[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 CATEGORY	MNG & HT	FA	CA	TOTAL	TOTAL
Unsatisfactory	18/9	1/8	5/8	24/25	50
Negative for Malignancy	48/61	13/13	30/8	91/82	173
Indeterminate	NA/7	NA/7	NA/13	NA/27	27
Suspicious for Follicular Neoplasm	8/NA	11/NA	5/NA	34/NA	34
Follicular/ Hürthle Cell Neoplasm	14/33	25/34	15/35	54/102	156
Suspicious for Malignancy	3/2	1/2	6/26	10/30	40
Malignancy	2/0	2/0	46/112	50/112	162
TOTAL	93/112	53/64	107/202	263/378	641

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