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The Cancer Letter Inc.
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publication date: Apr 22, 2016

Guest Editorial

30 Years after Chernobyl: Lessons Learned 

 

April 26 marks the 30th anniversary of the Chernobyl nuclear power facility accident in the former Soviet Union. Soon after the accident, I received a call from the Soviet ambassador to the U.S. on behalf of Mikhail Gorbachev asking me to come immediately to Moscow.

The world (but not Soviet citizens) had been following the spread of a radioactive cloud over Europe for several days and I offered the Soviet government access to advanced medical technologies I knew they lacked. I arrived to find about 205 of the most seriously-affected victims had been flown to Hospital 6 in Moscow connected to the Institute for Biophysics.

I was able to quickly assemble a team of experts from the U.S. (Richard Champlin and Paul Terasaki) and Israel (Yair Reisner) and, together with a superb group of Soviet physicians including Angelina Guskova, Alexander Baranov and Andrei Vorobiov, used diverse technologies including molecularly-cloned haematopoietc growth factors and transplants to treat the nuclear worker and firefighters exposed to high doses of radiation (1). Twenty-nine died despite our efforts, mostly of thermal and chemical damage. Fortunately, we were able to rescue the other 176. This was also the first chance to treat humans (including ourselves) with molecularly-cloned myeloid growth factors (but that’s another story [2]).

Most physicians are more interested in the long-term including radiation-related cancer and cardio-vascular disease. Fortunately, we are now in a reasonable position to comment what has happened over these 30 years and what may happen over the next several decades. Some of these data and predictions can inform our calculus on two related issues: nuclear energy and nuclear weapons.

The health impact of the Chernobyl accident was in some ways enormous and in others minor for expected and unexpected reasons. Despite extraordinary claims by people and organizations with either complex political and/or social agendas or limited scientific knowledge (often both) claiming thousands of deaths and injuries the direct long-term health effects from radiation exposures are small. The most startling and unexpected outcome was the rapid development of about 7000 excess thyroid cancers in children and young adults, cancers which resulted from drinking milk contaminated with radioactive iodine-131 in a population with background iodine deficiency (endemic goiter). Also, infrastructure limitations prevented us from rapidly distributing non-radioactive iodine tablets which would have blocked uptake of iodine-131 and from quarantining contaminated foods. (None of these conditions apply to the Fukushima nuclear power facility accident where I expect few if any thyroid cancers.) Fortunately, thyroid cancer in children is largely curable: there were fewer than 20 deaths. There is also a suggested increase in chronic lymphocytic leukaemia amongst the more than 100,000 personnel involved in mitigating the accident (called liquidators in Russian). However, I think these data shaky and more likely to reflect surveillance biases. Increases in more common cancers, like breast lung and colon cancer can be anticipated if one takes the relatively small radiation doses received by most of the surrounding population and multiples the risk by millions of people. Whether such a calculation is appropriate is controversial. Also, seeing no convincing increase in solid cancers yet is not surprising given the more than 30 years it took for most radiation-related cancers to develop in the A-bomb exposed population. The absence of a detectable increase in acute leukaemias or chronic myeloid leukaemia after Chernobyl is encouraging as these leukaemias were markedly-increased in the decade after the A-bomb explosions. If we use conventional cancer risk-estimators one might expect about 12,000 excess cancers from Chernobyl over the next 40 years about 4000 of which will be fatal. This is only about a 1 percent increase in the proportion of exposed persons expected to die from cancer were there no accident. (Our baseline lifetime cancer risks are rather high, about 50 percent in persons born after 1960.) This is not surprising given that only 10 percent of cancers in the A-bomb survivors were caused by exposure to radiation at substantially higher doses. Whether these level of detection with the current epidemiological techniques; we have no specific markers of radiation-induced cancers. Moreover, the increased cancer risks resulting from smoking tobacco (25-fold) and drinking alcohol (20,000 deaths per year in the U.S. [4]) far exceed those resulting from Chernobyl-related radiation exposures. There are increasing data radiation causes an increased risk of death from cardio-vascular diseases but typically at much higher doses than the Chernobyl population such that no radiation-induced increase is expected. Other good news: there are no convincing data of a deleterious impact of Chernobyl-related radiation on reproduction or genetic or birth abnormalities. The bottom line is that the average Ukrainian, Russian and Byelorussian is far more likely to be killed driving to a local store to buy cigarettes or alcohol than by radiation released by the Chernobyl accident. The same is for the chances of dying from environmental pollution from burning coal and oil in Kiev, Moscow and Minsk in winter than from radiation released from Chernobyl.

In contrast, environmental, social and economic impacts of Chernobyl are enormous. Plants and animals in areas contaminated by radionuclides released by the Chernobyl accident were severely affected. Genetic abnormalities were detected in many species and trees died. Although these problems are resolving because of radioactive decay and mitigation interventions, some will persist for more than 100 years because of the long half-lives of isotopes like cesium-137. About 300,000 persons were relocated because of the accident. The quality-of-life of many of these people is severely compromised by inappropriate concerns for their health (most received radiation doses unlikely to adversely affect them), unemployment and social dependency. The cost of the accident, including loss of agricultural land, employment and opportunities likely exceeds 250-400 billion USD.

Do these extraordinary data mean we should abandon nuclear energy? I think not. In considering any potential energy source we must compare costs, risks and opportunities. Fossil fuels are expensive, limited resources. Furthermore, their use entails substantial health risks: some obvious, some less so. Examples include not only lives lost mining, transporting and processing these fuels but also environmental pollution, global warming and thinning of the atmospheric ozone layer. The latter is expected to increase radiation doses to the earth’s population resulting in more cancers, especially melanoma. A less obvious cost are lives lost in geopolitical actions directed at protecting our energy sources. And the enormous bill for Chernobyl seems smaller daily as we spend billions in Iraq and Afghanistan. Perhaps most sinister is the possibility that defense of fossil fuels could lead us to a nuclear conflict which would release more radiation and cost more lives than a nuclear power facility accident. The recent treaty with Iran was a close call; the story is not over. In sum, the health and environmental consequences and costs of a fossil fuel-orientated society, including nuclear risks, may exceed those of wisely and safely using nuclear energy. We should continue to support evolving technologies to make nuclear energy safer and cheaper and reduce our addiction to fossil fuels. Japan after Fukushima is a good example. Closing Japan’s nuclear power facilities and importing oil has increased its carbon footprint 500 percent and adversely affected its economy.

Finally, there is a lesson here about nuclear weapons. The demise of the Soviet Union has increased rather than decreased the global nuclear threat. Also, the nature of the risk has changed. Consider terrorists using a conventional weapon intentionally contaminated with radioactive materials or sabotaging a nuclear power facility. Belgians have become acutely aware of these risks. Prevention is, of course, better than cure but our data and experiences from Chernobyl indicate the public’s fear of the radiation consequences of such events is exaggerated. These are weapons of mass distraction, not mass destruction to quote my UCLA colleague Bennett Ramberg. Education about what radiation can and cannot do to us is one step we can take to reduce the potential impact of nuclear terrorism.

 

The author is a physician/scientist who led the international medical response team at Chernobyl and teaches at Imperial College London. He and Eric Lax are authors of Radiation: What You Need to Know, published by A. Knopff.

 

References:

1.) Baranov A, Gale RP, Guskova A, et al. Bone marrow transplantation following the Chernobyl nuclear accident. N Engl J Med. 1989;321:205-13.

2.) Gale RP, Vorobiov A. First use of myeloid colony-stimulating factors in humans. Bone Marrow Transplantation. 2013;48:1358.

3.) Ahmad AS, Ormiston-Smith N, Sasieni PD. Trends in the lifetime risk of developing cancer in Great Britain: Comparison of risk for those born in 1930 to 1960. Br J Cancer 2015; 112:943-7.

4.) Nelson DE, Jarman DW, Rehm J, et al. Alcohol-attributable cancer deaths and years of potential life lost in the United States. Amer J Pub Health 2013;103:641-8.


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