FUKUSHIMA, Japan — Even if the worst nuclear accident in 25 years leads to many people developing cancer, we may never find out.
The ordinary rate of cancer is so high, and our understanding of the effects of radiation exposure so limited, that any increase in cases from the Fukushima nuclear-plant disaster may be undetectable.
Several experts said cancers caused by the radiation may be too few to show up in large population studies, such as the long-term survey just getting underway in Fukushima.
That could mean thousands of cancers under the radar in a study of millions of people, or it could be virtually none. Some of the dozen experts The Associated Press interviewed said they believe radiation doses most Japanese people have gotten fall in a “low-dose” range, where the effect remains unclear.
The cancer risk may be absent or just too small to detect, said Dr. Fred Mettler, a radiologist who led an international study of health effects from the 1986 Chernobyl disaster.
That’s partly because cancer is one of the top killers of people in industrialized nations. Odds are high that if you live long enough, you will die of cancer. The average lifetime cancer risk is about 40 percent.
In any case, the 2 million residents of Fukushima Prefecture, targeted in the 30-year survey, probably got too little radiation to have a noticeable effect on cancer rates, said Seiji Yasumura of Fukushima Medical University.
The idea that Fukushima-related cancers may go undetected gives no comfort to Edwin Lyman, a senior scientist with the Union of Concerned Scientists, a group that advocates for nuclear safety. He said that even if cancers don’t turn up in population studies, that “doesn’t mean the cancers aren’t there, and it doesn’t mean it doesn’t matter.”
He said authorities can do a lot to limit the toll by reducing future exposure to the radiation: “There’s some difficult choices ahead.”
The plant was damaged March 11 by a tsunami triggered by a magnitude-9 earthquake.
Citizens groups are setting up radiation-measuring centers where residents can take vegetables, milk or other foods for tests. Some people are turning to traditional Japanese diet — pickled plum, miso soup and brown rice — with the belief that it boosts the immune system.
“I try what I believe is the best because I don’t trust the government anymore,” says Chieko Shiina, a 65-year-old farmer.
