What many people, smokers and nonsmokers alike, may not know is that tobacco use increases risks of cancer at many sites in the body in addition to the lungs. Each of these is described below, together with related links. As noted at the outset, the paper describing the association between tobacco use and lung cancer stands as a classic in public health. Recently, the spread of tobacco use to developing countries has led to papers describing similar patterns there. In a study of 1,000,000 deaths in China , lung cancer risk was two to four times higher among men who smoked compared to men who did not smoke and this association was generally consistent over both rural and urban areas.
Lung cancer remains a disease with a dismal prognosis.
For oral cancers, men who smoke have a 27-times higher rate of oral cancer than men who do not smoke. For laryngeal cancer, rates are 12 times higher among smokers. Part of the explanation for tobacco's effects may come from mutations in a gene called p53 - mutations which are far more common among smokers with squamous cell head and neck cancers than among nonsmokers. In addition, the pattern of mutations in nonsmokers reflected endogenous mutations, likely to arise spontaneously, while those in the genes of smokers were changes more likely to arise from an external mutagenic agent. Smokers' risks of bladder cancer are 2-3 times higher compared to nonsmokers.