LONG-WAVELENGTH ULTRAVIOLET-LIGHT (UVA) AND SKIN-CANCER

Ultraviolet light is frequently used for cosmetic tanning of the skin. UV light is known to be carcinogenic, but this is attributed predominantly to short-wavelength UV radiation (UVB). However, new data indicate a carcinogenic role for long wavelength ultraviolet light (UVA) also. In vitro studies have demonstrated DNA-damaging effects of UVA. In animals squamous cell carcinomas and melanomas were induced by UVA alone or in combination with UVB. Reference to a possible carcinogenicity of UVA may also be derived from the therapeutic application of UVA together with psoralens (PUVA). In addition, recent epidemiological studies have associated the use of sunbeds with the development of malignant melanoma. In conclusion, the carcinogenicity of UVA in humans cannot be ruled out, but requires further validation. Long and repeated UVA exposure should be discouraged, because of the far-reaching risks involved.