OXFORD—Two articles in The Lancet questioned the effects of sunscreen against the development of skin cancer. According to the authors, non-melanoma skin cancer (NMSC) in the United States is on the rise, but since 1990 U.S. and U.K. sunscreen purchases have also increased. So if consumers are better protecting themselves against harmful UV rays why is skin cancer on the rise? Does sunscreen reduced the risk of cancer? The researchers suggested a series of answers for the contradiction, including: the improper use of sunscreen, sunscreen’s ineffectiveness to prevent skin cancer, or other factors other than UV rays are attributing to the increased risk of NMSC and melanoma. The possibility of reduced vitamin D synthesis due to sunscreen use was also mentioned, since vitamin D deficiency has been linked to the pathogenesis of many diseases (Lancet. 2010;376(9736):161-62).
The Lancet published a response to the first article, stating: “Although sunscreen use has not been shown to offer protection from melanoma and basal-cell carcinomas, there is ample evidence to support the protective effects of consistent application of sunscreens against squamous-cell carcinomas and precursor lesions, even in immune-compromised recipients of organ transplants. This differential protective effect of sunscreen use in subtypes of skin cancers can be partly attributed to the role of other environmental factors in the pathogenesis of NMSC. However, UV radiation remains the most consistently implicated factor in NMSC” (2010;376(9736):162).
The authors also noted randomized trials demonstrating the use of sunscreen can change sun-seeking behavior—wearing sunscreen can induce longer exposure to the sun. And, although the relation between sunscreens, vitamin D deficiency and cancers is still being examined, the use of sunscreens is still recommended as a cost-effective approach to the prevention of NMSC, and especially squamous-cell carcinoma.