Classifying cancer of the lip: an epidemiological perspective.

A review of papers related to oral cancer reveals some non-uniformity in the classification of cancer of the lip. This paper examines the incidence of lip cancer in England and Wales using age-standardized and age- and sex-specific rates, and relates the results to those for other sites of oral cancer. There is a falling trend in age-adjusted incidence rates for lip cancer but not for intra-oral cancers, and the age-specific incidence shows a plateau effect for lip cancer after about 75 yr of age, whereas the incidence rate continues to rise throughout life for intra-oral cancers. These differences underline the importance of classifying cancer of the lip separately from other oral cancers.