How many melanomas might be prevented if more people applied sunscreen regularly?

1. How many melanomas might be prevented if more people applied sunscreen regularly? C.M. Olsen, L.F. Wilson,A.C. Green, N. Biswas, J. Loyalka, D.C. Whiteman Population Health Department, QIMR Berghofer Medical Research Institute, 300 Herston Road, Herston, Queensland 4006, Australia British Journal of Dermatology. DOI: 10.111/bjd.16079

2. Senior author David Whiteman QIMR Berghofer Medical Research Institute Brisbane, Australia

3. Introduction What’s already known? • Sunscreen prevents sunburn and protects skin cells (including melanocytes) from mutations induced by ultraviolet radiation • Prospective cohort studies and one randomised trial suggest regular sunscreen use reduces risk of malignant melanoma (MM) • Regular use of sunscreen is uncommon, even in populations residing in areas of high ambient sunlight levels

4. Methods Objective: • To calculate the potential impact fraction (PIF) for MM in the United States (US) and Australia assuming a range of different intervention scenarios intended to increase sunscreen use

5. Methods • The PIF is the proportional difference between the observed number of MM under the prevailing levels of sunscreen use and the number expected under alternative scenarios of higher prevalence of sunscreen use • PREVENT Plus Software used to estimate number of potentially preventable MM in Australia and US under various scenarios

6. Methods • Prevalence of sunscreen use in US and Australia sourced from survey data • Published MM incidence projections for US Whites and for Australia from 2012 through 2031 were used as the baseline condition, with sunscreen prevalence estimate from national surveys • Relative risk for a protective effect of regular sunscreen use from long-term follow-up of the Nambour Skin Cancer Prevention Trial

7. Scenarios: • Model 1: Prevalence of sunscreen use increased by 5% per year over a 10 year period • Model 2: 100% of population used sunscreen daily with immediate implementation • Model 3: 100% of population used sunscreen daily with a 10 year implementation period • Model 4: Model 1, but for age < 75 only

8. Scenarios: Effect of timing of intervention: • Model 5: school age • Model 6: working age • Model 7: pre-retirement age

9. Results

10. Results

11. Results • Under a plausible public-health intervention scenario comprising incremental increases in sunscreen prevalence over a 10-year implementation program, authors estimated that cumulatively to 2031, 231,053 fewer MM would arise in the US white population (PIF 11%) and 28,071 fewer MM would arise in the Australian population (PIF 10%) • Theoretical maximum model of sunscreen use: almost 797,000 (PIF 38%) and 96,000 (PIF 34%) MM would be prevented in the US and Australia respectively between 2012-2031

12. Discussion What does this study add? • Under plausible scenarios of increasing prevalence of sunscreen use, cumulative incidence of MM between 2012-2031 could reduce by ~10% in high-incidence populations • Monitoring sunscreen use in populations is necessary to inform MM control efforts

13. The research team L to R: Louise Wilson, Catherine Olsen, David Whiteman, Adele Green

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