Diagnosis and Management of Small Thyroid Nodules: A Comparative Study with Six Guidelines for Thyroid Nodules

Purpose To investigate the diagnostic performances of six guidelines used to assess thyroid nodules and to determine whether any of these guidelines identify cancers of aggressive form in this population. Materials and Methods From March 2007 to February 2010, 4696 thyroid nodules that were 1-2 cm in 4585 patients were diagnosed as benign or malignant on the basis of cytopathologic results. Ultrasonographic examinations of the thyroid nodules were retrospectively reviewed and categorized according to the categories defined by six previously published guidelines for thyroid nodules. Diagnostic performances of each guideline for diagnosing thyroid cancer were calculated and compared by using the generalized estimating equation method for logistic regression. Multivariate regression analysis was used to analyze predictors for distant metastasis and recurrence and persistence in patients with small thyroid cancer. Results Of the 4696 thyroid nodules, 3652 (77.8%) were benign and 1044 (22.2%) were malignant. Followed were 873 patients who were diagnosed with small thyroid cancer, of whom 12 had distant metastasis and 66 had recurrence or persistence of disease. Specificity, positive predictive value, and accuracy were highest with criteria developed by Kim et al (83.1%, 59.6%, and 84.0%, respectively), while sensitivity and negative predictive value were highest with Thyroid Imaging Reporting and Data System developed by Kwak et al (98.8% and 98.6%, respectively; P < .001). Positive findings that indicated fine-needle aspiration in the guidelines did not show significant association with distant metastasis or recurrence or persistence (P > .05), but the study power was low to detect a difference. Conclusion With its high specificity and accuracy, criteria from Kim et al may be an effective guideline to use in the management of small thyroid nodules. ^© RSNA, 2016 Online supplemental material is available for this article.