Solar ultraviolet radiation is an important risk factor for cutaneous squamous cell carcinoma (SCC) and basal cell carcinoma (BCC). Dose-response relationships between cumulative UV exposure and risk for both entities as well as the role of occupational UV exposure in the development of BCC have not yet been conclusively investigated.
The primary objective of the research project FB 181 was the risk assessment of SCC and BCC of the skin with respect to natural UV exposure. Furthermore, instruments for the quantification of light damage (“Lichtschaden”) of the skin as well as instruments for assessment of the individual occupational and non-occupational UV exposure, which have been developed within the research project FB 170, were validated and reviewed for practicability.
A methodologically demanding, population-based and multicenter case-control study with two case groups (incident spontaneous squamous cell carcinoma; incident spontaneous basal cell carcinoma) and a control group was conducted to investigate the role of solar radiation in the development of SCC and BCC with particular focus on occupational and non-occupational UV exposure. A propensity score matching was conducted to ensure balanced proportions of age and sex within case and control groups. Potential risk factors such as positive family anamnesis, skin type, immunosuppression, age and sex were taken into account in the analyses on the association of UV exposure and skin cancer risk.
In total, 626 persons with SCC/actinic keratosis grade III or Bowen’s disease, 739 persons with BCC and 996 controls were recruited and examined.
Persons with high lifetime UV exposure levels (≥ 90. percentile) were at significantly higher risk of SCC in comparison to persons with medium lifetime UV exposure levels (40.-60. percentile). For BCC this association was not significant.
However, high occupational UV exposure was associated with a considerably increased risk for both, BCC and SCC. In persons with high occupational UV exposure (≥ 90. percentile) risk for SCC was at least doubled and almost doubled for BCC in comparison to persons with medium occupational UV exposure (40./44.-60. percentile). Farmers, outdoor construction workers as well as outdoor locksmiths, installers and pipe constructors yielded an especially high risk for both entities of non-melanoma skin cancer. One novel result with respect to former research in that field was the demonstration of positive dose-response relationships between cumulative natural UV exposure and risk for incident SCC and BCC. For both, SCC and BCC these dose-response relationships were not independent of the type of UV exposure (occupational/non-occupational). While there was no dose-response relationship obtained for non- occupational radiation recorded within the study, dose-response relationships for occupational exposure allowed for deviation of a dose doubling the risk of disease for both, SCC and BCC. Modifications by skin type were not analyzed and remain for further research. A positive association was not only shown for natural but also for artificial UV exposure. For both entities solarium use was positively associated with an increased risk of non-melanoma skin cancer.
The instruments for quantification of solar damage ("Lichtschaden") and the individual occupational and non-occupational UV exposure developed within the research project FB 170 proved to be valid, reliable and practicable within the field study being applied by investigators/physicians not being involved in the instrument development. However, special training of medical personal is required to ensure a correct usage.
The data collected within the project distinguish themselves by their high level of representativeness regarding selected parameters and by their high quality achieved by monitoring, electronic data collection as well as thorough plausibility checks. Results of the FB 181 research project provide substantial new knowledge for discussions regarding the role of occupational and non-occupational natural UV exposure in the development of non-melanoma skin cancer.
-cross sectoral-Type of hazard:
occupational disease, measuring methods, radiationDescription, key words:
UV radiation, skin tumors, squamous-cell carcinoma, basal-cell carcinoma