Pinning down the real benefits of sunscreen use for melanoma prevention is difficult to do. It has been demonstrated that regular sunscreen use may reduce the risk of developing actinic keratosis and subsequently lower the risk of squamous cell carcinoma. The evidence for sunscreen’s preventing melanoma, however, is mixed.
Problems with many studies in this area involve methodology. It can take more than a decade to develop melanoma, and risk factors include much more than just a high number of moles and a history of sunburn. Dozens of studies evaluating the relationship between sunscreen use and melanoma incidence show no clear association. In some studies, sunscreen use was even associated with an increased risk of melanoma.1
In a recent editorial in the Journal of Clinical Oncology, Tamar Nijsten, PhD, of Erasmus Medical Center in Rotterdam, Holland, writes that the long-term effects for sunscreen non-users may be significantly different from sunscreen users. Differences in skin pigment may be a factor, and how users apply sunscreen may affect outcomes when comparing the relationship between sunscreen use and melanoma development.2
Dr Nijsten points out that higher socioeconomic status may play a role in the development of skin cancer, and it is important to note Ultraviolet A (UVA)-seeking behavior, such as indoor tanning use and sunbathing vacations. The use of water-resistant sunscreens and how often individuals apply them after going in the water are factors that must be considered. “The concerns [with some studies] are the methodological issues,” Dr Nijsten told Cancer Therapy Advisor.