Changes in thyroid cancer incidence, post-2009 American Thyroid Association guidelines

Area of Science:

• Endocrinology
• Oncology
• Public Health

Background:

• Thyroid cancer incidence has tripled since the 1980s, with notable increases in women and small tumors.
• This rise is linked to advancements in diagnostic technologies like ultrasound and fine-needle aspiration.
• The American Thyroid Association (ATA) updated guidelines for differentiated thyroid cancers in 2009.

Purpose of the Study:

• To analyze thyroid cancer incidence trends by tumor size and gender after the 2009 ATA guideline revisions.
• To determine if the guideline changes influenced the observed incidence rates.

Main Methods:

• Analysis of differentiated thyroid cancer cases from 2000-2012 using the National Cancer Institute's Surveillance Epidemiology and End Results (SEER) program.
• Incidence rates were examined by gender and tumor size (<1.0 cm, 1.0-2.9 cm, 3.0-3.9 cm, ≥4.0 cm).
• Joinpoint Regression was used to calculate annual percentage change (APC) in incidence rates.

Main Results:

• From 2000-2009, thyroid cancer incidence increased by approximately 8% annually for both sexes across all tumor sizes.
• Post-2009, the rate of increase slowed to 3.0% in men and 2.8% in women.
• The deceleration was most pronounced in smaller tumors (<2.9 cm) among women, while male trends remained stable across all sizes.

Conclusions:

• The accelerated rise in thyroid cancer incidence has recently decelerated, particularly for small tumors and in women.
• This slowdown correlates with the 2009 American Thyroid Association guideline revisions.
• The findings suggest the guidelines may have influenced diagnostic practices and reporting trends.