Cigarettes have a less lethal cousin, and scientists call these 'smokeless tobacco', which carry little or no risk of cancer. Peter Lee and Jan Hamling, from P.N. Lee Statistics and Computing Ltd, conducted the analysis of 89 studies from the United States and Scandinavia.
They found that, after adjustment for concurrent smoking, any effect of current US products or Scandinavian snuff seems very limited.
"It is clear that any effect of smokeless tobacco on risk of cancer, if it exists at all, is quantitatively very much smaller than the known effects of smoking," Lee said.
In 2005 in US men aged 35 or over, there were a total of 142,205 deaths from seven cancers considered to be caused by smoking.
If these people had never smoked, the researchers estimated that the numbers would have reduced by 104,737, with the reduction in lung cancer deaths, 79,195, being the major contributor.
If smokeless tobacco was introduced to a similar population of never smokers, this meta-analysis shows that any increase in risk would be negligible compared to the lives saved by reducing cigarette use.
"Concerns about possible effects of smokeless tobacco on oral cancer are answered by our analyses showing a lack of relationship based on the combined evidence from those 14 studies published since 1990 which allow adequate control for effects of smoking," Lee added.