Radioiodine-induced thyroid cancer: Studies in the aftermath of the accident at Chernobyl.

While a great deal is known about the relationship between external radiation exposure and thyroid cancer, much less is known about the oncogenic effects of internal radiation exposure from isotopes of iodine. The accident at the Chernobyl nuclear power plant released massive quantities of radioiodine isotopes into the atmosphere. The large number of ensuing thyroid cancers in exposed children leaves little doubt that these malignancies have occurred as a result of the accident. However, carefully planned epidemiological studies are needed to confirm that these are due predominantly to I-131 exposure, to determine the dose-response relationship, to monitor for continuing effects and to evaluate other contributing factors. Preliminary evidence indicates that there is a distinct pattern of somatic genetic changes in the thyroid cancers from the Chernobyl area.