Cancer In Detail
Discuss social, ethical and biological issues associated with cancer
Cancer is
one of the most complex and devastating diseases that claim the
life of many
humans. Today there are one in three people worldwide who are
affected by
cancer, and almost 60% of these people will almost certainly die.
7000 New
Zealanders die every year from this disease. It is the second
largest killer
next to heart disease. Cancer does not just affect certain
groups of people, it
can affect anybody and it is not just one disease, it
refers to more than a
hundred diseases. Cancer is caused by carcinogens. At
present, hundreds of
chemicals are known to induce cancer. Normally, the
body’s cells divide in an
orderly way, allowing the body to grow and to heal
after injury. Damage or
mutations that occur to the proto-oncogenes (POG) and
tumour suppresser Genes (TSG)
in the genetic material (DNA and RNA) by these
carcinogens bring about Cancer,
which causes cells to have less control of
cell division and differentiation.
POGs lead to changed cells or
transformed cells and cause excessive cell
division. Further mutations cause
the cells to become immortal. These cells
continue to divide and form a ball
of cells. These cells require a lot of energy
and fluids flowing to maintain
the high rate of the cell division. When these
balls become too large for
fluids to flow through, the middle of the ball dies.
TSG’s act as
anti-proto-oncogenes, they regulate the rate of cell division.
POG’s and
TSG’s constantly compete to overpower each other. These TSG’s
can be mutated
and this brings about a change in the control mechanism of cell
division.
Cells are stimulated to divide through a growth factor. Growth
factor
molecules bind to cell membranes of cells and send a chemical message
to a
receptor in the cell membrane. The receptor sends a message through
the
cytoplasm to the nucleus to stimulate cell division. Sometimes when these
growth
factors are absent the receptor in the cell membrane is mutated to
send out the
message to the nucleus. Cells are also stimulated to divide
through the two
proteins, cyclins and cyclin-dependent kinases. When these
two join together,
this stimulates cell division. These proteins act on the
growth inhibitor
proteins P53 and PRP, which are growth inhibitor proteins.
Tumours may be
malignant, spreading or benign, non-spreading. Malignant
tumours are aggressive,
invasive, and mobile. They invade healthy tissue and
continue to divide. The
original cancer is called the primary tumour. If the
tumour is malignant, the
disease may develop in other parts of the body where
secondary tumours may form.
This is known as metastasis. Cancer causes
illness through local growth, spread
to distant organs, and overall effects
of the disease on the individual.
Treatments of cancer vary. Tumours may
be surgically removed if they have not
metastasised. Other methods are
usually used if the tumour has metastasised. For
chemotherapy drugs are used
to kill cancerous cells as they divide. Radiotherapy
is another standard way
of treating cancer, ionising radiation aimed at the
tumour will prevent the
cells from dividing further. So what makes cancer more
special than other
diseases? The answer is that there is no cure and scientists
are not
optimistic of finding one in the near future. Today people are far
more
knowledgeable about cancer and how it may be avoided than 10 years ago.
It has
now been found that as many as 80% of all cancers may be avoidable.
The most
common types of cancer in New Zealand are female breast (14%), male
prostate
(14%), trachea, bronchus, and lung (12%) and colon (11%) Given that
such a large
proportion of cancers may be avoidable, why isn’t there a
reduction in cancer
incidence? This may be because our educational programs
are not appropriate and
perhaps even due to people’s ignorance. Female breast
cancer and male prostate
cancer can almost always be cured if detected and
treated in time. For the early
detection of female breast cancer appropriate
programs such as monthly mammogram
and breast self-tests have been
introduced. But I believe that male prostate
cancer has not been addressed
enough (more?). 80% of lung cancers have been
found to be caused by smoking.
If smoking is such a huge cause of lung cancer
that kills almost 150 New
Zealanders every year, why can’t it be banned? This
is because large
multimillion-dollar tobacco companies such as Wills and Benson
and Hedges
have very successful advertising campaigns mainly sponsoring sports
teams.
Even though it seems like tobacco advertising has decreased, it was only
last
year when Benson and Hedges sponsored the triangular cricket series
in
Australia. With such a lot of income coming into the tobacco industry
they
cannot be taken on by small individual and private research
organisations. It is
also the ignorant buyer’s fault for purchasing tobacco
even though it has been
proven to be addictive and cancer causing. More than
any other ethnic group in
New Zealand, Maori girls have been found to
smoke the most. This could be
because they do not receive adequate support
from home and family or maybe
because most have a high rate of poverty since
they are a minority. In New
Zealand where certain cancers are at the
highest incidence in the world, the
government spends over 110 million
dollars each year on treating patients with
smoking related diseases
including lung cancer. If more money went into
preventing out young and Maori
teenagers picking up the smoking habit, the cost
might be reduced and lives
saved. Today billions of dollars are spent throughout
the world on cancer
especially in developed countries of the western world where
a lot of money
is freely available. Most of this research is carried out by
private
organisations and therefore ethnic minorities appeal to be included in
their
research. Dietary factors underlie as many as 35% of all cancers. Of
this
35%, almost 80% of the patients are colon cancer patients. The
government has
taken on a major preventative scheme, introducing the 5+a day
dietary standards
to improve the intake of more fruits and vegetables into
people’s daily diets.
This aims at reducing bowel cancer in New Zealand,
which will no doubt save
lives. For these reasons, cancer is a contemporary
issue. Biological, ethical
and social issues surround it. It also seems that
a lot has been done to prevent
it but there is so much further to go, and
this would ultimately reduce the
number of lives that the cancer claims.