Lung Cancer - An Overview
In this article series, we take a look at
some of the basic facts and information about lung cancer
...
Causes of lung cancer
As cigarette smoking is a major cause of lung
cancer nowadays, it is important to appreciate how smoking
affects and injures the lungs. This is because smoke inhalation
damages the normal cleaning process by which the lung protects
itself from injury.
The bronchi which conduct inhaled air to the
lung tissues are lined with a single coating of cells on which
lies a defensive coating of mucus.
The hair-like cilia on these cells beat in a
regular rhythm to advance mucus upwards continually from the
lung removing any inhaled particles which may have become
trapped in the process.
The competence of this cleaning mechanism is
damaged very quickly by smoke inhalation. The cilia disappear
and the coating they lie in thickens in an attempt to protect
the fine underlying tissues from injury. Once this damage has
occurred, the lung can no longer keep itself
uncontaminated.
As a result, the cancer-producing agents in
cigarette smoke remain ensnared in the mucus on the surface
lining of the airway. They then pass into the cells before
being removed by coughing which is the only cleansing mechanism
remaining.
Once they are within the body, these chemicals,
and their by-products, alter the very nature of the cells in
the lungs slowly and increasingly until finally cancer
develops.
Most lung cancers start in the lining of the
bronchi, though some cancers also begin in the trachea,
bronchioles, or alveoli.
Lung cancer is thought to develop over a period
of years. To start with there is probably areas of
pre-cancerous changes in the lung, but these changes don't form
a mass or tumour.
Unfortunately they can't be seen on an x-ray and
they don't cause any symptoms. As the cancer develops, it
continues to grow and forms a tumour which is then large enough
to be seen on x-rays.
These pre-cancerous changes can be exposed by
analysing cells in the lining of the airways of smoke-damaged
lungs. Molecular abnormalities considered to be pre-cancerous
have also been recognized in cells from people who are at high
risk of developing lung cancer. These pre-cancerous changes
usually progress to true cancer.
The article series "Lung
Cancer - An Overview" continues on the next page
...
For more information and articles about lung
cancer, go here: lung cancer.
DISCLAIMER:
This information is not presented by a medical
practitioner and is for educational and informational purposes
only. The content is not intended to be a substitute for
professional medical advice, diagnosis, or treatment. Always
seek the advice of your physician or other qualified health
care provider with any questions you may have regarding a
medical condition. Never disregard professional medical advice
or delay in seeking it because of something you have read.
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