© The Canadian Journal of Urology™; 21(Supplement 2); June 2014
Predicted PSA based on prostate volume
Larger-volume, benignprostates can also express higher
levels of PSA. Sometimes it is difficult to determine the
accurate volume of the prostate just by doing a DRE.
A transrectal ultrasound (TRUS) is very useful to
provide an accurate determination of the volume of a
prostate. The “predicted PSA” of a benign prostate is
“volume times 0.12.” This can provide an indication of
whether a serum PSA level is elevated due to a large,
benign prostate or due to cancer.
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PSA density
PSA density is total PSA divided by prostate volume.
A PSA density of greater than 0.15 is suggestive of
prostate cancer.
TRUS
Be careful of using a TRUS to detect prostate cancer.
There have been too many false positives and too
many false negatives over the years. Therefore,
guidelines do not recommend doing a TRUS to rule
out prostate cancer, although this test is very helpful
for determining the volume of the prostate.
As discussed in the article on BPH by Rosenberg in
this supplement,
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a PSA> 1.5 ng/mL, regardless of the
age of the patient, represents a prostate volume of at
least 30 ccs. Guidelines recommend that patients with
a prostate of > 30 ccs or a PSA > 1.5 ng/mL should be
treatedwith combination therapywith an alpha-blocker
and a 5-alpha reductase inhibitor (5-ARI) to prevent the
progression of BPH to urinary retention or the need for
surgery.
PSA response to 5-ARIs
As mentioned earlier, to treat an enlarged prostate
(> 30 ccs), guidelines recommend combination therapy
with an alpha-blocker and a 5-ARI. Alpha-blockers have
no impact on PSA. However, 5-ARIs ARE EXPECTED
to lower PSA. If we do not see an almost 50% drop in
PSA after 6 months of treatment with finasteride or
a continual drop to a PSA nadir (lowest level) after 6
months of treatment with dutasteride, then the patient
may have underlying cancer and should be referred to
a urologist. Before referring the patient, repeat the PSA
test 2 to 4 weeks later, to confirm an increase or a lack
of decrease from the previous value.
PCA3
Prostate cancer antigen type 3 is a newer test that may
be useful in a patient who has had a negative biopsy.
PCA3 is measured in urine. The first 200 ccs of urine
expressed after a vigorous rectal massage are analyzed
to determine the ratio of cells that express the PCA3
antigen to cells that do not. By definition, if the ratio is
> 35, then there is a high chance of detecting prostate
cancer on a biopsy.
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Phimosis
By definition, phimosis is a foreskin that is either so
tight or so stuck that it cannot be fully retracted, such
that the full head of the penis right back to the coronal
sulcus is exposed. In young boys and more elderly
men, phimosis can result in resistance to urinary
outflow causing burning, recurrent UTIs, or dribbling
after voiding, as the retained drops of urine seep out
from under the foreskin.
Some men will complain that there is cracking or
tearing of the foreskin or the frenulum (the tissue band
on the ventral aspect of the penis) with erections. The
persistence of urine on the glans under the foreskin can
also result in balanitis or inflammation on the head
of the penis. Often mothers will report that their son
has “white bumps” under the foreskin. These bumps
represent “retained smegma” that is loculated behind
the subcoronal adhesions. Finally, sometimes the
foreskin is so tight that a man cannot urinate at all, and
it is almost impossible to pass a catheter.
Treatment
To treat phimosis, in an infant or young boy, a parent
can be instructed to apply a daily steroid cream to the
boy’s foreskin and gently retract the boy’s foreskin in
the bath every night, and sometimes the adhesions will
open and the loculations can be expressed.
If it is just the frenulum that is tight and tearing, then
under local anesthetic, one can transect the frenulum
and it should heal easily. If there are remaining issues
and conservative measures do not work, and in an
emergency setting if the problem is passing a catheter,
then a dorsal slit may be performed under local
anesthetic.
Acircumcision is usually the best alternative if there
are significant complaints. Occasionally, if the patient
is strongly attached to his foreskin, then a partial,
more distal circumcision can be performed, where one
TABLE 3.
Age-specific normal PSAvelocity cut points
Age (years)
PSAvelocity cut point (ng/mL/year)
40-59
0.25
60-69
0.50
> 70
0.75
PSA = prostate-specific antigen
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A guide to the management of urologic dilemmas for the primary care physician (PCP)
