Characteristics of Malignant Neoplasms of the Hepatobiliary System in the Cohort of Occupationally-Exposed Workers

Introduction. The etiology of malignant neoplasms (MN) of the hepatobiliary system is multifarious, so when assessing the impact of ionizing radiation on the occurrence of tumors of this localization, non-radiation factors should be considered. The aim of the study was to describe cases of hepatobiliary system disease in the cohort of employees hired at the main plants of FSUE Mayak Production Association (PA «Mayak») in 1948-1982, who were exposed to occupational chronic radiation. Materials and Methods. The cohort under study included 22,377 persons (25% were women). The frequency of individual risk factors was compared among morphologically confirmed cases of hepatobiliary cancer and among workers who had not been ill with tumors of the indicated localization. Results. Up to December 31, 2018, the cohort had 59 cases of liver MCC (59% hepatocellular carcinoma, 17% cholangiocarcinoma, 25% hemangiosarcoma, and 2% anaplastic cancer) and 34 cases of gallbladder and biliary tract MCC (100% adenocarcinoma). The incidence of chronic diseases of gallbladder and biliary tract, cholelithiasis was statistically significantly higher among cases of hepatobiliary MNS in comparison with uninfected workers. In addition, there was a higher share of persons who had contact with harmful industrial factors before employment at PA «Mayak», as well as those with chronic liver diseases, excessive body weight and obesity among liver cancer patients. Doses of occupational exposure were highest in workers with liver hemangiosarcomas. Discussion. The data were obtained testifying to a possible role of non-radiation factors and ionizing radiation in the development of hepatobiliary cancer in the workers of the cohort under study. A peculiarity of the cohort is a high proportion of hemangiosarcomas in the structure of hepatic cancer. Conclusion. The non-radiational factors that, along with occupational exposure, could influence the incidence of hepatobiliary cancer among PA «Mayak» workers have been singled out. An analysis of risk caused by radiation and non-radiation factors is required to clarify the results of the study.