Trends of cutaneous melanoma in The Netherlands: increasing incidence rates among all Breslow thickness categories and rising mortality rates since 1989.

BACKGROUND: It has been debated that the epidemic of melanoma is largely due to overdiagnosis, since increases in incidence were mainly among thin melanomas and mortality rates remained stable. Our objective was to examine this controversy in The Netherlands.

PATIENTS AND METHODS: Information on newly diagnosed melanoma patients was obtained from The Netherlands Cancer Registry. European Standardized Rates and estimated annual percentage change were calculated for the period 1989-2008. Cohort-based, period-based and multivariate survival analyses were carried out.

RESULTS: The incidence rate of melanoma increased with 4.1% (95% confidence interval 3.6-4.5) annually. Incidence rates of both thin melanomas (≤ 1 mm) and thick melanomas (> 4 mm) increased since 1989. Mortality rates increased mainly in older patients (> 65 years). Ten-year relative survival of males improved significantly from 70% in 1989-1993 to 77% in 2004-2008 (P < 0.001) and for females the 10-year relative survival increased from 85% to 88% (P < 0.01). Recently diagnosed patients had a better prognosis even after adjusting for all known prognostic factors.

CONCLUSION: Since incidence of melanomas among all Breslow thickness categories increased as well as the mortality rates, the melanoma epidemic in The Netherlands seems to be real and not only due to overdiagnosis.