Alright, Dr. Scholz, well today we want to cover how to check for recurrent cancer
after treatment, and this is a common question we get at the PCRI because we understand that this
happens a lot with men and so, really, what are the first things we need to check for?
I mean, if you look at the averages, about a fourth or a third of men that have surgery or
radiation do deal with the cancer coming back later, and monitoring for relapsed cancer is,
in most cases—not prostate cancer—would involve getting regular scans to make sure that no spots
are showing up someplace else in the body after treatment. The prostate recurrence situation
is dominated really by PSA testing. PSA is somewhat maligned for its accuracy in screening,
but for detecting a recurrence after treatment it's really quite excellent, and I do get asked
by patients, "Do I need scans on a regular basis?" and if the PSA is behaving well, pretty much it's
a waste of time to be doing any scans. The PSA is very reliable for detecting a recurrence.
So, what should the PSA nadir down to after surgery then?
I'm glad you mentioned surgery because it's different with the different treatments. The
patients ought to have a PSA less than 0.1 after surgery. The... When we look at analyzing PSA
levels after treatment we subdivide it into three groups: surgery, radiation treatments,
and men that are having focal therapy. The follow-up methodology is a little different.
We do scans in men that have had focal therapy; men that have had focal therapy are those that
only a section of the prostate was treated and some of the prostate is
untreated and can generate a new cancer, and the best way to keep a close watch on those folks
is to do some sort of a scan like a color doppler or perhaps a 3T multiparametric MRI.
You mentioned radiation and how it's, you know,
the PSA nadiring is different from surgery to radiation, so what is it for radiation then?
Well, if you look at the academic studies they say
start thinking about a relapse if the PSA rises more than two points above its lowest point. So,
the problem is that how low it goes varies. Sometimes men get seed implants or IMRT or
proton therapy. Sometimes they get hormone treatment; sometimes they don't. When they
get hormone treatment the PSA goes lower. When the hormone treatment wears off the PSA will
come up a little bit—not from cancer. So, I think the general rule of thumb if you want to
throw a number out there is after treatment is all finished after all hormone therapy has worn
off and testosterone is back to normal, I would like to see the PSA consistently less than 0.5.
Less than a half a point. Could there be exceptions to that? Certainly, there can.
Probably the most notable is the phenomenon of delayed radiation prostatitis. We call it the PSA
bump. And PSAs can go way above 0.5; they can go up to two, three, four, five, or six
from irritation of the residual prostate not from cancer. So, there are exceptions to that,
but I like that threshold of like 0.5 that if men have had radiation and there are no other
concerns, probably no need for any kind of scanning if the PSA is less than 0.5.
And with the 0.5, you know, I know you had mentioned hormone therapy,
is it the same without the hormone therapy for you?
Well, I'm talking about after everything is worn off. As you know, some men get hormone therapy for
four months or 18 months and during that time the PSA should be less than 0.1, but once the hormone
therapy wears off and testosterone recovers, a radiated prostate will make some PSA. I'm not
talking about the cancer in the prostate but the prostate itself, and that small amount of PSA,
in general these days with modern state-of-the-art therapy, is going to be less than 0.5.
So, when it comes to the imaging, you know, we've heard a lot about axumin which. you know,
I know is covered by medicare and now we have these new PSMA scans. Which one's really better
and are there certain scans you would use in certain situations like surgery versus radiation?
So, those two scans of course were a huge breakthrough. Before we had these PET scans
(Axumin and PSMA PET) trying to find where the cancer was, was difficult or impossible,
but PSMA PET scans are clearly more accurate than Axumin PET scans. The PSMA PET scans can
localize recurrent cancer anywhere in the body with PSA levels as low as 0.2. Axumin PET scans,
I like to see the PSA above one before we start hoping that you're going to find out where the
cancer is coming from. So, these are the sorts of scans that we implement when the PSA seems to be
misbehaving and, of course, with someone who's had surgery if the PSA is above 0.2 and rising
the likelihood that there is cancer is very high.
So this is one of the advantages of surgery. I don't consider it a huge advantage but men that
have had surgery can potentially detect or relapse at an earlier stage when the PSA is 0.2 or 0.3
whereas with radiation we don't get suspicious until the PSA goes above 0.5.
One of the questions we get very often, especially in our youtube comments,
is really the PSMA scan worth paying out of pocket for? So, you know, it's a huge cost for
some people and so they're kind of wondering can I skate by with getting something better
and what specific situation would you say absolutely pay for this, it's worth it?
Well, it's kind of unique to prostate cancer that if there is a relapse, you get
a second chance for cure and whether you've had previous radiation or surgery or focal therapy
and you need accurate information so, of course, now in 2020 we have to pay for these scans—a
thousand to two or three thousand. Sometimes there are clinical trials where you can get
PSMA PET scans for free, but I think that it's a good investment of money to
try and get accurate information as to where the cancer is located because now with these
specialized radiation therapy treatments you get a second chance to cure the cancer. So,
this situation of having to pay for PSMA PET scans probably won't last very long.
We anticipate the FDA will approve the scans in—hopefully—in the next six to 12 months.
Thank you so much for watching. If you would like more information,
you can visit our website pcri.org. Also, subscribe to our YouTube channel;
we come out with new prostate cancer videos every week.