So, we have a patient who has Gleason 6 prostate cancer and they've had 46 rounds of radiation
their PSA has kind of hovered between three and four but it hasn't gone down,
and they're kind of wondering should it go down? I mean, is there some sort of
like PSA bump when it comes to radiation or what should have been the expectation?
Gleason 6's, as we've talked about before, are low-grade process; we don't
worry about them spreading. Prognosis for treatment if you undergo treatment obviously
is excellent because it's a type of prostate cancer that you can often watch rather than treat,
so that gives you courage if the PSA seems to be misbehaving that the underlying process is not
truly dangerous and we do know that radiation can sometimes cause erratic PSA tests for up to two
even three years after treatment. This phenomenon you mentioned already is called the PSA bump
and it is believed to be due to radiation inflammation, radiation prostatitis, and it's
unpredictable. It doesn't happen as frequently with the beam radiation that you described,
the 46 treatments, it''s more common with the seed implant radiation or the short course
SBRT radiation where they get five treatments over a ten day period, but it does happen with IMRT
and with proton therapy, perhaps in 5%-10% of patients, so at this point with the information
we have I wouldn't be concerned at all. I think it's just going to take some patience. The
resolution of this question is, of course, was there a higher grade cancer that was missed
on the random biopsy, which can happen, and in the background there's actually a bad cancer
that's misbehaving, and we can resolve those questions now with these new PSMA PET scans
which are now commercially available. Medicare is covering them. We're seeing,
unfortunately, some foot dragging on the privates and the HMOs and those sorts of things,
and the cost of buying one i think is somewhere in the three to five thousand dollar range so
they're not cheap, but it can be money well spent if people suspect for some reason
that there really is a cancer process ongoing in the background and they want to double check.
So, you can get a PSMA PET scan. On this person, with the information we have, it
sounds like patience is reasonable and that with time the PSA will probably settle down on its own.
When would we get a PSMA PET scan? I suppose if the PSA was steadily rising in an unremitting
fashion. People that have inflammatory bumps, you usually see sort of a zigzag if you graph the PSA
out over time. You'll see the PSA go up and come back down and up and down, whereas, with cancers,
there's a steady unremitting continuous upward progression. So, as you look at the pattern
of PSAs over time you can sometimes elucidate whether it's inflammatory or cancer on that basis,
and for that reason sometimes we'll check the PSA every month instead of every three months
which is the usual interval that we use in people that have you know normal declines.
So, we have a daughter who's writing in on behalf of her father and
he had surgery about a month ago and now the doctor is suggesting radiation.
She says that when they had the pathology, it came back negative, and so she's wondering, does she
commit to the radiation on behalf of her father? You know, she's kind of taking care of him.
It's interesting; in professional circles negative is a good thing and maybe to a lay person
negative means that there's something bad and the bad things could be a positive margin that means
that when they cut the gland out they could tell they cut through cancer and left cancer behind
or perhaps if they removed some lymph nodes maybe there was some cancer in the lymph nodes. So,
those are negative things, but if you look at a negative pathology report in medical terminology,
that means that there weren't any lymph nodes and there weren't any positive margins, but why
would anyone be considering radiation at that, you know, if everything is good? So, apparently
there was something that was left behind and I can't imagine why the doctors would want to
administer radiation for any other reason. The policy of giving radiation right after surgery
is based in some clinical trials that showed better 10-year outcomes and people that had
immediate radiation versus waited until a PSA rose above a certain threshold. There are some problems
with some of those trials because they let the PSAs rise too high in some of those trials. So,
if people are watched closely and assuming the PSA goes down to zero after the operation,
many doctors are starting to believe that if you jump in at the first sign of a PSA rise
that you're not going to lose much ground and that way you won't end up having to radiate everybody;
you can just radiate the people that have a rising PSA. The issues of radiation right
after surgery are not small. I mean, we know that there's a risk of incontinence and impotence from
the surgery itself and studies have shown that if you give radiation right after surgery that you're
going to increase the chances that that impotence and incontinence are going to to be more durable
and less likely to recover normal function. My general bias is to postpone the radiation
see if the PSA becomes undetectable—that only takes a brief time right after the surgery—and
if it is undetectable, then monitor closely, check PSAs frequently, and then if the PSA
starts to creep up later, either do a PSMA PET scan, or if you use the traditional approach,
start the radiation before the PSA rises up to 0.5. That's the the cutoff point where
long-term outcomes start to deteriorate if you allow the PSA to go too high.
Diving deeper here: when you say a short duration of time for the
PSA to lower after surgery, what would that duration of time be?
Oh, within a month or two.
And as far as percentages of, you know, adding salvage radiation, adding radiation after surgery,
how much more of a risk is there for an incontinence and impotence?
It's going to depend on what the risks are for the individual going in. It's not
like everyone that gets radiation will become impotent and incontinent. The the
best description I've heard is that in men that have recovered very good continents after surgery,
the radiation is not likely to make it worse, but in men that have only
achieved partial recovery from incontinence the radiation may freeze it in that status
and disallow it from getting better in the future. People don't usually rush into radiation right
after surgery; we don't believe that you have to do it right away, so if they do recommend
radiation usually they try and allow full recovery of sexual function and urinary function before the
radiation has started because the outcomes will be better in the long term that way.
So, salvage being right after surgery, and regular radiation with being without surgery,
is the monitoring process the same for both?
Yeah, I mean, typically we give do PSA testing every three months for a couple years
after the treatment, every six months for another two or three years, and then annually after that.
It seems to be a good policy. I mean, maybe you could, say, get away with every six month
checkups for the first five years would probably be fine as well. Most people don't have such rapid
doubling times that a three or six-month delay and starting treatment is going to change the
long-term outcome of the future. So yeah, usually every three months for the first couple years.
So what should patients, I mean, if they're having
salvage radiation versus regular, you know, radiation without surgery,
would the PSA need to be the same? Does it need to be like 0.1, and over what time frame?
Yes, it does. I mean, so patients that have had surgery and are undergoing radiation therapy for
for cure to try and keep the disease in control should,
after the radiation therapy, have a PSA that drops down to less than 0.05 or undetectable levels.
How long does it take PSAs to decline? Well, it depends on how high the PSA is when you start off,
and then there's quite a bit of variability. We don't feel that it really matters how quickly the
PSA declines, but if someone undergoes salvage radiation and they had a detectable PSA at the
time of starting the radiation, the PSA should slowly decline down to less than 0.05 over time.
It doesn't really matter how quickly, just so the PSA continues declining. When it stops going down,
if the nadir is above 0.1 or 0.2, then you have to deal with the possibility that there's still some
cancer there. Sometimes the surgeons will leave a little bit of prostate behind, and that can
cause a low stable PSA afterwards that you can detect, but if the PSA doesn't
get down to low levels at some point, then there's almost always persistent cancer.
So, what about in cases of younger men? We have somebody who's written in and they had
a PSA of about 47, then they had surgery. It's down to 0.5 and now the doctor's telling them
that they need external beam radiation and 6 months of hormone therapy as well.
Since they're about 48 years old, they're kind of— I think the doctor's being very aggressive
in his treatment strategically. Do you agree with this synopsis?
Well, I say what they're describing there would be a fairly traditional approach prior to
the advent of these new PSMA PET scans. I
can't imagine why they wouldn't want to do a PSMA PET scan. We can find prostate cancer down to PSAs
as low as 0.2. This person has a psa of 0.5 after surgery. I probably would have done the PSMA PET
scan prior to surgery and I probably wouldn't have recommended surgery for this patient.
It is what it is and at this point. Yes, he's a young man; he's still got a detectable PSA, and we
need to find out where the cancer is and certainly attack it aggressively with combination therapy,
radiation, when you find the cancer, hormone therapy maybe for not for six months,
maybe for 12 or 18 months and perhaps even a short course of Taxotere.
On the terms of radiation, we've had another patient write in and they
said that they had 28 rounds of radiation and now they're having hormone injections
and the doctor is wanting them to get Lupron shots every three months for the next two years.
They're wondering, do they continue just doing, you know, PET scans every year, MRIs every year,
PSA monitoring? Like, what should that monitoring process be like if their PSA is below 0.1?
Yeah, I think the good news
for prostate cancer patients as opposed to other types of cancers—breast, colon, lung
cancers—there's— PSA levels below 0.1 speak volumes about the fact that cancer is in remission
and you can trust that. PSA accuracy is sometimes denigrated because of it's it's not precise for
screening for cancer, but once you've treated the prostate, we expect the PSA to remain low
and definitely unless there's a problem. We have talked in the past about bumps and
whatnot and how to deal with that. If the PSA is remaining low, there's no need for scans. That's
the beauty of PSA testing for monitoring after treatment. If the PSA is at 0.1 or less close to,
or maybe undetectable in some assays, the idea of doing PET scans and cat scans and whatnot
is superfluous; you're not going to find any, and that is the good news. It's pretty simple.
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