Site-specific cancer mortality after low-level exposure to ionizing radiation: findings from an update of the International Nuclear Workers Study (INWORKS).

A major update to the International Nuclear Workers Study was undertaken that allows us to report updated estimates of associations between radiation and site-specific solid cancer mortality. A cohort of 309 932 nuclear workers employed in France, the United Kingdom, and the United States were monitored for external radiation exposure. Associations of radiation with cancer mortality were quantified as the excess relative rate (ERR) per gray (Gy) using a maximum likelihood and a Markov chain Monte Carlo method (to stabilize estimates via a hierarchical regression). The analysis included 28 089 deaths due to solid cancer, the most common being lung, prostate, and colon cancer. Using maximum likelihood, positive estimates of ERR per Gy were obtained for stomach, colon, rectum, pancreas, peritoneum, larynx, lung, pleura/mesothelioma, bone and connective tissue, skin, prostate, testis, bladder, kidney, thyroid, and residual cancers. Negative estimates of ERR per Gy were found cancers of oral cavity and pharynx, esophagus, and ovary. A hierarchical model stabilized site-specific estimates of association, including for lung (ERR per Gy = 0.65; 95% credible interval [CrI], 0.24-1.07), prostate (ERR per Gy = 0.44; 95% CrI, -0.06 to 0.91), and colon cancer (ERR per Gy = 0.53; 95% CrI, -0.07 to 1.11). The results contribute evidence regarding associations between low-dose radiation and cancer.