Epidemiology of head and neck cancer.

The epidemiology of head and neck cancer can be accounted for largely in terms of known carcinogens introduced into the body through the mouth. Though there are many environmental exposures--such as asbestos, radon, nickel and arsenic--which have strong carcinogenic effects, most of these have only a small impact on the general population because exposure is limited, usually to small occupational groups. Two prevalent exposures, however, tobacco and alcohol, are strong risk factors for nearly all sites in the head and neck, and together account for about 80%-90% of all cancers of the head and neck. There is evidence for biologic interaction between some occupational exposures and cigarette smoking for cancer of the lung, and tobacco and alcohol for cancer of the mouth. Based on this evidence for biologic interaction and the prevalence of smoking, it seems likely that tobacco is related to about 80% of all cancers of the head and neck in the United States.