Smokeless Tobacco not Cancer-less

Tobacco contains oral carcinogen

(RxWiki News) While smoking tobacco has declined recently, the use of smokeless tobacco - sometimes called snuff - has been increasing since 2009. This tobacco is without question less harmful than cigarettes, but is by no means safe.  Scientists now know why.

Recent research has identified  the chemical contained in smokeless tobacco -  (S)-N’-nitrosonornicotine or (S)-NNN - as a hefty oral carcinogen.

Researchers suggest there is "an urgent need to eliminate this powerful carcinogen from tobacco products."

"Call 1-800-QUIT-NOW for help giving up tobacco - in all forms."

The association between snuff and cancers isn't news, however scientists have never pinpointed the exact chemical that causes oral cancer in animals.  

Silvia Balbo, Ph.D., research associate at the Masonic Cancer Center of the University of Minnesota, led a team of investigators that analyzed various chemicals found in smokeless tobacco.

The team gave two forms of the chemical - (S)-NNN and (R)-NNN - to four groups of 24 rats. The animals were given either one of the chemicals alone, the chemicals in combination or tap water. The rats were exposed to (S)-NNN for 17 months and (R)-NNN for 20 months.

The dosing was similar to what a chronic smokeless tobacco user would be exposed to.

Every animal that received (S)-NNN had esophageal cancers and other oral tumors. Only five of the 24 rats given (R)-NNN developed oral tumors, and three in this group had esophageal tumors. In the group that received both chemicals, 12 animals developed esophageal and oral tumors. 

“(S)-NNN is the only chemical in smokeless tobacco known to cause oral cancer,” Balbo said. 

As a result of these findings, Balbo urged, “Measures should be taken to reduce this chemical in smokeless tobacco,” Balbo said. “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.”

Balbo and colleagues will be looking to identify additional carcinogens in smokeless tobacco. She wants to see how this research translates to humans in an effort to develop ways of testing exposures to these chemicals.

Findings from this study were presented at the American Association of Cancer Research (AACR) Annual Meeting 2012, held March 31-April 4. Research results are considered preliminary until published in peer-reviewed journals.

This research was funded by a grant from the National Institutes of Health.

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Review Date: 
April 2, 2012