To be more exact here with the wording, the researchers have found a “shift in (thyroid cancer) cases to cancer mutations consistent with radiation exposure from those consistent with random causes,” as worded by the press release.
As most people reading this will remember, the partial meltdown at the Three Mile Island facility — near Harrisburg, Pennsylvania — definitely released some radiation into the wider environment, but according to the United States Nuclear Regulatory Commission, the levels were low enough that no detectable health effects were associated with it.
The new work — which analyzed tumor samples from people who have been verified through an extensive vetting process to have lived in areas surrounding the nuclear facility at the time of the accident, to have stayed in the area, and to have later developed thyroid cancer there — shows that this apparently hasn’t, in fact, been the case.
The press release provides more:
“In this retrospective cohort study — meaning the patients in the study already had thyroid cancer and were known to have been exposed to the TMI accident — lead researcher Dr David Goldenberg, professor of surgery, and colleagues identified 44 patients who were treated at the Penn State Health Milton S Hershey Medical Center for the most common type of thyroid cancer, papillary thyroid cancer, between 1974 and 2014. The patients were then divided into two groups: at risk and control groups.
“Patients in the at-risk group were those who developed cancer between 1984 and 1996, consistent with known latency periods of radiation-induced thyroid cancer, and who lived in at-risk geographical areas — based on reported weather patterns — at the time of the accident.”
“This definition was designed to allow us to identify relatively acute effects of radiation exposure from the accident,” explained Goldenberg.
The press release continues: “Patients who developed cancer outside of the expected latency period were placed in the control group. Researchers searched through all thyroid cancer tumor samples in the hospital’s possession from the study period for patients who lived in at-risk regions Dauphin, York, eastern Cumberland, Lancaster and western Lebanon counties. They used genealogical software to verify that the patient was in an at-risk area during the accident, remained until cancer developed and was treated at the Medical Center. The tumor samples of those patients who were positively linked to the TMI accident area were then processed through the Penn State Institute for Personalized Medicine to determine genetic makeup of the cancer.
“While most thyroid cancers are sporadic, meaning they happen without clear reasons, exposure to radiation has been shown to change the molecular makeup of the cancer, according to the researchers. The researchers observed an increase in the genetic mutation caused by exposure to low-dose radiation in the at-risk group and a decrease in the incidence of sporadic thyroid cancer, identified by a specific genetic mutation known as BRAF. The BRAF mutation is typically not present in the radiation-induced types of thyroid cancer.
“The study indicates that these observations are consistent with other radiation-exposed populations. In the control group, 83% of patients had the BRAF mutation. The BRAF mutation was found in only 53% of patients in the at-risk group. In the at-risk group, there was also a rise in other molecular markers seen in radiation induced thyroid cancer, the researchers added.”
So, this is yet another example of the way that nuclear energy is probably not the safest (or most economical) way to go about providing people with electricity.
Goldenberg continued: “While no single marker can determine whether an individual tumor is radiation-induced, these data support the possibility that radiation released from TMI altered the molecular profile of thyroid cancers in the population surrounding the plant.”
The researchers are now planning to expand the work to include patients from other regional hospitals, to try and determine if the correlation is true on the larger scale as well.