An international evaluation of the cancer-preventive potential of sunscreens.

The IARC convened a working group of experts in Lyon, France, on 10-18 April, 2000, to evaluate the cancer-preventive activity of sunscreens and to compile the fifth volume of the IARC Handbooks of Cancer Prevention. The working group concluded that the topical use of sunscreens reduces the risk of sunburn in humans and that sunscreens probably prevent squamous-cell carcinoma of the skin when used mainly during unintentional sun exposure. No conclusion can be drawn about the cancer-preventive activity of topical use of sunscreens against basal-cell carcinoma and cutaneous melanoma. Use of sunscreens can extend the duration of intentional sun exposure, such as sunbathing. Such an extension may increase the risk for cutaneous melanoma. The working group warned against relying solely on sunscreens for protection from UV radiation.