Childhood thyroid cancer since accident at ChernobylBMJ 1995; 310 doi: https://doi.org/10.1136/bmj.310.6982.801 (Published 25 March 1995) Cite this as: BMJ 1995;310:801
- V A Stsjazhko,
- A F Tsyb,
- N D Tronko,
- G Souchkevitch,
- K F Baverstock
- Head Chernobyl Accident Health Effects Department, Ministry of Health, 220097 Minsk, Republic of Belarus
- Director Research Institute of Medical Radiology, Academy of Medical Sciences, SU-249020 Obninsk, Russian Federation
- Director Kiev Research Institute of Endocrinology and Metabolism, 254114 Kiev, Ukraine
- Radiation scientist Office of Global and Integraded Environmental Health, World Health Organisation, Geneva, Switzerland
- Radiation scientist World Health Organisation, European Centre for Environment and Health, Rome Division, I-00156 Rome, Italy
EDITOR,—We wish to report on a meeting of scientists from the three countries most closely affected by the accident at Chernobyl and from the World Health Organisation to review the programme of screening for and diagnosis of childhood thyroid cancer undertaken since the accident in April 1986. While the central purpose of the screening programme was humanitarian, during the review some of the information compiled was deemed to be of scientific interest.
The table shows that, before the accident, the annual incidences of childhood cancer were in line with spontaneous rates in many other parts of the world. For example, the rate observed during 1962-92 in England and Wales was about 0.5/million (E D Williams, personal communication).
In Belarus (population about 10 million), where the increase has been most pronounced, more than half the cases are reported from the Gomel region immediately to the north of Chernobyl (figure). Nearly all diagnoses in Belarus have been subject to international verification.
In all the countries, programmes of annual medical examinations were set up shortly after the accident to screen children for thyroid disease. Examinations included palpation of the neck, ultrasound imaging, and thyroid hormone testing. Between 40% and 70% of diagnosed cases were found through this programme.
In the Ukraine (population about 52 million) the increase in cases has been most pronounced in five regions in the north of the country. The greater part of the country was not subjected to high levels of contamination and showed a small increase, which may be due wholly or partly to increased awareness and thus ascertainment of cases.
Finally, and much more recently, an increase in cases has been reported in the Russian Federation (population about 150 million) in the region of Bryansk (population 1.5 million) close to Gomel in Belarus. Appreciable contamination also occurred in the Kaluga region (east of Bryansk region), but only two cases have been observed despite annual medical examinations.
All the regions in the table are characterised by the heavy contamination that occurred immediately after the accident; the table shows the contamination with caesium-137. The short half lives of the isotopes of iodine made their contribution to the dose harder to assess, but the table gives estimates of the range of the dose to children living in the various regions at the time of the accident. For those who continued to live in the contaminated region and to consume locally produced milk for the three months after the accident, most (about 85%) of the dose to the thyroid derived from iodine-131, while the remainder was from short lived isotopes of iodine. For those (a minority) evacuated to “clean” regions soon after the accident the fraction of the dose from short lived isotopes was greater, although total doses would have been lower.
These observations raise important questions of a public health nature about the consequences of exposure to radioactive fallout. These questions are of immediate concern to the countries affected but also of international concern so that, in the event of future accidents, appropriate public health measures can be implemented quickly and effectively. It is notable that in the regions most affected about 2.3 million children were resident at the time of the accident. This led to unprecedented exposure of a population to ionising radiation, which demands an international response.