US Fine-Needle Aspiration Biopsy for Thyroid Malignancy: Diagnostic Performance of Seven Society Guidelines Applied to 2000 Thyroid Nodules

Purpose: To compare the diagnostic performance of ultrasonography (US)-based fine-needle aspiration biopsy (FNAB) criteria from seven international societies in the detection of thyroid malignancy. Materials and Methods: This study included a total of 2000 consecutive thyroid nodules (> 1 cm) in 1802 patients with final diagnoses from January 2010 to May 2011. US features of the thyroid nodules were retrospectively reviewed and were classified according to the categories defined by the seven international society guidelines. The diagnostic performance of US-based FNAB criteria in the detection of thyroid malignancy and unnecessary FNAB rates were calculated and compared by using a generalized estimating equation method. Results: Of the 2000 thyroid nodules, 1546 (78.3%) were benign and 454 (22.7%) were malignant, with papillary carcinoma comprising 85.5% of all malignancies. The Korean Thyroid Association/Korean Society of Thyroid Radiology (KTA/KSThR) (94.5%), National Comprehensive Cancer Network (NCCN) (92.5%), and American Thyroid Association (ATA) (89.6%) guidelines were more sensitive than those of the American Association of Clinical Endocrinologists/American College of Endocrinology/Associazione Medici Endocrinologi (AACE/ACE/AME) (80.4%), American College of Radiology (ACR) (74.7%), French Society of Endocrinology (FSE) (72.7%), and Society of Radiology in Ultrasound (SRU) (70.9%) (P < .001), while the latter guidelines had higher specificity (P < .001). The rate of unnecessary FNAB was lowest with the ACR guidelines (25.3%), followed by the FSE (29.1%), AACE/ACE/AME (32.5%), SRU (45.2%), ATA (51.7%), NCCN (54.0%), and KTA/KSThR (56.9%) guidelines. Conclusion: Because the diagnostic performance of US-based FNAB criteria varies according to the individual international society guidelines, clinicians should be aware of the strengths and weaknesses of US-based FNAB criteria in the management of thyroid nodules.