2»J INTERNATIONAL CONFERENCE: UA0000554 LONG-TERM HEALTH CONSEQUENCES OF THE Kiev, , June 1-6, 1998

SCREENING OF LEUKEMIAS AND LYMPHOM AS IN AMONG PERSONS AFFECTED BY THE CHERNOBYL ACCIDENT IN CHILDHOOD 'TolochkoG.V., IvanovE.R, ShuvayevaL.P., Jaroshevich R.F., Ivanov B.E., RaspopovaN.L, Vinokurova G.G., Shapovaluk N.K., Melchakova N.M., Stepanova T.A., 2Nechay V.V., 2 Shumikhina T.P. Research Institute of Hematology and Blood Transfusion, , Belarus 2Hematological Clinic of Regional Hospital, , Belarus

Before the Chernobyl power plant accident epidemiology of hemopathies on the territory of Belarus was not studied, being a «blank spot» in the world descriptive leukosology. It was Chernobyl which disturbed the ecological situation by radioactive contamination of a greater part of Belarussian territory and made the monitoring of blood diseases rates, first of all among the childhood population, inevitable. Previously we discovered that the childhood hemoblastoses rates in all Belarussian regions and in the nation on the whole during 7 post-Chernobyl years tended to increase, however, without reaching statistically relevant values. This tendency was also noted in the analysis of radiation- dependent hemopathies - the acute leukemias and chronic myeloid leukemias - even on the territories with different levels of contamination by Chernobyl fallout. The present research in meant to epidemiological monitor all the cases of different hemoblastoses and to analyze the incidence rates among the population affected by the accident in childhood (to the age of 14 years old inclusive). By the present time we have screened the oncohematological morbidity in the concrete group of population - among persons affected by the Chernobyl accident in childhood and taken ill in 1986-1996 on the territory of Gomel region. In the pre-accident period (1979-1985), about 25 cases of childhood hemoblastoses were annually diagnosed in the region(6.2 per 100 000). 58% of these cases were leukemias, 42% Hodgkin lymphomas and non-Hodgkin lymphomas, correlation between the latter being 1:1.3. The hemoblastoses rates index in Gomel region was on average lower than in the nation on the whole, the relative risk rate reached 0.9 (for leukemias the risk rate was still lower, 0.8) of the risk rate ofBelarus. The 7 post-accident years somewhat (apocryphally) changed the picture: childhood hemoblastoses rates have increased by 15%, including leukemias by 24%. The leukemia standardized index (4.29 per 100 000) in Gomel region has approached the average Belarussian one (4.33). The annual variability of the indices has proved high, their fluctuation has mostly increased in the recent years: from the highest in 1992 to the lowest in 1993 during the whole screening period (up to 1996). Besides, in 1995 - during the tenth year after the accident - an increase of childhood chronic alymphoblastic leukemia rate was revealed in Gomel region. For acute leukemia, the group of risk proved 1-5 years old, and for the chronic process, 10-14 years old. These data testify to necessity to expand the research. I -5 years old are children born after the accident. Their disease can be indirectly determined the fetal development conditions and/or environment. As to 10-14 years old, during the accident they belonged to youngest group (under 4 years, old) and their hemogenic system disease could be induced by the direct impact of radiation and/or the synergism of the direct and indirect mechanisms. In this connection, we have singled out a monitoring group which comprises all the childhood population (at the moment of accident) of Gomel region (dates of birth: from April 26,1971 to April 25, 1986), who are by now 10-25 years old. And within this cohort, is singled out a group of children born in Gomel region during the 9 months after the accident who survived it in the intrauterine development; their inborn pathologies rates were monitored. Morbidity characteristics in these cohorts are compared with similar indices in the population of Gomel region and other regions ofBelarus. _____

Epidemiologies! aspects of the Chernobyl disaster 143