Overdiagnosis of Papillary Thyroid Cancer

Area of Science:

• Oncology
• Diagnostic Imaging
• Public Health

Background:

• Thyroid cancer overdiagnosis in the US has not been previously quantified, despite its potential impact.
• The implications of reduced thyroid ultrasonography use on overdiagnosis rates remain uncalculated.

Purpose of the Study:

• To estimate US population-level rates of papillary thyroid cancer (PTC) overdiagnosis.
• To determine the impact of reduced thyroid ultrasonography use on PTC incidence and overall mortality.

Main Methods:

• A validated simulation model (Papillary Thyroid Carcinoma Microsimulation Model) was used to analyze PTC incidence in the US adult population from 1991 to 2019.
• The model estimated overdiagnosis rates stratified by sex and projected changes in incidence and mortality with reduced ultrasonography use.

Main Results:

• Between 1991 and 2019, an estimated 72% to 94% of PTC cases in the US were overdiagnosed.
• Overdiagnosis rates were higher in women than men, both proportionally and absolutely.
• Reducing thyroid ultrasonography for nonpalpable nodules by 33% or 67% could decrease PTC incidence by 17% or 41%, respectively, with minimal impact on overall mortality.

Conclusions:

• Thyroid cancer overdiagnosis in the US is significant, even accounting for true incidence increases.
• Reducing unnecessary thyroid ultrasonography referrals, especially for nonpalpable nodules, can lower diagnoses and treatment harms without increasing mortality.