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Mei/May 2015
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Lead Article
I Hoofartikel
>>> 6
T
his article is a brief,
incomplete explanation
of a complex subject.
It covers the normal
cell, damage to the
DNA, change into a mutant cancer
cell, leading to uncontrolled mitosis,
eventually forming a clump of cancer
cells and finally radiotherapy as one of
the options for treatment.
The DNA is the same in every cell in
each individual’s body. Certain genes
are “switched on/off” so, although
both liver and skin cells have the
same DNA, they have different shapes
and function. Normal cells become
cancerous when their genetic control
(tumour suppressor genes) becomes
damaged and the cells divide out
of control. These cancerous cells
also do not respond to the process
of cell suicide (apoptosis) and the
clump of damaged cells grows larger.
Sometimes one or more of these
cancer cells travel via the lymph or
the blood vessels to other areas of
the body and colonise the new tissue,
referred to as metastasis.
The pain that is caused by the clump
of cancer cells is
due to pressure
on the nearby
nerve endings.
It can range
from irritation
to excruciating
pain, depending
in the cancer’s
location and the
rate of mitosis.
Different cells in
the body have
different rates of innate mitosis but,
if the tumour suppressor gene is
damaged, these cells increase their
mitotic activity uncontrollably and the
tumour grows alarmingly. Cancer can
grow in one place and just increase in
size and/or grow and metastasise in
other organs.
There are three basic forms of therapy
for treating cancerous growths with
many variations. The treatments are;
surgery, chemotherapy and radiation.
They can be used as single therapies,
or in conjunction with each other.
All cancer treatments try to remove
every cancerous cell; if any remain
the cancer might recur. Surgery is
the direct removal of the tumour.
Chemotherapy works by exposing the
cells with mutant DNA to chemo-toxic
drugs during mitosis and likewise
radiation using electrons. The potential
cancer cells can lie dormant from
months to years. Remission is that
period in the patient’s life during which
the cancer does not recur.
This article will focus on electron
radiation therapy.
The practical application of
electron radiotherapy.
Linear accelerator radiation machines
cost R30 million and produce electrons
or photons. Electrons penetrate the
Exponential rate of growth in two months, with major increase
in pain.
The practical
application
of electron
radiotherapy
as a
cancer treatment
for dogs and cats
Dr Georgina Crewe
Cancer is considered to be the leading cause of death in geriatric patients. These days our companion animals,
like us, live longer than previous generations. This is due to advances in nutrition, infectious disease control,
oncology treatments and specialist surgeries being available. Cancer is described as a disease of ageing and/or
inflammation. Oncologists in the US estimate that 50 percent of geriatric dogs and 33 percent of geriatric cats
will die of cancer.