Are Guidelines the Reason for Thyroid Cancer Plateau?

Research published in JAMA suggests that stricter guidelines limiting the indications for fine-needle aspiration (FNA) for thyroid nodules have resulted in a plateau of thyroid cancer incidence in the United States following years of an upward trend in incidence.

In 2009, the American Thyroid Association issued guidelines that limit the indications for FNA of sub-centimeter thyroid nodules, and in 2015, stricter guidelines advocated for no FNA of any sub-centimeter thyroid nodules.

Decline in thyroid cancer incidence in recent years

The observational study assessed data from the Surveillance, Epidemiology and End Results registry between 1992 and 2016. Researchers observed an increase of 6.6% in thyroid cancer incidence between 1998 and 2009, a 2.0% increase between 2009 and 2014, and a –2.4% decrease since 2014.

From 1992 to 2009, the incidence of sub-centimeter thyroid cancers steadily increased 1.2 per 100,000 to 4.7 per 100,000, with the greatest annual percentage change of 9.1% (95% CI, 8.4-9.8) occurring between 1996 and 2009. The trend stabilized from 2009 to 2013 and declined from 2013 to 2016.

The researchers hypothesized that the previous increase in thyroid cancer incidence was due to increased detection rather than a true increase in occurrence.