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Motivated by concerns about thyroid cancer in several communities in Iredell County, North Carolina, 30 miles north of Charlotte, researchers at UNC Lineberger Comprehensive Cancer Center have launched a multi-institutional study to investigate thyroid cancer incidence in North Carolina. The study follows recommendations made by two advisory panels in 2019 and 2020.

The Carolina Thyroid Cancer Study will examine relationships between thyroid cancer cases statewide and specific environmental exposures and other factors. The project will focus on all new thyroid cancer cases diagnosed in North Carolina from 1995 to 2021. Data sources include the North Carolina Central Cancer Registry and North Carolina databases containing information on environmental and other factors. The analyses will further examine all areas of elevated incidence or prevalence, or hotspots, of papillary thyroid cancer in the state. An earlier North Carolina Department of Health and Human Services analysis found elevated rates of papillary thyroid cancer in Iredell County compared to the state overall. The increase in Iredell County from 2005-2016 mirrored increases seen statewide and nationally.

State Senator Vickie Sawyer, who represents the 37th district, which includes Iredell and Mecklenburg Counties, co-sponsored a bipartisan bill in 2019 calling for the creation of an advisory panel to outline the development of a research program to investigate increased cancer incidence in North Carolina. “Our task force quickly determined that due to the size and scope of this research that it should be spearheaded at the state level,” Sawyer said. “I am grateful to my colleagues in the legislature who supported my efforts in securing funding for this project through the NC Collaboratory.”

The American Cancer Society estimates that more than 44,000 people in the United States will be diagnosed with thyroid cancer this year, and it will cause nearly 2,200 deaths. In North Carolina, there are projected to be 1,055 new cases and 55 deaths from thyroid cancer in 2024. Papillary thyroid cancer is the most common form of thyroid cancer and is considered the most treatable. Known risk factors for papillary thyroid cancer include radiation exposure and obesity.

Headshot of Andrew Olshan.
UNC Lineberger’s Andrew Olshan, PhD.

“The purpose of the Carolina Thyroid Cancer Study is to generate new and more comprehensive insights into the possible causes of the increased rate of papillary thyroid cancer in Iredell County and elsewhere in North Carolina,” said the study’s lead investigator, Andrew Olshan, PhD, associate director of population sciences at UNC Lineberger and Barbara Sorenson Hulka Distinguished Professor of Epidemiology at UNC Gillings School of Global Public Health.

The research will expand on a preliminary investigation by North Carolina Department of Health and Human Services and the North Carolina Department of Environmental Quality that examined environmental exposures and patterns of papillary thyroid cancer in Iredell County.

“We are very excited that the Carolina Thyroid Cancer Study has launched to improve our understanding of factors that might be linked to thyroid cancer,” said Zack Moore, MD, MPH, state epidemiologist at the North Carolina Department of Health and Human Services. “Answering these questions is critically important for many people in our communities who have dealt with thyroid cancer themselves or in loved ones.”

The study’s investigators include Chris Baggett, PhD, UNC Lineberger; Kathleen Gray, PhD, UNC Institute for the Environment; Virginia Guidry, PhD, Division of Public Health, North Carolina Department of Health and Human Services; Kate Hoffman, PhD, Duke University; Cari Kitahara, PhD, Radiation Epidemiology Branch, National Cancer Institute; Libby McClure, PhD, UNC Gillings; and Brian Reich, PhD, North Carolina State University.

The Carolina Thyroid Cancer Study is supported by funds the North Carolina General Assembly awarded to the North Carolina Collaboratory. The North Carolina General Assembly established the Collaboratory in 2016 to facilitate the dissemination of the policy and research expertise of the University of North Carolina System and other institutions of higher learning across the state for practical use by state and local government. The project is also supported by the UNC Center for Environmental Health and Susceptibility.

“As the state’s public cancer center and a University of North Carolina research institution, we are committed to helping investigate what might be driving the increased incidence of papillary thyroid cancer in Iredell County and elsewhere in North Carolina,” said UNC Lineberger Director Shelley Earp, MD. “Dr. Olshan has put together a great team of researchers from our sister cancer centers and universities, the state and the National Cancer Institute. The Carolina Thyroid Cancer Study, with support through the Collaboratory, will take on an important and complex public health issue.”

The researchers expect to conclude the study by July 2025.