Ep. 15 - Research Update: Protein Specific Antigen and Mortality
15 years ago, the USPTF changed their recommendations for when men should get PSA tests. The prior recommendations resulted in additional tests to reach a diagnosis but the PSA screening did not appear to influence mortality. A recent study may show that recommendation may have been premature
Welcome straight talk on health and your host Dr. Chet Zelasko. Together with WGVU in Grand Rapids, Michigan I examined the latest and greatest in the world of health. Whether it's research that makes headlines, another miracle diet, a new supplement or an exercise trend. I look at the science behind them and let you know whether they're real or not. You can check out the other things that I do on my website. Drchet.com and sign up for my free e-mails.
Now the first thing I'm going to say you may have heard before: medical testing is a blessing at times a curse at others and a source of controversy in the medical profession itself. I recently talked about colonoscopies and why they provide information about colon health tests that that are done with stool samples do not. But before we get into our topic of the day, which is we're going to be talking about protein-specific antigen and mortality. For those of you, you probably know the acronym PSA. Every man should. I want to give you a quick update on the colonoscopies. Now, the conclusion of the study was that there was no difference in mortality between the use of a colonoscopy and the fecal occult blood test also now known as the fecal immune-chemical test. Now I listen to another podcast done by an economist, who was also a physician's called Freakonomics MD. Now he spoke with a researcher who's published over 200 papers on colonoscopy. She she's from New York University, and he also had the privilege of interviewing the lead author of that colonoscopy study. Here's the important thing; while I personally think that colonoscopy is a better way to go, that study, if you remember, did not show there was a difference in mortality. But what both of these researchers agreed upon was that after 2 to 5, maybe even 7 more years of follow-up, you'll start to see a trend develop where the mortality rate in those that have colonoscopies will start to decline more so than those that just have what they now call the FIT test, fecal immune-chemical test. I don't remember whether I concluded this, but the only advantage that you're going to have using the fecal immune-chemical test is the possibility that with the stool sample they can do a couple different things. They can look at your genetics to see if you have the colon cancer genes or they can also check on your micro biome. Now, I don't know that they're equipped to do that. And I have no idea what expense it would be. But I think you're going to gain more information and so I’m going to modify what I said. Whatever schedule you work out with your doctor, making a shared decision on how often you should get a colonoscopy and, you know, or should you get one at all? Or should you rely on the FIT test? I think that you have to anticipate that you're going to be able to get more information from that. But it's going to take a while for the technology to make it cost effective because you don't want to end up with something that simple, a stool sample, that then is going to be more expensive than doing the colonoscopy. And that's what it really comes down to is economics, which is probably why someone with a degree in MD and economics analyzed it.
So the best policy is use what you've come up with with your physician and take it from there. And the same approach applies to when it comes to PSA. Again that stands for protein-specific antigen and that's a screening for prostate cancer. And lately, it's also been controversial. But I think a study that was recently published, very recently, gives us a little more clarity as to what should be done. Now, why has it been a controversy? Well, knowing what the PSA number actually means, the number that we try to get below is 4.0. However, one of the things that you have to understand is - there's a range you can go well up into the 20's. What you're looking for, though, is not so much the number, but what you do with that number. Let me give you an example: There are people who will have PSAs below 4.0. And yet, if pursued, they will be diagnosed with prostate cancer. There are people who have PSAs above 10 and when pursued, and I'll explain what that means, they come out and they don't have prostate cancer. And so the whole idea with the United States Physicians Task Force when they declared, let's say about 15 years ago, that we don't need to do that test on men 70 years and older anymore, or not as frequently, is that there's going to be a segment of society that gets lost because what happened is that as soon as those recommendations came out, the number of PSA tests dropped.
So the question then becomes, was there any difference in metastatic prostate cancer, where it spreads to other parts of the body, and/or was there an increase in mortality? Here's the thing. When you look a prostate cancer diagnosis, it's not just that simple, because there are people, men, diagnosed in their 70's who will never die of prostate cancer because of the type of prostate cancer they have and I don’t have time to go into all the details but some are slow growing some are fast growing. And I want to address he fast growing but the slow growing ones, someone could die with prostate cancer but not of it. Example that comes to mind is Robert Guillaume, the actor of from Benson and a variety of other things. He died of prostate cancer, but he was diagnosed and treated in his 70's, but he didn't die until he was in his mid 80's. And so that's a long time. And one of the things they look at is - is this going to impact that someone's life span, their normal life span? I don’t know how you make that decision. Certainly you want to leave it in their own hands, at any rate….
So where’s controversy today? Well, in JAMA Oncology in October 2022 PSA screening became controversial again. The Veterans Health Administration, as you might expect, can be a challenging bureaucracy. But the one thing that they do well is they track medical information. And so you have a population of millions of men… in this case the women don't apply because they don't get PSA tests, where you could, if you track them over a period of years, figure out whether do higher rates of PSA testing yield a reduction in metastatic cases of prostate cancer and a reduction in mortality.
And so researchers took that to task. And so they looked at millions of veterans. They chose times across the U.S. Veterans Health Administration from 2005 with the beginning population of 4,678,000 and change, to 2019 where the population had grown to 5,371,000, Now, the reason they chose those guidelines is because the task force had modified guidelines for PSA screening to recommend less frequent use of the test for men over 70. Over those years, there was a decrease in annual testing by 10 to 15% in non VA health care facilities. And that was, in fact, massed at the VA system as well. US PTF then, the physicians test first recommend screening all men and in PSA testing, they did that a few years later, not2005, but a few years later, and again, testing fell.
So what did they find out? They drilled down into the data and in certain, you know, you’re going to have different groups of physicians with different philosophies. The U.S. physicians task force gives recommendations and often times the recommendations influence the spending of money by healthcare systems. But in this case, because it was the VA health care system, they decided to leave it up to the physicians practicing it. So what they found was clearly that some facilities continued to do PSA testing on a more regular basis. Those that followed more regular testing had a decreased amount of metastatic prostate cancer and a decrease in mortality. Do we want to look at that as a condemnation of the U.S. physicians task force? Not necessarily, but things do change. And in this particular case, more frequent testing was the thing to do. I think because every case is unique, and what you have to understand is a PSA test can mean, well, now I got to have a biopsy and that's no fun. And if they find cancer, is it one that I got to live with and the hanging over my head or is this one that they can remove and am I going to survive that? All of that needs a frank discussion with your physician, whoever you're going to have taken care of that for you. You decide on a plan that you're going to follow with regular testing, if warranted, with biopsies, if necessary, and with the treatment plan if the diagnosis is made that it's serious enough to treat. That shared decision-making is something this relatively new but I think it's something that's important. It certainly may reduce your risk of one, having a harsh case of prostate cancer if you are diagnosed, and a better treatment plan overall in working with your physician. Unfortunately, that's all the time we have for the show until next. And this is Dr. Chet Zelasko saying health is a choice, people, choose wisely today and every day.