Workers at the Mayak nuclear facility in the Russian Federation offer the only adequate human data for evaluating
cancer risks from exposure to
plutonium. Risks of mortality from
cancers of the lung, liver and bone, the organs receiving the largest doses from
plutonium, were evaluated in a cohort of 17,740 workers initially hired 1948-1972 using, for the first time, recently improved individual organ dose estimates. Excess relative risk (ERR) models were used to evaluate risks as functions of internal (
plutonium) dose, external (primarily gamma) dose, gender, attained age and smoking. By December 31, 2003, 681
lung cancer deaths, 75
liver cancer deaths and 30
bone cancer deaths had occurred. Of these 786 deaths, 239 (30%) were attributed to
plutonium exposure. Significant
plutonium dose-response relationships (p < 0.001) were observed for all 3 endpoints, with lung and
liver cancer risks reasonably described by linear functions. At attained age 60, the ERRs per Gy for
lung cancer were 7.1 for males and 15 for females; the averaged-attained age ERRs for
liver cancer were 2.6 and 29 for males and females, respectively; those for
bone cancer were 0.76 and 3.4. This study is the first to present and compare dose-response analyses for
cancers of all 3 organs. The unique Mayak cohort with its high exposures and well characterized doses has allowed quantification of the
plutonium dose-response for lung, liver and
bone cancer risks based on direct human data. These results will play an important role in
plutonium risk assessment.