Philip J. Buffington, MD, discussed new screening methods and hormonal therapies being utilized for patients with metastatic prostate cancer.
Philip J. Buffington, MD
As advances continue to be made in screening and treatment for advanced prostate cancer, urologists maintain an important role in oncology care.
At the 2015 Large Urology Group Practice Association (LUGPA) meeting in Chicago November 5-7, Philip J. Buffington, MD, chief medical officer at The Urology Group, and other attendees met to discuss what is being done clinically within their particular practices.
Buffington sat down with Urologists in Cancer Care to talk about new screening methods and hormonal therapies being utilized for patients with metastatic prostate cancer.Philip J. Buffington: The hot new topic is fusion with ultrasound looking at high-risk prostate cancer found on an MRI. You fuse with ultrasound so that when we do biopsies, we can target the areas where we think there is high-grade prostate cancer. Fusion of MRI with ultrasound allows urologists to progress from blind, systematic biopsies to biopsies, which are mapped, targeted and tracked.
Traditionally for prostate cancer, we use ultrasound or sound waves to visualize the prostate. But it is not very good at targeting the cancer in the prostate. In other words, very rarely does prostate cancer show up on ultrasound. What this modality is good for is defining the anatomy of the prostate so an accurate biopsy and samples can be obtained from different parts of the prostate.
In our group practice, we now have eight areas of the prostate gland that we target. In some areas we take two biopsies, and some areas we take one biopsy. Basically, you’re kind of hitting the needle in the haystack. You’re passing enough biopsy cores through the prostate in the hope that you hope to hit the cancer, but you’re not actually seeing it.
With an MRI, although it's not very good at low-risk prostate cancer, it’s very good at showing high-risk prostate cancer, especially prostate cancer in the anterior prostate where it is not well-defined with an ultrasound probe. If you have high-risk prostate, or high-risk lesions seen on an MRI, software is available that enhances the ultrasound. Even though you're not seeing cancerous tissue with the ultrasound, the software will guide you to the spot that was abnormal on an MRI. That helps you pass the biopsy needle into that area.We do that type of scanning primarily for what we call repeat biopsies. If someone came in with an elevated prostate-specific antigen (PSA) for their initial biopsy, we wouldn’t necessarily conduct an MRI on that person. But if the patient had already had a biopsy done, let's say a year ago, and then the patient’s PSA went up again and I'm worried that maybe we missed the prostate cancer, I could then send you for an MRI first and then do a targeted biopsy of the abnormality on the MRI. That’s one population.
The other population is patients that are on what's called active surveillance. We know they have prostate cancer. It’s very low-risk, very low-grade cancer, maybe found on only one or two cores when we did the biopsy six months or a year ago. We’re following that patient and we’re not treating them. After a year, if I wonder if there was an area of higher-risk or higher-grade cancer that I missed with my initial ultrasound guided biopsy, I would do a repeat biopsy.
A lot of times on a repeat biopsy we will do an MRI on someone on active surveillance. Then we can target the biopsy to an area that’s more suspicious that we may have missed on the initial biopsy.Prostate cancer is unique in that it’s very sensitive to testosterone, which is a male hormone. One of the main treatments for metastatic prostate cancer, or prostate cancer that has spread beyond the prostate, is to treat it with some sort of therapy that blocks production of testosterone. Traditionally, back in the early days, it was by orchiectomy. You would remove the testicles and that would obviously stop the production of testosterone.
And then there were these drugs that were invented that were called LHRH drugs. They were drugs that were agonists of LH production, which is a hormone produced by your pituitary gland. Agonist means that it would hyper stimulate it. It initially stimulates the testicles to produce more testosterone, so you get what's called a flare phenomenon. For the first week or two the testicles produce a ton of testosterone and then they sort of go the other way. They stop producing testosterone.
Traditionally, those have been used to treat prostate cancer. The problem is that flare phenomenon can be problematic for someone with widespread metastatic disease. If you just give an LHRH drug, it stimulates the testosterone for the first two weeks, they’re in that flare phenomenon, and you can cause a lot of pain in the back or potentially paralysis.Firmagon came out after the LHRH drugs, and it is used as an antagonist. It blocks the production of LH from the pituitary gland to the testicles. So it really is a little cleaner, it doesn't cause this flare phenomenon for two weeks, and that's the real beauty and value of Firmagon.
The problem with Firmagon has been that it traditionally has only had a one-month length of time when you administer it, whereas the LHRH drugs will last 4 to 6 months. Someone treated with Firmagon traditionally has had to come in once a month to get that injection, whereas an LHRH drug, you can give every 4 or 6 months. But I think there are newer versions of Firmagon that are going to be longer-acting. That would obviously then be the best of both worlds. You no longer get that flare phenomenon and you can dose it every 4 or 6 months, or at least every 3 months.If someone comes in and I am worried because they have a very elevated PSA—someone with a PSA of 500 or 1000— and they come in with widespread metastatic disease in their bones, particularly with boney pain or partial paralysis from spinal involvement, I’d be very reluctant to give a drug that’s going to give a flare phenomenon. For those patients we always try to use Firmagon.