Trends in the incidence of thyroid cancer in Incheon Province, South Korea, from 2004 to 2013: A representative sample study from Incheon cancer registry.

The incidence of thyroid cancer has increased from 2004 to 2013 in Incheon Province, South Korea, with the increase being most significant for small tumors. These findings indicate that the increased incidence is primarily due to the widespread use of screening and not an actual increase in clinically significant thyroid cancer.