In 2016, the American Thyroid Association (ATA) published its latest update on management guidelines of thyroid nodules and thyroid cancer (Thyroid. 26:1–133). The guidelines came nearly seven years after the previous update in 2009 (Thyroid. 19:1167–1214). Experts interviewed for this article shared how these guidelines changed patient care. Among the changes they cited are less aggressive detection of thyroid nodules, use of molecular diagnostics to further evaluate biopsies, hemithyroidectomy for low-risk thyroid cancer, pre-operative assessment of the voice and larynx, an increase in the threshold for delivering radioactive iodine for thyroid cancer, and active surveillance in select patients with small thyroid cancers.
Explore This IssueFebruary 2020
“The guidelines had a profound impact on clinical practice that spanned the entire breadth of how we assess and manage patients with thyroid nodules and thyroid cancer,” said David Terris, MD, Regents’ Professor of otolaryngology and endocrinology at Augusta University in Georgia and surgical director of the Augusta University Thyroid and Parathyroid Center.
Detection and Diagnosis of Thyroid Nodules
One key area of change in the guidelines is the recommendation for less aggressive detection efforts. Dr. Terris pointed to evidence showing that much of this increase is due to overly aggressive detection efforts that have led to identification of biologically unimportant nodules and even micro-cancers that probably don’t need treatment (Endocr Pract. 2015;21:686-696). He cited, for example, the rapid increase in thyroid cancers detected over the past decade, particularly in South Korea, where diagnosis of thyroid cancer increased nine-fold (Endocr Pract. 2015;21:686-696). Prior to the 2015 guidelines, nodules 10 mm or greater were recommended for biopsy, and if the biopsy indicated cancer or was indeterminate, then surgery was performed, Dr. Terris explained. The 2015 guidelines changed this threshold. “Now the bar is 20 mm unless the nodule looks really concerning, so we’ve doubled the size of the nodule for which we would consider a biopsy,” he said.
A second important change endorsed by the 2015 guidelines, he said, is the use of molecular diagnostics to augment the information obtained when biopsies are performed. “For many years there were basically three results you could get with a biopsy—cancer, benign, or indeterminate. The indeterminate category represented about 30%-40% of biopsies, and most of these patients ended up undergoing surgery when many probably didn’t need it,” he said.
With molecular diagnostics, he said, clinicians can further differentiate the indeterminate nodules. “More than 50% of these nodules will have a molecular fingerprint strongly suggesting that they are benign,” he said. “So we’ve been able to avoid surgery on a bunch of the patients in the indeterminate category.”
David L. Steward, MD, director of head and neck surgery, endocrine surgery, and clinical research at the University of Cincinnati College of Medicine, said the 2015 guidelines also had an impact on the use of ultrasound to help guide management of indeterminate nodules. “The latest 2015 guidelines resulted in much more selective fine-needle biopsy of thyroid nodules based more on sonographic pattern and risk of malignancy rather than just size alone,” he said.
Dr. Steward highlighted the importance of this impact on clinical practice given the increasing number of incidental nodules detected through imaging. Further, he said that cytopathological classification using the Bethesda system (Thyroid. 2009;19:1167-1214), has improved consensus in reporting of results but has resulted in another problem. “Cytologically indeterminate nodules (Bethesda III and IV) are increasingly common, and this is a problem that patients and clinicians face,” he said, explaining that 20%-30% of these are at risk of being malignant.
Maisie Shindo, MD, professor of otolaryngology–head and neck surgery at Oregon Health & Science University School of Medicine in Portland, agreed that the 2015 guidelines helped to determine which nodules to biopsy and how to further categorize biopsied nodules through molecular diagnostics. But she emphasized that the use of molecular diagnostics was still relatively new when the guidelines were published, so the recommendations on its use weren’t specific. “The guideline recommended you can incorporate molecular markers in the decision making,” she said. “If molecular testing is going to be used, patients should be counseled regarding the potential benefits and limitations of the testing and about possible uncertainties in the therapeutic and long-term clinical implications of the results.”