The evidence that sunscreens prevent skin cancer may not be as strong as people would like to believe. That is the conclusion from a recent Cochrane review.
What Did the Cochrane Review Find?
The Cochrane Collaboration is an impartial volunteer group of scientists who analyze research evidence on medical interventions according to strict criteria. The authors looked for randomized controlled trials of sunscreen to prevent basal or squamous cell carcinoma. After searching the literature up to May, 2016, they found one eligible study.
The Study in Australia:
The research was conducted in Australia with 1,621 adult volunteers over the course of four and a half years. In this study, there was no significant difference in the rate of skin cancer between those assigned to use sunscreen every day and those who used it only intermittently, when they thought they might otherwise burn.
The investigators probably considered it unethical to keep people from using sunscreen at all. In Australia, fair-skinned people have a high risk of developing skin cancer. Intermittent or as-needed sunscreen use might have been enough to keep a statistically significant difference from emerging.
The Cochrane Conclusion:
The researchers concluded, “We were unable to demonstrate from the available evidence whether sunscreen was effective for the prevention of basal cell carcinoma (BCC) or cutaneous squamous cell carcinoma (cSCC).”
They did not study the connection between sunscreen and melanoma, the most dangerous type of skin cancer. Critics were quick to point out that absence of evidence does not mean sunscreen doesn’t help. It might well be as good as all the dermatologists believe it is. But we would prefer to have better scientific support for a product people use every day with the expectation that it will prevent skin cancer.
Cochrane Library, online July 25, 2016
Remember, in addition to applying sunscreen liberally at least half an hour before exposure to bright sunlight, dermatologists also recommend wide-brimmed hats, long sleeves and long pants and staying inside or in shade during the hours of most intense sunshine in the middle of the day. These steps are believed to help prevent skin cancer and are worth following.
