bad things happen. Do it at least 3 times, and the cell will die. At our institution, the most frequent use of this has been in the area of salvage treatment for radiation therapy failure. Here, I think it is an advance over the much more difficult old efforts to remove a radiated prostate gland from the fibrotic tissue that results from modern radiation therapy techniques. In the old days, you could pretty much count on this kind of surgery resulting in 100% impotence and very high rates of incontinence. Now, with the more modern probes, the incontinence rates are much lower, and some patients can be salvaged with much less morbidity (although impotence rates are still nearly 100%). In addition, cryoprobes can be used to treat just part of the prostate, leading to our own institution’s interest in targeted focal therapy. I will deal with this in some future post, but suffice it to say, that you can stick a probe or two into a small tumor in the kidney, liver, or really any organ, freeze the tumor, and it will cure some of the patients. There is an excellent professionally done video of how our institution approaches this put together and posted by Mike Landess. Much research remains to be done in this area. However, as to use of cryotherapy for the initial treatment of the whole prostate gland, I would again stay away from that. My view is that the standard treatments (you already know about) have a better chance of controlling your prostate cancer. If you are not a good candidate for surgery, then I would recommend radiation therapy rather than having a urologist utilize cryotherapy – not enough long term followup data for me to be confident in this approach for “whole gland treatment”.
I hope you have a great weekend, and please feel free to comment and subscribe to this blog if you want it to continue!