SAT454 Repetition Of Fine Needle Aspiration Cytology After An Initial Nondiagnostic Result: Does An Optimal Timing Exist?

Abstract

Abstract Disclosure: I. Cosme: None. E.L. Nobre: None. M.J. Bugalho: None. Background: The optimal time to repeat a fine-needle aspiration cytology (FNAC) of a thyroid nodule, after a nondiagnostic (ND) result, is not established. It has been proposed to wait at least 3 months for a 2nd FNAC, in order to mitigate the possible inflammatory cytological changes induced by a previous FNAC. This study aimed to evaluate whether the time between 2 consecutive FNACs, influences the final cytological result. We analysed the occurrence of ND or atypia of undetermined significance/follicular lesion of undetermined significance (AUS/FLUS) in the 2nd FNAC, in different repetition time intervals. Methods: Retrospective study (2017-2020) including thyroid nodules with a first ND FNAC, submitted to a 2nd FNAC. All FNACs were ultrasound-guided. Demographic data, time interval between FNACs and their results were collected. The 2nd FNAC results were analysed according to FNACs´ repetition interval. We considered 2 intervals: ≤ vs > 3 months and ≤ vs >6 months after the initial FNAC. The 2nd FNAC results were classified as ND, AUS/FLUS or diagnostic (including the other Bethesda FNAC categories). Results: Included 190 nodules (190 patients, 82.1% women, mean age 60±13.7 years) with a 1st ND FNAC submitted to a 2nd FNAC. The 2nd FNAC result remained ND in 63 cases, was AUS/FLUS in 9 and diagnostic in 118 (benign in 116 cases, follicular neoplasm/suspicious follicular neoplasm in 1 and malignant in 1 case). There were no statistical differences in 2nd FNAC result performed ≤3 months (13 ND, 2 AUS/FLUS, 19 diagnostic) vs >3 months (50 ND, 7 AUS/FLUS, 99 diagnostic) - p=0.71. Considering a wider time interval between FNACs, there were also no statistical differences in the 2nd FNAC result: ≤ 6 months (32 ND, 3 AUS/FLUS, 59 diagnostic) vs >6 months (31 ND, 6 AUS/FLUS, 59 diagnostic) - p=0.61. Conclusions: The time interval between FNACs was not relevant to the final cytological result. Early FNAC repetition did not increase the cases of ND or AUS/FLUS. Presentation: Saturday, June 17, 2023