For the first time ever, researchers have identified a specific chemical, which is a strong inducer of oral tumors, in smokeless tobacco, according to results presented at the American Association for Cancer Research Annual Meeting on Monday.
Chewing tobacco and snuff are types of smokeless tobacco. The two leading smokeless tobacco brands in the U.S. are Skoal and Copenhagen.
Although smokeless tobacco products have long been linked with certain cancers, including oral cavity cancers and esophageal cancers, no specific chemical in smokeless tobacco known to cause oral cancer has been identified until now.
According to Silvia Balbo, research associate at the Masonic Cancer Center of the University of Minnesota in Minneapolis, Minnesota, the chemical called, "(S)-N'-nitrosonornicotine, or (S)-NNN", is the only chemical in smokeless tobacco known to cause oral cancer.
The finding was based on animal study, in which two forms of NNN called (S)-NNN and (R)-NNN were administered to four groups of 24 rats, with the total dose being roughly equivalent to the amount of (S)-NNN to which a smokeless tobacco user would be exposed from chronic use of these products. The rats were randomized to receive either (S)-NNN alone, (R)-NNN alone, a combination of both or tap water.
All rats, which were given (S)-NNN, had esophageal tumors and oral tumors, and died by 17 months. Out of the 24 rats, which were given (R)-NNN, only five had oral tumors and three had esophageal tumors.
Commenting on the finding, Balbo said, "Measures should be taken to reduce this chemical in smokeless tobacco. If it is not possible to stop the use of smokeless tobacco products, we should advocate for a reduction of this chemical in these products".
In future studies, Balbo and her colleagues hope to identify other chemicals that may be carcinogens in smokeless tobacco and to understand what level of these chemicals is present in smokeless tobacco products.
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