About the Author Adèle Green, PhD. Adèle Green is a Senior Scientist at the QIMR Berghofer Institute of Medical Research in Brisbane, Australia, Senior Research Scientist at Cancer Research UK Manchester Institute, and Professor of Epidemi- ology, University of Manchester. She trained in medicine and was awarded a PhD at the University of Queensland in 1984. Her research career has focused on the causes, treatment, and prevention of various cancers, especially melanoma and other skin cancer. She has received a number of awards for her research and related activities, including 2013 Queensland Australian of the Year and the inaugu- ral Global Leader award from the International Dermo-Epidemiology Association. She is a Fellow of the Academy of Health & Medical Sciences, a member of the International Commission on Non-Ionizing Radiation Protection, and has served on the Scientifi c Council of the International Agency for Research on Cancer.

J. Cosmet. Sci., 71, 191–196 (July/August 2020) 191 Regular Application of Sunscreen Can Prevent Skin Cancer ADÈLE C. GREEN, Population Studies Department, QIMR Berghofer Medical Research Institute, Brisbane, 4006 Australia, C RUK Manchester Institute and Faculty of Biology, Medicine and Health, University of Manchester, Manchester Academic Health Sciences Centre, Manchester, M13 9PL United Kingdom (A.C.G.) Synopsis This review summarizes the evidence on the protection against skin cancer afforded by sunscreen. Solid evidence can come only from randomized controlled trials, despite a multitude of case–control and cohort studies that have addressed the issue, because observational evidence is intractably confounded since those at highest risk of skin cancer are naturally the highest users of sunscreen. Findings of the single human trial conducted in subtropical Australia during 1992–1996 with follow-up to 2014 showed that the application of a broad-spectrum, sun protection factor 16 sunscreen to exposed skin of the head and neck and upper limbs at least 3–4 days per week in adulthood can reduce the risk of developing cutaneous squamous cell carcinoma and melanoma but does not appear to reduce the risk of basal cell carcinoma (BCC) overall, although it may reduce the occurrence of multiple BCCs over time. Skin cancers constitute the most common types of cancer in predominantly white-skinned populations. There are three major types of skin cancer—the most common is basal cell carcinoma (BCC), with squamous cell carcinoma (SCC) the second most common and more serious because of its propensity to metastasize, and the least common but poten- tially fatal if not treated early is melanoma. Together, these cancers impose a costly bur- den on affected populations because of the extensive healthcare resources needed to treat them. Personal costs are also substantial and include cosmetic as well as out-of-pocket costs because skin cancer affects the face most frequently followed by other body sites that are often or occasionally exposed (1). High exposure to solar ultraviolet (UV) radiation, the shortest wavelength component of sunlight on earth, is a cause of all three types of skin cancer (2), although the exact pattern and total amount of sun exposure required differs for each type (1,2). Thus, mainly white- skinned populations are most susceptible to skin cancer, likely because they lack the UV-shielding melanin skin pigment possessed by dark-skinned populations (see the article by Antony Young in this issue). High UV levels also explain why the continually exposed skin of the face, head and neck in general, and forearms and hands are the body sites most Address all correspondence to adele.green@qimrberghofer.edu.au.