CANCERPHOBIA
caused by weakening of the walls of
capillaries in the
dermis
(the inner
layer of the skin). Campbell de M or-
gan’s
spots
are
common
in
adults,
especially elderly people.
Campylobacter
A group of bacteria that are among the
most common causes of gastrointes-
tinal disorders. Campylobacter bacteria
are harboured by animals and can be
passed on to humans through conta-
minated food,
especially
in poultry,
causing
food poisoning.
These bacteria
also cause a form of
colitis,
an inflam -
matory disease of the colon.
canal
A narrow tubular passage or channel in
the body, such as the
ear
canal, w hich
leads from the outer to the middle ear,
or the alimentary canal, w hich is part
of the
digestive system.
cancer
Any of a group of diseases that are
characterized
by
the
abnormal
and
unrestrained growth of cells in body
organs or tissues. Cancerous tumours
can form in any tissue in the body, but
they most commonly develop in major
organs, such as in the lungs, breasts,
intestines, skin, stomach, or pancreas.
Cancerous tumours can also develop in
the nasal sinuses, the testes or ovaries,
or the lips or tongue. Cancers may also
develop in the tissues of the bone mar-
row
that
form
blood
cells
(see
leukaemia)
and in the lymphatic system,
the muscles, or the bones.
Cancers
differ from benign
(non-
cancerous)
neoplasms
(growths) in that
they spread and infiltrate surrounding
normal tissue. The tumours can cause
blockages in hollow organs, such as
w ithin the digestive tract. They can also
destroy nerves and erode bone. Cancer
cells may also spread through the blood
vessels or lymphatic system to other
organs
to
form
secondary tumours,
known as metastases (see
metastasis).
CAUSES
Tumour-forming
cells
develop when
the
oncogenes
(genes controlling cell
growth and multiplication) in a cell or
cells undergo a series of changes. A
small group of abnormal cells develop
that divide more rapidly than normal,
lack
differentiation
(they
no
longer
perform
their
specialized task),
and
may escape the normal control of hor-
mones and nerves.
Possible causes of cancer include envi-
ronmental factors (such as sunlight and
pollutants), alcohol consumption, diet-
ary
factors,
and,
most
particularly,
smoking,
w hich
is
responsible
for
more cancers than any other agent. All
of these factors may provoke critical
changes w ithin body cells in people
w ho are already susceptible to develop-
ing
cancer.
Susceptibility
to
certain
cancers may be inherited.
SYMPTOMS
Cancer symptoms depend on the site of
the growth, the tissue of origin, and
the extent of the tumour. They may be a
direct feature of the growth (for exam-
ple, lumps or skin changes) or may
result from disruption of the function
of a vital organ or blockage of a part of
the body by the tumour. Unexplained
weight loss is a feature of many differ-
ent types of cancer.
DIAGNOSIS
Screening tests (see
cancer screening
)
are
increasingly being used to detect early
signs of certain types of cancer in peo-
ple who are thought to be at risk. Early
detection
of
cancer
optimizes
the
chance
of a
cure;
for
this
reason,
screening for breast cancer, cancer of
the cervix, and intestinal cancer has
reduced mortality from these tumours.
Diagnosis of cancer after symptoms have
appeared is based on a physical examina-
tion, and confirmed by
biopsy
(removal
of a sample of abnormal tissue for
microscopic analysis) and imaging tests.
There are four main types of proce-
dure used to detect cancer: cytology
(cell) tests, imaging techniques, chemi-
cal tests, and direct inspection.
TREATMENT AND OUTLOOK
Many cancers are now curable, usually
by combinations of surgery,
radiother-
apy,
and
anticancer drugs
.
For details of a
specific type of cancer, refer to the art-
icle on that organ (for example, see
lung cancer; stomach cancer
) .
cancerphobia
An intense fear of developing cancer,
out of proportion to the actual risk,
that significantly affects the life of the
sufferer. An individual who has cancer-
phobia may become convinced that
symptoms
such
as
headaches,
skin
problems,
constipation,
or
difficulty
in
swallowing,
are
signs
of cancer.
Patterns of behaviour that are typical of
obsessive-compulsive disorder
(such as
prolonged washing
rituals)
may be
adopted in an attempt to reduce the
C
TREATMENT OF CANCER
The treatment of many cancers is still
primarily surgical. Excision of an early
tumour will often give a complete cure.
There may be small, undetectable
metastases (secondary tumours) at
the time of operation, so surgery is
commonly combined with radiotherapy
and anticancer drugs. The aim of these
treatments is to suppress or arrest the
rate of cell division in any tumour cells
left after surgery. Anticancer drugs
often have unpleasant side effects
because it is sometimes difficult to
direct specific drugs to their target,
and normal cells and tissues maybe
disrupted along with the tumour cells.
Cancer
T r e a t e d
a r e a
Before radiotherapy
The photograph shows a skin cancer on the
backofthe hand before treatment.
After radiotherapy
This was the appearance a few weeks later,
after a course of radiotherapy.
139
previous page 138 BMA A Z Family Medical Encyclopedia   2004 read online next page 140 BMA A Z Family Medical Encyclopedia   2004 read online Home Toggle text on/off