Incident basal cell carcinoma and occupational ionizing radiation exposure in United States radiologic technologists, 1983-2006

*Terrence Lee, Radiation Epidemiology Branch, National Cancer Institute 

Keywords: Basal Cell Carcinoma, Occupational Ionizing Radiation, Radiologic Technologists

Background: Basal cell carcinoma (BCC) is the most frequently diagnosed neoplasm in Caucasian populations. Ionizing radiation (IR) is a risk factor for BCC as has been seen in atomic bomb survivors and patients irradiated for medical reasons. However, it is not known if low levels of IR over a protracted period are associated with increased risk of BCC. The possible interaction of IR and solar ultra-violet (UV) radiation on the risk of BCC is also unclear. Methods: The United States Radiologic Technologists (USRT) Study is a longitudinal cohort study of radiologic technologists living in all 50-states. Questionnaires were administered in 1984-1989, 1994-1998, and 2003-2005 and elicited information on cancer outcomes, demographic characteristics, medical history, work practices, residential and sunburn history, and other environmental and lifestyle risk factors. Skin IR doses for each participant were estimated using a combination of badge dose readings, work practices and literature based exposure data. UV radiation was estimated using NOAA satellite and cloud cover information. Cox proportional hazards modeling and EPICURE were used to estimate relative risks in particular interactions of ionizing radiation dose and UV skin exposure. Preliminary Results: 55, 237 individuals were included among whom 5,439 developed an incident BCC. Other results of preliminary analyses will be presented. Conclusions: Few studies can address risk of BCC from IR exposure below 100 mGy or evaluate interaction with UV radiation. Results of these analyses will be helpful in understanding such relationships and will look forward to discussions about them at the meeting.