Do sunscreens promote melanoma?
MILAN, ITALY. Conventional medical wisdom has it that the liberal use of sunscreens helps prevent skin cancer and melanoma. Several researchers have challenged this assumption. Scientists from three European cancer research institutes now report a clear association between sunscreen use and the risk of developing melanoma. Their study involved 631 children in their first year of primary school in four European cities (Brussels, Bochum, Lyon and Rome). The parents of the children were interviewed to determine their child's use of sunscreens and protective clothing and the amount of sun exposure they were exposed to - particularly during annual holidays. The children were examined to determine the number of moles (nevi) that they had on their body. Other research has established a strong correlation between a high nevus count and melanoma risk. The researchers found that the children who habitually used sunscreens had a 68 per cent higher nevus count than did the children who never used sunscreens. This increased risk remained after adjusting for such other variables as skin type, eye colour, and extent of sun exposure. Wearing protective clothing when in the sun was associated with a 41 per cent lower nevus count. The strength (SPF factor) of the sunscreen used was not related to nevus count and neither was the number of sunburns experienced by the children. As a matter of fact, the highest risk associated with sunscreen use was found among children who had never experienced a sunburn. The researchers conclude that the use of sunscreens encourages longer sun exposure, which in turn increases the risk of mole development and subsequent melanoma. They also suggest that sunscreen use could be responsible for part of the increase in non-melanoma skin cancers observed among white populations.
In an accompanying editorial Dr. Maria Turner of the National Cancer Institute concludes that the evidence is still insufficient to discard the use of sunscreens.
NOTE: See also "Sunscreens and Cancer" by Hans R. Larsen.