Normal Cancer Rate Found Near Three Mile Island Plant

By MATTHEW L. WALD

new study of 32,100 people living within five miles of the Three Mile Island nuclear plant near Harrisburg, Pa., found no significant difference in the overall rate of cancer deaths compared with the general population. The study did find some differences when cancers were analyzed by time period, type of cancer and sex of the patient.

The study, by researchers at the University of Pittsburgh's Graduate School of Public Health, said that their surveillance "provides no consistent evidence that radioactivity released during the nuclear accident has had a significant impact on the overall mortality experience of these residents."

But the study also said that "several elevations persist and certain potential dose-response relationships cannot be definitively excluded."

The study generally agreed with earlier evaluations, that the 1979 accident did not add significantly to cancer risk. But the researchers said their study was stronger because it covered from 1979 through the end of 1998 and that cancers that take years to develop would have done so by then.

The study is to be published today on http://ehis.niehs.nih.gov, a Web site that is part of the National Institutes of Health. It will be published later in the institutes' journal, Environmental Health Perspectives.

The lead author, Dr. Evelyn O. Talbott, said in a telephone interview, "When you compare observed with expected cancer, there was virtually no difference."

But Dr. Talbott added, "We did see one blip." From 1985 to 1989, 24 women in the group died of lymphoma or hematopoietic tissue (blood-forming organs), up from 14 that were expected to contract the disease during that period.

Among men, she said, the rates of those cancers were the same as what was expected, but the cancers were more common in those whom researchers believe were exposed to more radiation from the accident than in those who are thought to have received less. (The accident exposures were calculated, not measured.) Even the largest dose from the accident, though, was "very tiny," she said.

"You would expect, really by chance, when you do 20 or more analyses, you're going to have a couple that by random chance come up," Dr. Talbott said.

But she added, "You still need to report it when you see it."

The study was not thorough enough to capture other risk factors, she said. "Did we adjust for everything under the sun? No," she said.

Among the questions that researchers might pursue, she said, is whether those with higher cancer rates had more exposure to medical X-rays, pesticides or other possible risk factors.

After the explosion of the Chernobyl reactor, in Ukraine, in 1986, researchers found numerous cases of thyroid cancer. But the new Three Mile Island study found only one thyroid cancer death in the area over the period.