title: The incidence of malignant neoplasms in individuals working in areas of ionizing radiation in hospitals.
abstract: OBJECTIVE
  To assess the radiation risk of carcinogenesis in individuals professionally exposed to low-level ionizing radiation in a longitudinal cohort study.
  
  
  METHODS
  Analysed were the incidence and mortality induced by malignant neoplasms in a cohort of 1,560 occupationally exposed individuals (OEI) working in areas of ionizing radiation during 1992-2002 (study group). Assessment of exposure to radiation was recorded by personal thermoluminescent dosimeters (TLD), regular periodic health checkups, and bio-dosimetric data (chromosomal aberrations). Incidence and mortality were calculated using conventional epidemiological methods. The same methodology was applied in 5,480,408 individuals from the general population of central Serbia (PCS), not professionally exposed to ionizing radiation (control group).
  
  
  RESULTS
  The annual incidence rate of malignancies was 163 for males and 282 for females, per 100,000 OEI and mortality 44 for males and 11 for females. For general PCS the annual incidence rate of malignancies was 374 for males and 347 for females per 100,000, while mortality was 267 for males and 191 for females. Solid malignant neoplasms prevailed in OEI. The frequency of chromosomal aberrations in the group of OEI with malignant neoplasms was 0.33%, compared with 0.20-0.50% of the general population. The incidence of pharyngeal carcinomas in the group of occupationally exposed males was 5-fold higher than in males of the general PCS. In females of OEI the risk of malignant neoplasms such as uterus, ovary, bone marrow, lymphomas, thyroid, larynx and breast was increased compared with the general PCS.
  
  
  CONCLUSIONS
  The incidence rate of malignancies in the group of OEI to low-level ionizing radiation was not significantly different from the incidence rates of malignant diseases in the general PCS. The same applied for mortality. Differences were observed between the OEI and the general PCS in the localization of malignant neoplasms and sex.
authors.affiliation: University of Belgrade, Faculty of Medicine, Institute of Occupational Medicine and Radiological Protection, Belgrade, Serbia. m.masha@beotel.net
authors.forename: S
authors.initials: S
authors.lastname: Milacic
mesh_terms: D002869:Chromosome Aberrations; D015331:Cohort Studies; D004307:Dose-Response Relationship, Radiation; D005260:Female; D006801:Humans; D015994:Incidence; D008137:Longitudinal Studies; D008297:Male; D009369:Neoplasms / Q000532:radiotherapy*; D009381:Neoplasms, Radiation-Induced / Q000453:epidemiology* / Q000209:etiology; D016273:Occupational Exposure; D011839:Radiation, Ionizing; D012737:Sex Factors