An International Agency for Research on Cancer report from 2016 stated that more than half a million people are estimated to have been overdiagnosed with thyroid cancer in 12 countries.

In an attempt to reverse this trend, experts at the University of Alabama at Birmingham recently published American College of Radiology guidelines for an ultrasound-based risk stratification system to determine if nodules require a biopsy or additional ultrasound imaging.

“We aren't doing this to cut costs, but rather to restrict biopsies to the patients who truly need them,” Dr. Franklin Tessler, professor at the university, told HCB News. “Cost saving is a desirable benefit, but it was not the primary goal.”

The industry made many attempts over the past 15 years to create guidelines, but most were based on details of the appearance and size of nodules seen with high-resolution ultrasound. Because the systems were complex and lacked congruence, there was limited adoption.

The Thyroid Imaging, Reporting and Data System (TI-RADS) is modeled after ACR’s widely accepted risk stratification system for breast lesions, called the Breast Imaging Reporting and Data System (BI-RADS).

Tessler and his colleagues ensured that the new guidelines were founded on ultrasound features, easy to implement across a wide range of ultrasound practices, able to classify all thyroid nodules and based on solid evidence.

TI-RADS has five different categories for nodule appearance including composition, echogenicity shape, margin and echogenic foci. The shape category has two choices — wider-than-tall verses taller-than-wide — and the other categories have four choices each.

Each choice has a point value from 0 to 3 points. For example, wider-than-tall is 0 points and taller-than-wide is 3 points.

If the nodule’s sum is either 0 or 2 points, the guidelines recommend against biopsy or follow-up imaging. If the nodule’s sum is 3 points, a biopsy is recommended in cases where it’s 2.5 centimeters-plus or an inch-plus, and follow-up imaging is recommended if it’s 1.5 centimeters-plus.

For nodules with 4 to 6 points, the guidelines recommend a biopsy if it’s 1.5 centimeters-plus, and follow-ups if it’s 1 centimeter-plus. For nodules with 7 points or more, the guidelines recommend a biopsy if it’s 1 centimeter-plus and follow-up if it’s 0.5 centimeters-plus.

“The larger size thresholds for recommending biopsy under ACR TI-RADS mean that fewer nodules will undergo [biopsy] and that, alone, will decrease health care costs,” said Tessler. “Additionally, some patients with indeterminate [biopsy] results require surgery to achieve a definitive diagnosis, so eliminating some of that would also would lower expenses.”

But he added that although the potential is there, the magnitude of the effect of these new guidelines remains to be seen.

When asked if the ultrasound community will adopt these guidelines, Tessler said, “The ultrasound community is varied. Several specialties other than radiologists perform thyroid biopsies. However, many radiology practices I know of adopted the 2005 SRU consensus criteria. I'm hopeful that the same will be true for ACR TI-RADS, particularly since it was developed under the ACR's auspices. Other groups may also adopt it after consideration.”

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