Evaluating the Effect of Multiple Passes to the Same Thyroid Nodule in the Fine-Needle Aspiration Biopsy Session on Obtaining Adequate or the Atypia of Undetermined Significance/Follicular Lesion of Undetermined Significance Cytological Result

Background: To determine whether multiple fine-needle passes to the same thyroid nodule in the fine-needle aspiration (FNA) biopsy session affect sufficient and/or atypia of undetermined significance/follicular lesion of undetermined significance (AUS/FLUS) cytological result. Methods: Ultrasonography(US) and cyto-histopathology results of the nodules of patients were retrospectively analyzed. The nodules were divided into 2 groups according to the number of needle passes performed in the same FNA session as those with 1 pass (1-pass group) and those with 2 or 3 passes (multiple-pass group). Results: Totally, 1409 (93.9%) nodules were performed 1 pass, and 91 (6.1 %) were performed multiple pass(n = 91).The rates of cystic/mixed nodule, macrocalcification, and Thyroid Imaging Reporting and Data System 3 score were higher in the multiple-pass group (P = .001, P = .039, P = .006, respectively). Adequacy and AUS/FLUS rates were similar between the 2 groups. When nodules with macrocalcifications and cystic/ mixed structures were evaluated as 2 separate subgroups, the rates of the adequacy and AUS/FLUS were similar between 1-pass and multiple-pass groups within each subgroup. The number of passes showed no univariate or multivariate significant effect on sufficient and/or AUS/FLUS cytology results (P > .05). Conclusion: Although more passes are performed in cystic/mixed and macrocalcified nodules estimating that the material would be insufficient with macroscopic on-site evaluation, needle insertion of 2 or 3 times does not affect obtaining sufficient and/or AUS/FLUS cytology compared to 1 pass. Keywords: Thyroid nodule, fine-needle biopsy, number of needle pass, adequacy, AUS/FLUS