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

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.