Re: Medical Research-Evidence


"George Conklin" <georgeconklin1@xxxxxxxxxxxxx> wrote in message
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"George Conklin" <georgeconklin1@xxxxxxxxxxxxx> wrote in message
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Prostate cancer treatments are being evaluated, such as
the
PIVOT
study. But some going on for 10 years have yielded no results
yet,
strongly
suggesting that all current modes of treatment cure those who
would
not
die
of the disease anyway. Those who advocate PSA tests and
aggressive
treatments now claim that the best results will show up AFTER
15
years!!!
But that is another 5 years out, and then it will be raised to
20.

There is recent 10 year data showing a survival benefit of
surgery
vs.
watchful waiting. It's long been known that survival benefit
studies
would
need to go out at least that far except in metastatic cases.



Here is a comment from another newsgroup:

Both Dale and George are correct.

Dale is correct in that radical prostectomy has been shown to
lower
the
death rate due to prostate cancer (see the New England Journal of
Medicine article at:
http://content.nejm.org/cgi/content/abstract/347/11/781).

George is correct in that radical prostectomy has been shown to
have
no
significant difference over watchful waiting in overall survival
(see
the New England Journal of Medicine article at:
http://content.nejm.org/cgi/content/abstract/347/11/781).

Now, what do you have to add with a link?

You're using outdated information. That study had a mean followup
of
only
6.2 years, which was too short for a survival study with prostate
cancer.
Allow me to refer to a followup the same study you posted above,
done
with
the same patient population and the same authors, just longer
timepoints
for
data:

3 years later, a newer/better study was published in the same
Journal:

"Radical Prostatectomy versus Watchful Waiting in Early Prostate
Cancer",
May 12, 2005 by Bill-Axelson and Holmberg et al. (same authors,
longer
followup)
This paper is *the* landmark paper for this topic in the field.

The study showed that "radical prostatectomy reduces
disease-specific
mortality, overall mortality, and the risks of metastasis and local
progression".


and then the following, which is what Herman talks about allowing
the
patient to make decisions:

You're welcome for the reference.

"THE ABSOLUTE REDUCTION IN THE RISK OF DEATH AFTER 10 YEARS IS
SMALL...."

The risk of death was not seen at 6 years, which was to be expected.
3
years later it was noticed - before it should have been expected to be
seen - and was both clinically and statistically significant. The
more
time
that elapses, the more signficant the differences will become.


This was expected for high-dose chemotherapy for recurrent breast
cancer
too, but it did not work out that way. (The so-called bone marrow
transplants).

Even if the results get no better than they are now, their is a
signficant
difference, clincally and statistically.

What Herman was trying to tell you is that this is not so.

Herman is not a a doctor and a physician is in a better situation to
determine what is CLINICALLY significant.

Very small
differences must be evaluated carefully even if statistically significant.
The original authors state differences are small. Why dispute them?

I'm not disputing them. I support them. You just don't seem to understand
that a relatively small difference can be a very important one...
especially if you're amonge the extra 20 lives saved in that study.

I'm not one of those guys who advocates prostatectomy for every
patient
with
prostate cancer. I think there are a large number of patients for
whom
watchful waiting is appropriate. However, we can now say,
conclusively,
that in the face of diagnosed prostate cancer, surgery will save
lives.

Well, if you believe the data, a few. What about surgical mortality?
Did they happen to include that?

Of course. If I recall, there we no reported deaths. I'm at an
institution
that does about 5-10 per week and I can't recall the last time we had a
mortality from this surgery. But yes, mortality was included and should
always be inlcuded in such outcomes studies.

OK.

As for believing the data, I'd hope you would believe, since it was
merely
an extension of a study that you believed enough to post a link to.


I read the article, and noted that the differences are small. I wonder
why the American studies are holding back their results.

See below, they just finished enrollment a few years ago, which is about 5
years after the Euro study finished enrollment. That's why.

Just a few
differences in classification of deaths in the study you cite would change
the results.

Yes. It may have lessened the results. Or it may have strengthened them.

When multiple causes of death are present, a committee
decision that death was due to disease 1 or 2 is highly subjective. Those
comments were widely discussed at the time the study was released.

All cancer survival studies have this problem - so while I agree that it is
an issue, it's not one we can avoid. I could, of course, use the same
argument to say there may be differences in studies that didn't show a
difference for this very reason... but since there isn't a good way around
it, I leave it alone. So should you.

The American studies

Are not done yet.

are 10 years old and have no released their data
yet. Had they found even 1% differences, they would have gone to the
press
and hollared loudly. The PIVOT studies seem silent too. Why? No
results.
There were a lot of other questions raised by the Scandinavian data too
last
year.

FACT:
The Euro study completed enrollment in 1999. PIVOT just completed
enrollment 2 or 3 years ago. The data are far too immature and won't be
ready for a few more years.


On NPR there was a study from a man who called it the "Minneapolis
Study,"
as I recall, and it had been going 8 years with no results. The study
director was interviewed. I did not have a tape machine going.

You can speculate all you want. The FACT is that the study close enrollment
a half decade later than the recently published Euro study, so their not
having results yet is entirely expected.

The study showed 30 men dying of prostate cancer in the surgical
arm
with
50
men dying of prostate cancer in the watchful waiting arm. The
total
number
of deaths from other causes were 53 and 56, resepectively - so
equivalent.

For Herman - that is both statistically and clinically significant
:)

These numbers will likely to become even more disparate between the
two
groups as time goes on, since that is the nature and natural
history
of
prostate cancer. In truth, this study found a signficant survival
advantage
a few years earlier than most had predicted.

So you can tell your poster in the other newsgroup his data is
outdated
and
now you, George, have been given evidence that early intervention
prostate
cancer saves lives.

Good day.

And let me remind you a point I made earlier: the progress against
adult
cancers is SMALL.

That's an opinion, one that I don't share.

You even gave me an article which said small. What you boys do in
the
medical business is inflate your egos. You are such a prime example.

First, there is more to progress than survival.

No one said there was not.

Then we have made "progress against cancer:"

The ability to treat the
crippling symptoms of metastatic disease beyond cure is of major
importance.

That was said about high-dose treatment of breast cancer too, but it
turned out maybe not to be true.

I don't know your hangup with breast cancer. Palliative hormonal treatment
for prostate cancer has been around for decades and is very effective. If
you want to debate breast cancer, start a new thread.

Second, prostate cancer is just one cancer, and given the indolent nature
of
it and other factors it will never be the poster child for progress in
cancer. However, there are HUGE surival differences if you look at other
treated vs. untreated cancers such as bladder and kidney.

Huge, as in how much added life expetancy? Surgical removal of a kidney
as opposed to what? Doing nothing? I was more interested in the prostate
cancers because my father was treated at 65 and died at 90 from something
else. (Radiation). He taught 38 years of premeds so had a lot of doctors
to choose from that he had had as a student.

Prostate cancer is very different from kidney cancer. Survival will be more
difficult to show, it will take much longer studies, etc. Kidney cancer or
bladder cancer is quite the opposite. If not treated pronto, either can
progress rapidly to death. Surgery can result in cures in large numbers of
patients, espeically lower stage disease. The numbers depend on the type of
cancer, the stage, the treatments, etc. But there is not the same
controversy as there is with prostate cancer - with renal and bladder
cancers rapid surgical intervention clearly can be life saving for many.


.

Relevant Pages

  • Re: Medical Research-Evidence
    ... "Radical Prostatectomy versus Watchful Waiting in Early Prostate ... What Herman was trying to tell you is that this is not so. ... The only issue is whether a treatment works. ... differences in cancer survival rates over very long periods of time may be ...
    (talk.politics.medicine)
  • Re: Delayed Treatments for Prostate Cancer
    ... "Incidence of Initial Local Therapy Among Men With Lower-Risk Prostate ... Cancer in the United States "? ... Treatment may result in morbidity. ...
    (talk.politics.medicine)
  • Number of prostate biopsies
    ... "If during an DRE the uro feels a nodule, is it really necessary to take more than one biopsy, right from the nodule? ... There could be cancer even if no nodule was felt. ... The importance in taking multiple cores from around the prostate is in determining the percentage of cores which show up positive for prostate cancer. ... Basically, if 50% or more come up positive, then there is almost no chance that localized treatment will effect a cure. ...
    (sci.med.prostate.cancer)
  • Re: Delayed Treatments for Prostate Cancer
    ... "Incidence of Initial Local Therapy Among Men With Lower-Risk Prostate ... Cancer in the United States "? ... It was a retrospective review of thousands of patients in the SEER database. ... Treatment may result in morbidity. ...
    (talk.politics.medicine)
  • Re: Medical Research-Evidence
    ... "Radical Prostatectomy versus Watchful Waiting in Early Prostate ... The only issue is whether a treatment works. ... differences in cancer survival rates over very long periods of time may be ... advantage for surgery vs. watchful waiting. ...
    (talk.politics.medicine)