Frozen Lumpectomy For Prostate
Ice on the tip of a probe; focal cryoablation is freezing and killing cancer in the prostate.
Bob Wilson traveled hundreds of miles to have this treatment instead of the complete removal of his prostate.
“I want to continue to live as normally as I can for as long as I can and there’s a lot of side effects with radical prostatectomy that I didn’t want.” Wilson told Ivanhoe.
A new study shows the results of focal cryoablation on 70 patients followed for an average of 10 years. Continence after first treatment was 100 percent. Potency after first treatment was 94 percent and disease-free survival for all patients was 90 percent.
Dr. Gary Onik, MD, Interventional Oncologist and Professor of Mechanical Engineering at Carnegie Mellon University, was amazed by the results.
“And what we found is that in our group, high risk patients had the exact same 90 percent chance of being disease free. That’s remarkable.” Dr. Onik told Ivanhoe.
George Tholke is one of the patients in the study. The day after the procedure, he played tennis.
“To me it’s a slam dunk, it’s logical. You can go back and redo it if anything is wrong.” Tholke said.
Dr. Onik has been using a 3-D mapping technique to gather tissue samples for a more precise diagnosis. He believes most prostate cancer patients could be candidates for this treatment; freezing a common cancer in its tracks.
He also said men with advanced prostate cancer may not benefit from the focal cryoablation. This is the first long term study of this treatment and researchers said the results need to be confirmed with a larger patient group.
PROSTATE CANCER: The prostate is a gland found only in males that is typically around the size of a walnut in younger men and can grow larger in older men. It’s located below the bladder and creates a fluid that nourishes the sperm. When gland cells begin forming in an uncontrolled manner, a tumor can form in the tissue of the prostate, leading to prostate cancer. More than 60 percent of prostate cancers are found in males over the age of 65 and rarely occur in men under 40 years old. Some forms of prostate cancer can grow and spread quickly, leading to problems in other parts of the body. Doctors refer to this as metastatic prostate cancer. (Source: www.nihseniorhealth.gov/prostatecancer/prostatecancerdefined)
TREATMENT: Treatments for major cases of prostate cancer include:
- Radiation therapy using high-powered energy to kill cancer cells
- Hormone therapy to halt your body’s production of testosterone which prostate cancer cells need in order to grow
- Surgery to completely remove the prostate. (Source: www.mayoclinic.org)
Gary Onik, M.D., Professor of Mechanical Engineering at Carnegie Mellon University talks about a new treatment for prostate cancer.
Tell me about the study that you just published, why it’s so significant and what you found.
Dr. Onik: The idea behind the study was to do for men what a lumpectomy has done for women so that instead of having a radical mastectomy, women now have a lumpectomy and they found that the cancer results were just as good. Men are still getting radical prostatectomies with all of the morbidity that’s associated with it like incontinence and impotence to a very high degree. What we were trying to do with this study was just kill the cancer, basically give men a lumpectomy and still have good cancer control results and decrease the morbidity. That was the idea behind this original study. We started this 18 years ago so this is not something new.
What’s new in the study?
Dr. Onik: What’s new in the study is that we finally had a large number of patients that we have followed for at least an average of 10 years. We e can say things about the morbidity and the complication rates which we always knew were far lower than anything else. How good the cancer results were going to be was the question. What we have found remarkable in a way was that the patients who needed cancer treatment the most, the patients who were dying from prostate cancer, actually did as well as anyone else in this study. Traditionally, if you had radiation or had a radical prostatectomy and you were a high risk patient, at 10 years your chance of being disease free was about 50-60 percent. What we have found is that in our group, medium to high-risk patients had the exact same 90 percent chance of being disease free as the low risk patients, which is remarkable. That means that somehow we have changed the biology of prostate cancer so that we can get those high-risk patients who are now dying of prostate cancer into a disease-free category. Why? Well we know that you can’t cut out a portion of prostate so we couldn’t do a lumpectomy for prostate cancer. We had to kill it or destroy that cancer in other ways. What we did is target it with freezing and we could destroy the tissue and then leave it in. If you go back in the literature, there are a number of instances where patients had prostate cancer, had it frozen and all of the gross metastatic disease all over their body went away. The patient’s body was recognizing their tumor in a different way. What we think is going on here is that by killing the cancer, releasing those cancer antigens in that specific patient we’re basically giving the patient their own cancer vaccine. They are now recognizing their tumor with their body’s immune cells going all over their body, recognizing the microscopic cancers that will grow up in 10 years and killing them off before they have a chance to grow up.
You haven’t proved that right?
Dr. Onik: No, our theory is based on a lot of scientific data leading up to it. There are numerous studies showing the immunologic effect of cryosurgery. I feel strongly enough about it that while there are other ways to do a lumpectomy now for men with prostate cancer, everybody is coming out of the woodwork to try and kill a portion of a prostate gland based on our older studies; I feel I have to use cryosurgery because those other things don’t have an immunologic effect because they burn the tissue and they denature the proteins, like cooking a hard-boiled egg. You know it doesn’t look like an egg anymore. But when you freeze something and then thaw it; it still looks like what you thawed or froze. There could be other reasons but I think this is the most compelling reason and it’s enough for me to say that this is the way I’m going to have to do it because I can’t wait 10 years to find out that something else doesn’t work as well. It’s great at killing the tissue and it’s safe, so why not do that. An exciting portion of this is that we now have ways of boosting that immune system. We already know in animal models that if you add certain drugs to cryosurgery it will prevent metastatic disease; we already know that, so you know what the next steps are going to be. We already have made a major impact in the possibility of saving patient’s lives with prostate cancer if we go this route versus the traditional route. It we add certain things that boost that immune system, we’re going to make this even better. We are at the very beginning. It’s like we’ve been going down this same road with prostate cancer. It’s got ruts and it’s got potholes and all we keep doing is filling the potholes and we still have the same problems. We haven’t made any real advance in treating patients and changing their ability to live well and we still have patients dying, 30,000 patients a year dying from prostate cancer.
Do you think the results of the study will be a game changer?
Dr. Onik: I have no doubt it’s a game changer. The question is what happens from here. The results really are remarkable. We never thought we could get results like this in these high-risk patients that were doomed. A large percentage of them were to get recurrent disease and we’re preventing that now. Now what? Do we keep going down the same road or do we start taking resources and putting them towards this new road and see where we can go with that? You know prostate cancer is a big business, is that business going to change? These are all the questions that need to be answered if we can take advantage of what we’ve learned here. It’s like we picked up the corner of the curtain and see the wizard standing there. Are we going to go the full way or are things going to just keep going the way they’re going. Our job is to try and make change.
Who is not a candidate for this?
Dr. Onik: That’s a great question. What we are finding is that in studies that have already been done, looking at the criteria for doing focal therapy, 95 percent of patients can have this done. You have to stage them in a certain way so that you know exactly where their cancer is and those are things that we’ve talked about in the past. But if we can do those staging procedures then the overwhelming majority of patients can have this approach.
But who wouldn’t be a good candidate?
Dr. Onik: If I had a patient who had every biopsy in their gland show cancer, then I would say no, you can’t have this approach and you can’t have a focal therapy. I would still do a cryotherapy rather than a radical prostatectomy because that patient can still get the benefit of the immune response and there are studies that show even when you do a whole gland you get that same response, not just in focal therapy.
You would freeze the whole gland?
Dr. Onik: Yes, I would freeze the whole gland. What people don’t know about surgery is that the more aggressive the disease, the less chance you have of having all of the cancer removed. So in general if you take 100 patients who have a radical prostatectomy by the robot or by anything else, the data from numerous studies show that one in four patients do not have their cancer fully removed. They have what’s called a positive margin, but the cancer is left behind. With cryosurgery you’re going to get a recurrence. They’re trying to radiate those patients to try and prevent those recurrences. With cryosurgery I can just go back and do more so it’s not a lost situation. If I do focal therapy and you have a recurrence somewhere, I can go back and I can treat again without much problem.
But in terms of the focal, a man who can’t have a lumpectomy would be?
Dr. Onik: Somebody who had cancer throughout their whole gland. If there’s a portion of their gland that doesn’t have cancer in it then I’m going to try and leave that because that normal tissue is going to save them from having problems. It may allow them to be continent or something along those lines. Even if I can’t save their nerve bundles and save their potency. I try and do as little as possible. If there’s normal tissue I’m going to do my best to try and save some of it, which has worked very well for us.
FOR MORE INFORMATION, PLEASE CONTACT:
Gary Onik, MD
Professor of Mechanical Engineering
Carnegie Mellon University
Phone: (321) 297-4489