New Risk-Stratification Guidelines for Thyroid Nodules

Jennifer A. Sipos, MD; Mark Harmel, MPH


May 06, 2016

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I have been asked to talk to you about the risk stratification of thyroid nodules. The American Thyroid Association developed a new set of treatment guidelines for the evaluation and management of thyroid nodules.[1] As part of that treatment guideline, the stratification of nodules was established. This set of guidelines is different from previous iterations in that more of a pattern-based approach to thyroid nodules is utilized.

Nodules are stratified into one of five categories. Nodules in the first category have a simple cyst appearance and a very low risk for malignancy. These nodules do not require aspiration because of their low risk for malignancy regardless of their size. They may be aspirated for therapeutic purposes, however, if the patient has compressive symptoms.

Nodules in the next category are also cystic but have some solid component. These have a very low risk for malignancy—less than 3%—and may be aspirated when larger than 2 cm. These are typically spongiform nodules; when looked at in cross-section, they appear to have a sponge or honeycomb pattern.

The next category of nodules consists of low-risk nodules, which have a 5%-10% risk for malignancy. These nodules may be aspirated when they are larger than 1.5 cm. They are solid and iso- or hyperechoic compared with the surrounding thyroid tissue, meaning that they are brighter than or the same echogenicity as the surrounding thyroid tissue. Only 10%-15% of thyroid cancers follow this pattern. These nodules do not require aspiration until they are 1.5 cm.

The next category of intermediate-risk nodules carries a 10%-20% risk for malignancy. This category has the highest sensitivity for malignancy, at 60%-80%, but most nodules in this category are benign. They are solid and hypoechoic with well-defined borders. These lesions do not have any other suspicious sonographic features.

The final category consists of nodules that are highly suspicious. Both these and the intermediate-suspicion nodules should be aspirated when larger than 1 cm. The difference between the two groups, however, is that the highly suspicious lesions are hypoechoic and have one or more suspicious features, including extrathyroidal extension, microcalcifications, height greater than width, or a disrupted rim calcification. The identification of one of these types of nodules is associated with a very high risk for malignancy. These nodules should be aspirated when smaller than the nodules described before.

Nodules are very commonly seen in our population. They may be stratified so that we can further divert our resources to those nodules that have a higher risk for malignancy. The pattern-recognition system established by the American Thyroid Association allows us to stratify those nodules with higher-risk features to fine-needle aspiration at smaller size; nodules that have less aggressive features may be aspirated once they reach a larger-size threshold.


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