Should we wait 3 months for a repeat aspiration in non‐diagnostic/indeterminate thyroid nodules? A cancer centre experience

• Published in: Cytopathology (Oxford) 2020-11, Vol.31 (6), p.525-532
• Main Authors: Valerio, Ediel, Pastorello, Ricardo Garcia, Calsavara, Vinicius, Porfírio, Mônica Modesto, Engelman, Gustavo Gonçalves, Francisco Dalcin, José, Bovolim, Graziele, Domingos, Tábata, De Brot, Louise, Saieg, Mauro
• Format: Article
• Language: English
• Subjects: cytology; Diagnosis; fine needle aspiration; Nodules; Regression analysis; Thyroid cancer; Thyroid gland; thyroid nodule
• ISSN: 0956-5507; 1365-2303
• DOI: 10.1111/cyt.12887

Introduction The Bethesda System recommends repeat fine needle aspiration (rFNA) as a management option for nodules classified under the non‐diagnostic (ND) and atypia of undetermined significance (AUS/FLUS) categories. We evaluated the impact of an rFNA in diagnostic resolution and the role of early (≤3 months) vs delayed (more than 3 months) rFNA of nodules initially diagnosed as ND and AUS/FLUS. Methods We retrospectively collected all thyroid FNA performed in a 4‐year period with repeat aspiration. For cases initially signed out as ND or AUS/FLUS, diagnostic resolution was defined as a change to a Bethesda System category other than these two on rFNA. Comparison and regression models were fitted to identify the impact of time of rFNA on diagnostic resolution. Results In total, 184 cases were initially assigned as ND and 143 as AUS/FLUS, with overall diagnostic resolution rates for the reassessment of these nodules calculated at 70.1% and 62.9%, respectively. For ND cases, time of rFNA was not significantly associated with diagnostic resolution (P > .05). For AUS/FLUS nodules, however, repeat aspiration performed in more than 3 months after the initial diagnosis was 2.5 times more likely to achieve a resolution in diagnosis than early rFNA (P = .024). Conclusions Repeat aspiration of ND and AUS/FLUS nodules helped define diagnosis for the majority of cases, being highly effective in determining correct patient management. For AUS/FLUS nodules, repeat aspiration performed more than 3 months after the initial diagnosis was associated with a higher diagnostic resolution. This retrospective study has shown that repeat aspiration of nondiagnostic/indeterminate (AUS) thyroid nodules resulted in a definitive diagnosis in the majority of cases. No statistical difference was seen for diagnostic resolution rates before and after three months. These results may stimulate further prospective, large centre, randomized studies, to determine the optimal timing for resampling thyroid nodules with inconclusive diagnoses.