here to PRINT
Specific Antigen (PSA) test - what is it?
Prostate Specific Antigen (PSA)
is a chemical produced normally by prostate cells. It is a
type of chemical known as an enzyme, and it is believed to
have a role in liquefying semen after ejaculation (which may
help in sperm motility).
PSA testing can help diagnose
prostate cancer in early stages when it may be
localised to the prostate gland and can be treated.
PSA is only produced by prostate
cells (it is prostate specific), but is produced
by both cancerous and non-cancerous prostate cells (it is
not cancer specific). Although PSA is
the best example we have of a marker for prostate cancer this
non-specificity for cancer means that there are reservations
about the interpretation of raised values.
Essentially, one of the following
scenarios may commonly occur
- A man with prostate
cancer may not have a raised PSA test (this is known
as a false-negative result)
- A man with a raised
PSA may not have prostate cancer (this is known as
recommendations for Further Investigations
The current recommendations for
further investigations are that if either the DRE is abnormal,
or the PSA test is raised above the age adjusted limit then
further investigations should be performed.
Should I have
a PSA test, and what will it mean?
If a PSA test is performed and
is normal this is not cast-iron proof that you do not have
prostate cancer, and your doctor may still wish to perform
further tests if your prostate feels abnormal. Equally if
your PSA is raised this does not necessarily mean that you
do have prostate cancer.
If you choose to have a PSA test
done you should be prepared to undergo a prostate biopsy if
the PSA value is sufficiently raised to justify this course
Further information is available
from the following web site: www.prostate-cancer.org.uk/
here to go back to the Prostate Cancer Main Menu