Rapid and continuous increases in incidence rates of basal cell carcinoma in the southeast Netherlands since 1973

This study is aimed to determine the characteristics of the trends in incidence of basal cell carcinoma (BCC) in the Netherlands. We used incidence data of BCC from the Eindhoven Cancer Registry (Comprehensive Cancer Centre South) in the south of the Netherlands from 1973 to 2000. Data were age-adjusted and age-specific rates were calculated. Joinpoint and age-period-birth cohort modelling were applied. Between 1973 and 2000, age-adjusted incidence rates of BCC increased in both sexes, most markedly among (young) females. Recent increases were most marked on the trunk. The male data fitted age-drift models, suggesting a linear increase in rates over time, not attributable to either period- or cohort effects. In females, age-cohort-drift models described the data adequately, suggesting changes in intermittent UV exposures in subsequent cohorts. Incidence of BCC in the Netherlands is increasing rapidly, especially at body sites that are not chronically exposed to sunlight. The most likely explanation is an increased intermittent overexposure to UV radiation. This could have introduced an equal fractional increase in risk at all ages in all cohorts. There is no indication of an end to this trend in BCC.