Background: The thyroid cancer incidence rate has tripled in the United States since the 1980s, especially among women and small-sized tumors. This trend has been attributed to increased detection due to the availability of ultrasound and fine-needle aspiration technology. In 2009, the American Thyroid Association (ATA) released revisions to their guidelines for well-differentiated thyroid cancers.
Objective: To examine trends in thyroid cancer incidence rates by tumor size and gender following the 2009 ATA guideline revisions.
Methods: Cases of differentiated thyroid cancer diagnosed from 2000 to 2012 were analyzed from the National Cancer Institute Surveillance Epidemiology and End Results program, 18 registries. Trends in incidence rates based on gender (males, females) and tumor size (< 1.0 cm, 1.0-2.9 cm, 3.0-3.9 cm, ≥ 4.0 cm) were analyzed using Joinpoint Regression and reported as the annual percentage change (APC).
Results: From 2000 to 2009, overall thyroid cancer incidence rates increased rapidly by about 8% per year in both sexes. Incidence rates increased across all tumor sizes, but especially in tumors 1.0 to 2.9 cm (men, APC = 7.7; women, APC = 7.8) and < 1.0 cm (men, APC = 7.8; women = 10.9) for both genders. Since 2009, the trend slowed in men (APC = 3.0) and women (APC = 2.8). The deceleration among females was confined to tumors less than 2.9 cm. Trends for all size groups in males remained constant from 2000 to 2012.
Conclusion: The rapid increase in thyroid cancer incidence rates over the past three decades has recently slowed, especially among small-sized cancers and women, which coincides with the 2009 ATA guideline revisions.
Level of evidence: 2c. Laryngoscope, 127:2437-2441, 2017.
Keywords: Thyroid cancer; guidelines; incidence rate.
© 2017 The American Laryngological, Rhinological and Otological Society, Inc.