SPF30 sunscreens have been known to prevent sunburn. Now, a new study from the Ohio State University Wexner Medical Centre reveals that applying SPF30 sunscreen can also delay the onset of melanoma.
“Sunscreens are known to prevent skin from burning when exposed to UV sunlight, which is a major risk factor for melanoma,” says principal investigator Christin Burd. “However, it has not been possible to test whether sunscreens prevent melanoma because these are generally manufactured as cosmetics and tested in human volunteers or synthetic skin models.”
To test the ability of sunscreens to prevent sunburns and melanoma, the researchers applied the product onto the skin of mice that was initially applied with the chemical 4-hydroxytamoxifen (4OHT). A single dose of UVB light caused the melanomas to appear more quickly and extensively on mice that did not use the sunscreen.
However, those mice that were applied with SPF30 sunscreen delayed the development of melanoma. The team also observed that the number of tumours decreased unlike in the previous experiment.
“There were some minor differences in melanoma prevention amongst the different SPF30-labeled sunscreens,” adds Burd. “However, we later discovered that even though the sunscreens were all marketed as SPF30, some were actually predicted to have a higher rating. For this reason, it is hard to compare the melanoma-preventing capacity of the different sunscreens at this time.”
Nevertheless, the researchers admit that further investigations are needed. The experiment involved exposing the mice to a short dose of UVB that had the equivalent of one week worth of sun exposure. Since sunscreens are not designed to manage this level of exposure at one time, the researchers speculate that results could have been different if they reduced the UVB dose.
“We are currently seeking funding to purchase a solar simulator which will better model all wavelengths of sunlight,” Burd says. “However, funding these studies can be hard to come by because sunscreens are primarily developed by the cosmetics industry, which has pledged not to use animals in the development of their products.”
The researchers hope that the finding could pave the way to new developments in melanoma prevention. They plan to continue their investigation to determine which sunscreen content offers the best protection against melanoma.