ASK THE EXPERT: Does sunscreen cause cancer?

By Francesca Fusco, MD

Dr Fusco is a dermatologist in private practice in New York City.

Q. Does Sunscreen Cause Cancer? I am concerned that sunscreen will do me more harm than good. I have heard that the benefits of going into the sun to obtain vitamin D outweigh the risks of developing skin cancer. Since people have been out in the sun for thousands of years and started developing skin cancer only after sunscreens came out, it seems the chemicals in sunscreen, and not the sun, are causing skin cancer.

A. Actually, skin cancers have always existed. While there has been an increase in the lifetime risk of developing invasive melanoma (in 1935, the risk was 1 in 500; it is now 1 in 55), this can be attributed to a number of factors, including longer lifespans (the sun damage that leads to skin cancers generally accumulates over time); the thinning ozone layer, which allows greater amounts of harmful ultraviolet radiation (UVR) to penetrate the earth’s atmosphere; the increased popularity of outdoor activities; clothing styles that leave more skin exposed; and the advent and popularity of tanning booths. Improved diagnostic techniques also allow doctors to detect more skin cancers at an early stage.

Until the 1920s, a tan was not considered a desirable attribute. Fair, untanned skin indicated that a person did not have to work outdoors and enjoyed higher social standing. Fashionable people wore protective clothing, including hats, to avoid tanning. But in 1929, fashion and beauty magazines began promoting tans as signs of beauty, health, and affluence. The greater UV exposure that tanning entails, rather than the advent of commercial sunscreens, provides the most compelling explanation for the increase in skin cancers.

Current evidence points to the need to protect skin against the sun’s rays, regardless of skin type and ethnicity, and most dermatologists recommend using sunscreens that protect against both ultraviolet A (UVA) and ultraviolet B (UVB) rays, in addition to following other protective measures to lower the risk of cancerous and precancerous lesions.

The truth is that the body can produce only a certain amount of vitamin D from UVR; after reaching that limit, additional UV exposure actually results in the breakdown of the vitamin! UV exposure does not represent the only — or the best — source of Vitamin D. Dietary sources such as fatty fish (salmon), cod liver oil, and fortified milk and orange juice provide substantial amounts of the vitamin, as do supplements, which are available at relatively low cost. Current evidence strongly suggests that the detrimental effects of exposure to UVR outweigh the benefits, especially since vitamin D can be obtained without risking your health.

Published in the Fall 2008 Edition of the Sun & Skin News