Photoprotection and prevention of melanoma.

This article summarizes the current position on primary prevention of melanoma, including what is the evidence relating sunlight exposure to the development of melanoma, what forms of photoprotection there are and what are their relative values. There have been increasing incidence and mortality rates due to melanoma in most countries where they are being recorded. The initial approach in many countries has been to develop some form of early detection program in an attempt to diagnose and treat at a curable stage the melanomas that are occurring now. Primary prevention of melanoma is the more long term approach to the problem which many countries are now considering and a number are actively pursuing. Recent concern about stratospheric ozone depletion has contributed to the desire for the primary prevention approach. There are epidemiological data associating the risk of melanoma with increased exposure to sunlight in people with fair skin. They show that it is sunlight exposure in childhood and in doses sufficient to cause sunburn remembered many years later, that is particularly associated with risk of melanoma in adulthood. The exact spectrum of radiation in sunlight which is responsible for these tumours is not known, although the ultraviolet range is believed to be most important, particularly UVB but probably also UVA. The approach to photoprotection is a reduction in the overall exposure to sunlight, not just a single component of it. The natural protection of shade, clothing and hats is promoted as the best protection. Sunscreens have assumed a major component of primary prevention programs based on their convenience of use and also on their widespread promotion by those people who have a commercial interest in them. These products protect predominantly in the UVB range for which there is a sun protection factor (SPF) grading, as well as having some activity in the UVA range (for which there is not yet a satisfactory grading method).