The International Agency for Research on Cancer (IARC) has moved sunbeds (UV tanning beds) up to the highest cancer risk category—group 1—'carcinogenic to humans'. The use of sunlamps and sunbeds was until now classified as "probably carcinogenic to humans" (group 2A). IARC also moved ultraviolet radiation into group 1. These and other findings are revealed in a Special Report in the August edition of The Lancet Oncology, produced by Dr Fatiha El Ghissassi and her colleagues, IARC, Lyon, France, on behalf of the WHO International Agency for Research on Cancer Monograph Working Group.
The authors say: "The use of UV-emitting tanning devices is widespread in many developed countries, especially among young women. A comprehensive meta-analysis concluded that the risk of skin melanoma is increased by 75 percent when use of tanning devices starts before 30 years of age. Additionally, several case–control studies provide consistent evidence of a positive association between the use of UV-emitting tanning devices and ocular melanoma. Therefore, the Working Group raised the classification of the use of UV-emitting tanning devices to Group 1, 'carcinogenic to humans'."
The characteristic genetic mutation that is caused by solar (ultraviolet/UV) radiation has long been attributed to UVB radiation. However, the same mutation was detected in the skin of UVA-treated mice, and in UVA-induced mouse skin tumours. Thus IARC reclassified UV radiation as a whole (UVA, UVB and UVC) as carcinogenic to humans, or group 1. UVA, UBC, and UVC radiation were each previously in group 2A, "probably carcinogenic to humans".
The working group also concluded that there was sufficient evidence for ocular melanoma in welders; however, because welders are exposed to other harmful agents, the risk could not be specifically attributed to UV radiation. The authors say: "A full review of the carcinogenic hazards of welding will be undertaken with high priority."
All types of ionising radiation were also classified as Group 1. This was the first time all these types of radiation were reviewed by one working group during one meeting. Examples of ionising radiation are:
- Radon gas (seeping from soil, rocks, and building materials), which enters the lungs and causes damage (affecting the whole population). The Special Report says that radon is the second leading cause of lung cancer (8—15% of cases) after tobacco smoke
- Plutonium and its decay products, affecting the bones, liver and lungs of plutonium workers.
- Radium and its decay products, affecting the bones of medical patients
- Phosphorous-32 and its decay products, causing acute leukaemia in medical patients
- Radioiodines, affecting the thyroids in children and adolescent survivors of nuclear reactor accidents
Source: The Lancet Oncology
(26 Aug 2014)