ACR TI-RADS Standards Committee member and Principal Investigator of the ACR TI-RADS Research Registry, Jenny Hoang, MBBS, MBA, MHS, gave a groundbreaking presentation at a Neuroradiology event in NYC last month. She highlighted the three main shifts in culture and practice that have happened with thyroid cancer over the course of the last decade.

It was noted that between the 1980’s and 2009, there had been an exponential increase in thyroid cancer diagnosis and thyroidectomies. This was due to an increase in CT and MRI screenings followed by more ultrasounds and biopsies. However, despite this increase, patient mortality outcomes remained the same. Patients were being over-diagnosed and overtreated.

A white paper written by the ACR Incidental Thyroid Findings Committee was published in 2014 to combat this issue by creating flow charts explaining what to do with incidental thyroid nodules (ITN) found on MRI and CT scans. The flow chart recommended that if you saw suspicious findings such as lymphadenopathy or invasion, then to do an ultrasound and biopsy. Otherwise, if the patient was less than 35, then the nodule had a threshold of 1 centimeter for a thyroid ultrasound. If the patient was over 35, the nodule had a 1.5-centimeter threshold. Around this time, radiologists were typically recommending workups at 1 cm. Retrospective studies showed a 46% reduction in the workup of ITN when compared to a 1 cm threshold, as well as a 54% reduction when compared to nodules reported in the impression. When applied to the SEER database, the same number of cancers were captured as they were at the 1 cm cut off. Unfortunately, this paper received pushback from the American Thyroid Association (ATA), who continued to recommend diagnostic ultrasounds on every CT and MRI finding. However, in 2016 the New England Journal of Medicine published a landmark paper on the impact of overdiagnosis of thyroid cancer in high income countries. It was discovered that in the U.S. alone, overdiagnosis accounted for 70-80% of thyroid cancer cases. The contents of this paper became a global phenomenon. Finally, the ATA recognized the overdiagnosis of thyroid cancer. The U.S. Preventative Services went on to put out a statement telling physicians not to screen asymptomatic patients for thyroid cancer.

Following these events, the ACR TI-RADS published a white paper in 2017 that increased the size threshold of thyroid lesions to biopsy. For moderately suspicious lesions, the size threshold increased by 5 mm. For mildly suspicious lesions, the threshold increased by 1 cm. For non-suspicious lesions, the paper recommended no biopsy. In a retrospective study on 100 nodules with 15 malignancies that had been biopsied, this ACR TI-RADS policy was shown to reduce the number of biopsies by 21-35% when compared to other risk stratification TI-RADS. When applied to all patients with nodules on diagnostic ultrasounds, biopsies were reduced by 25-50%.

Ultimately, these papers have had a large impact on the diagnosis and treatment of thyroid cancer patients. Prior to 2014, if a patient had a thyroid cancer lesion more than 1 cm, they would have a total thyroidectomy and a central node dissection for a 1-121 scan to look for residual disease. This would most likely be followed by radioactive iodine treatment. The ATA Guidelines have been changed to minimize the need for such an aggressive form of treatment. For low-risk cancers, they recommended just a lobectomy without neck dissection or radioactive iodine treatment. Since the publication of these guidelines, there has been both an increase in lobectomies and a decrease in thyroidectomies across the board. The American Joint Committee on Cancer (AJCC) Staging System has also changed, placing more patients in Stage I and II in its 8th edition. Furthermore, patients with papillary thyroid cancers of up to 2 cm now have the option of Active Surveillance, which consists of ultrasounds every six months for two years and annually thereafter. The literature supports the safety of this approach, showing no difference in the recurrence rate between those who operated immediately and those who waited.

To hear the full presentation, click here: Thyroid Cancer: Changes in a Decade - YouTube

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ACR TI-RADS Standards Committee Member Presents on Major Shifts in Thyroid Cancer Treatment