Chernobyl, radiation and thyroid cancer

The effects of radiation on man have been largely based on atomic bomb studies, Chernobyl exposure differs in radiation type, dose rate and tissue distribution. This review analyses the way in which Chernobyl studies have altered our understanding of radiation and thyroid carcinoma. Latency for radiation-related thyroid carcinoma is not fixed at 10 years; the time of detection of the first cases depends on the size of the outbreak. Radioiodine is not of low carcinogenicity, it is an effective thyroid carcinogen for young children for explicable reasons. Clinical, morphological and molecular studies after Chernobyl show a correlation with tumour latency, with short latency tumours largely showing RET PTC3 rearrangements, a solid type of papillary carcinoma and an aggressive clinical behaviour. As latency increases, the pattern changes too. Interaction of radiation with the genome results particularly in double-strand DNA breaks the precursor of rearrangements. The relationship between radiation, the type of oncogene mutation and other findings are discussed. Finally, the importance of continuing to study the consequences of an accident of a type we all hope will not occur again are stressed.