Current Guidelines for the Management of Thyroid Nodules

Robert A. Levine, MD, FACE, ECNU

Disclosures

Endocr Pract. 2012;18(4):596-599. 

In This Article

Similarities and Differences

The 3 foregoing sets of guidelines for management of thyroid nodules have numerous similarities and several disparities. With limited prospective studies regarding cost or outcome, many of the recommendations in all 3 sets are based on expert opinion. All recommend biopsy of any thyroid nodule larger than 1 cm in diameter with suspicious features, including microcalcifications, profoundly hypoechoic echotexture, taller than wide shape, or infiltrative margins. The AACE and KSTR guidelines recommend that nodules of any size with suspicious features undergo biopsy, whereas the ATA guidelines do not recommend biopsy of subcentimeter nodules unless the patient has a high-risk history. The KSTR guidelines discuss clinical risk factors in the introduction but, unlike the other guidelines, do not use them in the decision process determining the need for biopsy. The ATA and AACE guidelines consider intranodular vascularity to be a risk factor for malignancy. On the basis of recent data from Moon et al[4] and others, however, the KSTR guidelines do not consider vascularity as a risk factor.

There are several other discrepancies among the guidelines. For example, a thyroid nodule between 6 and 9 mm with suspicious features (other than microcalcifications) would undergo biopsy on the basis of the AACE and KSTR guidelines but not the ATA guidelines. An isoechoic or hyperechoic nodule larger than 1 to 1.5 cm would undergo biopsy on the basis of the ATA and KSTR guidelines, but the AACE guidelines do not provide guidance regarding isoechoic and hyperechoic nodules. As suggested by Bonavita et al,[5] hyperechoic nodules in a background of thyroiditis are very likely benign and may not necessitate biopsy.

The 3 sets of guidelines have very different approaches to the management of complex cysts. The ATA guidelines recommend biopsy of all complex cysts larger than 1.5 to 2 cm in diameter. Because of the risk of cystic papillary carcinoma, the AACE guidelines recommend biopsy of all complex cysts. Complex cysts can vary from a predominantly cystic lesion, with a tiny benign-appearing solid mural component, to a predominantly solid lesion with cystic components. The solid components can have benign or suspicious features. The ATA and AACE guidelines do not consider the numerous potential variations in complex cysts. The KSTR guidelines recommend biopsy only if suspicious features are detected in the solid component—a recommendation that makes more sense than use of size criteria alone.

Unfortunately, very few thyroid nodules will escape biopsy under each set of guidelines. Each of the guidelines recommends biopsy for the vast majority of nodules, even those without suspicious features, when they are larger than 1 cm in diameter. In light of the epidemic proportions of thyroid nodular disease, coupled with the overall favorable outcome of most cases of thyroid cancer (many of which likely remain undiagnosed throughout a patient's life), many patients will undergo biopsy and a surgical procedure for a disease that possibly would not have an adverse outcome if simply followed without intervention.

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