Light exposure of the lower leg as a pathogenetic factor in the occurrence of malignant melanoma

Abstract

Of the 1,198 women and men studied in Mainz from 1966 to 1987 there was an approximately fivefold increase in the incidence of melanoma. Among the men melanomas on the trunk (59.9%) predominated, whereas among the women melanomas on the extremities (40.0%) were more common, especially on the lower leg (26.3%). Comparing the decades 1966-1976 and 1977-1987 there was a significant decrease in melanomas affecting women's lower legs (1966-1976: 33%,; 1977-1987: 24.2%). Fashion-dependent sun exposure of this body area might offer an explanation. It could be demonstrated that common stocking materials do not sufficiently protect against UV radiation (average permeability for UV light about 55%), therefore an intense sun exposure of the lower leg in the fifties and sixties (nylon stockings and knee-long skirts) and a less intense sun exposure in the seventies (skirts of all lengths and trousers) can be assumed. The difference in the incidence of women's melanomas on the lower leg in our two subgroups correlates indeed with the fashion-dependent insolation 10-20 years before tumour diagnosis.