Could Over-Screening Be Behind Higher Thyroid Cancer Rates Among 9/11 Responders?

April 20, 2020

Study comparison should three-times more cancers among first responders, many of whom are asymptomatic.

First responders for 9/11 experience up to three times the thyroid cancer diagnoses compared to the general population. But, new research indicates exposure to toxic elements during the initial aftermath of the terrorist attacks might not be completely to blame.

In a study published April 20 in JAMA Internal Medicine, investigators, led by Hilary Colbeth, MPH, from the Fire Department of the City of New York and Montefiore Medical Center, pointed to potential over-screening as the ultimate reason behind the higher prevalence of thyroid cancer detection in this group.

During the days and weeks after the attacks, first responders at the World Trade Center (WTC) likely came in contact with significantly high levels of a myriad of toxins, putting them at higher risk for developing any number of cancers. Consequently, they have been routinely screened for the past 19 years with annual imaging services, including CT, MRI, and PET scans.

It’s this higher level of screening – not the actual toxic exposures – that the study authors credit for providers detecting more cancers among these patients.

“The elevated thyroid cancer rate may be … an artifact of such frequent and detailed medical surveillance,” the authors wrote.

The study evaluated health data from 14,987 male firefighters and emergency medical responders who worked in the aftermath of the September 11 attacks on the World Trade Center. As participants in the WTC Health Program, they received thorough screening services, including chest CTs and MRIs of the head and neck, every 12 months to 18 months.

In the 18 years post-attack, 72 patients developed thyroid cancer – 98 percent were diagnosed with papillary thyroid cancer and one person received a follicular carcinoma diagnosis. No one died from the disease, and no cancers progressed to metastatic tumors.

To compare the cancer rates from the first responders to the general population, the investigators also analyzed a similar patient sample from Olmsted County, Minnesota. While an initial comparison showed no differences between the groups, the researchers identified an increase in cancer detection after the U.S. Congress approved the James L. Zadroga 9/11 Health and Compensation Act. The legislation augmented the access to care that first responders had.

With greater access to care, the thyroid cancer rate among first responders rose to twice that of the men in Minnesota. The first responders were also much more likely to not exhibit symptoms – 81.5 percent versus 54.5 percent, respectively. These results indicate, the authors wrote, that incidental detection contributed to the elevated incidence of WTC-exposed thyroid cancers that has been reported in previous studies.

Additionally, it’s possible, they wrote, that many first responders underwent expensive lobectomies or total thyroidectomies based on the identification of a cancer that posed little threat. In many cases, they contend, a wait-and-see approach might be a better option for this patient group.

“The American Thyroid Association has recommended adopting an active surveillance program for low-risk papillary microcarcinomas, which could be a treatment option for qualifying WTC-exposed patients.”