How your doctors
make the diagnosis
In the GP's
surgery
Usually you begin by seeing your family doctor
(general practitioner) who will examine you and ask you about
your general health. The first two tests for diagnosing cancer
of the prostate are a rectal examination and a blood
test.
For the rectal
examination your doctor places a gloved finger into your back
passage to feel the prostate and check for any
abnormalities.
PSA
Test
A sample of blood is taken to check for a
substance called PSA (prostate specific antigen). PSA is a
substance produced by the prostate and a small amount normally
leaks into the blood. Men with cancer of the prostate tend to
have more PSA in their blood. However, this test is not always
reliable as PSA levels also increase with age and with other
conditions of the prostate such as infection or the
non-cancerous condition, benign prostatic hypertrophy (BPH).
As a rule the higher the level of PSA the more likely it is to
be cancer. Once the cancer has been treated the level of PSA
will fall. For this reason, measuring PSA levels is a helpful
way of assessing the progress of the disease and the
effectiveness of treatment.
If your GP finds any
abnormalities he or she will refer you to hospital for further
tests.
What is
PSA?
PSA stands for prostate-specific antigen, a
natural chemical produced by the prostate. Glands which are
enlarged, whether as a result of cancer or another condition,
produce more PSA. PSA testing can be used to help with:
A number of other tests may be
done to see if you have prostate cancer. No one test on its
own is conclusive
At the
hospital
Although the following tests can be used
to diagnose cancer of the prostate you do not need to have all
of them done. The advantages and disadvantages of each method
should be explained to you before you agree to any of them.
Your doctor should tell you how and when you will get the
results.
Trans-rectal
ultrasound scan
Ultrasound scans use sound waves to
build up a picture of the inside of the body. To scan the
prostate gland a small probe is passed into the back passage
and the image appears on a screen. This type of scan is used
to measure the exact size of the prostate. A sample of cells
(biopsy) can be taken at the same time for examination under
the microscope.
The scan may be slightly
uncomfortable but it only takes a few minutes.
Biopsy
If the initial tests (rectal
examination, PSA or ultrasound) show the possibility of
cancer, you may be asked to have a biopsy, in which a sample
of cells is taken from the prostate to be looked at under a
microscope. The biopsy is usually done through the back
passage (rectum). This test is usually a little uncomfortable,
and can sometimes be painful, but it does not need a general
anaesthetic. Antibiotics should be given to reduce any risk of
infection. For a few days following this test you may notice
bleeding when passing water or after sex.
Cystoscopy
In this procedure the
doctor looks through a telescopic tube to examine the urethra
and bladder. If necessary any blockage can be removed. The
cystoscopy may be done using a local anaesthetic jelly. If a
TURP were going to be carried out, a general or spinal
anaesthetic would be used.
Intravenous
urogram
This test is known as an IVU or IVP, and
will show up abnormalities in the kidneys or urinary system.
It will be done in the X-ray department and usually takes
about an hour.
A dye is injected into a
vein, usually in the arm, and is carried by your bloodstream
to your kidneys. The doctor can watch the passage of the dye
from your kidneys to the bladder on an X-ray screen.
The dye sometimes makes
you feel hot and flushed for a few minutes but this feeling
gradually disappears and you should be able to go home or to
work as soon as the test is over.
X-rays
A
chest X-ray and X-rays of the bones are often taken to see if
there has been any spread of the cancer to other parts of the
body.
Isotope bone
scan
Bone scans are very sensitive and can detect
cancer before it shows up on X-ray.
For this test a very
small amount of a mildly radioactive substance is injected
into a vein, usually in your arm. A scan is taken of the whole
body and as abnormal bone absorbs more of the radioactive
substance than normal bone this shows up on the scan as
highlighted areas.
After the injection you
will have to wait for up to three hours before the scan can be
taken so it is a good idea to take a book or magazine with
you.
The level of
radioactivity that is used is very small and does not cause
any harm.
This scan can also detect
other conditions affecting the bones such as arthritis, so
further tests such as an X-ray of the abnormal area may be
necessary to confirm that it is cancer. CT scan (CAT
scan)
A CT scan is a more specialised type of
X-ray. A number of pictures are taken from different angles
and fed into a computer which shows detailed pictures of the
inside of the body. These may show if the cancer has spread to
other parts of the body.
To reveal more detail, a
dye containing iodine may be injected into a vein in your arm.
You may feel hot all over for a few minutes. Once you are in a
comfortable position the scan can be taken. The scan is
painless but it will mean lying still for about 30-40
minutes.
You should be able to go
home as soon as your scan is over.
Magnetic Resonance
Imaging (MRI or NMR scan)
This test is similar to a
CT scan but uses magnetism instead of X-rays to build up
cross-sectional pictures of your body.
During the test you will
be asked to lie very still on a couch inside a metal cylinder.
It can be slightly uncomfortable and some people feel a bit
claustrophobic during the scan which is also very noisy! You
can usually take someone with you into the room to keep you
company.
How the tests are
used
These clinical tests will indicate the extent
or stage of the prostate cancer, and the biopsy specimens will
be analysed to find out the likely aggressiveness of the
cancer. A method of assessment called the Gleason grading
system is often used for this purpose. In this system grade 2
indicates a slowly developing cancer, and grade 10 the most
aggressive. The Gleason grade and the other test results taken
together can be used to decide which is the most suitable
treatment programme.
It will probably take
several days for the results of your tests to be ready and
this waiting period will obviously be an anxious time for you.
You may find it helpful to talk things over with your doctor,
a relative or close friend.
