CANCER SCREENING
C
TESTS USED TO DETECT CANCER
Cytology
tests
These tests reveal the presence of
abnormal cells. One example is the
cervical smear test
,
an investigation
in which cells are scraped from the
cervix (neck of the uterus) and
examined microscopically to detect
potential or early cancer of the cervix.
Another example is urine cytology,
used to detect bladder cancer. Cells
can also be removed from solid
lumps; this procedure is often
carried out on breast lumps.
Imaging
techniques
Imaging tests can sometimes reveal
changes in the appearance oftissue
that are suggestive of cancer. One
such test is a low-dose X-ray used in
mammography
to detect early
breast cancer. Another is
ultrasound
scanning;
for example, pelvic
ultrasound scans can detect cancer
of the ovary. CT scanning and MRI
provide detailed images of internal
anatomy and are particularly useful
for showing inaccessible areas, such
as the brain and the backofthe
abdominal cavity.
Chemical
tests
Tests on blood, urine, or faeces can
show the presence of substances
suggestive of cancer. For example,
microscopic amounts of blood in the
faeces may be due to cancer of the
colon; high blood levels of prostate
specific antigen (PSA) are sometimes
due to prostate cancer.
Viewing
techniques
Viewing tests involve looking inside a
hollow organ using an
endoscope
(a
tube with a viewing lens). They are
usually performed only when cancer
is already suspected. Examples
include
colonoscopy, gastroscopy,
cystoscopy,
and
laparoscopy
(viewing of the colon, stomach,
bladder, and abdominal cavity,
respectively).
risk of cancer.
Psychotherapy
,
including
behaviour therapy
,
may be of benefit.
(See also
phobia
. )
cancer screening
Tests that are carried out to detect can-
cer before symptoms have developed.
Cancer screening is used particularly
for groups of people who are thought
to be susceptible because of their age,
occupation, lifestyle, or genetic predis-
position. Early detection often increases
the chance of a cure. Tests for cancers of
the cervix (see
cervical smear test)
,
breast
(see
mammography
) ,
bladder, and colon
have proved effective in reducing m or-
tality from these conditions.
cancrum
The medical term for canker or ulcera-
tion. It mainly refers to the mouth and
lips, when the condition is known as
cancrum oris. (See also
noma
. )
candidiasis
Infection
by
the
fungus
C
andida
albicans
,
also
known
as
thrush
or
moniliasis. Candidiasis affects areas of
mucous membrane in the body, most
commonly the vagina and the inside of
the mouth. In infants, candidiasis can
occur in conjunction with
nappy rash.
CAUSES
The fungus is normally present in the
mouth and the vagina, but in some
situations it may multiply excessively.
Candidiasis may occur if
antibiotic drugs
destroy the harmless bacteria that con-
trol the growth of the fungus, or if the
body’s resistance to infection is low -
ered.
Certain disorders,
for example
diabetes mellitus
,
and
the
hormonal
changes that occur during pregnancy
or with
oral contraceptives
,
may also
encourage growth of the fungus.
Candidiasis
can
be
contracted
by
having
sexual
intercourse
with
an
infected partner. The infection is far
more common in women than in men.
SYMPTOMS
Symptoms of vaginal infection include
a thick, white discharge, genital irrita-
tion, and discomfort on passing urine.
Less commonly, the penis is infected,
usually causing
balanitis
(inflammation
of the head of the penis). Oral candi-
diasis
produces
sore,
creamy-yellow,
raised patches inside the mouth.
Candidiasis
may
spread
from
the
genitals or mouth to other moist areas
of the body. It may also affect the
gastrointestinal tract, especially in peo-
ple with impaired immune systems,
such as those taking
immunosuppressant
drugs
or w ho have H IV (the virus that
leads to
AIDS
) .
DIAGNOSIS AND TREATMENT
Candidiasis is diagnosed by examina-
tion of a sample taken from the white
discharge or from patches.
The condition is treated topically with
antifungal drugs
such as clotrimazole or
w ith oral antifungals. The drugs are
given in the form of creams, vaginal
pessaries, or throat lozenges. Treatment
of candidiasis is usually successful, but
the condition may recur.
Canesten cream
A brand name for the
antifungal drug
clotrimazole, used to treat fungal infec-
tions
of the skin and
genitals
(for
example,
candidiasis
).
canine tooth
See
teeth.
cannabis
A preparation that is derived from the
hemp plant C
annabis
s a tiv a
and usually
used to produce euphoria and halluci-
nations (see
marijuana).
cannula
A smooth, blunt-ended tube that is
inserted into a blood vessel, lymphatic
vessel, or body cavity, in order to intro-
duce or withdraw fluids.
Cannulas are used for
blood transfu-
sions
and
intravenous infusions
and for
draining
pleural effusions
(fluid around
the lungs). If necessary, a cannula may
be left in place for several days if con-
tinuous testing of, or introduction of,
fluids is required.
canthus
The anatomical term for the corner of
the
eye (
the angle at w hich the upper
and lower eyelids meet).
capacity, iron-binding
A measure of the level of transferrin, a
protein that acts in addition to
haemo-
globin
(the oxygen-carrying pigment in
the blood) to bind and transport iron
in the blood. Measuring iron-binding
capacity may help to establish the cause
of
anaemia
(a reduced level of haemo-
globin in the blood).
Transferrin is formed mainly in the
liver.
The amount produced is deter-
mined by the amount of iron that is
stored in the body. W hen iron stores are
low, as occurs in iron-deficiency anae-
mia (see
anaemia, iron-deficiency),
more
transferrin is produced to enable the
blood to carry as much iron as possi-
ble. The level of transferrin and the
iron-binding capacity of the blood are
thereby raised, although the level of
iron in the body is low.
140
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