Malignancies after Chernobyl Accident: What Is True and What Is Untrue

Abstract

Several publications in the field of pathology, overestimating medical consequences of the Chernobyl nuclear accident, are reviewed here. Among the causes of high registered incidence of pediatric thyroid cancer after the accident was the screening effect with detection of advanced cases. This explains also for the relatively high prevalence of dedifferentiated histological patterns and pronounced invasiveness described as the features of Chernobyl-related thyroid cancer. Mechanisms of false-positive diagnostics of thyroid and urinary bladder lesions are analyzed here. Morphological features of renal cell carcinoma from Chernobyl and adjacent areas are discussed in relation to the averagely late detection of malignancies. In conclusion, results of some molecular-genetic and other studies based on Chernobyl material should be re-evaluated, considering that many tumors detected during the first decade after the accident by the screening or brought from non-contaminated areas were advanced tumors, some of them misinterpreted as aggressive radiogenic cancers developing after a short latency.

Hormesis and radiation safety norms: Comments for an update

“…Summarizing the above and previously published arguments, 1,26,51,91 the harm caused by radioactive contamination would tend to zero with a dose rate tending to a wide range level of the natural radiation background. Within a certain range, the dose–effect relationship might become inverse due to hormesis.…”

“…38,[48][49][50] The overtreatment of supposedly radiogenic urinary bladder lesions after the CA was discussed elsewhere. 21,51 Mechanisms of false-positivity have been discussed previously; among others, the misinterpretation of nuclear pleomorphism as a malignancy criterion of thyroid nodules was not unusual in the former SU of the 1990s. 51 If a thyroid nodule is found by the screening, a fine-needle aspiration is usually performed.…”

“…38,48 –50 The overtreatment of supposedly radiogenic urinary bladder lesions after the CA was discussed elsewhere. 21,51…”

“…Mechanisms of false-positivity have been discussed previously; among others, the misinterpretation of nuclear pleomorphism as a malignancy criterion of thyroid nodules was not unusual in the former SU of the 1990s. 51 If a thyroid nodule is found by the screening, a fine-needle aspiration is usually performed. Thyroid cytology is accompanied by some percentage of inconclusive results, when histological examination is indicated.…”

“…The surgical specimen was sent to a pathologist, who could be sometimes prone, after the in toto removal of the nodule, to confirm malignancy even in case of uncertainty. 51 Frozen sections were sometimes used, being suboptimal for histological diagnostics of thyroid nodules. Radiophobia and cancerophobia contributed to the overdiagnosis of cancer, which can be illustrated by the following citation (from Russian): “Practically all nodular thyroid lesions, independently of their size, were regarded at that time in children as potentially malignant tumors, requiring an urgent surgical operation.” 25 The number of found nodules was additionally increased due to the iodine deficiency with enhanced incidence of goiter in the contaminated territories providing more opportunities for the false-positive conclusions; more details are in the study by Jargin.…”