797 Appropriate sunscreen use in childhood reduces melanoma risk: The New York State Medicaid population model

      The incidence of melanoma has increased dramatically in recent years. Over-the-counter sunscreen use in childhood has been shown to lower the lifetime risk of melanoma in Australia, but previous studies in the U.S. have failed to demonstrate benefit. We hypothesize that short follow-up and a failure to take into account inappropriate sunscreen application practices may contribute to the lack of positive findings. Here, we created a predictive model for the impact of different regimens of sunscreen use on melanoma incidence in the pediatric New York State Medicaid population. A Markov model was developed to analyze ideal use conditions (almost daily), some use (50% of ideal), and none. Total sunscreen use for children was estimated at about 15-20 ml per application, with the number of applications depending on time of year. The model population was based on SEER data and published literature. The model incorporated various salient population characteristics including gender, ethnicity (white, non-white), and sunbed use. The model time frame was 79 years, the average life expectancy in the U.S. Our model found that compared to no sunscreen use, ideal sunscreen application is associated with a significant 43% risk reduction of lifetime melanoma development, while some sunscreen application is associated with a 17.5% risk reduction. These findings suggest that in order to demonstrate reduction in melanoma incidence, it is important to ensure appropriate sunscreen application conditions and also to look at long-term follow-up.