Penn State College of Medicine Wednesday reported that its researchers are showing, for the first time, a possible correlation between the partial meltdown at Three Mile Island in Middletown and thyroid cancer cases in the counties surrounding the plant.
TMI had a partial meltdown on March 28, 1979. The college said that during the incident, radiation was released into the environment. The U.S. Nuclear Regulatory Commission said the radiation released was in small amounts with no detectable health effects.
The study appeared Monday in a supplement to Laryngoscope.
Researchers with the college looked at tumor samples of thyroid cancer patients who were verified to have lived in the areas around TMI at the time of the accident and who remained in the area. The college said its researchers believe there was a shift from random causes to cancer mutations consistent with specifically radiation exposure.
The study looked at 44 patients who were treated at Penn State Hershey Medical Center for the most common type of thyroid cancer—papillary thyroid cancer—between 1974 and 2014. Patients were then split into groups, with some put into the “at-risk” group that included people who developed cancer between 1984 and 1996—consistent with the latency period of radiation-induced thyroid cancer.
The geographic at-risk areas were considered to be eastern Cumberland County, as well as all of Dauphin, York and Lancaster counties and western Lebanon county.
“This definition was designed to allow us to identify relatively acute effects of radiation exposure from the accident,” lead researcher Dr. David Goldenberg said in a news release.
A limitation to the study, however, is the small sample size, limited to tumor samples of patients treated at Hershey Medical Center. The college said the next step in the research is a study with a larger number of patients from other regional hospitals to determine if the correlation continues in a larger sample.
The college said past studies about thyroid cancer and TMI have showed variable results.
“Much of the variability associated with these studies is likely due to the relatively small size of the population surrounding the TMI plant relative to the large population required to detect statistically significant increases in cancer incidence following low-level radiation, combined with a high degree of mobility in the local population,” Goldenberg said.