Trends in lip cancer incidence in Vaud, Switzerland.

Recent trends in lip cancer incidence in the Swiss Canton of Vaud (approximately 600,000 inhabitants in 1990) were analysed over the period 1975-1990, when a total of 87 cases were registered. A steady and substantial decline was observed in both sexes, since age-standardised (world) rates declined from 1.8 to 0.6/100,000 males and from 0.14 to 0.02/100,000 females. These downward trends were evident across subsequent age groups. These trends were apparently not due to changes in registration or classification criteria in the study period and are discussed in terms of decreased occupational exposure to ultraviolet light, and reduced pipe and cigar smoking.