Increasing incidence rates of squamous cell carcinoma of the skin in Sweden.

The incidence of squamous cell carcinoma of the skin is increasing world-wide, and in Sweden this tumour is one of the most rapidly increasing malignancies. The aim of this study was to investigate incidence trends of squamous cell carcinoma in Sweden. For the 39,805 tumours registered in the Swedish Cancer Registry 1961-1995, incidence rates were calculated according to gender, age, anatomical site and unit surface area. Multivariate analysis was performed with the age-period-cohort model. Age-standardized incidence rates increased substantially in both men (+425%) and women (+146%) during this period. The highest rates per unit surface area were seen for chronically sun-exposed head-neck sites. Age-specific incidence rates increased in ages > or =60 years during the study period. Multivariate analyses showed that age, period and cohort effects in men could best explain the incidence rates, while in women the age-period effects model was adequate. In conclusion, a rapidly increasing incidence trend for squamous cell carcinoma was found, probably explained by increased accumulated sun exposure and increasing incidence among the elderly.