Radiation epidemiology classification of malignant neoplasms in Chernobyl clean-up workers

This article presents radiation epidemiology approach to classification of malignant neoplasms in accordance with ICD10 diagnostic categories and codes with the use of statistical links between radiation dose and cancer in clean-up workers of the Chernobyl accident. Modern statistical methods of intelligent data analysis were used for examination of statistical relationships (association) between radiation dose and the disease of a correspondent diagnostic category and code. Cancer cases registered from 1986-over 2019 in Chernobyl clean-up workers (males), who entered the Chernobyl 30-km exclusion zone in 1986 through 1987, were taken in the analysis. Average dose of external whole body g-radiation exposure was 0.128 Gy. The total number of cancer cases was 9542; the average age at diagnosis was 57.4 years. The data are accumulated in the National Radiation and Epidemiological Register (NRER). To detect statistical relationships between radiation doses and cancer diagnoses Data Mining techniques free of apriori assumptions of probability distribution of dose and diagnosis were used. The analysis was made with the use of tables of contingency of disease cases in two dose groups (group 1: dose 0.1 Gy) and in two age groups (age group 1: 52 years). Statistically significant relationships between categories of diagnosis and radiation dose were found for malignant neoplasm of esophagus (category C15; age group 2); malignant neoplasm of stomach (category C16; age group 1); malignant neoplasm of bronchus and lung (category C34; age group 1); malignant neoplasm of prostate (category C61, age group 2); malignant neoplasm of bladder (category C67, age group 2). Significant relationships for individual codes were found for malignant neoplasm of stomach unspecified (code С16.9, age group 1); malignant neoplasm of main bronchus (code С34.0, age group 1); malignant neoplasm of unspecified part of bronchus or lung (code С34.9, age group 1); malignant neoplasm of bladder unspecified (code С67.9, age group 2). To make radiation dose-death relationship more clear research of stochastic effects using intelligent data analysis techniques should be continued.