Alright, Dr. Scholz. So, we're covering the topic of PSA today which is a very vast topic.
There are multiple facets to it. But can you talk about the origins of PSA and also what
a normal PSA should be to a man who does not have prostate cancer?
Yeah, obviously very controversial and very important. We're talking about, you know,
tens of millions of men that are, you know, 40 or 50 or older that should be doing this
blood test once a year just make sure they don't let prostate cancer slip through. One
patient described the PSA as the "check-engine-light" blood test for men. Because it is a check-engine-light,
people understand that it's not really measuring anything, it's just saying "hey, there's a
light on, better go to the mechanic, get checked out, found out what's going on."
So, why would that be controversial? We've all heard about people saying bad things about
PSA and the reason is, is that when you go to the mechanic, sometimes, the mechanic does
work on your car that you don't need, and in the prostate cancer world I don't think
it's because of dishonesty per se, but I think it has to do with as technology has moved
forward over the last 10-15 years it's been hard for the physicians to keep up with how
quickly things are changing and, historically, when you hear the word cancer you think "action,
get to surgery, save your life from the cancer" and that was a reasonable conclusion 15 or
20 years ago, but now we know that there's many types of mild prostate cancer that don't
need immediate treatment, and the industry is coming around slowly, but that's where
the controversy lies. There's no problem with the test itself as long as you interpret it
as a check engine light and not as something that will tell you "yes" or "no," "I need treatment."
That is determined by other factors: Biopsy results, scan results, and thorough study
as to what type of prostate cancer you're dealing with.
Right, right. So when it comes to—Why is PSA so controversial? I mean, this is a huge
topic, but it seems like a lot of urologists were giving PSA tests and they stopped and
now it's kind of coming back...
Yeah, the urologists have been pretty steadily behind PSA throughout this whole time period,
but the primary care physicians, the one that are performing most of these screening tests
have been concerned that their patients have been shuffled into too much treatment, and
to protect their patients, some of them have decided it was in their best interest to stop
doing PSA testing. It's kind of a baby with the bath water problem, you know—yeah, you
do spare some men from overtreatment, but then on the other end of the spectrum, you
have some men with bad cancers that are getting outside the prostate without someone detecting
it at a curable stage.
So, how much do you think the PSA task force had to do with that situation?
Well, they pretty much started it. This is the group of government-appointed body back
in 2012 that came out and said all these negative things. They recanted in 2016 and the PSA
was brought back as a viable blood test if it's used properly.
So, can you discuss, you know, if they're gonna get a PSA test, they get their results
from their primary care physician, what should a normal PSA be for a man who does not have
prostate cancer?
So, the usual threshold, depending on the lab, would be either 4.0 or less would be normal,
or 2.5 or less would be normal. Different labs and different PSAs are out there. That's a reasonable threshold
to use as an action point for further intervention. It's not a perfect test, but when you're screening
millions of people, you have to set some sort of threshold to take action.
So, what happens if the PSA comes back and it's under 1?
So, very low PSAs portend a very good prognosis. Men that are under 1 are at very low risk
of getting clinically significant prostate cancers. People say, "one!" I mean, normally,
a normal PSA would be around less than 4 or less than 2.5, why do I say 1? Well, it turns
out that people can have significant prostate cancers with a PSA of 2 or 3, and that means
that you can't just blanket statement say if it's under 4, everything is fine; however,
you know, you have to draw the line somewhere. Are we going to be doing MRIs on everybody
with a PSA over 1? No. So, the other things that are looked at are how big the prostate
is, how fast the PSA is changing over time, and maybe we should address those each individually...
Yeah, I think that's good.
So, let's look at—let's talk about the ratio of how high the PSA to how big the prostate
is. This is called PSA density and a normal PSA ratio is about 10:1. So, if the prostate
has been measured with an ultrasound or an MRI and the gland is say, 30cc, 40cc, which
would be a normal size prostate, the PSA should be around 3-4. If the gland is really enlarged
as is the case for some men as they get older, you're looking at 60, 80, or even 100cc prostate,
then those men can have PSAs that are 6 to 8 to 10 and still be normal without any necessary
indication that there's underlying cancer. So, that's a rough rule of thumb, and again,
it doesn't provide enough precision to just say for sure there's no cancer, but at least
it doesn't raise alarm bells for someone who has a 20 or 30cc prostate and their PSA is
10. That's a lot different for someone who has a 100cc prostate and their PSA is 10.
Well, when you have a man who's in that situation which is a common helpline scenario. So, his
PSA, let's say, is 6 or 7, but then we find out that he has a larger prostate, so he finds
out he has a large prostate but we can't just rule it out because it's a larger prostate,
so what're the next steps that he should do with talking to his doctor?
Well, everyone should get a digital rectal exam, and then they—the sort of stopgap
method that we talked about would be to either get a blood test called OPKO 4k or a urine
test called Select MDX. Now, these tests are useful if they come back with extreme results.
Unfortunately, they don't say you do or don't have significant cancer. What they do is they
say—they give you a percentage likelihood that you have significant cancer and that's
useful if, let's say, the percentage likelihood is 4%. It's not very useful if it says it's
like 31%. So, you say, well that's a risk. Or if it comes back and says that your risk
of significant cancer is 80 or 90%, you say, okay that's helpful, I gotta check this out.
This is really a concern. So, the OPKO 4K and the Select MDX don't always lead to complete
resolution, but when they do, I think if you come back with a risk of 4%, you say, well
why don't we just watch this? Let's get another PSA in six months and maybe even repeat the
OPKO 4K in six months and if it's holding steadily at a very favorable range, maybe
you're done. You just keep an eye on it. For the men that come back where it's ambiguous,
then you're on to some sort of a scan. We typically recommend, you know, getting a multi
parametric MRI, 3-Tesla multiparametric MRI, or color-doppler ultrasound, or, of course,
many places like to do random needle biopsies. That's been pretty much the standard now for
about 30 years. I tend to prefer the imaging, the non-invasive approach which has actually
been shown to be more accurate, of course, not as risky because random biopsies can result
in serious infections.
Right, and with the MRIs, they can get targeted biopsies if anything is found?
Right, so if they find a suspicious spot with the scanning that we're talking about, then
they can do a one or two needle biopsy and the risk of infection will be much lower.
Right, right, wow.
That's a lot to think about for a patient... So if you guys want a break down, you should
really see the timestamps in our video description because you can click into each subject and
go over that for studying later.
Thank you so much for watching. If you have questions you would like us to ask our prostate
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