A combination of risk stratification systems for thyroid nodules and cervical lymph nodes may improve the diagnosis and management of thyroid nodules

Abstract

Introduction: To assess the performance of the European Thyroid Association Thyroid Imaging and Reporting Data System (EU-TIRADS) and the Korean Thyroid Imaging Reporting and Data System (K-TIRADS), which combine risk stratification systems for thyroid nodules (TN-RSS) and cervical lymph nodes (LN-RSS) in diagnosing malignant and metastatic thyroid cancer in a single referral center.

Methods: We retrospectively analyzed 2,055 consecutive patients who underwent thyroidectomy or fine-needle aspiration (FNA) from January 2021 to December 2022. TNs and LNs were categorized according to the ultrasonography (US) features of EU-TIRADS and K-TIRADS, respectively. The diagnostic performance and postponed malignancy rate (PMR) were compared with those of EU-TIRADS and K-TIRADS. PMR was defined as the number of patients with malignant nodules not recommended for biopsy among patients with cervical LN metastasis.

Results: According to the EU-TIRADS and K-TIRADS, for TN-RSS alone, there were no significant differences in sensitivity, specificity, accuracy, unnecessary FNA rate (UFR), missed malignancy rate (MMR), and PMR between the two TIRADSs (29.0% vs. 28.8%, 50.5% vs. 51.1%, 32.3% vs. 32.2%, 23.6% vs. 23.5%, 88.6% vs. 88.5%, and 54.2% vs. 54.5%, P > 0.05 for all). Combining the LN-RSS increased the diagnostic accuracy (42.7% vs. 32.3% in EU-TIRADS; 38.8% vs. 32.2% in K-TIRADS) and decreased the PMR (54.2% vs. 33.9% in EU-TIRADS; 54.5% vs. 39.3% in K-TIRADS). EU-TIRADS had higher sensitivity and accuracy and lower PMR than K-TIRADS (41.3% vs. 36.7%, 42.7% vs. 38.8%,33.9% vs. 39.3%, P < 0.05 for all).

Conclusions: A combination of TN-RSS and LN-RSS for the management of thyroid nodules may be associated with a reduction in PMR, with enhanced sensitivity and accuracy for thyroid cancers in EU-TIRADS and K-TIRADS. These results may offer a new direction for the detection of aggressive thyroid cancers.

Keywords: lymph nodes; management; risk stratification system; thyroid nodules; ultrasound.

Figure 1

Flowchart showing the recruitment of study participants.

Figure 2

Longitudinal ultrasonography image from a 39-year-old woman with papillary thyroid carcinoma shows a 6-mm solid, hypoechoic, and ill-defined margin thyroid nodule with punctate echogenic foci, associated with LN metastases presenting as diffuse hyperechogenicity with punctate echogenic foci, L/S<2.The nodule was classified as EU-TIRADS 5:high risk or K-TIRADS 5:high suspicion. The LNs in level VI were classified as “suspicious for malignancy” according to the EU-TIRADS category and “suspicious” for the K-TIRADS category. The FNA failed based on nodule size, while according to the LNs was suggested.

Figure 3

Longitudinal ultrasonography image from a 34-year-old woman with papillary thyroid carcinoma shows a 7.5-mm solid, hypoechoic, and irregular margin thyroid nodule with punctate echogenic foci, associated with no suspicious lymph node. The nodule was classified as EU-TIRADS 5:high risk or K-TIRADS 5:high suspicion. The nodular failed FNA based on nodule size.