Sunscreens and Skin Cancer: An Update

The carcinogenicity of UV rays has been well established. That sunscreens protect against UV radiation is also well established. Therefore, the role of protection of sunscreens against UV rays can be considered to be based on the principle of causality. However, in practice, the role of sunscreens in preventing skin cancer has not been conclusively established as yet. Based on current evidence, sunscreen use has been known to be associated with a reduction in the occurrence of squamous cell carcinomas, while for basal cell carcinomas, the differences did not reach statistical significance. Similarly, for melanoma the evidence for a protective effect of sunscreens is unclear, though some benefit was noted in the Nambour trials. One important reason for this could be the nature of sunscreen products used in these studies. These sunscreens predominantly protected against UVB had UV filter combinations that were subsequently found to be unstable and were generally of a much lower SPF than modern-day sunscreens. Further, in skin of colour, skin cancers are less common due to the protection provided by the high melanin content in the skin. Interestingly, when they do occur, melanoma cancers in SOC are common in areas not exposed to the sun, wherein then the role of sunscreens becomes questionable for such instances. However, globally, the occurrence of skin cancer is on the rise, and sunscreens remain one of the most accessible, widely known, and popular ways to protect against skin cancer. Formulation advances, newer filters, and a better understanding of how sunscreens interact with the human body and the environment are all very important to ensuring safe and effective sunscreen use for the future.