Contact: Jessie Geraci-Perez
(608) 220-1514
Reducing certain ultrasounds could safely lower diagnoses without increasing deaths
MADISON, Wis. – Most cases of papillary thyroid cancer in the United States may have been overdiagnosed over the past three decades, meaning they were detected and treated surgically without improving population rates of death due to the cancer, according to a recent study from researchers at the University of Wisconsin School of Medicine and Public Health.
It had been shown previously that this type of thyroid cancer is relatively common and usually does not progress. Using autopsy studies, other researchers in the field have shown that approximately 10% of adults have small papillary thyroid cancer nodules at end of life that did not contribute to their death.
The UW study analyzed national data from 1991 to 2019 and estimated that 72% to 94% of papillary thyroid cancers, the most common type of thyroid cancer, detected during that period were likely overdiagnosed. Researchers say the increase is largely tied to the widespread use of imaging, particularly ultrasound, which can detect these small, slow-growing cancers that are unlikely to cause harm, according to Dr. Louise Davies, professor of otolaryngology-head and neck surgery at the UW School of Medicine and Public Health.
“Even when we account for a potential true increase in the underlying rates of thyroid cancer, the majority of thyroid cancers diagnosed and treated over the past 30 years represent overdiagnosis,” said Davies, who is also an otolaryngologist at UW Health. “Overdiagnosis can lead to unnecessary surgery or other interventions, with side effects of needing lifelong thyroid hormone therapy, and avoidable psychological and financial harm.”
The study found that overdiagnosis affected women more often than men. Researchers estimate that between 443,000 and 574,000 women and 108,000 to 155,000 men were overdiagnosed over the 28-year period.
Using a mathematical simulation model, the researchers evaluated how reducing the use of ultrasound for thyroid nodules that cannot be felt during a physical exam might affect diagnosis rates and outcomes. They found that a one-third reduction in such ultrasounds would reduce diagnoses by 17%, while a two-thirds reduction would cut diagnoses by 41%. Even with those reductions, mortality rates changed by less than 0.1%.
The findings suggest that more selective use of thyroid ultrasound could significantly reduce unnecessary diagnoses and treatments without increasing the risk of death, according to Dr. David Francis, professor of otolaryngology-head and neck surgery at the UW School of Medicine and Public Health.
“Small changes in referral practices could reduce overdiagnosis by tens of thousands of cases each year, without changing mortality,” said Francis, who is also an otolaryngologist at UW Health. “This is a powerful opportunity to create guidelines that would help align practice with evidence and reduce overtreatment.”
Thyroid cancer diagnoses in the U.S. have more than tripled since the early 1990s, while death rates have remained stable. The researchers say the findings support the need for clearer guidelines on when to use thyroid ultrasound and risk-based approaches to care aimed at reducing unnecessary treatment while maintaining patient safety.
“This is about making sure patients receive care that truly benefits them,” Francis said. “By being thoughtful about when we use imaging, we can reduce unnecessary diagnoses and treatments while still identifying and treating the cancers more likely to cause harm.”
