Does tobacco really increase the risk of developing cancer?
The association of cancer with tobacco has been known since the
1930s, and the US Surgeon General’s report of 1964 identified that smokers had a 10 fold increase in the risk of developing lung cancer while heavy smokers were 20 times more likely to
develop lung cancer than a non smoker. The harmful effect of tobacco is best
illustrated in the increased risk of cancer among passive smokers. i.e. those
who inhale “second hand” smoke, exhaled by a smoker or from the burning end of
a cigarette / bidi etc. ; their risk of developing cancer has been estimated to
be 20 – 30 % higher than a person who does not live with a smoker.
Is any form of tobacco safe?
No form
of tobacco is safe. Hence cigarettes, bidi, pipe, hookah, tobacco laced pan and
pan masala, chewed tobacco as well as snuff (naswar in Hindi) are equally
harmful. Chewed tobacco is associated more strongly with cancer of the cheek,
tongue and tonsil, while smoked tobacco is associated with a higher risk of
lung cancer and cancer of the voice box. All forms of tobacco induce “field
cancerisation” wherein, the inner lining of the pathway for food and air, i.e.
mouth, throat, food pipe and airways becomes prone to cancer.
Does the quantum of tobacco use, daily as well as cumulative, have
any impact on the risk of developing cancer?
Yes,
the number of “pack years” determines the risk of developing cancer. In
addition, it may worsen the outcome of treatment in some situations. Patients
who continue to smoke while receiving treatment for cancer do worse than
patients who quit.
Is tobacco implicated in any other cancers besides those of the
mouth, throat and lung?
In addition to cancer of
the mouth (lips, cheek, tongue), throat ( tonsil, voice box, pharynx), persons
consuming tobacco in any form are more likely to have cancer of the food pipe,
stomach, pancreas, kidney, urinary bladder, large intestine, cervix ( the
opening of the uterus) and ovary. In addition they have a higher chance of
developing a form of blood cancer, acute myeloid leukemia
Are women equally at risk of developing tobacco induced cancers?
Women are at least equally
at risk of developing cancer, if not more. According to the United States
Surgeon General’s report of 2014, women
smokers have 27.5 times the risk of developing lung cancer compared to women who
do not smoke. According to the same report, this figure is 25 times for men. Certain
cancers specific to women i.e. those of the cervix and ovary, occur more
commonly in smokers than in women who do not smoke.
Are low tar cigarettes safer or are they a marketing gimmick?
It has been proven that those who smoke low tar cigarettes pull
harder on the cigarette to achieve the
“desired effect” of tobacco thus making these cigarettes as harmful
as regular cigarettes. “ Low tar”, “ slim” etc. are calculated sub
liminal messages that marketers of tobacco send out to women smokers that the
latter need to be aware of. In addition, there has been a concerted campaign by
the tobacco industry to associate smoking with glamour. In North America, this campaign has been
thwarted, somewhat, by the anti smoking movement, which has been successful in
reducing rates of smoking. This in turn has lead to a drop in the rate of lung
cancer. A similar downward trend has not been noted in India, in either the
prevalence of smoking or in the risk of developing tobacco induced cancers.
Is tobacco implicated only in cancer causation or does it cause
other diseases too?
While the association of
tobacco and heart disease is well known, consuming tobacco also increase the
risk of facial wrinkles and osteoporosis;
hip fractures are more common among smokers. In addition women (and men) who
smoke are more likely to have a severe lung ailment , chronic obstructive lung
disease. Tobacco also interferes with fertility and increases the chances
of stillbirth and low birth weight babies.
