US study adds weight to increased risk of basal cell skin cancer from exposure to solar UV radiation.
This was a retrospective cohort study that examined the association between ultraviolet radiation (UVR) and basal cell carcinoma (BCC) The study followed 63,912 white cancer-free US radiologic technologists with known ultraviolet exposure (irradiance at up to 5 residential locations) for 5–22 years. 2151 technologists reported incident primary BCC within the study period. The authors reported that the absolute risk of BCC increased with increased cumulative UVR exposure. The authors also reported that the relative risk showed substantial variation with time after exposure and age at exposure, so that risk is highest for the period 10–14 years after UVR exposure and for those exposed under the age of 25. Some limitations described by the authors in the study included that the BCC incidence was self-reported, however, a large number of these were verified through medical records. Also, residency used for exposure assessment was self-reported. Assumptions were made that this cohort of workers spent a large proportion of their time indoors due to their profession and could not take into account individual behaviour such as excessive outdoor activity and UVR exposure received on holidays.
Despite some of the limitations described by the authors, this study added to the body of evidence that UVR exposure is a causal factor in the development of BCC. Evidence for the association between UVR exposure and the development of other skin cancer types such as squamous cell carcinoma and melanoma has been clearer in the body of scientific evidence. This large study strengthens the evidence of an increase in BBC with increasing cumulative UVR exposure. The results support the advice from both ARPANSA and Cancer Council Australia about limiting UV exposure and applying sun protection measures.