NEW YORK — In a study of radiology technicians, chronic exposure to ionizing radiation, even at low levels, raised the risk of a common type of skin cancer called basal cell carcinoma. The risk was greatest in subjects with lighter compared to darker eye and hair color.
Although ionizing radiation is a known cause of nonmelanoma skin cancer, the risk seen with chronic occupational radiation exposure and the interaction with UV radiation exposure has been unclear.
To investigate, Dr. Shinji Yoshinaga, from the National Institute of Radiological Sciences in Chiba, Japan, and colleagues analyzed data from 65,304 white radiologic technologists in the US who completed surveys in 1983 to 1989 and in 1994 to 1998.
The first survey included a variety of demographic, health, and work-related questions, while the second focused largely on cancer and related risk factors.
A total of 1355 cases of basal cell carcinoma and 270 cases of squamous cell carcinoma, another type of skin cancer, were observed in the study group.
Long-term exposure to ionizing radiation appeared to raise the risk of basal cell, but not squamous cell, carcinoma, according to a report in the International Journal of Cancer.
The effects were most pronounced for people who began working during the 1950s and earlier, a period when radiation exposure levels were relatively high.
Compared with technicians who started working after 1960, those who began in the 1940s were about two times more likely to develop basal cell skin cancer. Technicians who began working in the 1950s were roughly 1.4 times more likely to develop basal cell cancer.
“Our study…provided indirect evidence of an increased risk of basal cell carcinoma associated with chronic occupational exposure to ionizing radiation at low to moderate doses,” the authors state.
SOURCE: International Journal of Cancer, July 10, 2005.