[Skin pigmentation, nevi and sunlight as etiologic factors of cutaneous malignant melanoma]

In this review, an attempt is made to provide a status on the current knowledge concerning the connection between skin pigmentation, naevi, sunshine and development of cutaneous malignant melanoma. Our knowledge is based partly on descriptive epidemiological reports, and partly on information obtained from case control investigations. The descriptive investigations have revealed characteristic geographical and ethnic differences in the distribution of the disease. Cancerregistry data have revealed a rapid increase in the incidence among white populations during the past 30-40 years with particularly pronounced increase for the areas of the body normally covered with clothes. Lacking consistency between indicators for cumulative exposure to sunlight and descriptive epidemiological studies have led to the hypothesis that intermittent exposure to sunlight is particularly harmful. Case control investigations have provided further support to this hypothesis and have demonstrated that sunbathing is associated with an increased risk for development of melanoma, particularly during childhood and particularly if it leads to sunburning. In addition, the risk of development of melanoma is increased in persons with a tendency to freckle and/or with many naevi. On this background, certain risk groups may be informed about prophylactic measures with subsequent possibility of reducing the number of new cases of cutaneous melanoma in the future. Finally, it is emphasized that the disease is multifactorial in origin and that the pathogenesis is not fully elucidated.