Increasing incidence of cutaneous melanoma, ultraviolet radiation and the clinician.

Incidence of melanoma is certainly rising all over the world and this observation has been related to a more frequent and prolonged exposure to the rays of the sun. The authors critically review pertinent literature and conclude that descriptive epidemiology of melanoma does not give survival trends and does not support the claim that melanoma is ultraviolet (UV) dependent. Analytical epidemiology has not reached a consensus on this aspect. Experimental data available are also difficult to interpret because there are consistent differences of susceptibility to UV among different animals, among lamps used and methods of measuring employed in various laboratories. Information available shows that the maximal relative biological activity of UV in humans is at about 305 nm. This evaluation greatly depends on (1) thickness of the skin, (2) the quantity and quality of secretions that cover the skin, (3) cleanness of the skin, (4) the latitude, (5) the weather, (6) the hour of the day and (7) the presence of chemical carcinogens in the air and on the skin. The authors stress the importance of the criteria of clinical diagnosis recently introduced in clinical practice and higher public awareness as the causes of the increasing incidence of melanoma.