Dynamics of thyroid cancer incidence in Russia following the Chernobyl accident.

This paper presents an analysis of thyroid cancer incidence in the territories of Russia most contaminated after the Chernobyl accident. In the work, data on incidence in the Bryansk, Kaluga, Orel and Tula regions (5298000 persons) are used. Altogether, 2599 cases of thyroid cancer are considered from 1982 to 1995. Of them, 143 cases were among the population who were children and adolescents at the time of the accident in 1986. The work uses the approach based on comparison of distributions of thyroid cancer cases by age at diagnosis and age at exposure. It has been shown that since 1991 the age structure of the incidence has changed significantly with a growing proportion of cases among children and adolescents. The change in the structure occurred due to the radiation factor, specifically as a result of exposure of thyroid to incorporated 131I. It has been shown that the standardised incidence ratio (SIR) of thyroid cancer among children who were 0-4 years at exposure in 1991-6 was 6 to 10 times higher than among adults. On the average, SIR for children and adolescents at the time of exposure is about three times higher than in adults.