Incidence of cutaneous malignant melanoma in Denmark, 1978-2007

BACKGROUND: Incidence rates of cutaneous malignant melanoma (CMM) have been increasing markedly worldwide. The ongoing debate about possible overdiagnosis remains unresolved.

OBJECTIVES: To determine the population-based incidence of CMM in Denmark between 1978 and 2007 and to analyse sex-, site- and extent of disease-specific changes in incidence rates of CMM over time.

METHODS: We used the virtually complete nationwide Danish Cancer Register in this population-based study, which contains data on 25,851 cases reported in Denmark between 1978 and 2007. We calculated age-standardized (world standard population) incidence rates per 100,000 person-years and age-specific rates.

RESULTS: The age-standardized incidence rates increased from 6·5 to 14·4 among men and from 8·6 to 18·9 among women. During the last 5 years of the study period, a sudden marked increase was seen in women of all ages and in men aged 65 years or older. The most marked site-specific change was in the incidence of melanoma on the trunk in both men and women. An increase in the rates of disease with regional spread was seen during the last 10 years of observation.

CONCLUSIONS: The incidence rate of CMM more than doubled in Denmark between 1978 and 2007. The increases in both site-specific incidence rates and CMM with regional spread suggest an association with risk behaviour, such as intermittent sun exposure, although possible overdiagnosis must be taken into account in evaluating the implications of the increase.