On March 25, ron replied to me:
> Hi Steve...Have you been tracking your T level?
Yes. T on March 20 was 437, about the same as last September.
(snip)
> Also, since you're on Avodart your
> checkpoint of PSA=1.0 is roughly equivalent to PSA=2.0 for a man not
> taking it, but I suspect you already know this...
This doubling idea is controversial. It applies when one is on a 5AR
inhibitor such as
Proscar or Avodart for tx of BPH. Reduction of the PSA
expression is genuine and is not a "masking." It is caused by reduction
in the size of the gland.
After primary PCa tx, the doubling is inapplicable. The PSA is what it is.
For a detailed discussion, see the following essay by Ralph Valle, whose
PCa expertise is unequaled by any other layman, and IMO is greater in
scope and depth than that of many medics. It was written before advent
of Avodart (dutasteride), also a 5AR inhibitor..
"The question of Proscar (finasteride) reducing PSA by 50% needs review.
Finasteride was developed by Merck to treat BPH. Since BPH and PCa are two
diseases that could cause a PSA elevation and those prostate conditions can
and do coexist in many males, Merck promoted studies known as The
Finasteride Group Study to ensure that men treated with finasteride for BPH
would not be at increased risk of PCa by having reduced levels of PSA.
"In those studies, men treated with Proscar for prostate enlargement
experienced a blood serum PSA reduction of approximately 50%. There is
ample
evidence that this PSA reduction is related to a reduction in gland volume
(maximized by one year of treatment) caused by cell death and reduced cell
proliferation. In other words, the PSA reduction is not an artifact causing
a masking effect on the measuring test, but simply an effect caused by
definitive biological factors induced by the inhibition of DHT.
"In Dominican Republic there are several families of men born with a
genetic
disorder by which they do not convert testosterone to dihydrotestosterone
(DHT). These men all have prostate atrophy, do not experience either BPH or
prostate cancer and are capable of procreation. It is a medical fact that
DHT is recognized as the androgen involved in the development of the
prostate gland.
"Finasteride is medically used to treat BPH and there was a prostate cancer
prevention study using Proscar in which 18,000 men participated. There
is no
question that inhibiting the formation of DHT has a significant impact in
the prostate gland. This trial resulted in nearly 25% reduction on PCa for
the participants on the active arm pf the study.
"The use of Proscar to treat prostate cancer is not a recognized label use
for this product. In spite of this, Proscar is used in hormone suppression
protocols when maximal suppression is intended. It is used in intermittent
androgen suppression during the off-cycle period to extend the time off
medications. Drs. Leibowitz, Strum/Scholz and Bruchovsky have successfully
used Proscar to effectively extend the off-cycle period. Dr. William Fair
studied the use of Proscar in treating stage D PCa and concluded that a
decrease in serum PSA in the finasteride treatment group suggests that
finasteride exerts a minor effect in patients with prostate cancer. This
effect does not approach that seen with medical or surgical castration, but
it is important because finasteride's lack of toxicity.
"JE Damber and coworkers in Sweden showed that finasteride treatment
decreases VEGF expression in the human prostate. Vascular endothelial
growth
factor (VEGF) is a potent regulatory factor of angiogenesis in human
prostate tissue. Also Wang and coworkers at New York University
demonstrated
that the level of androgen receptor was dramatically decreased in the cells
treated with finasteride.
"Merck's action to demonstrate that the use of finasteride in BPH does not
result in an impairment of prostate cancer detection by a 50% reduction in
PSA level has caused much confusion. The PSA reduction is real and
caused by
the action of Proscar in inhibiting DHT, VEGF expression and down
regulation
of the androgen receptor and not by a PSA masking effect without a direct
biological effect on androgen dependent cancer cells. In other words,in the
treatment of prostate cancer the 50% PSA reduction factor is not
applicable.
In such PCa patients, PSA results are what they are.
Sources:
"Fair WR et al.Multicenter, randomized, double-blind, placebo
controlled study to investigate the effect of finasteride (MK-906) on stage
D prostate cancer. J Urol 1992 Oct;148(4):1201-4
"Damber JE et al. Effects of finasteride on vascular endothelial growth
factor. Scand J Urol Nephrol 2002;36(3):182-7
"Bruchovsky N et al Intermittent androgen suppression for prostate cancer:
Canadian Prospective Trial and related observations. Mol Urol 2000
Fall;4(3):191-9;discussion 201
"Wang LG et al Down-regulation of prostate-specific antigen expression by
finasteride through inhibition of complex formation between androgen
receptor and steroid receptor-binding consensus in the promoter of the PSA
gene in LNCaP cells. Cancer Res 1997 Feb 15;57(4):714-9"
Thanks to anyone who got this far ;-)
Regards,
Steve J