engleski

The increasing incidence of thyroid cancer in Croatia coinciding with Chernobyl nuclear catastrophe

During the accident at Chernobyl nuclear power plant, on April 26th 1986, about 100 MCi of short-lived radioiodines (I-132, 133, 135) and 40 MCi of I-131 were released into the atmosphere.The main zones of soil contaminations were to the west, northwest and northeast of Chernobyl. However, after May 1st , substantial increase of the emission was reported, with the maximum on May 5th 1986. Since April 30th, during heavy rainfall in south central Europe, a radioactive material was transported into Croatia - mostly to northwestern part. Accumulated I-131 deposition in KBq/m2, as calculated by the MESUS model, for the period April 26th - May 6th 1986, for European countries (excluding former USSR): Poland 110, Austria 20-150, Italy 5-100, Bavaria 130 , ex Czechoslovakia 50, Croatia 100, W. Europe 0-20 . Estimated accumulation in thyroid of children and adolescents was 0, 05-200 mSv, meaning up to 20 cGy. The risk of cancer increases progressively from 10 cGy up to 1500 cGy larger doses are cellulicidal, so the risk of getting cancer is lower. After latent period, of about 3 years after exposal, the first childhood "Chernobyl" papillary cancers of thyroid gland (ChPTCs) appeared. CHARACTERISTICS OF ChPTC is frequently associated with autoimmune thyroiditis, solid/follicular subtype of ChPTC, extrathyroid spreading, common regional and distant metastases and rearrangement of the RET oncogene - RET PTC 1 (lower doses), RET PTC 3 (higher doses) The rationale of our research is to evaluate the Chernobyl catastrophe as a causative factor of accelerated increase of the thyroid cancer and to anticipate the possible further increase of incidence in the next years. Our research is aimed in three directions :1.Comparison of the PTC prior and after latent period of Chernobyl, regarding autoimmune thyroiditis, adenomas and nodules coinciding tumors, 2.Epidemiological tracing target cohorts of patients born 1966– 1986, 3.Attempt to find rearrangements of thyrosine-kinase domains of the RET genes, in group of 50 patients with PTC. Comparison of PTC according to histological findings in the remaining parenchym suggest that Chernobyl catastrophe could be one of the causes of increasing incidence of PTC in Croatia . Histological and epidemiological data, together with clinical observations and data from mid-eastern European countries, suggest that increase of thyroid cancer, particularly in population born 1966 - 1986, is caused, at least partly, by Chernobyl catastrophe .

Papillary thyroid cancer; Chernobyl catastrophe

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