PP22-1 In Long Term Follow up of Thyroid Nodules with Benign Cytology, Growth May Not be the Best Predictor of a False Negative Result

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

Poster Board SAT 279
Shirin Haddady*1, Leena Shahla2, Mira Sofia Tiglao Torres3 and Marjorie Safran4
1Boston University Medical School, Boston, 2University of Massachusetts Medical School, Worcester, MA, 3University of Massachusetts, Worcester, MA, 4University of Massachusetts Medical School, Pittsfield, MA
Introduction: Thyroid nodules are common and mostly benign. Periodic monitoring of nodules reported benign by cytology has been recommended with consideration of repeat Fine Needle Aspiration (FNA) with significant growth.1   This recommendation has been the subject of several recent studies; the result of some has challenged the necessity of further work up with increasing size of a nodule2,3,4,5.  In addition, the optimum length of follow up to identify nodules with false-negative FNA results is not clear. The objective of this study is to determine the rate of growth of benign thyroid nodules followed for 36 months or longer and its association with the risk of missed malignancy with initial FNA.

Method: Retrospective study of 1087 thyroid nodules with benign cytology from 2005 to 2012 was conducted. The information about the rate of surgery in all nodules and the rate of growth in nodules with a follow up period for 36 months or longer was obtained. Growth was defined as minimum of 50% increase in volume or 20% increase in two dimensions of the nodule6.

Result: 360 nodules were followed for at least 36 months (mean: 64; range: 36 to 144). Growth was identified in 74 (20%) of them and surgery was performed in 30 (8%). The rate of surgery was 24% in nodules with growth and 4% in nodules without growth. 1 malignancy (papillary thyroid carcinoma) was identified in a nodule without growth 36 months after initial FNA. The rate of repeat FNA was 61% in nodules with growth and 20% in nodules without growth. The result of repeat FNA was suspicious for papillary thyroid carcinoma in 2 nodules. Both nodules had remained stable during the course of follow up. Rate of surgery for nodules followed for less than 36 months was higher (20%) and the surgery was done mostly due to the large size of the nodule, compressive symptoms or for a cytology result other than benign for another nodule in the same patient. In this group, 2 additional malignancies (papillary thyroid carcinoma) were identified after surgery.

Conclusion: Repeat investigation of asymptomatic benign thyroid nodules based solely on their growth may lead to increased rate of surgeries and repeat FNA biopsies without any significant additional benefit for diagnosis of missed malignancies.

References: 1- Cooper D.S. et al. 2009 Thyroid (19): 1167.  2- Lee S. et al. 2013 J AM Coll Surg (217): 81. 3- Lim D. J. et al; 2013 Endocrinol Metb (28): 110.  4-Kim S. Y. et al; 2014 Radiology (271): 272. 5- Durante C. et al; 2015 JAMA (313): 926.  6- Brauer V.F.H. et al; 2005 Thyroid (15): 1169.

Nothing to Disclose: SH, LS, MSTT, MS

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