AN ESTIMATED 72% to 94% of papillary thyroid cancer (PTC) cases were overdiagnosed in the USA between 1991 and 2019, a 2026 computer modelling study has found.
Thyroid Cancer and Ultrasonography
Thyroid cancer incidence in the USA is up by 250% since 1990, primarily due to the detection of small, early-stage PTC without any improvement in mortality rates.
This pattern is a problem mirrored in various countries around the world.
Ultrasonography referral marks the beginning of the diagnostic pathway to thyroid cancer, and there are currently no official guidelines on when to refer patients for ultrasonography.
Patients are generally referred for symptoms, physical examination findings, or after incidental nodules are discovered on imaging performed for other reasons.
Researchers proposed that the issue of overdiagnosis in the relevant context is urgent and worsening over time.
Overdiagnosis Rates
Researchers used a validated simulation mode of contemporary PTC incidence in all adults in the USA between 1991 and 2019.
The proportion of overdiagnosis was slightly higher for women who saw overdiagnosis rates of 75% to 95%. Men had PTC overdiagnosis rates of 63% to 90%.
The study found that reducing the use of thyroid ultrasonography for nonpalpable nodules by 33% and 67% would have decreased PTC incidence by 17% and 41% in 2019, respectively, with a negligible change in overall mortality.
Researchers found that rates of overdiagnosis persisted after accounting for underlying increased risk in the development of PTC.
Study Limitations
The study acknowledged the possibility of not all data being generalisable, such as if ultrasonography data differs from those in clinical practice across various institutions or areas.
Researchers also only focused on the mortality implications of PTC and did not assess and quality of life implications.
Future of Thyroid Cancer Diagnosis
Whilst recognising that some degree of overdiagnosis is unavoidable in clinical practice, researchers emphasised the opportunity to reduce unnecessary diagnoses without increasing mortality.
In turn, cancer diagnoses and associated psychological and treatment burdens could be lowered without compromising general population health.
References
Francis DO et al. Overdiagnosis of papillary thyroid cancer. JAMA Netw Open. 2026;DOI:10.1001/jamanetworkopen.2025.59852.
Li M et al. Global trends in thyroid cancer incidence and the impact of overdiagnosis. Lancet Diabetes Endocrinol. 2020;8(6):468-470.
Davies L et al. Increasing incidence of thyroid cancer in the United States, 1973-2002. JAMA. 2006;295(18):2164-2167.
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