Abstract
Cancer risk assessment was conducted on a population who received low dose-rate gamma-irradiation after occupying buildings containing 60Co-contaminated steels for more than 10 years in Taiwan. More than 7,000 people were registered and the occurrence of various cancers ascertained till the end of 2002 via the National Cancer Registry Program in Taiwan. The cancer incidences were compared with the populations with the same temporal and geographic characteristics in Taiwan, by standardized incidence ratios (SIRs) after adjusting for age, gender, and latent periods for developing cancers and further association with cumulative radiation exposure via Cox regression. A total of 141 individuals with various cancers were observed, while the risks were significantly increased for acute lymphocytic leukemia, all leukemias, and hemato-lymphoid malignancies in men, and thyroid cancers in women. Women were also show with higher risks of all cancers combined and solid cancers than men. All cancers and solid cancers were further shown with exposure-dependent increased risks in those received initial exposure before 30 years old. The results indicated increased risks of developing various cancers in human population with protracted low dose-rate radiation exposure.
