Predicting extrathyroidal extension (ETE) of differentiated thyroid carcinoma (DTC) preoperatively by using ultrasonography (US)

Bahcecioglu Adile Begum; Merdin Fatma Avcı; Aksu Ozge Bas; Sak Serpil Dizbay; Gulcelik Neşe Ersoz; Sevim Gullu; Erdoğan Murat Faik

doi:10.1530/endoabs.101.PS3-22-07

PS3-22-07

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Endocrine Abstracts (2024) 101 PS3-22-07 | DOI: 10.1530/endoabs.101.PS3-22-07

ETA2024 Poster Presentations Diagnosis of thyroid cancer-2 (11 abstracts)

Predicting extrathyroidal extension (ETE) of differentiated thyroid carcinoma (DTC) preoperatively by using ultrasonography (US)

Adile Begum Bahcecioglu ¹ , Fatma Avcı Merdin ² , Ozge Bas Aksu ³ , Serpil Dizbay Sak ⁴ , Neşe Ersöz Gülçelik ⁵ , Sevim Gullu ⁶ & Murat Faik Erdoğan ²

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Author affiliations

¹University of Health Sciences, Gülhane Training and Research Hospital, Department of Endocrinology and Metabolism, Ankara, Turkey; ²Ankara University School of Medicine, Endocrinology and Metabolism, Turkey; ³Ankara University, Faculty of Medicine, Department of Endocrinology and Metabolism, Ankara, Turkey; ⁴Ankara University School of Medicine, Pathology, Turkey; ⁵University of Health Sciences, Gulhane Training and Research Hospital, Endocrinology and Metabolism, Turkey; ⁶Ankara University Faculty of Medicine, Faculty of Medicine, Endocrinology and Metabolic Disorders, Ankara, Turkey

Objective: Neck US is essential in the preoperative endocrinological evaluation of malignant thyroid nodules and determining surgical approach. Extrathyroidal extension (ETE) in DTC is a significant risk factor for recurrence. Our study aim is to assess ultrasonographic features predicting minor ETE.

Method: In our two-center prospective study, we recorded US videos of DTC nodules adjacent to the capsule, with no thyroid parenchyma between the capsule. Experienced sonographers evaluated these videos for ETE-related sonographic characteristics (ERSC) blindly to pathology results. The relationship between these features and ETE presence was evaluated.

Results: Mean age of the study group was 45±14 years, mean nodule diameter was 14.3 ± 9.7 mm. ETE was found in 17 out of 140 DTC nodules (12%)., Eighty-nine percent of nodules were papillary thyroid carcinoma (PTC), with 76% of these being classic subtype PTC. Six nodules had non-invasive follicular thyroid neoplasm with papillary-like nuclear features, six had invasive encapsulated follicular variant papillary carcinoma, and three had follicular carcinoma. The frequencies of ERSC and their association with ETE presence are detailed in Table 1.

Table 1. Diagnostic Performance of Sonographic Findings of Minor ETE
ETE-related sonographic characteristics	ETE positive nodules (n = 17)	ETE negative nodules (n = 123)	P	PPV	NPV	Sensitive %	Specificity %	Diagnostic Accuracy %
Capsular disruption	13 (77%)	5 (4%)	<0.001	72%	97%	77%	96%	94%
Contour bulging	11 (65%)	38 (31%)	0.006	22%	93%	65%	70%	69%
Nodule vascularity extending beyond the thyroid capsule	3 (18%)	1 (0.8%)	<0.001	75%	90%	18%	99%	89%
Ratio of contact area with adjacent capsule (contact diameter/nodule diameter)	<12.5%: 0 12.5-25% : 8 (47%) 25-37.5%: 6 (35%) >50%: 3 (18%)	<12.5%: 19 (14%) 12.5-25% : 63 (51%) 25-37.5%: 36 (29%) >50%: 5 (4%)	0.0053	18%*	92%*	18%*	96%*	%86*
Replacement of adjacent strap muscle	9 (53%)	1 (0.8%)	<0.001	90%	94%	53%	99%	94%
ETE: extrathyroidal extension, PPV: positive predictive value, NPV: negative predictive value *results of the ratio of the contact area with the adjacent capsule being >50%.

Conclusion: It has been determined that the features with the highest PPV for detecting ETE during US, are replacement of adjacent anterior neck muscles and vascularity of nodules extending beyond the thyroid capsule. The ratio of contact area with the adjacent capsule and contour bulging are the features with the lowest PPV. The highest NPV and the highest diagnostic accuracy were observed in capsular discontinuity and replacement of adjacent anterior neck muscles.