Is thyroid cancer being overdiagnosed?

An article published in the New England Journal of Medicine and discussed on Vox, showed that the incidence of thyroid cancer in South Korea has skyrocketed in recent years while mortality from the cancer has remained relatively stable. The figure below shows the relationship between incidence and mortality from thyroid cancer for high-income countries in 2012. While the difference between incidence and mortality from thyroid cancer is extremely large in South Korea, indicating a potential problem of overdiagnosis, many of the other high-income countries, like the United States, are likely to suffer from the same problem.

Incidence and mortality from thyroid cancer in high income countries in 2012

Notes: The y-axis contains a list of 46 high-income countries based on the World Bank classification as of July 1, 2014. Countries are rank ordered based on incidence from high to low.

The next figure shows the relationship over time in the United States between incidence and mortality of thyroid cancer. The incidence of thyroid cancer has been rapidly increasing since 1975 while mortality has remained relatively stable, indicating that like South Korea, the United States likely has an overdiagnosis problem when it comes to thyroid cancer.

Incidence and mortality from thyroid cancer in the U.S., 1975-2010

Notes: Rates are age-adjusted to the 2000 US Standard Population.

Data Source Figure 1: Ferlay J, Soerjomataram I, Ervik M, et al. GLOBOCAN 2012 v1.0, Cancer Incidence and Mortality Worldwide: IARC CancerBase No.11 [Internet]. Lyon, France: International Agency for Research on Cancer; 2013. Available from: Accessed on February 11, 2015.
Data Source Figure 2: Incidence data comes from SEER 9 areas (San Francisco, Connecticut, Detroit, Hawaii, Iowa, New Mexico, Seattle, Utah and Atlanta) and Mortality data comes from US Mortality Files, NCHS, CDC. All data was downloaded from on February 11, 2015.

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