Van Meter Award winner explores contribution of obesity to thyroid cancer incidence, mortality
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CHICAGO — The American Thyroid Association’s annual Van Meter Award, presented to an investigator younger than 45 years who has made outstanding contributions to thyroid research, was conferred on a cancer epidemiologist for her work elucidating the contributions of environment and lifestyle, particularly obesity, to the rising incidence of thyroid cancer. The 2019 recipient, kept secret until the award lecture at the annual meeting, is Cari Kitahara, PhD, an investigator in the Division of Cancer Epidemiology and Genetics, Radiation Epidemiology Branch, of NIH’s National Cancer Institute (NCI).
“Using data from the NCI cohort consortium, [Kitahara] initiated the first pooled analyses of prospective studies to evaluate a wide range of exposures in relation to thyroid cancer risk, revealing obesity to be the most important modifiable risk factor for incidence and thyroid cancer-related death,” Julie Ann Sosa, MD, professor of surgery and of medicine (oncology) and chief of endocrine surgery at the Duke University School of Medicine, said while introducing Kitahara. “Citing her results of her largest pooled study on this topic, the International Agency for Research on Cancer, added thyroid cancer to the list of cancers with sufficient evidence of a causal relationship with excess adiposity.”
Increase in thyroid cancer incidence is largely the result of diagnostic technologies and overdiagnosis; however, rising obesity is related to some true increase in thyroid cancers, Kitahara said during the presentation.
In a pooled analysis of prospective cohort studies, Kitahara and colleagues found a 17% increased risk for thyroid cancer for every 5 U increase in BMI among men and women, indicating a stronger association of obesity with thyroid cancer than with postmenopausal breast, colon or pancreatic cancer, she said. In an expanded study, the researchers found a stronger link to thyroid cancer for young adult BMI compared with BMI calculated later in adulthood.
“These associations were much stronger when we restricted the outcome to thyroid cancer and mortality as opposed to incidence,” Kitahara said. “This suggested that greater body size and adiposity may be associated with more aggressive forms of the disease.”
In another recent study, Kitahara and colleagues determined that the population attributable risk for obesity rose from 11% in 1995 to 16% in 2015 for all papillary thyroid cancers (PTCs) and from 51% to 63% for large thyroid cancers. With no obesity, Kitahara said, there would have been a 13% reduction in overall incidence of PTC and a 59% reduction in large PTCs.
“I do think there is also an important role for primary prevention and reduction of incidence of [thyroid cancer],” Kitahara said. “Particularly, by avoiding unnecessary radiation exposure among children, to ionizing radiation, as well as reducing the overweight and obese population. However, there may be other important, modifiable factors that have yet to be discovered, and thus, greater priority should be given to epidemiologic, clinical and basic science research aimed at better elucidating the etiology of this disease.” – by Jill Rollet
Reference:
Kitahara C. Van Meter Award Lecture. Presented at: 89th Annual Meeting of the American Thyroid Association; Oct. 30-Nov. 3, 2019; Chicago.
Disclosures: Kitahara and Sosa report no relevant financial disclosures.