Table 2.
Prevalence of malignancy for each class of the US scores, according to cytological outcome: KTIRADS, ATA, AACE/ACE-AME, EUTIRADS, ACRTIRADS
| Expected FNA | Observed FNA | Potential spared FNA | ||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Class | Expected malignancyc, % | Size (mm) | Negative cytologya, % (no.) | Positive cytologyb, % (no.) | Total FNA (no.) | Size (mm) | Negative cytologya, % (no.) | Positive cytologyb, % (no.) | Total FNA (N) | Size (mm) | Negative cytologya, % (no.) | Positive cytologyb, % (no.) | Total FNA (no.) | |
| KTIRADS | KTIRADS2 | < 3 | ≥ 20 | 97% (227) | 3% (7) | 234 | - | 95.3% (348) | 4.7% (17) | 365 | - | 92.4% (121) | 7.6% (10) | 131 |
| KTIRADS3 | 3–15 | ≥ 15 | 91.7% (2102) | 8.3% (191) | 2293 | - | 92.2% (2607) | 7.8% (220) | 2827 | - | 94.6% (505) | 5.4% (29) | 534 | |
| KTIRADS4 | 15–50 | ≥ 10 | 88.1% (2381) | 11.9% (323) | 2704 | ≥ 10 | 88.1% (2381) | 11.9% (323) | 2704 | |||||
| KTIRADS5 | > 60 | ≥ 10 | 74.2% (429) | 25.8% (149) | 578 | ≥ 10 | 74.2% (429) | 25.8% (149) | 578 | |||||
| KTIRADS tot | 5809 | 6474 | 665 | |||||||||||
| ATA | Benign | < 1 | - | - | - | - | - | 100% (53) | 0% (0) | 53 | - | - | - | - |
| Very low risk | < 3 | ≥ 20 | 100% (9) | 0% (0) | 9 | - | 100% (12) | 0% (0) | 12 | - | 100% (3) | 0% (0) | 3 | |
| Low risk | 5–10 | ≥ 15 | 92.3% (2681) | 7.7% (225) | 2906 | - | 92.6% (3319) | 7.4% (266) | 3585 | - | 94.0% (638) | 6.0% (41) | 679 | |
| Intermediate risk | 10-20 | ≥ 10 | 88.6% (1135) | 11.4% (146) | 1281 | ≥ 10 | 88.6% (1135) | 11.4% (146) | 1281 | |||||
| High risk | > 70–90 | ≥ 10 | 78.4% (851) | 21.6% (234) | 1085 | ≥ 10 | 78.4% (851) | 21.6% (234) | 1085 | |||||
| ATA Tot | 5281 | 6016* | 682 | |||||||||||
| AACE/ACE-AME | Low risk | < 1 | > 20 | 93.2% (828) | 6.8% (60) | 888 | - | 93.5%(1481) | 6.5% (103) | 1584 | - | 93.8% (653) | 6.2% (43) | 696 |
| Intermediate risk | 5-20% | > 20 | 90.6% (1405) | 9.4% (145) | 1550 | ≥ 10 | 90.8% (3016) | 9.2% (306) | 3322 | - | 90.9% (1611) | 9.1% (161) | 1772 | |
| High risk | 50–90% | ≥ 10 | 80.9% (1268) | 19.1% (300) | 1568 | ≥ 10 | 80.9% (1268) | 19.1% (300) | 1568 | - | ||||
| AACE Tot | 4006 | 6474 | 2468 | |||||||||||
| EUTIRADS | EUTIRADS 2 | 0 | - | 100% (8) | 0% (0) | 8 | - | 100% (57) | 0% (0) | 57 | - | 100% (8) | 0% (0) | 49 |
| EUTIRADS 3 | 2–4% | > 20 | 91.8% (1054) | 8.2% (94) | 1148 | - | 91.6% (1760) | 8.4% (161) | 1921 | - | 91.4% (706) | 8.7% (67) | 773 | |
| EUTIRADS 4 | 6–17% | > 15 | 91.8% (1991) | 8.2% (179) | 2170 | ≥ 10 | 91.5% (2680) | 8.5% (248) | 2928 | - | 90.9% (689) | 9.1% (69) | 758 | |
| EUTIRADS 5 | 26–87% | > 10 | 81.4% (1194) | 18.6% (272) | 1466 | ≥ 10 | 80.9% (1268) | 19.1% (300) | 1568 | - | 72.5% (74) | 27.4% (28) | 102 | |
| EUTIRADS Tot | 4792 | 6474 | 1682 | |||||||||||
| ACRTIRADS | ACRTIRADS 1 | < 2% | - | 100% (8) | 0% (0) | 8 | - | 100% (19) | 0% (0) | 19 | 100% (11) | 0% (0) | 11 | |
| ACRTIRADS 2 | < 2% | - | 100% (18) | 0% (0) | 18 | - | 98.7% (226) | 1.3% (3) | 229 | 99.1% (208) | 1.4% (3) | 211 | ||
| ACRTIRADS 3 | 5% | ≥ 25 | 92.2% (166) | 7.8% (14) | 180 | - | 94.4% (571) | 5.6% (34) | 605 | 95.3% (405) | 4.7% (20) | 425 | ||
| ACRTIRADS 4 | 5-20 | ≥ 15 | 91.0% (2472) | 9.0 % (245) | 2717 | ≥ 10 | 91.1% (3093) | 8.9% (301) | 3394 | 91.7% (621) | 8.3 % (56) | 667 | ||
| ACRTIRADS 5 | > 20 | ≥ 10 | 83.3% (1856) | 16.7% (193) | 2227 | ≥ 10 | 83.3% (1856) | 16.7% (193) | 2227 | |||||
| ACRTIRADS Tot | 5150 | 6474 | 1324 | |||||||||||
aAccording to SIAPEC-IAP classification, TIR 2 or TIR 3A in at least two consecutive samples were considered as negative cytology, while TIR 3B, TIR 4, and TIR 5 as positive cytology
b(With surgical referral). According to British Thyroid Association, all Thy3 obtained before 2014 were also categorized as positive cytology and potentially referred to surgery
cExpected malignancy according to each US score class
*For 458 nodules, the ATA score was not applicable