A new article published in the CMAJ reported that several well-conducted randomized controlled trials with long follow-up have showed that sunscreen use reduces the risk of squamous cell and melanoma skin cancers.

The authors discussed that commercial sunscreens protect against the skin-damaging effects of ultraviolet radiation through either chemical or physical ingredients. The Canadian Dermatology Association recommends the use of an adequate dose of a broad-spectrum sunscreen with a sun protection factor of at least 30—for most children and adults—as part of a comprehensive photo protection strategy.

Meanwhile, emerging evidence suggest that some chemical sunscreen ingredients are systemically absorbed, but the clinical importance of this remains unclear. As exposure to ultraviolet radiation is estimated to be associated with 80%-90% of skin cancers, the use of sunscreen—which blocks ultraviolet radiation—is promoted as an important means of preventing skin cancers, as well as sunburn and skin photoaging. Use of sunscreen has been shown to reduce the incidence of both melanoma and nonmelanoma skin cancers.

Both the Canadian Dermatology Association and the American Academy of Dermatology recommend the use of sunscreen for the prevention of skin cancer. Evidence support the effectiveness of sunscreens in preventing the signs of photoaging – including wrinkles, telangiectasia and pigmentary alterations induced by ultraviolet radiation.

The American Academy of Dermatology recommends regular sunscreen use with an SPF of 30 or higher for people of all skin types. For children older than 6 months, as well as adults, the Canadian Dermatology Association recommends the use of broad-spectrum sunscreens with an SPF of 30 or greater. Split-face studies have shown that sunscreens with an SPF of 100 are superior to sunscreens with an SPF of 50 for preventing sunburns under actual use conditions, in both a beach setting and a high-altitude skiing setting.

Source: CMAJ. December 14, 2020 192 (50) E1802-E1808; DOI: https://doi.org/10.1503/cmaj.201085