Utilization and Impact of Repeat Biopsy for Follicular Lesion/Atypia of Undetermined Significance

Abstract

Repeat biopsy was underutilized in FLUS/AUS cases. Repeat biopsy allows a significant proportion of FLUS/AUS patients without other indications for surgery to move to surveillance. In patients who have indications for thyroidectomy regardless of FLUS/AUS results,repeat biopsy does not appear necessary. Malignancy and thyroidectomy rates were similar among patients who did or did not have a repeat biopsy. Further data must be obtained to determine the long-term outcomes for surveillance of FLUS/AUS lesions in patients who do not undergo surgical removal.

Surgical Outcome of Thyroid Nodules with Atypia of Undetermined Significance and Follicular Lesion of Undetermined Significance in Fine Needle Aspiration Biopsy

“…2,14 We found that the incidence of AUS/FLUS on repeated FNAB (42.5%) is within the range of previously published data of 20 to 48.5%, 4,8,12,14 and that the risk of malignancy in two consecutive AUS/FLUS was 50%, higher than most published data of 13.5 to 43%. 4,7,8,14 Our data support the significant benefit of repeating FNAB in triaging patients with AUS/FLUS; those who have a diagnosis of malignancy or follicular neoplasm/ suspicious for follicular neoplasm should undergo surgery. In our patients, the risk of malignancy in benign diagnoses after the second FNAB was 27.3%, which is close to what was published by Vanderlaan (29%).…”

“…This will justify the continued surveillance in patients who otherwise do not have an indication for surgical intervention. Similar conclusions were made by Broome et al 4 and Chen et al 6 The latter authors advised to repeat FNAB after 3 to 6 months, and if the repeated biopsy is nondiagnostic or again interpreted as AUS/FLUS, then surgery is indicated. On the contrary, some authors observed that no difference in malignancy rate between one and repeated FNABs.…”

“…10 It has been recommended that if there is an indication for surgical intervention, it is not necessary to repeat the FNAB. 4 Although it has been suggested that the usage of AUS/FLUS should not exceed 7% of thyroid FNABs, 3,7,9,10 there is variation of this percentage from 3 to 29% across laboratories and from 2.5 to 28.6% among cytopathologists. 5 Ultrasound findings can facilitate reaching a diagnosis of nodules with AUS/FLUS, 11 although they may not differentiate benign from malignant nodules.…”

“…The Bethesda System for Reporting Thyroid Cytopathology (BSRTC) has six categories, one of which is AUS or FLUS, which is a heterogeneous group that is difficult to classify as benign, follicular neoplasm, suspicious for malignancy, or malignant. [1][2][3][4][5][6] In AUS/FLUS, the risk of malignancy in resected nodules is 5 to 15%, but a variation from 6 to 48% is in record. [6][7][8][9] It has been reported that with repeated FNAB in AUS/ FLUS cases, about 56 to 68% will have a more definitive result and 15.6 to 48.6% will be interpreted as AUS/FLUS.…”

Fine-Needle Aspirations in Atypia of Undetermined Significance: Usefulness of Repeated FNA of Thyroid Nodules

“…although re-FNA diagnosis is more precise, about 20% -25% of nodules repeatedly receive the results of AUS/FLUS (12) which end up with inaccurate judgment. Also, the malignancy rates associated with AUS/FLUS with or without repeat FNAB have been reported with variable results in different series (7,11,(13)(14)(15)(16)(17)(18)(19).…”