Table 8. Comparison of unnecessary FNAB rates for the diagnosis of thyroid cancer in all nodules.
| Guidelines | FNABs, n (%) |
Malignant nodules among FNAB nodules, n (%) | Benign nodules among FNAB nodules (A), n (%) | Unnecessary FNAB rate (%) | False-positive rate§ (%) |
|---|---|---|---|---|---|
| ACR-TIRADS 2017 | 679 (29.41) | 274 (40.35) | 405 (59.65) | 17.54 (A/2,309) | 28.56 (405/1,418) |
| ATA 2016 | 879 (39.94) | 265 (30.14) | 614 (69.86) | 27.90 (A/2,201) | 45.75 (614/1,342) |
| K-TIRADS 2016 | 946 (40.97) | 284 (30.02) | 662 (69.98) | 28.67 (A/2,309) | 46.69 (662/1,418) |
| C-TIRADS 2020 | 891 (38.59) | 369 (41.41) | 522 (58.59) | 22.61 (A/2,309) | 36.81 (522/1,418) |
Data in parentheses are percentages for no. of FNABs, no. of malignant nodules among FNAB nodules, and no. of benign nodules among FNAB nodules. §, data in parentheses are the raw data from which the false-positive rate was calculated. FNAB, fine-needle aspiration biopsy; ACR-TIRADS 2017, the Thyroid Imaging Reporting and Data System of 2017 American College of Radiology (10); ATA 2016, the 2016 American Thyroid Association guideline (11); K-TIRADS 2016, the Thyroid Imaging Reporting and Data System of 2016 Korean Thyroid Association/Korean Society of Thyroid Radiology (5); C-TIRADS 2020, the 2020 Chinese Thyroid Imaging Reporting and Data System (3).