Smokeless Tobacco Products Do Raise Cancer Risk (HealthDay)

WEDNESDAY, July 2 (HealthDay News) -- Smokeless tobacco products(STPs), which include products such as snuff and chew tobacco, doincrease the user's risk of cancer -- just not as much as smokingdoes.

So say researchers who examined worldwide patterns of STP use and theassociated risk of cancer.

Reporting in the July issue of The Lancet Oncology, a team ledby Dr. Paolo Boffeta, of the International Agency for Research on Cancer,in France, noted that STPs contain more than 30 carcinogens, includingnitrosamines and metals.

Their analysis of studies from around the world found that STP usershad an overall 80 percent increased risk of oral cancer and a 60 percentincreased risk of esophageal cancer. They also had a similar increase inthe risk of pancreatic cancer. European studies suggest no increased riskof lung cancer among STP users, but American studies suggest an 80 percentincreased risk of lung cancer, the team said.

Cancer rates associated with STPs vary between countries. For example,more than 50 percent of oral cancers in India and Sudan are attributableto STPs, compared with 4 percent in the U.S.

The findings are published in a special edition of the journal devotedto lung cancer.

Overall, studies do support a strong association between STPs andcancer, said the authors, who did not recommend smokeless tobacco as asubstitute for smoking.

"We do not intend to address explicitly the use of smokeless tobacco toreduce the risk from tobacco smoking -- e.g., by promoting smokers toswitch to smokeless products or by introducing these products in apopulation where the habit is not prevalent," the researchersconcluded.

"Nevertheless, several conclusions can be reached based on theavailable data ... the risk of cancer, especially that of oral and lungcancer, is probably lower in smokeless tobacco users in the USA andnorthern Europe than in smokers, and the risk of cancer is higher insmokeless tobacco users than in non-users of any form of tobacco," theteam wrote. "Available data for a possible benefit of switching fromsmoking to smokeless tobacco come from few studies and models from the USAand Sweden."

Another article in the July issue of The Lancet Oncologysuggests that DNA screening for certain biomarkers could help assess lungcancer risk in people exposed to secondhand smoke.

Many carcinogens in cigarette smoke are known to cause DNA lesionscalled DNA adducts and many carcinogens are known to leave uniquesignatures on cancer-related genes in the form of specific mutations atspecific locations, noted Dr. Ahmad Besaratinia and Dr. Gerd Pfeifer, ofthe Beckman Research Institute of the City of Hope National Medical Centerin Duarte, Calif.

They noted that a technique called DNA-lesion footprinting, inconjunction with mutagenicity analysis, is currently used to findcarcinogen signatures. They proposed this technique be used incancer-relevant genes, which are commonly mutated in smoke-related lungcancer.

In fact, this method has already been used successfully to find adductsconnected with various smoke-derived carcinogens, the researcherssaid.

More information

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