So, Dr. Scholz, we have many questions regarding relapse therapy from our YouTube comments section,
and I thought today we would answer some of them.
So, can you characterize what are the factors that would determine that prostate cancer has relapsed?
Usually a rising PSA-- the problem with that is that you can have rising PSA in men who have not
relapsed, so a distinction has to be made. In the old days we had to let the PSA rise above a
certain threshold to say, like, two points above the nadir (with nadir being the lowest PSA that's
attained after therapy, so, whether you have surgery or radiation, the PSA goes down to a
lowest point, that's called the nadir) and then if the PSA started rising two whole points above
that, for radiation patients that was called a relapse. It wasn't always the case because
you can have PSA bumps where people get delayed radiation prostatitis and the PSA can rise more
than two points and then settle back down on its own; that's not cancer. that's inflammation in
the residual prostate after radiation. I think one thing to comment on about relapse disease is
in the prostate cancer realm it's quite different from other cancers.
The patients who have relapse disease after treatment for prostate cancer, and of course
you have to have been in a remission to be relapsed, we're not talking about people that
embark with really bad cancers and they can never get into a remission, but people that have gone
into a remission and then relapse and develop a rising PSA, that is indeed from cancer. The
remarkable thing about prostate cancer is that you have a good chance to try and cure the relapse.
Most other cancers, if you think of lung and pancreas and whatnot, if they relapse,
the vast majority are incurable and this is one of the components of that dreadful word cancer
that creates all kinds of fear and consternation. People know intuitively that you've got one chance
the first time you treat it to cure it and if you don't cure it, you could go on and die from it.
So, there are many reasons that prostate cancer is not as dangerous and deadly as other cancers:
better treatments, better monitoring tools, but the fact that you get another chance to cure it
even if it relapses is a remarkably good aspect of prostate cancer,
to get a second try and in some cases even a third try if the second attempt fails.
So, I mean, you've seen thousands of prostate cancer patients over your career,
how many have you seen, like, have a remission, get a relapse disease,
and then actually come to cure? Is there a certain percentage that you would see? Is it rather high?
Many. Many have been cured. There are different types of relapses, and of course,
this is getting defined with greater precision now that we have these new PSMA PET scans. So,
the location of the relapse is very important. The type of cancer that was treated initially
is important; if someone already had lymph node disease when they were had their initial therapy,
if they have a relapse, their chances for cure are not going to be as good as someone that
had disease that was only in the prostate gland and remains in the prostate gland.
So, the type of relapse is important in terms of predicting whether someone is likely to be cured.
The good news, of course, is that even in the men that are not cured, the relapses can be controlled
probably for an average of about 15 to 18 years with modern state of the art hormone therapy. So,
it's not super desirable to be on hormone therapy; it has a number of side effects that
aren't that pleasant, but it is very effective in keeping the disease in check for many many years.
So, you've used two different terms here:
'cured' and 'remission.' Can you explain the differences to people because I think that if
somebody came out of remission, relapsed, and then was cured, you know,
would they consider that back in remission or what's the definition of cured at that point?
Right, so the idea of remission, and of course there's partial remissions
and complete remission--the terminology is used for all cancers not just for prostate
cancer--so a complete remission means that no detectable cancer anywhere in the body
in the absence of any ongoing treatment. So, it's not that they've been suppressed,
but that they've been suppressed and then treatment is ceased
and the disease remains undetectable; that's a complete remission. That's not a cure because
if there is a tiny speck of cancer somewhere in the body--left behind--that wasn't eradicated
over a period of years it can manifest by growing and become detectable, and then that's a relapse.
So, people who have no detectable cancer are in remission and if they remain in remission for a
specified period of time--three to five years or so--then we start talking about the likelihood
that they've been cured because no relapse has occurred over a specified period of time.
So, you mentioned a couple factors that would add to remission and
obviously paying attention to the type of prostate cancer but you mentioned location.
So, regarding location if the cancer is in the pelvic nodes,
does that make it less likely to be able to be cured and if so what by what percentages?
I tend to think of prostate cancer with one big divide between the patients that still
have disease that appears to be confined into the prostate or the prostate area
and people that have anything else. We hear a lot of talk about, you know, maybe should I
have a biopsy because it might spread the cancer? People are failing to realize that it's not the
the fact that the cancer got into the bloodstream because someone poked a needle at it. The problem
with metastasis occurring is that they can only occur if the cancer cells themselves have the
biologic capacity to land put down roots and prosper in another part of the body,
and that's just a different biologic type of cancer. So, it's not the fact that it got out
of the prostate that caused it to metastasize, it's the fact that the cancer cells were of a
genre that can grow in different locations. So, the presence of any cancer in a distant
location is a very worrisome development, but you point out that the location itself whether
it's the lymph nodes or the bones or what part of the body or the lymph nodes located in could have
relevance into predicting whether this person is more or less curable, and yes,
the patients that have lymph nodes that are close to where the prostate used to be have the best
chance for being cured even though they have early metastasis and then as the disease spreads further
and more widely and as more and more spots appear the chances for cure start to drop off sharply,
but I have seen patients cured who've had one or two bone mets, and I've seen patients
cured that have had lymph nodes that are outside the pelvis. That is less frequent,
and patients that have any lymph node metastasis are not looking at high cure rates. You might
say that as many as 50% of men that have a single isolated lymph node and otherwise favorable
profile could be cured with salvage therapy. Salvage therapy being radiation to that lymph
node, hormone treatment for 12 to 18 months with a first and second generation agent, and probably
a very short course of chemotherapy like four injections of a medicine called Taxotere.
So, you mentioned different genres of you know types of prostate cancer, ones that are more
aggressive that are going to travel and get down roots in different parts of the body.
Is there a way to test for these types of genres before
maybe in the newly diagnosed setting when a patient's just coming into this space?
Well, this is the role that gleason score has played for many years is. Patients with
higher gleason scores are at greater risk for something that can spread outside the gland,
and that's probably the best we have. There's genetic testing that tries to do similar
type of predictive, but it's not that good. It's greatly revered and it's used a lot because it's
better than nothing, but it doesn't give a lot of precision. I've had many patients with
untreated Gleason 8 or 9 disease that have not developed any metastases, and of course,
we hear about the bad cases where people develop widespread metastasis with these higher
Gleason scores and sometimes even with Gleason 7s--low-ish Gleason scores. It's a probabilistic
construct, a prediction of risk but it doesn't give you true clarity in an individual this
will or won't spread and how far it will spread. That is usually something that is
discovered over a period of time after people get treated, you see how the situation behaves.
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