Impact of smoking and smokeless tobacco on the risk of cancer of the head and neck.

A case-control epidemiologic study was conducted to determine the relationship between quantities and types of tobacco and the risk of cancers of individual sites within the head and neck. Substantial variations were found to exist in the tobacco-associated risk for each site. The use of cigarettes was associated with an increased risk of cancers of all sites, except the salivary glands. Cancers of the floor of the mouth and larynx exhibited the highest cigarette-related risks. Cigar smokers experienced excess risks of cancers of the tongue, pharynx, and larynx. Pipe smokers experienced elevated risks of cancer of the tongue, mouth, pharynx, and larynx. Among users of smokeless tobacco, increased risks of cancer of the mouth and gum, pharynx, and salivary glands were observed.