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TOBACCO
AND CANCER
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TOBACCO MENACE |
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 There
has been a tremendous increase in the Tobacco related
malignancies. In India about 60 to 70% of cancers
in Males and 30 to 40% of cancers in Females have
been associated to Tobacco consumption. The practice
of inhaling Tobacco smoke became popular only In
the 20th century and ranks as the greatest public
health catastrophe of our time. According to the
epidemiologist R. Peto about 3 million deaths are
attributed to smoking worldwide today and by 2025
there will be approximately 10 million deaths with
7 million occurring in Developing countries. |
| Tobacco
consist of about 43 carcinogens, the chief among
which are Polynuclear aromatic hydrocarbon(PAH),
Tobacco specific nitrosamines (TSNA), benzene, heterocylic
hydrocarbons, etc. Nicotine is the pharamacological
agent that is responsible for the addictive properties
of Tobacco and also the major source of TSNA. It
is absorbed through Nasal passages and Lung in case
of Smoking while through mucosa of oral cavity in
case of smokeless tobacco. Once in blood nicotine
is transported to specific receptor sites in the
Brain and interaction with these receptor sites
is believed to be the basis for production of a
chemical dependence on tobacco. |
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Tobacco consist of substances that function as Initiators,
Promoters or Co-carcinogens. Tumour initiators are
substances that bond covalently with the cell DNA
and produce an altered cell. This altered cell will
remain dormant in the body unless some promoters
or co-carcinogens induce further changes in them.
This initiated cell may be formed even by a single
exposure. Promoters and co-carcinogens are substances
that stimulate proliferation of initiated cells
and on long run results in cancer development. |
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 Why
every smoker or tobacco chewer does not develop
cancer? |
| Well!
Various epidemiological studies have shown that
there is some Genetic susceptibility to cancer development
after tobacco consumption. There are many enzymes
in the body that detoxify the carcinogens present
in tobacco. Absence or alteration of function of
these enzymes, which are genetically determined,
is responsible for cancer development. Also there
are some genes in the body, which are altered by
tobacco consumption like p53 tumour suppressor gene
and ras family of oncogene. When altered they lead
to cancer development. |
| Tobacco
consumption is related to a number of cancers like
those of Lung, oral cavity, and pharynx, Esophagus,
Urinary bladder, Kidney, Pancreas, Stomach and Cervix.
Majority of these cancers are dose related i.e.
number of cigarettes smoked per day, years smoked
or tobacco consumed. A person who smokes more than
a pack of cigarette per day have a risk that is
20 times that of a non-smoker for developing lung
cancer. A synergistic, multiplicative effect appears
to exist between smoking and drinking alcohol Eg:
risk of developing cancer of Larynx is as much as
75% higher in people who use both tobacco and alcohol
as compared to people using either alone. 1 in 10
of heavy smokers develop lung cancer. According
to 1990 estimates person who died of smoking related
diseases would have lived an additional 15 years
if they had never smoked. |
| Quitting
smoking and tobacco chewing is associated with a
gradual decline in that persons risk relative to
a non-smoker. Also it decreases by 50% the chance
of developing second cancers in patients with oral
cancers. |
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Many investigations have been done to find out the
role of Environmental Tobacco smoke (ETS) also known
as Passive Smoking for cancer development. The Environmental
Protection agency reviewed 30 epidemiological studies
of ETS and lung cancer and concluded that ETS is
a human carcinogen that increases the risk of lung
cancer by 30% in non-smokers. There is also increase
risks of lung cancer in Adults who are exposed to
ETS as children. One study has shown that it doubles
the risk. |
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In spite of knowing or unknowing these factors there
has been an increase in tobacco related cancers.
Chewing tobacco is responsible for 90% of cancers
of oral cavity in Men and 60% of them in Women.
There has been recently an increase in tobacco consumption
among children and adolescents. The probable reasons
for these include low self-image, poor academic
career, receptivity to tobacco advertisements, risk
taking and deviant behaviour and perceptives of
maturity, attractiveness and independence. Also
less effective parenting behaviour in child family
and parental use of tobacco and alcohol is responsible
for their consuming tobacco at an earlier age. |
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It's high time that we should wake up and start
taking measures to stop smoking before it smokes
us up. Government has to take various stern measures
like increasing taxes on tobacco products, increase
the areas of tobacco free areas, banning tobacco
advertisements and its sale to minors. People and
children have to be educated about hazards of consuming
tobacco by use of mass media. Persons who are heavy
consumers have to be identified and vigorously coaxed
to leave tobacco. Reducing or even eliminating Nicotine
(the main component responsible for addiction) from
cigarettes and Gutkas though technically feasible
holds the future for eradicating the potentials
for addiction. A healthier 21st century requires
a societal commitment to reducing and eradicating
tobacco menace. |
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