Incidence and mortality rates of tumors of the hematopoietic and lymphoid tissues in a cohort of workers chronically exposed to ionizing radiation

Abstract

   Introduction. Individuals acutely exposed to ionizing radiation demonstrated an increased risk of incidence of malignant neoplasms of the hematopoietic and lymphoid tissues (HLTT). Meanwhile papers describing the impact of chronic radiation exposure on the hematopoietic system are sparse.Aim — to assess incidence and mortality rates for HLTT in a cohort of workers exposed to chronic, occupational ionizing radiation.   Materials and methods. Incidence and mortality rates of HLTT were assessed for workers of a nuclear industrial enterprise who had been hired at the facility from 1948–1982 and followed up until the end of 2018 (22,377 workers). All workers of the study cohort were externally and/or internally exposed to ionizing radiation during occupational industrial activities. In the studied cohort of workers, 186 cases and 123 deaths (as a main cause) from HLTT were registered throughout the entire follow-up period (1948–2018).   Results. Crude incidence and mortality rates of HLTT in workers of the study cohort were associated with sex, attained age of workers and calendar follow-up period. Standardized incidence and mortality rates for males were significantly higher compared to females. The standardized HLTT incidence rates (per 1000 person-years of observation) were 0.36 ± 0.03 in males and 0.23 ± 0.04 in females while the standardized HLTT mortality rates were 0.16 ± 0.02 in males and 0.09 ± 0.02 in females.   Conclusions. The study revealed significant increasing trends for incidence rates of chronic leukemia and lymphoma by the end of the follow-up period (31. 12. 2018).