Results of Long-Term Medical Observation of Direct Participants of the Accident at the Chernobyl Npp in the Russian Federation

Purpose: to present the materials of long-term (38 years) monitoring of the health status of a group of patients who had underwent acute radiation syndrome (ARS) in 1986 as a result of the Chernobyl accident and had been living in the territory of the Russian Federation. Materials and methods: the results of cytogenetic dynamic observation of 74 direct participants in the Chernobyl accident who had been examining at the clinic in the period from 1986 to 2012, as well as the results of dynamic inpatient observation of 10 of them permanently residing in Moscow, are summarized. Medical supervision consisted of annual planned hospitalizations in connection with patient requests, or emergency hospitalizations in connection with the detection of acute or exacerbation of a chronic disease. Laboratory and instrumental examination of organs and organ systems critical to the effects of radiation, as well as an extended cancer search, was carried out. Results: according to cytogenetic studies for all degrees of severity of ARS, starting from the 1st degree, the frequency of translocations in blood lymphocytes significantly exceeds the spontaneous level. The initial level of translocations depends on the initial dose estimate. The time of decrease in the frequency of translocations due to the presence of part of the translocations in unstable cells, from the initial value to an established constant level, apparently occurs in the first 5-8 years. Analysis of individual blood curves revealed transient moderate cytopenia, most often thrombocytopenia. Myelodysplastic syndrome (MDS) and leukemias were detected in 5 patients (2- Moscow group, 3- Ukranian group) from the entire group who underwent ARS as a result of the Chernobyl accident, which significantly exceeds the expected level. The diagnosis of radiation cataract was established in 11 patients. Two patients underwent surgical treatment. In the acute period ARS local radiation injuries (LRI) was detected in 59 patients. By 2005, 38 patients with the effects of LRI were observed (33 in Ukraine and 5 in Moscow). The most severe long-term consequences in the form of pronounced cicatricial atrophic changes, radiation fibrosis, and late radiation ulcers were detected in patients with grade III – IV LRI. 1 out of 10 observed patients developed primary multiple metachronous cancer of the genitourinary system, 2 patients – prostate cancer, 1 – metastatic lesion with an undetected primary tumor, 3 – multiple foci of basal cell skin cancer. The causes of death in 8 out of 10 patients were: cardiovascular pathology, MDS and leukemia, cirrhosis of the liver, oncological disease with undetected primary localization of the tumor, suicide in an oncological patient. Conclusions: The experience of providing medical care to victims of the Chernobyl accident with acute radiation injuries and further in the period of long-term consequences indicates the need to maintain constant readiness to provide medical care in case of a radiation accident, as well as adequate information during and after the accident, which will reduce the long-term consequences. Patients who have undergone ARS need lifelong medical supervision and the provision of necessary medical care. The main causes of permanent disability of patients who have undergone ARS are the consequences of LRI (recurrent late radiation ulcers, radiation fibrosis, contractures, scars, etc.). Radiation cataract is the cause of temporary disability (before surgical treatment). Patients who have undergone ARS need adequate social adaptation. The revealed effect of exposure to relatively uniform radiation is an increase in the frequency of MDS and leukemia.