Testosterone, Prostate Specific Antigen and Prostate Cancer
by
Michael C. Scally, M.D.
Author of
"Anabolic Steroids - A Question of Muscle: Human Subject Abuses in Anabolic Steroid Research "
Harvard Medical School - M.D.; Harvard-M.I.T. Program In Health Science & Technology
Massachusetts Institute of Technology, B.S. Chemistry/Life Sciences
Prostate Specific Antigen (PSA), TRT, and Finasteride
Q: I have watched my PSA rise and have had some urological problems
recently. I have seen 3 urologists. One said discontinue TRT now and the other two
were not quick to discontinue anything. Should older guys be thinking about a
5AR while on exo test?
A: Brief discussion below. Also, have you considered the use of
finasteride,
etc.? A thought after any pathology has been ruled out.
Benign Prostatic Hyperplasia - The development of BPH requires the presence
of androgens and that the marked reduction in serum testosterone caused
by chemical or surgical castration causes reduced prostate volume. Studies
have failed to demonstrate exacerbation of voiding symptoms attributable
to BPH during testosterone supplementation.
Prostate volume, as determined by ultrasonography, does increase significantly
during testosterone-replacement therapy.Urine flow rates, postvoiding
residual urine volumes, and prostate voiding symptoms did not change
significantly in these studies. This is explained by the poor correlation
between prostate volume and urinary symptoms. Individual men with hypogonadism
may occasionally have increased voiding symptoms with TRT.
Prostate Cancer - There is no scientific peer-reviewed literature that
definitely establishes a link between the administration of testosterone
and the increasing the risk or development of prostate cancer. There
is no compelling evidence that testosterone has a causative role in
prostate cancer or to suggest men with higher testosterone levels are
at greater risk of prostate cancer or that treating hypogonadism with
exogenous androgens increases this risk. Just remember the incidence
of prostate cancer rises with aging which is associated with declining
testosterone levels. Prostate cancer becomes more prevalent exactly
at the time of a man's life when testosterone levels decline.
Over 200,000 men are given a diagnosis of prostate cancer each year
and most are first detected by a rise in the PSA level unrelated to
testosterone therapy.
Interestingly the underlying prevalence of occult prostate cancer in
men with low testosterone levels appears to be substantial. A history
of prostate cancer has been considered an absolute contraindication
to testosterone-replacement therapy which is now under active debate
for men who are deemed cured.
PSA – The 2002 U.S. Preventative Services Task Force recommendations
on the screening for prostatic cancer concludes that the evidence is
insufficient to recommend for or against routine screening for prostate
cancer using prostate-specific androgens (PSA) testing or digital rectal
examination (DRE), "Screening is associated with important harms including
frequent false-positive results and unnecessary anxiety, biopsies, and
potential complications of treatment of some cases of cancer that have
never affected a patient's health. The USPSTF concludes that evidence
is insufficient to determine whether the benefits outweigh the harms
for a screened population."
PSA values used to trigger prostate biopsy include an increase of 1.5
ng per milliliter within two years or a total increase of 2.0 ng per
milliliter over any period. These recommendations have been based on
observational population studies in untreated men. I would use 0.75
ng over 12 months.
These are free downloadable files.
Rhoden EL, Morgentaler A., Risks of testosterone-replacement therapy
and recommendations for monitoring, N Engl J Med. 2004 Jan 29;350(5):482-92.
Screening for prostate cancer: recommendation and rationale. (2002).
Ann Intern Med, 137(11), 915-916.
Recommendations if PSA is high BUT Prostate Biopsy is Negative
Q: if a man tests high on a single PSA or shows some acceleration in
PSA with numbers as you suggest AND evaluation by biopsy proves negative,
should continued high scores on PSA be ignored? Should avadart or something
similar be used to lower the score?
A: I had a number of patients with an elevated PSA. Each was checked
out by a urologist with periodic monitoring. The acceleration is something
I would particularly careful for. It is pretty unusual to have sexual
dysfunction while on T and an alpha –reductase blocker. I usually suggested
to patients. One could use
Dutasteride (forgot the brand name) instead
of Finasteride but it is probably not worth the cost. Overall, dutasteride
is a more efficient steroid 5 -reductase inhibitor than finasteride.
They have been shown to be protective for prostate cancer. But, as I
said previously there are no studies linking TRT to PrCa. Testosterone
replacement therapy in men with erectile dysfunction and hypogonadism
is associated with a minor PSA elevation.
In a study in hypogonadal men with and without high grade prostatic
intraepithelial neoplasia (PIN), which is considered a prostatic precancerous
lesion, after 1 year of TRT men with PIN did not have a greater increase
in PSA or a significantly increased risk of cancer than men without
PIN. These results indicate that TRT is not contraindicated in men with
a history of PIN.
Dihydrotestosterone (DHT) is the primary metabolite of testosterone
in the prostate and skin. Testosterone is converted to DHT by 5alpha-reductase,
which exists in two iso-enzyme forms (types 1 and 2). DHTis associated
with development of benign prostatic hyperplasia (BPH), and reduction
in its level with 5 alpha-reductase inhibitors improves the symptoms
associated with BPH and reduces the risk of acute urinary retention
and prostate surgery. A selective inhibitor of the type 2 iso-enzyme
(finasteride) has been shown to decrease serum DHT by about 70%.
We hypothesized that inhibition of both iso-enzymes with the dual inhibitor
Dutasteride would more effectively suppress serum DHT levels than selective
inhibition of only the type 2 iso-enzyme.
DIHYDROTESTOSTERONE (DHT), A STEROID hormone produced from testosterone
by the enzyme 5alpha- reductase is the primary active metabolite of
testosterone. In male fetal development and puberty, it is essential
for normal masculinization of the external genitalia and normal development
of the prostate gland. In later life, DHT is associated with the development
of benign prostatic hyperplasia (BPH) and androgenetic alopecia. The
enzyme 5 alpha-reductase is present throughout the body in two forms,
type 1 and type 2. Type 1 has been reported to be located predominantly
in the skin, both in hair follicles and sebaceous glands, as well as
in the liver, prostate, and kidney. Type 2 is found in the male genitalia
and the prostate; recent research has also identified type 1 mRNA and
enzyme activity in the prostate.
The first available 5-alpha reductase inhibitor (finasteride) is selective
for the type 2 iso-enzyme. Its clinical utility in reducing enlarged
prostates, relieving symptoms associated with BPH, and reducing the
risk of associated complications has been documented in several clinical
trials. More recently, 5 alpha-reductase inhibition has been proven
effective in treating androgenetic alopecia. Finasteride suppresses
serum DHT by about 70%. Dutasteride is a 6-azasteroid, which inhibits
both type 1 and type 2 5_-reductase iso-enzymes. The IC50 for type 1
5 alpha-reductase is 0.7 and 81.0 nm for dutasteride and finasteride,
respectively, and for type 2 5 alpha-reductase, 0.05 and 0.16 nm, respectively.
New Markers for Prostate Cancer
Q: have you used the AMACR in lieu of the PSA? Is AMACR ready
to replace PSA as a PC indicator?
A: I have no personal experience with AMCAR. I do not think it is even
commercially available. For others a brief background follows with some
links to downloadable articles.
Prostate specific antigen (PSA) is a sensitive serum marker for pathology
in the prostate (cancer, infection, benign hyperplasia). The level of
PSA, however, is poorly correlated with grade and stage of prostate
cancer. Genomic and proteomic methodology has recently been used to
discover more then 200 putative new markers for prostate cancer like
alpha-methylacyl CoA racemase (AMACR), hepsin, glutathione S-transferase
?, EZH2 and DD3(PCA3). To date, none of these markers have been adequately
validated for clinical use.
Prostate cancer is the second-leading cause of cancer-related death
in American men (1). Although the use of prostate-specific antigen (PSA)
screening has led to the earlier detection of prostate cancer, the impact
of PSA screening on cancer-specific mortality is still unknown, pending
the results of prospective randomized screening trials. Interpretation
of the serum PSA test is made on the basis of PSA levels, with levels
of 0–4 ng/mL being considered normal and levels of greater than 4 ng/mL
being considered clinically significant for prostate cancer screening.
A major limitation of the serum PSA test is its lack of specificity
for prostate cancer, especially in the intermediate range of PSA levels
(4–10 ng/mL). In this range, the specificity of the PSA test to detect
prostate cancer has been reported to be only 20% at a sensitivity of
80%. This poor specificity is, in part, associated with the fact that
serum PSA levels can be increased in patients with nonmalignant conditions
such as benign prostatic hyperplasia or prostatitis and that PSA is
highly expressed in both benign prostatic epithelia and prostate cancer
cells.
One such prostate cancer biomarker is -methylacyl-CoA racemase (AMACR),
an enzyme that catalyzes the racemization of R-stereoisomers of branched-chain
fatty acids to S-stereoisomers and plays an important role in peroxisomal
-oxidation of branched-chain fatty acids. Differential display and expression
array analyses have identified the AMACR gene as a gene whose expression
is higher specifically in prostate cancer epithelia relative to benign
prostatic epithelia. AMACR is a highly specific and sensitive marker
for cancer cells within the prostate gland. In addition, a recent study
demonstrated that sequence variants of AMACR may be associated with
prostate cancer risk. Although AMACR may be potentially useful in the
diagnosis of prostate cancer from tissue specimens, it would have considerably
more utility as a tumor marker if it could be detected in serum.
http://jncicancerspectrum.oxfordjournals.org/cgi/content/full/jnci;96/11/834
http://ajp.amjpathol.org/cgi/content/full/164/3/831
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