Table 2.
Time interval until first follow-up of a benign thyroid nodule and the risk of growth, repeat FNAs, thyroidectomies, malignancies and mortality
| Follow-up time, years | n | 15 % Growth, % (n) | 50 % Growth, % (n) | Repeat FNAs, % (n) | Outcomes of repeat FNAs | Thyroidectomies, % (n) | Indication for thyroidectomy | Malignancies, % (n) | Disease- related mortality, % (n) |
|---|---|---|---|---|---|---|---|---|---|
| 0.5–1 | 489 | 30.3 (148) | 8.6 (42) | 5.1 (25) | 21 Benign 1 AUS 3 Non-diagnostica |
0.8 (4) | 3 US Large size/growth 1 Compressive symptoms |
0.2 (1) | 0 (0) |
| >1–2 | 715 | 34.8 (249) | 15.1 (108) | 5.6 (40) | 29 Benign 4 AUS 1 Susp. foll. neopl. 1 Susp. PTC 5 Non-diagnosticb |
0.8 (6) | 4 Abnormal repeat FNA 2 US Large size/growth |
0.3 (2) | 0 (0) |
| >2–3 | 249 | 40.2 (100) | 19.7 (49) | 8.8 (22) | 18 Benign 1 AUS 1 Susp. foll. neopl. 1 Malignant 1 Non-diagnosticc |
1.2 (3) | 3 Abnormal repeat FNA | 0.8 (2) | 0 (0) |
| >3–4 | 143 | 50.3 (72) | 34.3 (49) | 18.9 (27) | 22 Benign 3 AUS 2 Susp. foll. neopl. |
4.9 (7) | 3 Abnormal repeat FNA 2 Compressive symptoms 1 US Large size/growth 1 Afirma GEC positive |
0.7 (1) | 0 (0) |
| >4 (range 4.0–14.1) | 223 | 52.5 (117) | 35.0 (78) | 19.3 (43) | 35 Benign 3 AUS 1 Susp. Hurthle cell neopl. 1 Malignant 3 Non-diagnosticd |
4.0 (9) | 5 Compressive symptoms 2 Abnormal repeat FNA 1 US Large size/growth 1 Afirma GEC positive |
0.4 (1) | 0 (0) |
| P value | <0.0001 | <0.0001 | <0.0001 | 0.0001 | 0.77 | – |
aAll nodules were >75 % cystic and had therefore a negligible low risk of malignancy and were not rebiopsied
bThree nodules were >75 % cystic and had therefore a negligible low risk of malignancy and were not rebiopsied. One nodule did not change in size during follow-up, and was therefore not rebiopsied. One nodule was surgically removed (lobectomy) due to its large size (4.4 cm) and histological diagnosis confirmed a 3.3 cm follicular variant PTC (see Table 3 subject no. 3)
cNodule did not change in size during follow-up, and was therefore not rebiopsied
dOne nodule >75 % cystic and another 50–75 % cystic, which had therefore a negligible low risk of malignancy. The third nodule underwent total thyroidectomy as this patient had another nodule diagnosed with malignant cytology. Histopathology confirmed a 1.1 cm follicular variant PTC, while the nodule with the non-diagnostic biopsy was histologically confirmed to be benign
FNA, Fine needle aspiration; AUS, Atypical cells of undetermined significance; PTC, Papillary thyroid carcinoma; GEC, Gene expression classifier. All malignancies were determined by histopathology and the malignancy percentage indicates the rate of malignancies for the respective follow-up time group