Cancer
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Summary
The use of snus was previously often associated with an increased risk of oral cancer. This view was based on results from epidemiologic studies dealing mainly with smokeless tobacco products from other part of the world than Sweden and on the fact that such products contain compounds that may cause cancer. Much discussed are the tobacco specific nitrosamines (TSNA), which can cause cancer in animals. Swedish snus contains TSNA, although in lower concentrations than in many other smokeless tobacco products.
The incidence of oral cancer is relatively low in Sweden and the use of snus is a frequently occurring habit among men. Swedish scientists have therefore found it important to examine if there is an association between use of Swedish snus and cancer.
The scientific literature on the use of Swedish snus and its association with oral cancer comprises two recently published case-control studies. The association between snus use and oesophagus and gastric cancer has been examined in two case-control studies, and the mortality from cancer among snus users has been evaluated in a prospective cohort study.
Important research results on Swedish snus
- Use of Swedish snus is not a risk factor for oral cancer.
- No association has been established between use of Swedish snus and neck and oesophagus cancer.
- There is no association between snus use and gastric cancer.
- There is no significant increased risk for cutaneous squamous cell carcinoma (CSCC) associated with the use of snus.
- Smokeless tobacco (snus and chewing tobacco) may be a risk factor for pancreatic cancer. However, in this study the use of smokeless tobacco was not associated with statistically significant increases in risk of cancers of the oral cavity/pharynx, esophagus, stomach, lung, kidney or bladder.
- The mortality from cancer is not increased among Swedish snus users.
Advanced
Cancer in the oral cavity, throat and oesophagus
Two population based case-control studies, published by Schildt et al. (1998) and Lewin et al. (1998), did not show any association between snus use and risk for oral cancer.
Schildt’s study comprised all cases diagnosed with oral cancer in Northern Sweden in 1980-1989 and matched controls. No increased risk of oral cancer could be observed among the snus users. By contrast, smoking and alcohol consumption were risk factors for this disease.
In Lewin’s study, the study base comprised the population in Stockholm and Southern Sweden in 1988-1991. The association between tobacco and/or alcohol consumption and cancer in the oral cavity, throat and oesophagus was studied. The results showed that there was no increased risk for cancer at these sites in active snus users. Smoking and alcohol consumption had a strong interactive effect on the risk of head and neck cancer.
In addition to these extensive epidemiologic studies, the literature on snus use and oral cancer includes also a few case reports. Accordingly, Zatterstrom et al. (2004) described a case, in which a 90-year old man, who had been using snus for the past 70 years, suffered from cancer in the oral cavity.
Gastric cancer
Saliva produced during the use of Swedish snus is often swallowed. It has therefore been important to examine whether Swedish snus is associated with an increased risk of gastric cancer. Ye et al. (1999) examined the association between use of tobacco and alcohol and risk for gastric cancer of various sub-sites and histologic type in a population based study comprising all cases of gastric cancer in five counties in Northern and Central Sweden in 1989-1995 and matched controls. They found no evidence that use of Swedish snus increased the risk of these types of cancer. Smoking was, however, a risk factor.
The association between use of tobacco and alcohol and the risk of oesophagus and gastric cancer was studied by Lagergren et al. (2000). The study base comprised all cases diagnosed with any of these cancer types in Sweden in 1995-1997 and matched controls. The results obtained showed that use of Swedish snus is not a risk factor for oesophagus and gastric cancer.
Pancreatic cancer
Araghi et (2017) analysed the relationship between snus and pancreatic cancer in a prospective study utilizing 9 cohorts, including 424.152, yielding 9.276.054 person-years of observation. A total of 1.423 cases of pancreatic cancer was identified. No association between snus use and pancreatic cancer was seen.
Skin cancer (Cutaneous Squamous Cell Carcinoma (CSCC))
In a large cohort study in Sweden, comprising more than 300000 construction workers, the relationship between use of snus and incidence of cutaneous squamous cell carcinoma was investigated. The results showed that neither tobacco smoking nor snus use was associated with an increased risk of CSCC. In fact, the use of snus was associated with a decreased risk of CSCC, i.e. the incidence of CSCC was lower in snus users than in non-tobacco users (Odenbro et al., 2005).
Mortality from cancer
In a prospective study comprising a large number of construction workers Bolinder et al. (1994) found that the mortality from cancer was not increased in Swedish snus users.
REFERENCES
Boffetta, P., Aagnes, B., Weiderpass, E., and Andersen, A. 2005. Smokeless tobacco and risk of cancer of the pancreas and other organs. Int. J. Cancer 114: 992-995. Bolinder, G., Alfredsson, L., Englund, A., and de Faire, U. 1994. Smokeless tobacco use and increased cardiovascular mortality among Swedish construction workers. Am. J. Public Health 84:399-404. Lagergren, J., Bergström, R., Lindgren, A., and Nyrén, 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. Lewin, F., Norell, S.E., Johansson, H., Gustavsson, P., Wennerberg, J., Björklund, A., and Rutqvist, L.E. 1998. 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 82:1367-1375. Odenbro, Å., Bellocco, R., Boffetta, P., Lindelöf, B., and Adami, J. 2005. Tobacco smoking, snuff dipping and the risk of cutaneous squamous cell carcinoma: a nationwide cohort study in Sweden. Br. J. Cancer 92: 1326-1328. Schildt, E.-B., Eriksson, M., Hardell, L., and Magnuson, A. 1998. Oral snuff, smoking habits and alcohol consumption in relation to oral cancer in a Swedish case-control study. Int. J. Cancer 77:341-346. Ye, W.M., Ekström, A.M., Hansson, L.-E., Bergström, R., and Nyrén, O. 1999. Tobacco, alcohol and the risk of gastric cancer by sub-site and histological type. Int. J. Cancer 83:223-229.
