Thyroid cancer after the Chernobyl nuclear disaster

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Thyroid cancer after the Chernobyl nuclear disaster

The Chernobyl 'disaster is a nuclear accident that occurred on the night of April 26, 1986 at 1:23:45 UTC + 4 in Reactor No. 4 of the Chernobyl' nuclear power plant, in the then Ukrainian Soviet Socialist Republic. In 2021 it is the most serious accident in the history of civil nuclear power and the only one, together with that of Fukushima in 2011, to be classified with the seventh level, the highest, of the INES catastrophic scale.

At the root of the disaster there seems to be procedural errors during a safety test on the RBMK No. 4 nuclear reactor of the plant. It was a system approval test, to verify the possibility of powering the cooling system pumps even in the event of an electrical blackout, feeding them with electricity produced by the inertial movement of the turbines, for the time necessary to activate the groups.

of emergency diesel-electric generation. Cancer registries from Belarus, Russia and Ukraine, together with epidemiological studies based on other sources, showed a dramatic increase in the incidence of thyroid cancer in the population at the time of the accident aged 0-18 residing in areas of Belarus , Russia and Ukraine hit by the disaster.

Up to 2002, more than 4000, up to almost 5000 cases of thyroid cancer have been recorded in this population, with an increase of up to 10 times compared to the period before the disaster. Most of these 4,000 thyroid cancers are undoubtedly attributable to iodine-131 intake in the days immediately following the disaster.

The study: Thyroid Cancer After Chernobyl: Re-Evaluation Needed, published on the Türk patoloji dergisi, proposes, years after the disaster, a reassessment of cases of thyroid cancer. We can read: "Thyroid carcinoma in people exposed to radiation during their childhood and adolescence is the only solid cancer for which the incidence increase as a result of the Chernobyl accident is regarded to be proven.

The main evidence in favor of a cause-effect relationship between radiation and thyroid cancer incidence increase comes from epidemiologic studies. Bias in some studies was caused by the screening effect, improved diagnostics after the accident, overdiagnosis, registration of patients from non-contaminated territories as Chernobyl victims, recall bias, dose-dependent selection and self-selection.

Prior to the accident, the registered incidence of pediatric thyroid carcinoma was lower in the former Soviet Union than in other industrialized countries ie there were undiagnosed cases in the population. The screening found not only small nodules but also late- stage tumors interpreted as radiogenic cancers developing after a short latency cted during first 10 years after the accident were larger than those detected later on average, many tumors being poorly differentiated and metastatic.

The relationship of thyroid cancer and Chernobyl exposures is not denied here; however, it is argued that the quantity of radiogenic cases has been overestimated according to the mechanisms discussed in this paper. In addition, it is suggested that results of some Chernobyl-related molecular-genetic and other studies should be re-evaluated, considering that many tumors detected by the screening or brought from non-contaminated areas and registered as exposed to the fallout were advanced cancers."