5G Mobile Phone Technology and the Risk of Skin Cancer: A Risk Assessment by the SEAWave Consortium

To meet the ever-growing demands of wireless communication and enable new applications, the 5th generation (5G) New Radio (NR) cellular system was developed to offer better connectivity, to reduce latency, and enable higher data transfer rates. The use of the 5G frequency spectrum is divided into two frequency ranges, Frequency Range 1 (5G NR FR1) from 0.41 GHz to 7.125 GHz, operating in the same frequency range as the 2G-4G cellular systems and WLAN systems, and Frequency Range 2 (5G NR FR2) from 24.25 to 52.60 GHz using millimetre waves (mmWaves) to enable fast transfer of large amounts of data. Since 2019, FR1 has been rapidly deployed in Europe. Until today, in Europe, FR2 has very limited applications. The objective of SEAWave project was to conduct two risk assessments, one for FR1 and one for FR2. Risk assessment procedure included evaluation of evidence of an association between skin cancer and exposure to FR1 and FR2 radiofrequency electromagnetic field (RF-EMF), with the skin being the most exposed organ during use. Both assessments are based on: a comprehensive review of the scientific literature available before the end of the project and the consolidated findings from research studies generated within the SEAWave project. Experiments conducted within SEAWave project included: (i) In vivo experiments on Carcinogenesis-susceptible (Car-S) mice and Patched heterozygous knockout mice (Ptch1 +/-) to investigate the effects of prolonged exposure to 5G FR2 RF-EMF at 27.5 GHz on the development of squamous cell carcinoma (SCC) and basal cell carcinoma (BCC), two of the most common skin tumours. In addition, skin inflammation and nociceptive signalling were analysed in dorsal skin samples taken from mice after early stage whole-body exposure in the first 21 days of postnatal life and after 100 days and 6 months of exposure; (ii) Clinical trial where participants' inner arms were exposed to 5G FR2 RF-EMF at 27.5 GHz to study transcriptomic changes in skin samples induced by 5G FR2 RF-EMF exposure, with particular attention to inflammatory processes; (iii) In vitro experiments using different primary human skin cell lines, that is, light-pigmented primary epidermal juvenile and adult keratinocytes (NHEK-f.c. and NHEK-c.) and light-pigmented primary epidermal adult melanocytes (NHEM) exposed to 5G FR2 RF-EMF at 27.5 GHz to study several endpoints including genotoxicity, aneugenicity, telomere measurement, DNA methylation and transcriptomics. The overall evidence for an association between skin cancer and 5G FR1 has been classified as 'inconclusive' based on the evaluations of human evidence, evidence from animal studies and mechanistic studies classified as 'inadequate'. 5G FR1 evaluations were mainly based on literature review. The overall evidence for an association between skin cancer and 5G FR2 has been classified as 'inconclusive' based on the evaluations of human evidence, and evidence from animal studies and mechanistic studies classified as 'inadequate'. 5G FR2 evaluations were mainly based on findings from the SEAWave project. All classifications were unanimous except for the 5G FR2 mechanistic evidence which a minority considered 'limited'; even with limited evidence the overall assessment for 5G FR2 would have remained 'inconclusive'. An impact evaluation completes the risk assessment, as for inconclusive evidence no quantitative risk assessment could be carried out.