Increase in and stabilization of incidence and mortality of primary cutaneous malignant melanoma in western Netherlands, 1980–95



In summer 1989, a skin cancer campaign was organized in the coastal area of western Netherlands. In order to assess the impact of this and future campaigns on detection rates for melanomas of various thicknesses, a frame of reference for the epidemiology of cutaneous melanoma was established. We performed a retrospective investigation of all melanomas diagnosed in this region in the period 1980–95. A total of 3705 (2967 invasive and 738 in situ melanomas) cases was analysed. During the 1980s the age-adjusted incidence of invasive melanoma steadily increased (from five in 100,000 to 11 in 100,000 for men and from nine in 100,000 to 14 in 100,000 for women). Since 1988/89 the rate has remained stable for men and has increased only slightly among women. Detection rates for in situ melanomas followed the same pattern. Mortality rates remained largely unchanged for both sexes (European standard rates are about 2.6 in 100,000 for men and 2.2 in 100,000 for women). The median Breslow thickness decreased from 1.2 to 1.1 mm for men and from 1.1 to 0.8 mm for women. A marked increase occurred in the proportion of thin melanomas in comparison with intermediate and thick tumours, particularly among women. The female/male ratio declined in the period studied from 2.0 to 1.5. Directly after the campaign in 1989 a temporary increase occurred in the total number of melanomas diagnosed, largely due to more thin melanomas (≤ 1.50 mm). These findings are discussed, particularly the possible implications of the most remarkable finding of this study: the stabilization of the incidence rates in recent years. We conclude, given the recent stabilization of rates and the relative favourable thickness, that screening or surveillance should be confined to high-risk groups.