DNA ploidy & PET scan

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Stephen Jordan - 03 Dec 2004 21:45 GMT

My onc was not receptive to the idea of having the following two
diagnostic tests performed:

1. DNA ploidy, which determines to what extent PCa cells have diploid
DNA and aneuploid DNA. The first is normal DNA and is affected by ADT,
the second is abnormal and hormone-refractory.

The onc, whose subspecialty is radiation, told me that at one time the
DNA ploidy test was thought to be a possibly certain means of
forecasting the future course of the disease, but it proved not to be.

Comment?

2. He was also not receptive to having a (11C)choline PET scan
performed. I'm less clear on his reason; have the impression that he's
unfamiliar with it but hope I'm mistaken.

This scan is supposed to have 82% sensitivity and 94% specificity in
staging of lymph nodes in PCa cases.

Comment?

Regards,

Steve J
__
"Never give in--never, never, never, never, in nothing great or small,
large or petty, never give in except to convictions of honour and good
sense. Never yield to force; never yield to the apparently overwhelming
might of the enemy.''
--Sir Winston L. S. Churchill

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ron - 04 Dec 2004 03:40 GMT

> My onc was not receptive to the idea of having the following two
> diagnostic tests performed:
[quoted text clipped - 8 lines]
>
> Comment?

Hi Steve...Dr. Strum still recommends ploidy analysis on P2P.
Bostwick Labs is a provider of this measurement. Like PSA or GS,
measurements between labs are often difficult to compare, but results
from a lab can be compared in a meaningful fashion. It has been shown
that biopsy ploidy correlates with ploidy from pathological specimens.
Ploidy correlates with ADT efficacy and cancer specific survival. It
seems logical that it should. I suspect that like DRE, PSA and GS,
ploidy is more meanigful when viewed within the context of these other
tests, rather than alone. If you search "ploidy analysis, prostate
cancer" on PubMed or Google you'll get lots of relevant hits...Best
wishes and good health, Ron

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Alan Meyer - 05 Dec 2004 02:32 GMT

> My onc was not receptive to the idea of having the following two
> diagnostic tests performed:
[quoted text clipped - 17 lines]
>
> Comment?

Steve,

I'm not familiar with these tests and can't comment on them
specifically.

My general feeling about testing is that, if it's not risky or invasive,
the more information the better. However there's also the question
of cost. A doctor may think that he has to have two alternative plans
for what he would do if the test came out one way vs. what he'd do
if it came out the other way - in order to justify the cost of the test.
If he can't order different treatments based on test outcome, he
might have trouble justifying the cost to the insurance providers.

Sometimes the outcome may make no difference to the treatment
but a considerable difference to the patient. For example, if one
test outcome predicts longer life and the other early death, a
patient might well make important life choices based on the
result.

If you can argue for one of those differences (either in treatment
choice or in patient choices), and the doctor agrees with your
analysis, maybe he'll perform the tests for you.

Alan

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