Effects of sunscreen on skin cancer and photoaging

Application of sunscreen to the skin is widely used as an adjunct strategy, along with wearing protective clothing and seeking shade, to protect against skin cancer and photoaging that result from excessive sun exposure. Many epidemiological studies of case–control and cohort study design have studied the effects of sunscreen use on skin cancer, and more recently photoaging, but their findings have been mostly uninformative. This review of results of randomized controlled trials shows that the evidence, though limited, supports beneficial effects of sunscreen application on the occurrence of skin cancers and skin photoaging.     

Sun‐exposure knowledge and protection behavior in a North Chinese population: a questionnaire‐based study

Background: Sun exposure can cause a range of skin disorders. Skin damage can be prevented by following certain sun‐protection measures. However, the majority of reported studies regarding sun‐exposure knowledge and behavior have involved Caucasian populations. Methods: A self‐administered multiple‐choice questionnaire was administered. The questionnaire consisted of 13 questions aimed at evaluating people's knowledge, awareness, and protection behavior regarding sun exposure, and their knowledge of sunscreens and sunscreen use. Results: A total of 623 volunteers were enrolled, including 238 men (38.2%) and 385 women (61.8%). The percentages of correct answers regarding sun‐exposure knowledge and awareness ranged from 50% to 80%. Overall, 58.8% used sunscreen as a sun‐protection measure in daily life, followed by use of protective clothes (49.3%), sun umbrella (45.4%), sunglasses (45.3%), and hat (42.2%). Fifty‐two percent thought that suntan was harmful or not attractive. The mean sun‐protection factor (SPF) of the sunscreens used was 27.7 ± 9.2 and the mean UVA protection grade (PA) was 2.3 ± 0.6. Conclusions: Knowledge and awareness concerning the harmful effects of sun exposure are widespread among the Chinese population. Sunscreens with high SPF and PA are the most commonly used among Chinese people. Clear sex differences were observed. There is a significant difference in the attitude toward suntan between Chinese and Caucasian populations.     

Cancers in Australia attributable to exposure to solar ultraviolet radiation and prevented by regular sunscreen use

Objectives: To estimate the proportion and numbers of cancers occurring in Australia attributable to solar ultraviolet radiation (UVR) and the proportion and numbers prevented by regular sun protection factor (SPF) 15+ sunscreen use. Methods: We estimated the population attributable fraction (PAF) and numbers of melanomas and keratinocyte cancers (i.e. basal cell carcinomas and squamous cell carcinomas) due to exposure to ambient UVR resulting from residing in Australia versus residing in the UK (for melanoma) or Scandinavia (for keratinocyte cancers). We also estimated the prevented fraction (PF): the proportion of cancers that would have occurred but were likely prevented by regular sunscreen use. Results: An estimated 7,220 melanomas (PAF 63%) and essentially all keratinocyte cancers occurring in Australia were attributable to high ambient UVR levels in Australia. We estimated that regular sunscreen use prevented around 14,190 (PF 9.3%) and 1,730 (PF 14%) people from developing SCC and melanoma, respectively. Conclusions: Although our approach was conservative, a high proportion of skin cancers in Australia are attributable to high ambient levels of UVR. Prevailing levels of sunscreen use probably reduced skin cancer incidence by 10–15%. Implications: Most skin cancers are preventable. Sunscreen should be a component of a comprehensive sun protection strategy.