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Mouth and throat
cancer: due to smoking and
drinking, not moist snuff
- Smoking
and alcohol increases the risk of mouth and throat cancer: Swedish
or US
moist snuff does not.
- Human
papilloma virus of the kind that causes
cervical cancer was
associated with nearly half of mouth cancer in one large recent
study.4 5
·
All
studies below refer to snuff taken mainly before snuff nitrosamines were
lowered in the 1980s to current very low levels of 1 to 2 ppm. Future
risks of cancer will tend to be lower still.
·
High
nitrosamine (> 1000 ppm) snuff from Sudan (toombak),
or from India, or dry snuff in Southern US white women before 1980 after an
average 55 years of use,1 does cause
mouth cancer. Regulations are required to exclude such products from New Zealand.
www.smokeless.org.nz/snuffregulations.htm
_________________________________________________________________________________________
SWEDEN
All four published
Swedish case-control studies show no increase of cancer risk from moist
oral snuff:
1. Head and neck cancer
(lip to larynx, including nasal).
Lewin et al from 1988 to 1990,
studied 2 million person-years of risk among men age 40-79 years of age
yielding 605 cases of head and neck cancer, for comparison with 756
controls, in 1988-90. Tobacco smokers were 6.5 times more likely to
develop cancer, and heavy drinkers (50 g alcohol per day) were 5.5 times
more likely than light drinkers (10g or less per day). The risk of
smoking and drinking together almost multiplied the separate risks. No increased risk was found for the
use of Swedish snuff.2
2. Mouth cancer Schildt from 1980 to 1989, studied 410 new cases of
mouth cancer (versus 410 controls, and compared with no exposure to each
risk factor, smoking increased the risk 80%, (relative risk 1.8) and as did
spirits 60% but the risks for
snuff users showed no increased
risk (OR 0.7, 95% Confidence interval 0.4, 1.1), even though 20% of
men had used or still used snuff.3
3. Mouth and
throat cancer Rosenquist from 2000 to 2004, investigated 132 new cases of mouth and throat
cancer and compared their risk factors with those of 320 matched
controls. In multivariate analysis, smoking 11-20 cigarettes a day
increased risks 2.4 times (more than not smoking), and drinking alcohol
(350 g per week or more) increased risks 2.6 times, but there was no increased risk for Swedish moist
snuff (OR 1.1; 95% CI 0.5, 2.5), whether fermented or not in
manufacture.4 Regular dental care halved the risk.5
Strikingly, high risk human papillomavirus
(HPV) of the same types found in cervical cancer, infected 47% of the
cases, versus 1% of the controls; HPV was linked to a 63-fold increased
risk of mouth cancer. (95% CI 14, 280).4 5
Thus the planned immunization of New Zealand girls with an anti-HPV vaccine could
possibly prevent some mouth cancers in addition to the planned lowering
of cervical cancer risk.
4. Esophageal
cancer. Lagergren interviewed 618 patients
with cancer of the esophagus. Smoking and alcohol combined increased the
risk of squamous cell cancer of the esophagus
23 fold, but snuff had no effect on cancer of the esophagus, whether adenocarcinoma or squamous
cell carcinoma.6
Cancer
due to snus use in Sweden
is rare - as shown by a case study published of a
90-year old man with squamous cell carcinoma at
the exact position in the mouth he had regularly placed snus for 70
years.7
“Swedish snus does not
increase the risk of oral cancer" US Institute of Medicine 20018
UNITED STATES OF AMERICA
Case-control
studies. All five US studies of
moist oral snuff published up to 2002 showed risks close to the above
results from Sweden. Most
studies failed to control for smoking and alcohol. Overall there was no
increased risk (Summary relative risk 1.00 (95% CI 0.8, 1.2) for moist
snuff.9)
Nitrosamine levels in US snuff declined in the 1980s,10
and so in later studies cancer risk due to snuff should be even lower.
Cohort study: All cancers and mouth cancer: From
1982-1992, 6779 interviewees 45-75 years of age participating in the
NHANES national health surveys were identified and followed up. Because
smoking is a major cause of mouth cancer, smokers were excluded and
cancer incidence in 414 subjects who exclusively used smokeless tobacco
was followed-up. The incidence of all cancers and of mouth cancer among
exclusively-smokeless users was not increased above that of non-tobacco
users. Combined users of cigarettes and smokeless tobacco had cancer
risks no greater than for cigarettes alone.11
Thickening of the mucosa Smokeless tobacco keratosis
(STK) or snuff dippers lesion, is a thickening
of the epithelium, at the site of snus use, due to local irritation, and
occurring in most regular snus users. It is recognized by WHO as separate
from oral leucoplakia, a condition often due to
smoking, which may develop into cancer. Loose snus and long duration of
use per day make STK more likely.10
NEW ZEALAND – why then was snuff banned?
Oral snuffs
were banned along with smokeless tobacco (spit tobacco) in 1987,
following the US Surgeon General’s 1986 report citing a four-fold
increased risk of oral cancers from the use by southern US women (custom
forbad smoking) of average age 80 years, who had used dry snuff between gums and cheek
for an average of 55 years. Nowadays, regulation could require testing of
tobacco samples to ban import of any oral snuffs likely to cause cancer.
Conclusion. Moist oral snuff subject
to regulatory controls does not need to carry a cancer warning.12
Cigarettes and smoking tobacco should
carry such a warning, as should alcoholic beverages.13
1 McGuirt WF, Wray A. Oral carcinoma and Smokeless
tobacco use: a clinical profile, ch.3 in. US National Cancer Institute
Smoking and Tobacco Control Monograph 2: Smokeless Tobacco or Health: An
International Perspective. NCI.
2 Lewin F.et
al. Norell, S.E. , Johansson, H., Gustavsson,
P., Wennerberg, J., Bjorklund,
A., and Rutqvist, L.E. Smoking tobacco, oral snuff and alcohol in the etiology of squamous cell carcinoma of the head and neck: A
population –based case-referent study in Sweden. Cancer 1998; 82:
1367-75.
3. Schildt EB Eriksson, M., Hardell, L., and Magnuson, A. Oral snuff, smoking
habits and alcohol consumption in relation to oral cancer in a Swedish
case-control study. Int J Cancer 1998; 77: 341-6.
4. Rosequist K, Wennerberg J. Schildt EB, Bladstrom A, Hansson BG, Andersson G. Use of Swedish moist snuff, smoking and
alcohol consumption in the aetiology of oral
and oropharyngeal squamous
cell carcinoma. A population-based case control study in southern Sweden. Acta Otolaryngol
2005; 125: 991-8.
5. Rosenquist K.
Risk factors in oral and oropharyngeal squamous cell carcinoma: a population-based study in Southern Sweden. Swed Dental J Suppl 2005; (179) 1-66.
6. Lagergren, J., Bergstrom, R., Lindgren, A., and Nyren, O. 2000. The role of tobacco, snuff
and
alcohol use in the aetiology of cancer of the oesophagus
and gastric cardia. Int. J. Cancer 85:340-346.
7 .Zätterström, U.K., Svensson, M., Sand, L., Nordgren, H., and
Hirsch, J.M. 2004. Oral
cancer after using Swedish snus (smokeless tobacco) for 70 years –
A case report. Oral. Dis. 10:50-53.
8 Institute of Medicine. Clearing the Smoke.
Stratton K. et al. Editors. Washington DC. National Academy Press 2001.
9. Rodu B, Cole P.
Smokeless tobacco use and cancer of the upper respiratory tract. Oral Surg 2002; 93: 511-5.
10 Rodu B. Jansson C. Smokeless tobacco and
oral cancer: a review of the risks and determinants. Crit
Rev Oral Biol Med 2004; 15:252-63.
11. Accortt NA. Waterbor JW, Beall C,
Howard G. Cancer incidence amount a cohort of smokeless tobacco users (United States). Cancer Causes and Control 2005; 16: 1107-1115.
12. EU decision on warnings on snus cans sold
in Sweden, European Commission. 2001.
13
For Australian picture warnings on cigar packets, see www.smokeless.org.nz/cigarsmokingrisks.htm
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