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What is cancer?
The human body produces about
500 billion new cells each day. Sometimes defective cells are formed
which start to multiply very fast. Cancer occurs when the carefully
controlled processes of cell division and differentiation become disrupted
in this way. Cells grow independently and invade surrounding tissues
to form a tumour, which ultimately causes death unless the process is
reversed through surgery or other treatments.
Cancer cells can also spread from the original tumour to other parts
of the body, where secondary tumours form. This is called metastasis.
What causes cancer?
A whole range of factors are associated with increased risk of cancer,
from diet to smoking, radiation (including too much direct sunlight)
the environment, pollution, lifestyle and genetic predisposition. It
is rarely possible to ascribe a simple cause and effect with cancer.
Some of these factors are examined in more detail below, along with
preventative measures and the important role of nutrition.
How big a killer is cancer?
Cancer accounts for about 20% of all deaths in developed countries and
is the second most common cause of death after heart disease. Specific
patterns of cancer vary widely throughout the world. Britain, as in
most Westernised countries, deaths from cancer seem to have risen since
the 1950s.
MORE on Cancer
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