Smokeless tobacco use and risk of cancer of the pancreas and other organs

Abstract

Limited data are available on the carcinogenicity of smokeless tobacco products in organs other than the mouth. Snus is a smokeless tobacco product widely used in Norway. We studied 10,136 Norwegian men enrolled since 1966 in a prospective cohort study, 31.7% of whom were exposed to snus. The relative risk of pancreatic cancer for snus use was 1.67 (95% confidence interval [CI] ‫؍‬ 1.12, 2.50); that of oral and pharyngeal cancer was 1.10 (95% CI ‫؍‬ 0.50, 2.41), that of esophageal cancer was 1.40 (95% CI ‫؍‬ 0.61, 3.24), and that of stomach cancer was 1.11 (95% CI ‫؍‬ 0.83, 1.48). The relative risks of cancers of the lung (either all histological types or adenocarcinoma), urinary bladder and kidney were not increased among snus users. The increase in the relative risk of pancreatic cancer was similar in former and current snus users and was restricted to current tobacco smokers. Our study suggests that smokeless tobacco products may be carcinogenic on the pancreas. Tobacco-specific N-nitrosamines are plausible candidates for the carcinogenicity of smokeless tobacco products in the pancreas.

Smokeless tobacco brand switching: A means to reduce toxicant exposure?

“…However, the manufacturing process of ST products in the U.S. is fundamentally different from that of snus in Sweden (Foulds et al, 2003), and further investigation is required to determine if a reduction in NNK exposure with U.S. ST brand switching results in a cancer risk reduction. Available evidence suggests that snus use may be associated with an increased risk for cardiovascular events (Foulds et al, 2003) and pancreatic cancer (Boffetta et al, 2005); therefore, ST products with lower concentrations of toxicants, such as snus, should not be considered safe.…”

Flawed methods

“…Finally, we believe that Bofetta et al 1 do provide arguments in favor of the role of smokeless tobacco products to reduce the burden of smoking-related cancer. The consistent lack of an association between non-smoking tobacco and several major, smoking-related cancers clearly illustrates the ''harm reduction'' potential of the type of smokeless products currently used in northern Europe.…”

“…2 For instance, the odds ratio for frequent use vs. no use was 10.8 (adjusted for smoking). It is enigmatic why Bofetta et al 1 elected not to include alcohol use in their statistical analysis despite the fact that alcohol probably is a strong confounding factor. Moreover, data on alcohol use are obviously available for this cohort.…”

“…The proportion of nonverified cases was 35%. It is problematic that Bofetta et al 1 do not mention the proportion of histologically verified cases in their analysis, nor do they present results separately for such cases.…”

“…Bofetta et al 1 report results for 8 selected cancer sites. No significant increase in risk associated with use of non-smoking tobacco was observed for 7 of these (head-neck, esophagus, stomach, lung, lung adenocarcinoma, kidney and urinary bladder).…”