• Only slight risk of cancer after Japan tsunami, WHO says

    By Maria Cheng, Associated Press
    People exposed to the highest doses of radiation during Japan's Fukushima nuclear plant disaster in 2011 may have a slightly higher risk of cancer but one so small it probably won't be detectable, the World Health Organization said in a report released Thursday. 

    A group of experts convened by the agency assessed the risk of various cancers based on estimates of how much radiation people at the epicenter of the nuclear disaster received, namely those directly under the plumes of radiation in the most affected communities in Fukushima, a rural agricultural area about 150 miles north of Tokyo.

    Some 110,000 people living around the Fukushima Dai-ichi nuclear plant were evacuated after the big March 11, 2011, earthquake and tsunami knocked out the plant's power and cooling systems, causing meltdowns in three reactors and spewing radiation into the surrounding air, soil and water.

    Experts calculated that people in the most affected regions had an additional 4 to 7 percent overall risk of developing cancers, including leukemia and breast cancer. In Japan, men have about a 41 percent lifetime risk of developing cancer of an organ, while a woman's lifetime risk is about 29 percent. For those most hit by the radiation after Fukushima, their chances of cancer would rise by about 1 percent.

    "These are pretty small proportional increases," said Richard Wakeford of the University of Manchester, one of the authors of the report.

    "The additional risk is quite small and will probably be hidden by the noise of other (cancer) risks like people's lifestyle choices and statistical fluctuations," he said. "It's more important not to start smoking than having been in Fukushima."

    Experts had been particularly worried about a spike in thyroid cancer, since iodine released in nuclear accidents is absorbed by the thyroid, especially in children. After the Chernobyl disaster, about 6,000 children exposed to radiation later developed thyroid cancer because many drank contaminated milk after the accident.

    In Japan, dairy radiation levels were closely monitored, but children are not big milk drinkers there.

    WHO estimated that women exposed as infants to the most radiation after the Fukushima accident would have a 70 percent higher chance of getting thyroid cancer in their lifetimes. But thyroid cancer is extremely rare and the normal lifetime risk of developing it is about 0.75 percent. That lifetime risk would be 0.5 percent higher for those women who got the highest radiation doses as babies.

    Wakeford said the increase in such cancers may be so small it will probably not be observable.

    For people beyond the most directly affected areas of Fukushima, Wakeford said the projected risk from the radiation dropped dramatically. "The risks to everyone else were just infinitesimal."

    Some experts said it was surprising that any increase in cancer was even predicted and believe that the low-dose radiation people in Fukushima received hasn't been proven to raise the chances of cancer.

    "On the basis of the radiation doses people have received, there is no reason to think there would be an increase in cancer in the next 50 years," said Wade Allison, an emeritus professor of physics at Oxford University, who was not connected to the WHO report. "The very small increase in cancers means that it's even less than the risk of crossing the road," he said.

    Gerry Thomas, a professor of molecular pathology at Imperial College London, accused the WHO of hyping the cancer risk.

    "It's understandable that WHO wants to err on the side of caution, but telling the Japanese about a barely significant personal risk may not be helpful," she said.

    Thomas said the WHO report used inflated estimates of radiation doses and didn't properly take into account Japan's quick evacuation of people from Fukushima.

    "This will fuel fears in Japan that could be more dangerous than the physical effects of radiation," she said, noting that people living under stress have higher rates of heart problems, suicide and mental illness.

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  • Radiation may up breast cancer risk in some women

    By Maria Cheng, AP 
    LONDON -- Mammograms aimed at finding breast cancer might actually raise the chances of developing it in young women whose genes put them at higher risk for the disease, a study by leading European cancer agencies suggests.

     

    The added radiation from mammograms and other types of tests with chest radiation might be especially harmful to them and an MRI is probably a safer method of screening women under 30 who are at high risk because of gene mutations, the authors conclude.

    The study can't prove a link between the radiation and breast cancer, but is one of the biggest ever to look at the issue. The research was published Thursday in the journal BMJ.

    "This will raise questions and caution flags about how we treat women with (gene) mutations," said Dr. Len Lichtenfeld, deputy chief medical officer of the American Cancer Society. He and the society had no role in the research.

    Mammograms are most often used in women over 40, unless they are at high risk, like carrying a mutation of the BRCA1 or BRCA2 gene. Having such a mutation increases the risk of developing cancer five-fold. About one in 400 women has the gene abnormalities, which are more common in Eastern European Jewish populations. Unlike mammograms, an MRI, or magnetic resonance imaging scan, does not involve radiation.

    The breast cancer screening tests have been proven to save lives and are clearly beneficial for women aged 50 and over who have an average risk of breast cancer. Experts are divided about their value in women younger than 50.

    Some studies have suggested women with the genetic mutations could be more sensitive to radiation because the genes are involved in fixing DNA problems. If those genes are damaged by radiation, they may not be able to repair DNA properly, raising the cancer risk.

    In several European countries including Britain, the Netherlands and Spain, doctors already advise women with BRCA mutations to get MRIs instead of mammograms before age 30. In the U.S., there is no specific advice from a leading task force of government advisers, but the American Cancer Society recommends yearly mammograms and MRIs from age 30 for women with BRCA gene mutations.

    In the BMJ study, European researchers followed nearly 2,000 women over 18 with one of the gene mutations in Britain, France and the Netherlands. Participants reported their previous chest X-rays and mammograms, including the age of their first screening and the number of procedures. About 850 women were later diagnosed with breast cancer. Roughly half of them had X-rays while one third had at least one mammogram, at an average age of 29.

    The researchers did not have a breakdown of how many women were exposed to chest radiation before age 30 but estimated that for every 100 women aged 30 with a gene mutation, nine will develop breast cancer by age 40. They projected the number of cases would increase by five if all of them had one mammogram before age 30. But they cautioned their results should be interpreted with caution because most women didn't have a mammogram before 30.

    Researchers found women with a history of chest radiation in their 20s had a 43 percent increased relative risk of breast cancer compared to women who had no chest radiation at that age. Any exposure before age 20 seemed to raise the risk by 62 percent. Radiation after age 30 did not seem to affect breast cancer risk.

    "We believe countries who use mammograms in women under 30 should reconsider their guidelines," said Anouk Pijpe of the Netherlands Cancer Institute, one of the study authors. "It may be possible to reduce the risk of breast cancer in (high-risk) women by using MRIs, so we believe physicians and patients should consider that."

    The study was paid for by European cancer groups.

    Lichtenfeld said the study wouldn't immediately change advice from the American Cancer Society but said concerned women should talk to their doctor about their options. "It's not possible today to make a blanket statement about what women (with the gene mutations) should do, but physicians and patients need to weigh the risks and benefits carefully," he said.

    He also warned that women who need scans involving radiation shouldn't avoid them because of breast cancer fears.

    "No one should think that they should never get an X-ray because they have the BRCA1 or 2 gene mutations," he said. "Just be careful that the X-rays you get are really the ones that you need."

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  • After Fukushima, residents spared of nuclear contamination

    By Christopher Wanjek, LiveScience

    Residents near the Fukushima Daiichi nuclear power plant in Japan may have been spared the brunt of the deadly radiation that spewed from the failed reactors in March 2011, according to a study appearing tomorrow (Aug. 15) in the Journal of the American Medical Association.

    Doctors from Tokyo University measured levels of radioactive cesium, a measure of radiation exposure, in nearly 10,000 children and adults living in Minamisoma, a city just 14 miles (23 kilometers) north of the Fukushima Daiichi plant. They found the residents' exposure to be minimal, equivalent on average to less than half of a chest X-ray.

    The study is hopeful news for the millions of Japanese in the Fukushima area, although their lives and livelihoods have been forever tainted by the catastrophe.

    The earthquake and tsunami that struck Japan on March 11, 2011, took more than 15,000 lives and devastated the Tohoku region in north central Japan. Hundreds of thousands of buildings were destroyed and nearly a half million people were displaced. [ In Pictures: Japan Earthquake & Tsunami ]

    The tsunami knocked out the Fukushima Daiichi nuclear power plant, ultimately causing a meltdown in three of its reactors. Deadly radiation soon blew across the region. Residents within a 12-mile (19 km) ring around the plant — including most in Minamisoma — were evacuated. Worrisome levels of radiation were found in the region's water and soil during the subsequent months.

    As horrific as the events were, few if any people have died from the radiation exposure. Deaths thus far have been attributed to the earthquake and tsunami and hospital evacuations.

    The study reported in JAMA is the first to measure radiation exposure in humans after the nuclear accident, the Tokyo researchers said.

    Like others in the region, many residents of Minamisoma returned to their homes a few months after the accident to try to rebuild their lives. The city had been hit hard by the tsunami itself; hundreds of homes were washed away, and hundreds of people had died.

    In September 2011 researchers began to enroll nearly a quarter of the city's population in a study to measure levels of two types of radioactive cesium isotopes: cesium-134 and cesium-137, with half-lives of two years and 30 years, respectively. (A half-life is the time it takes for half of the radioactive material to decay.) These isotopes are representative of total nuclear radiation exposure, the researchers said.

    Only about a third of the residents studied had detectable levels of cesium, and this included about 16 percent of the children and 38 percent of adults. The radiation dose for nearly all participants was less than 1 millisievert, a level considered safe for the public. Only one person had a higher level, and that was 1.07 mSv. For reference, a CT scan of the head is about 1.5 mSv.

    So while at least one city in the affected area dodged the bullet, the Japanese aren't yet completely safe from radiation contamination.

    "I don't think most people will experience long-term health problems related to the nuclear accident if we can keep providing safe and uncontaminated food to the residents," Masaharu Tsubokura, first author on the report, told LiveScience. "In Chernobyl, residents nearby the nuclear plant were still exposed to radiation even decades after the incident because of the intake of the contaminated food. Food control is the key issue in lowering internal contamination."

    Japan will have to continue monitoring for food contamination for decades, Tsubokura said. The researchers added that this glimmer of good news about low radiation exposure must be viewed in the full scope of the disaster, where most residents in the area have suffered a great emotional and financial burden.

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  • Experts discount claims of U.S. deaths from Japan radiation

    By Linda Carroll

    A provocative new study released this week suggests as many as 14,000 Americans may have died as a result of exposure to radioactive particles blown here from Japan after the Fukushima nuclear reactor meltdown in March. But even though the report is gaining some attention, experts say there is no scientific basis for its claims. 

    The study, published in the International Journal of Health Services, was based on mortality data from the Centers for Disease Control and Prevention and compared death rates before and after the cloud of radioactive air rising out of the crippled reactor hit U.S. shores.

    Joseph Mangano, the lead author of the new report, says the number of deaths in the spring of 2011 was 4.46 percent higher than in the previous spring and the most likely cause was the higher levels of radiation.

    Mangano also found an increase of 2.34 percent in the winter of 2011 compared to the previous year, but he called that increase “standard,” as opposed to the beginning of a trend. Mangano said he couldn’t prove that the higher than expected death rate was due to radiation, but he said he believed it was the leading contender. He was unable to point to any studies showing how low levels of radiation in the U.S. would cause death.

    While U.S. deaths did rise in 2011, radiation doesn't make sense as the cause, experts say.

    “There’s nothing in the radiation health effects research to substantiate those claims,” said Bernadette Burden, a spokesperson for the CDC.

    Radiation expert Andrew Maidment said that the levels of radiation that blew over the U.S. were too low to have caused any deaths – especially in such a short period of time following the disaster. 

    “For acute radiation sickness you would need much higher levels of radioactivity,” said Maidment, an associate professor of radiology and chief of the physics section in the department of radiology at the University of Pennsylvania. “The levels they are talking about we see naturally occurring across the country.”

    What Maidment means is that normal radiation levels vary from region to region around the nation. And though the levels rose in certain areas as a result of the cloud of particles coming from the reactor, those levels still weren’t the highest measured around the U.S. so, they’re still within the norm for the U.S.

    Cancers typically associated with lower levels of radiation take years to develop, Maidment explained. “With leukemia, you’re talking about five to seven years,” he said. “And there’s a 10 to 20 year delay for solid tumors. I know of no mechanism that could get you instantaneous mortality from radiation at lower levels.”

    Dr. Robert L. Brent agreed. “The exposure of the USA population was extremely small and could not account for any acute lethal effects of radiation,” said Brent, a member of the National Counsel for Radiation Protection and distinguished professor of pediatrics, radiology and pathology at the Jefferson Medical College and the Dupont Hospital for Children.

    "The authors indicated that SIDS (Sudden Infant Death Syndrome) was increased according to the mortality figures the authors obtained from the CDC," said Brent. "To infer that SIDS can be produced by low or high exposures to protracted radiation is naïve. That is not even a remote possibility."

    So, how can you explain the rise in U.S. deaths following the reactor disaster?

    There’s something called biological variability, Brent said. “For example, if you look at reports from the CDC on birth defects, you might find in a particular month a single case of Down Syndrome. The next month there might be seven. That’s biological variability.”

    You can’t assume that a bump in the death rate was caused by a particular factor just because the timing was right, Brent said. “It has to be biologically plausible before you think about linking the two.”

    Some associations are just the result of chance, experts said.

    Maidment said it’s always possible that the events in Japan made some people in the U.S. very worried. “One thing we do know is that stress correlates with mortality,” he added. “It might be interesting to see if there was an increase in mortality after other highly stressful events, such as 9/11.”

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