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As
rrany
malignant tumors,
the
cause
of
lung
cancer
is
quite
complicated,
and no single etiological agent
could
be identified
yet.
After more
than
twenty years
of
research,
scientists
have found that
the
rrcjor factorin
the
development
of lung cancer
is
the
inhalation
of
carcinogenic
pollutants,
especially tobacco
smoke,
by
susceptible
hosts. The
death
rate of lung
cancer
in
smokers
is
about
10
to
13
fimes
higher than that
of
non-smokers.
The
other
carcinogenic
substances
are
chromiun,
asbestos,
coal tar,
and pitch
dust.
Environmental
air
pollution
and
chronic
lung
disease
are
also
involved in
the
development
of
lung
cancer.
Prevention
of lung
cancer
in
general population
is
very
important.
Measures
should
be
taken
to
decreasing
the
incidence, they are:
improving
the
environmental
protection,
decreasing
air
opllution,
preventing
the
inhalation
of
carcinogenic
dust
and
noxious
gas,
launching a campaign
to
stop
smoking and treatment
of
chronic
lung
disease.
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18
