Indian Journal of Endocrinology and Metabolism

: 2011  |  Volume : 15  |  Issue : 2  |  Page : 96--98

Nuclear detonation, thyroid cancer and potassium iodide prophylaxis

Viroj Wiwanitkit 
 Wiwanitkit House, Bangkhae, Bangkok, Thailand

Correspondence Address:
Viroj Wiwanitkit
Wiwanitkit House, Bangkhae, Bangkok 10330


The recent nuclear disaster at Japan has raised global concerns about effects of radioactive leakage in the environment, associated hazards, and how they can be prevented. In this article, we have tried to explain about the guidelines laid down by World Health Organization for a potassium iodide prophylaxis following a nuclear disaster, and its mechanism of action in preventing thyroid cancer. Data was collected mainly from the studies carried out during the Chernobyl disaster of Russia in 1986 and the hazardous effects especially on the thyroid gland were studied. It was seen that radioactive iodine leakage from the nuclear plants mainly affected the thyroid gland, and especially children were at a higher risk at developing the cancers. Potassium Iodide prophylaxis can be administered in order to prevent an increase in the incidence of thyroid cancers in the population of an area affected by a nuclear disaster. However, one has to be cautious while giving it, as using it without indication has its own risks.

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Wiwanitkit V. Nuclear detonation, thyroid cancer and potassium iodide prophylaxis.Indian J Endocr Metab 2011;15:96-98

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Wiwanitkit V. Nuclear detonation, thyroid cancer and potassium iodide prophylaxis. Indian J Endocr Metab [serial online] 2011 [cited 2021 Sep 26 ];15:96-98
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In the second week of March 2011, a massive earthquake of magnitude 9.0 on the Richter scale struck Japan causing a tsunami, [1] which mainly affected the areas of Fukushima, Miyagi and Iwate. Similar to another recent tragic tsunami of Southeast Asia, the tsunami in Japan is also expected to cause several thousands of deaths. [1] It not only disrupted the infrastructure in the affected areas, but also caused the total destruction of the atomic nuclear electricity plants in the disaster area of Fukushima. [1] Such a crisis of nuclear detonation due to a tsunami has never been witnessed before in history.

A number of reports about the ill-effects on the health of the population residing in these affected areas have come forward, changes in normal contents at the cellular level, being their main consideration. [2] The increased incidence of cancer, especially of the thyroid, post the radioactive leakage from the nuclear plant, is of concern, with respect to public health and endocrinology. [3],[4],[5] Such a situation is new, and requires global attention. Hence, in this article, the author has attempted to summarize about the occurrence of thyroid cancer following a nuclear leakage crisis, and has discussed the possibility of adopting prophylactic measures by making use of potassium iodide in such situations.

 Effect of Radioactive Substance Leakage from the Nuclear Plant on Thyroid Gland

The effect of exposure to leaked radioactive substances from a nuclear plant on the thyroid gland was first observed in 1986 in Russia, after the Chernobyl disaster. [6],[7] Kriukov first noted the abnormalities introduced in the thyroid gland structure after the incident in the ultrasonic scanning of the individuals staying in the affected areas. [4] Also, the incidence of thyroid cancer was found to be increased. [5] Baverstock and Williams reported that, "radiation to the thyroid from radioisotopes of iodine has caused several thousand cases of thyroid cancer, but very few deaths; exposed children being most susceptible". [8] Finally, it should be noted that only the incidence of thyroid cancer, and not others, was found to be significantly increased in the populations affected by the Chernobyl disaster, [9] and the risk was most significant in children. [8]

Many hypothesis have been put forth to explain this increase in the incidence of thyroid cancers. According to the first theory, the leaked radioactive iodine from the nuclear reactors can find an easy way into the thyroid gland, and thus cause the mutagenic changes. [5] According to another theory, the population also showed many genetic abnormalities of the thyroid cells, and molecular biology studies revealed translocation of the Rearranged During Transfection (RET) gene, in carcinoma type Rearranged during Transfection/Papillary Thyroid Carcinoma Type 1 (RET/PTC1) in elderly and Rearranged during Transfection/Papillary Thyroid Carcinoma Type 3 (RET/PTC3) in children, and expression of Tyrosine-protein kinase receptor UFO/ AXL receptor tyrosine kinase (Axl) and growth arrest-specific 6 (Gas6) in children, predisposing such individuals to the development of cancer. [9] The impairment of T cell activity and senility of the immune system, which slows down the killing of the cancerous cells, is also proposed. [10]

 Potassium Iodide Prophylaxis in the Crisis

The recent Japanese nuclear detonation crisis has raised global public health concerns and several measures are being taken to prevent the radioactive contamination. Entering into the affected areas has been prohibited by the government, and consumption of edible products and water from these areas is banned. Also, the proposition of giving a potassium iodide prophylaxis to the masses is being discussed. [11],[12],[13] The concept behind giving the iodide prophylaxis is the observation that stable iodine supplementation in an iodine deficient population can modify the risk of development of thyroid cancer. [14]

However, the use of iodide prophylaxis has to follow the recommended guidelines, [15] as the use without indication can have its own risks. [16] Crocker noted that "It is recommended that all appropriate counter-radiation measures be considered in the case of a reactor accident; however, the harmful side effects of the various actions be weighed carefully." [17] According to guidelines laid down by World Health Organization (WHO), pregnant and breast-feeding women, infants and children under 18 years of age should be given the iodide prophylaxis first, and the potassium iodide should be used immediately where inhalation of radioactive iodine occurs. [18] More information for potassium iodide prophylaxis in cases of nuclear leakage is presented in [Table 1]. Following the guidelines given in [Table 1] has shown to reduce the cancer risk by a factor of three. [18] Also, [Figure 1] presents the mechanism due to which this practice has been shown to be effective in preventing thyroid cancer. However, it is important to note that the prophylaxis should not be delayed, and be started as soon as possible, as the efficacy of the prophylaxis will be significantly decreased if it is started late (the golden period is within the first 3 hours of exposure). [18]{Table 1}{Figure 1}


Thus, it can be concluded that though potassium iodide prophylaxis may prove useful in preventing an increase in the incidence of thyroid cancer post a nuclear disaster, it has to given following the recommended WHO guidelines, and only when indicated.


1Matsumoto M, Inoue K. Earthquake, tsunami, radiation leak, and crisis in rural health in Japan. Rural Remote Health 2011. (Online): 1759. Available from: [last cited on 2011 Mar 13].
2Lenskaia RV, Rumiantsev AG , Buiankin VM, Ageĭkin VA, Baĭdun LV, Borodina TM, et al. Changes in the indicators of bone marrow and blood based on the complex cytological examination of 28 children from the Bryansk region 1 year after the accident at the Chernobyl atomic power plant. Gematol Transfuziol 1991;36:25-8.
3Ichimaru M, Ishimaru T. Review of thirty years study of Hiroshima and Nagasaki atomic bomb survivors. II. Biological effects. D. Leukemia and related disorders. J Radiat Res (Tokyo) 1975;16 Suppl:89-96.
4Kriukov EA. Ultrasonic study of the thyroid in the population living in areas contaminated by radioactive substances after the accident at the Chernobyl Atomic Electric Power Station. Voen Med Zh 1992:12-3.
5Chernobyl 7 years after the disaster. Increased number of thyroid cancer. Lakartidningen 1993;90:1934.
6Perry AR, Iglar AF. The accident at Chernobyl: Radiation doses and effects. Radiol Technol 1990;61:290-4.
7Il'in LA, Balonov MI, Buldakov LA, Bur'iak VN, Gordeev KI. The ecological characteristics and biomedical consequences of the accident at the Chernobyl Atomic Electric Power Station. Med Radiol (Mosk) 1989;34:59-81.
8Baverstock K, Williams D. The chernobyl accident 20 years on: An assessment of the health consequences and the international response. Environ Health Perspect 2006;114:1312-7.
9Zonenberg A, Zarzycki W, Leoniak M. The effect of Chernobyl accident on the development of malignant diseases--situation after 20 years. Endokrynol Pol 2006;57:244-52.
10Yarilin AA, Belyakov IM, Kusmenok OI, Arshinov VY, Simonova AV, Nadezhina NM, et al. Late T cell deficiency in victims of the Chernobyl radiation accident: Possible mechanisms of induction. Int J Radiat Biol 1993;63:519-28.
11Blando J, Robertson C, Pearl K, Dixon C, Valcin M, Bresnitz E. Evaluation of potassium iodide prophylaxis knowledge and nuclear emergency preparedness: New Jersey 2005. Am J Public Health 2007;97 Suppl 1:S100-2.
12Shleien B, Halperin JA, Bilstad JM, Botstein P, Dutra EV Jr. Recommendations on the use of potassium iodide as a thyroid-blocking agent in radiation accidents: An FDA update. Bull N Y Acad Med 1983;59:1009-19.
13Resolution concerning the stockpiling of potassium iodide in New York City in the event of a nuclear accident. The Committee on Public Health, The New York Academy of Medicine. Bull N Y Acad Med 1981;57:395-9.
14Robbins J. Indications for using potassium iodide to protect the thyroid from low level internal irradiation. Bull N Y Acad Med 1983;59:1028-38.
15Kesminiene A, Cardis E . Cancer epidemiology after the Chernobyl accident. B ull Cancer 2007;94:423-30.
16Yalow RS. Risks in mass distribution of potassium iodide. Bull N Y Acad Med 1983;59:1020-7.
17Crocker DG. Nuclear reactor accidents-The use of KI as a blocking agent against radioiodine uptake in the thyroid--A review. Health Phys 1984;46:1265-79.
18Jaworska A. Iodine prophylaxis following nuclear accidents. Tidsskr Nor Laegeforen 2007;127:28-30.