[402] The Bethesda Thyroid FNA Classification System Versus the Old School Approach: Have We Really Improved Anything?

Z Elaba, D Chhieng, A Viray, A Adeniran, C Theoharis. Yale University, New Haven, CT

Background: Our institutional early adoption of the Bethesda Thyroid Fine Needle Aspiration (FNA) Classification System is compared to our previously utilized diagnostic terminology and an operating characteristic is calculated.
Design: A total of 5114 thyroid FNAs were reviewed. 3207 FNAs from 2468 patients were retrieved from the archive of 2008; the diagnoses were reported based on the recent proposed Bethesda Classification System for reporting thyroid FNA. As a control group, 1907 FNAs from 1493 patients were retrieved from the archive of 2007; the diagnoses were reported according to individual pathologists' preference. We compared the frequency distribution and the histologic follow up of the diagnostic categories before and after the adoption of the Bethesda Classification System for reporting thyroid FNA.
Results: The specificities of the Bethesda System as a screening test for neoplasm and as a diagnostic test for malignancy were 68% and 93% respectively. The negative predictive values (NPV) of Bethesda for screening for neoplasm and diagnosing malignancy were 91% and 100% respectively. The specificities of non-Bethesda terminology as a screening test for neoplasm and as a diagnostic test for malignancy were 61% and 86% respectively. The NPVs of non-Bethesda for screening for neoplasm and diagnosing malignancy were 50%% and 56% respectively. Due to the limited number of negative cases with histologic follow-up, sensitivity and positive predictive value cannot be accurately estimated.

CYTOLOGIC-HISTOLOGIC CORRELATION
HISTOLOGIC FOLLOW-UP (2007/2008)
CYTOLOGIC CATEGORYMNG & HTFACATOTALTOTAL
Unsatisfactory18/91/85/824/2550
Negative for Malignancy48/6113/1330/891/82173
IndeterminateNA/7NA/7NA/13NA/2727
Suspicious for Follicular Neoplasm8/NA11/NA5/NA34/NA34
Follicular/ Hürthle Cell Neoplasm14/3325/3415/3554/102156
Suspicious for Malignancy3/21/26/2610/3040
Malignancy2/02/046/11250/112162
TOTAL93/11253/64107/202263/378641
MNG-multinodular goiter, HT-Hashimoto thyroiditis, FA-follicular/ Hürthle Cell neoplasm, CA-malignant neoplasm


Conclusions: Our findings suggest that there is no statistically significant difference in the distribution of diagnostic categories before and after the adopotion of the Bethesda System. However, the use of the Bethesda Thyroid FNA classification system significantly improves our ability to diagnose and triage thyroid malignancies and neoplasms preoperatively.
Category: Cytopathology

Tuesday, March 23, 2010 9:30 AM

Poster Session III # 91, Tuesday Morning

 

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