American Thyroid Association (ATA) 2015 Thyroid Nodule Guidelines in Clinical Practice: Comparison of ATA Suspicion Pattern (ATASP) with Fine Needle Aspiration (FNA) Cytology Categorization  

Program: Abstracts - Orals, Poster Previews, and Posters
Session: SAT 270-310-Thyroid Neoplasia (posters)
Clinical/Translational
Saturday, April 2, 2016: 1:15 PM-3:15 PM
Exhibit/Poster Hall (BCEC)

Poster Board SAT 276
Kristen Kobaly*1, Caroline S. Kim2, Jill E Langer3 and Susan J Mandel4
1University of Pennsylvania, Philadelphia, PA, 2Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 3University of Pennsylvania School of Medicine, Philadelphia, PA, 4Perelman School of Medicine, University of Pennsylvania, Ardmore, PA
The 2015 ATA Guidelines define 5 sonographic suspicion patterns and expected malignancy rates for thyroid nodules: benign (BS <1%), very low (VLS <3%), low (LS 5-10%), intermediate (IS 10-20%), high (HS >70-90%)1. We compared ATASP with FNA cytology (cyto) categorization  to assess performance of the guidelines in clinical practice.

Hypothesis: The new ATA sonographic patterns will predict cyto categorization for the vast majority of nodules.

Design:  Retrospective comparison (11/2014- 6/2015) of thyroid FNA cytology results with ATASP designation from 229 consecutive subjects  with 248 nodules undergoing FNA.  Cyto results reported using Bethesda classification: benign (B), atypia/follicular lesion of undetermined significance (AUS), follicular neoplasm (FN), suspicious for malignancy (SM), malignant (M) or non-diagnostic (ND).

 Results:  Biopsied nodule patterns were: HS (n=10, 4%), IS (n=39, 16%), LS (n=95, 38%), VLS (n=60, 24%), BS (n=0), Other (n=44, 18%; 40 calcified, 4 noncalcified).

 Cyto within each pattern was:

HS: B (n=3, 30%), M (n=7, 70%);

IS: B (n=20, 51%), AUS (n=5, 13%), FN (n=11, 28%), SM (n=1, 3%), M (n=2, 5%), ND (n=0);

LS: B (n=70, 74%), AUS (n=5, 5%), FN (n=15, 16%), SM (n=3, 3%), M (n=1, 1%), ND (n=1, 1%);

VLS: B (n=54, 90%), AUS (n=1, 2%), FN (n=2, 3%), ND (n=3, 5%), SM/M (n=0); Other: B (n=38, 86%), AUS (n=1, 2%), FN (n=3, 7%), SM (n=2, 5%), M/ND (n=0).

 40 nodules with macrocalcifications in the Other group were analyzed based upon greyscale sonographic pattern. Cyto was: HS: (NA); IS: B (n=5,71%), FLUS (n=1,14%), SM (n=1, 14%); LS: B(n=20,95%), FN (n=1,5%); VLS: B(n=7,87.5%), FN (n=1,12.5%). Four nodules had uninterrupted peripheral or dense calcifications limiting the ability to visualize underlying nodule greyscale pattern; three of these nodules were B and one was SM.    

Conclusions:  This study provides preliminary validation that the ATASP aligns with anticipated FNA cyto diagnoses. Malignant cyto rates in the HS group correlated with the expected malignancy rates. Although the malignant cyto rate was lower for other patterns, the extrapolated cancer rate at surgery for indeterminate cyto nodules based upon Bethesda criteria is within range (IS 15%; LS 8%; VLS <3%). This lends support that the ATA sonographic patterns identify high risk nodules and surveillance without FNA may be appropriate in VLS nodules. 

18% of nodules could not be categorized using the ATASP mostly due to the presence of macrocalcifications but had a low malignancy rate.  ATASP includes micro- and interrupted peripheral calcifications in HS nodules but other macrocalcifications are not categorized. Our data suggest non HS nodules with macrocalcifications are as likely to have benign cyto as non-calcified nodules with the same greyscale sonographic pattern but numbers are small. Limitations of this study to be addressed in the future include small sample size and the need to assess surgical pathology outcomes. 

(1)  Haugen, BR et al. 2015 American Thyroid Association Management Guidelines for Adult Patients with Thyroid Nodules and Differentiated Thyroid Cancer. Thyroid. 2015 Oct 14.

Nothing to Disclose: KK, CSK, JEL, SJM

*Please take note of The Endocrine Society's News Embargo Policy at https://www.endocrine.org/news-room/endo-annual-meeting/pr-resources-for-endo

Sources of Research Support: This work was funded by the Thyroid Cancer Patient Research and Education Fund.