The Frequency of ‘Atypia of Undetermined Significance’ Interpretations for Thyroid Fine-Needle Aspirations Is Negatively Correlated with Histologically Proven Malignant Outcomes

Abstract

Objective: Cytopathologists’ usage patterns for ‘atypia of undetermined significance’ (AUS) in thyroid fine-needle aspiration (FNA) are not well understood. AUS rates over a 5-year period were analyzed to quantify variability and identify correlations with experience and histologic outcomes. Study Design: A retrospective review of thyroid FNAs from a tertiary-care hospital from 2005 to 2009 was performed. Results were compiled for individual cytopathologists, stratified by year, and correlated with histologic outcomes. Results: Thyroid FNAs (5,327) were evaluated by 7 cytopathologists, with an overall AUS rate of 11.2%. The annual AUS rate remained relatively constant over this time period, though notable inter- and intrapathologist variability was seen. The AUS rate was significantly lower for those with cytopathology boards (10.3%) compared to those without (14.0%). There was no correlation between the AUS rate and cytopathologist experience or thyroid FNA volume. The AUS rate and malignant outcome were inversely related: the higher an individual’s AUS rate was, the lower the rate of malignancy for that AUS cohort was. Conclusions: Individual cytopathologist AUS rates were variable and often exceeded the recommended target of 7%. The application of recently published defined diagnostic criteria, along with directed cytopathologist feedback, may reduce observer variability and appropriately lower AUS utilization.

Thyroid Fine-Needle Aspiration Reporting Rates and Outcomes Before and After Bethesda Implementation Within a Combined Academic and Community Hospital System

“…[9][10][11][12][13][14][15][16][17][18] These same studies have also reported their respective rates of malignancy as ranging from 6% to 48% for cases classified as AUS/FLUS with available followup. [9][10][11][12][14][15][16][17][18][19] It was noted at the time of the National Cancer Institute State of the Science Conference that the original recommendations may need to be revisited. Recently published data suggest that there is still some variation in incidence and risk of malignancy for the AUS/FLUS category.…”

“…It has also been previously suggested that the reported rates of malignancy may be elevated because they are calculated from a subset of nodules that were selected for surgery, and therefore do not account for an inherent selection bias. 18 By design, most patients with nodules classified as AUS/FLUS will have benign nodules and will not undergo surgical resection, and their outcomes will not be known. 25 Other possibilities for such wide variation in the rate of AUS/FLUS cases among laboratories include differences in diagnostic threshold, experience, preparation methods, and the availability of rapid onsite evaluation.…”

“…One study did specifically address the issues of experience and board certification in cytopathology, and it noted statistical significance in the variation of AUS/FLUS rates between board-certified cytopathologists versus non-board-certified cytopathologists, although the study authors noted a small sample size (5 of 7 cytopathologists were board certified in cytopathology). 18 Because of the wide variation in reported AUS/FLUS rates from early studies, some authors have attempted to resolve this dilemma with the creation of a standardized performance measure similar to the ''atypical squamous cells of undetermined significance'' to ''squamous intraepithelial lesion'' (ASCUS/SIL) ratio used for cervical/vaginal Papanicolaou tests. 26 One such proposed performance measure has been the AUS/M ratio, which would compare the AUS/ FLUS rate versus the malignant (M) rate.…”

Malignancy Rates in Bethesda Category AUS/FLUS: Single Center Experience

“…However, the published reports after the widespread use of BRSTC informed highly variable risk of malignancy ranging between 6 %-96,7% in this group (3)(4)(5)(6)(7)(8). The malignancy rate in AUS/FLUS category of our center was 45,8% and is placed centrally in previosly reported wide risk spectrum (3)(4)(5)(6)(7)(8).…”

Podejrzenie nowotworu pęcherzykowego czy nowotwór pęcherzykowy? Dylemat patologa i chirurga

“…These studies often come from different medical centres, and the stains vary because of the need to collect a sufficiently large cohort. An overwhelming majority of researchers use Papanicolau stain [5,6,10,14,18,[20][21][22][23][24][25][26][27][28].…”