Estimation of individual relative risk of malignant neoplasm using cytogenetic examination data of the Chernobyl accident clean up workers

Abstract

The purpose of this work was to differentiate groups of Chernobyl clean up workers with elevated individual relative risk (IRR) of tumor development on the basis of lymphocyte cytogenetic changes considered as cancerogenic factors.

Materials and methods

A cohort of 2076 liquidators who worked in the accident zone in 1986–1987 was examined for cytogenetic changes in the irradiated lymphocytes, cultured using a standard technique. All kinds of chromosome aberrations accessible with the traditional chromosome-painting method were determined.

Results

The risk of development of malignant neoplasm in the cohort investigated was calculated for 155 persons, i.e. their prevalence being 7,47%. The frequency of chromosomal aberrations has the lowest value of self-descriptiveness at cohort stratification in groups with malignant and in those without it, and the frequency of pair fragments and chromatid aberrations has the highest value. The calculation of IRR has revealed the existence of groups with different risk level among 337 persons without pathology at the time of cytogenetic examination. Only 45,1% of persons had their IRR close to the value of the relative risk of development of malignant neoplasm. In comparison with the mean value for the population of Ukraine, IRR changed from 5 to 45 and for 75% of persons from cohort it did not exceed 20.

Conclusions

The method of evaluation presented in this work shows that cytogenetic examination is an important part of monitoring of the Chernobyl clean-up workers which makes it possible to reveal groups with different risk levels among persons without malignant neoplasm at the time of investigation.