Primary prevention of keratinocyte carcinoma among outdoor workers, the general population and medical professionals: a systematic review updated for 2019.

Worldwide 2-3 million cases of keratinocyte carcinoma (KC) are diagnosed annually. Sun-related knowledge is essential for adequate protection against solar ultraviolet radiation (UVR), the main risk factor for KC. The goal was (i) to provide an updated overview of primary prevention against KC including skin cancer-related knowledge, attitudes and sun protection behaviour (SPB) of outdoor workers, the general population and medical professionals as well as (ii) to evaluate the effectiveness and acceptability of sun protection programmes. We conducted a systematic review of articles indexed for MEDLINE on PubMed using selected MeSH terms and keywords related to the studied topic as well as an extensive hand search of publications between 1 January 2012 and 31 December 2018. We identified 51 relevant cross-sectional studies and 22 interventional studies. Sun-related knowledge and attitude showed substantial differences with some alarming results, including people who had not even heard about skin cancer before. Reported SPB varied enormously between the included studies, with none of the studies providing an overall sufficient SPB in their examined sun protection measures. However, sun protection programmes using new technologies seem to have great potential to increase sun-related knowledge and SPB. In countries worldwide, particularly in those where KC is not yet a public health issue, UVR protection should be promoted by healthcare institutions and authorities, politicians, cancer foundations and dermatologists to increase awareness as well as SPB and to decrease the worldwide burden of KC.