Skin cancer, melanoma, and sunlight

Recent theoretical studies suggest that the earth's ozone layer which filters ultraviolet radiation may be depleted by a fleet of supersonic transports or by continued use of chlorofluoromethanes. It is now generally accepted that short wavelength ultraviolet radiation leads to the development of skin cancer. In this report we demonstrate an approach to estimating the increase in skin cancer incidence associated with increases in skin cancer incidence associated with increases in ultraviolet radiation. The purpose is to demonstrate the logic used and the assumptions that must be made when such estiamtes are made or cited. We emphasize that such estimates should be considered crude until the many assumptions can be investigated.Evidence exists that short wave ultraviolet radiation causes skin cancer. The National Cancer Institute conducted a skin cancer incidence survey and published the results in 1975. The survey showed a 2-3 times higher nonmelanoma skin cancer incidence in all latitudes than had been shown previously. In a theoretical study of carcinogenic ultraviolet radiation, 1 expert has estimated that, if the ozone concentration in the stratosphere were reduced by 10%, the total increase in ultraviolet radiation would be 19% in the middle and 22% in the Equatorial latitudes. Using this formula and the data from the National Cancer Institute survey, a demonstration is made of an approach to estimating the increase in skin cancer which would result from these increased ultraviolet radiation levels. Estimates of the relative effect on skin cancer incidence and mortality by radiation dose increases of 10-30% are tabulated. Increases are greater for nonmelanoma than for melanoma, for men than for women, and for incidence than for mortality.