Increased thyroid cancer incidence corresponds to increased use of thyroid ultrasound and fine-needle aspiration: a study of the Veterans Affairs health care system.

BACKGROUND: Thyroid cancer incidence has increased in the last several decades and may represent either a true increase in the number of cases or increased screening. The objective of this study was to examine thyroid cancer incidence and the use of thyroid ultrasound and fine-needle aspiration (FNA) screening in the Veterans Affairs (VA) health care system. The authors hypothesized that the incidence of thyroid cancer would correspond to increases in the use of these diagnostic modalities.
METHODS: This was a multiyear, cross-sectional study using VA administrative data from 2000 to 2012. Joinpoint regression analysis was used to identify trends in thyroid cancer incidence and the use of thyroid ultrasound and FNA.
RESULTS: An increase in thyroid cancer incidence occurred from 10.3 per 100,000 individuals in 2000 to 21.5 per 100,000 individuals in 2012. The rate of thyroid ultrasound use increased from 125.6 per 100,000 individuals in 2001 to 572.1 per 100,000 individuals in 2012, and the rate of thyroid FNA use increased from 7.0 per 100,000 individuals in 2000 to 46.2 per 100,000 individuals in 2012. A statistically significant increase in thyroid cancer incidence between 2000 and 2008 (annual percent change [APC], 3.81; P < .05) was followed by a more pronounced increase between 2008 and 2012 (APC, 10.32; P < .05). A simultaneous increase in the use of thyroid ultrasound occurred between 2002 and 2012 (APC, 15.48; P < .05) and the use of thyroid FNA between 2000 and 2012 (APC, 18.36; P < .05).
CONCLUSIONS: Although the incidence of thyroid cancer doubled, a nearly 5-fold increase in the use of thyroid ultrasound and a nearly 7-fold increase in the use of thyroid FNA occurred between 2000 and 2012. These findings suggest that the increase in thyroid cancer incidence may be related to increases in the use of thyroid ultrasound and FNA.