Performance of EU-TIRADS in malignancy risk stratification of thyroid nodules: a meta-analysis

Comparison of the diagnostic accuracy of K-TIRADS and EU-TIRADS guidelines for detection of thyroid malignancy on ultrasound

INTRODUCTION

This retrospective study compared the diagnostic accuracy of histopathologically proven thyroid nodules between the Korean Thyroid Imaging Reporting and Data System (K-TIRADS) and the European Thyroid Imaging Reporting and Data System (EU-TIRADS) guidelines for the management of thyroid nodules characterized by ultrasonography.

MATERIAL AND METHODS

For thyroid nodules resected from 2018 to 2021 at our institution, static ultrasound images of each nodule were reviews and stratify into both systems. Agreement between above two classifications was compared based on histopathological results.

RESULTS

A total 403 thyroid nodules from 213 patients were evaluated. Each nodule was characterized by ultrasonography and stratified into K-TIRADS and EU-TIRADS classifications. The diagnostic accuracy was as follows: K-TIRADS sensitivity 85.3% (95% CI, 78.7-91.9) specificity 76.8% (95% CI, 72.1-81.7), positive predictive value 57.8% (95% CI, 50.1-65.4) negative predictive value 93.4% (95% CI, 90.3-96.5); EU-TIRADS sensitivity 86.2% (95% CI, 79.7-92.7), specificity 75.5% (95% CI, 70.6-80.4), positive predictive value 56.6% (95% CI, 49.1-64.2), negative predictive value 93.7% (95% CI, 90.6-96.8). Excellent agreement in risk stratifications between both systems was found (kappa 0.86).

CONCLUSIONS

Ultrasound thyroid nodules categorized by either by K-TIRADS or EU-TIRADS are useful to predicting malignancy and perform risk stratification with similar results.

IMPLICATIONS FOR PRACTICE

This study confirmed that both K-TIRADS and EU-TIRADS have high diagnostic accuracy and both guidelines may be used as an effective tool for management planning of patients with thyroid nodules in daily clinical practice.

Performance of European Thyroid Imaging Reporting and Data System in Stratifying Malignancy Risk of Thyroid Nodules: A Prospective Study

Background

There is a limited number of studies reporting the performance of European Thyroid Imaging Reporting and Data System (EU-TIRADS) guideline in identifying thyroid nodule malignancy. We aimed to evaluate diagnostic accuracy of EU-TIRADS regardless of thyroid nodule size.

Methods

During August 2019-November 2021, subjects with thyroid nodules were prospectively included. Sonographic characteristics were recorded and scored as per EU-TIRADS guideline. Finally, fine-needle aspiration (FNA) was performed, and cytological findings were reported.

Results

Totally, 1266 thyroid nodules from 984 subjects were assessed, of which 295 nodules were smaller than 10 mm and 971 nodules were 10 mm or larger. Among nodules <10 mm, prevalence rates of malignancy for EU-TIRADS classes 2-5 were 0.0%, 3.7%, 20.6%, and 40.9%, respectively; these rates among nodules ≥10 mm were 2.3%, 4.0%, 19.3%, and 43.2%, respectively. The accuracy values of EU-TIRADS class 5 and EU-TIRADS class 4 or 5 in diagnosis of malignancy for nodules <10 mm were 86.4% and 79.7%, respectively; these rates for nodules ≥10 mm were 83.8% and 76.3%, respectively. Hypoechogenicity, microcalcification, ill-defined and irregular margins were predictors for malignancy regardless of thyroid nodule size.

Conclusion

EU-TIRADS could provide an acceptable malignancy risk stratification that is helpful for better distinguishing benignity from malignancy, as well as preventing unnecessary FNA biopsies, in thyroid nodules irrespective of their size.

A prospective comparison of ACR-TIRADS and EU-TIRADS in thyroid nodule assessment for FNA-US

OBJECTIVE

Prospective data on the accuracy of ultrasound (US) classification systems in thyroid nodules are still scarce. The aim of this study is to compare the accuracy of the American College of Radiology Thyroid Imaging Reporting and Data System (ACR-TIRADS) and European (EU)-TIRADS classification systems.

DESIGN AND PATIENTS

Consecutive patients with one or more thyroid nodule(s) who underwent fine-needle aspiration (FNA) under ultrasonographic guidance (FNA-US) were prospectively evaluated.

MEASUREMENTS

Clinical evaluation and US data were collected. The reference standard used for this study was FNA-US cytology and histopathological diagnosis.

RESULTS

A total of 186 thyroid nodules in 166 patients were evaluated, resulting in 168 nodules from 149 patients with conclusive benign or malignant results. Sensitivity, specificity, negative predictive value (NPV) and false negative (FN) were 100.0%, 28.7%, 100.0% and 0.0%, respectively, for ACR-TIRADS; and 90.0%, 19.1%, 96.8% and 9.1% (n = 1), respectively, for EU-TIRADS. The number of unnecessary FNA-US indicated by ACR-TIRADS was lower than EU-TIRADS (71.3% vs. 80.9%, p = .017), and the number of possibly avoided FNA-US was higher (26.7% vs. 17.8%). Using the same threshold of ACR-TIRADS to indicate FNA-US in EU-TIRADS 3 nodules (2.5 cm), there was an improvement in specificity (30.6%) and avoided FNA-US (28.6%). The best performance of both systems was demonstrated when FNA-US would be indicated only in highly suspicious nodules and/or in the presence of lymphadenopathy, with 85.7% and 89.3% of possibly avoided FNA-US for ACR-TIRADS and EU-TIRADS, respectively, without increasing FN.

CONCLUSION

Both systems presented high sensitivity, but low specificity in selecting nodules for FNA-US. The use of nodular size for FNA-US selection is questioned.

Patients undergoing endocrine consultation and first diagnosis of nodular disease: Indications of thyroid ultrasound and completeness of ultrasound reports

PURPOSE

To evaluate reasons for performing ultrasonography (US) and completeness of US reports in patients undergoing endocrine consultation with the first diagnosis of nodular disease.

METHODS

Since January 1 to June 30, 2021, we prospectively collected patient data (age and thyroid-stimulating hormone concentrations), reasons for performing thyroid US, and completeness of reports regarding the description of the thyroid gland and nodules. In the case of multiple nodules, we considered the nodule suspected of malignancy and the largest one. To evaluate the accuracy of thyroid nodule description, we referred to the five characteristics suggested by the ACR TI-RADS system.

RESULTS

A total of 341 patients with thyroid nodules received endocrine consultation (female, 78%). The most frequent reasons for performing thyroid US were unrelated to a suspected thyroid disease (31.7%), followed by incidentaloma (23.5%), dysfunction or positivity for thyroid antibodies (19.1%), symptomatic or visible nodules (17.6%), and family history of any thyroid disease (8.2%). Gland texture was not reported in 41.9%. The depth of the lobes was the dimension reported most frequently (42.2%), but any diameter was not reported in 57.8% of the cases. As regards the description of the most relevant nodule, length was reported more frequently (75.9%). Margins and echogenicity were more frequently described (54.5% and 44.3%, respectively) than other characteristics (composition: 27%; shape: 8.8%; echogenic foci: 6.7%). No reports had indicated the malignancy risk stratification.

CONCLUSIONS

The results of the study demonstrate that in patients undergoing endocrine consultation with first detected thyroid nodules, US was mostly performed in asymptomatic cases, US reports were incomplete, and no risk stratification system was reported.

Changes in thyroid nodule cytology rates after institutional implementation of the Thyroid Imaging Reporting and Data System

BACKGROUND

The American College of Radiology Thyroid Imaging Reporting and Data System for ultrasound classification of malignancy risk was developed to better triage thyroid nodules for fine-needle aspiration biopsy. To examine further, we compared thyroid cytologic classification rates in nodules before and after institutional Thyroid Imaging Reporting and Data System implementation.

METHODS

Cytology diagnoses by Bethesda criteria (categories I-VI) from January 2014 to October 2021 were retrieved; observed changes in yearly category frequency were analyzed by linear regression; and pooled cohorts of pre- (2014-2018) and post-Thyroid Imaging Reporting and Data System (2019-2021) cytology call rates were compared.

RESULTS

Overall, 7,413 cytologic specimens were included (range/year 715-1,444). From 2014 to 2021, the proportion of benign (Bethesda category II) diagnosis per year declined stepwise from 49.7% to 19.4%, and atypia of undetermined significance/follicular lesion of undetermined significance (Bethesda category III) increased sequentially from 21.3% to 51.5%. Between 2014 and 2021, Bethesda category III diagnosis increased on average by 4.8% per year (95% confidence internal, 3.29-5.54; P < .001) and Bethesda category II results decreased on average by 4.4% per year (95% confidence interval, 6.29-3.42; P < .001). When comparing pre- and post-Thyroid Imaging Reporting and Data System, the proportion of Bethesda category II cytology results decreased (43.1% vs 21%; P = .001) while Bethesda category III (28.3% vs 47.7%; P = .002) and Bethesda category V (1.1% vs 1.7%; P = .015) results increased.

CONCLUSION

After implementation of American College of Radiology Thyroid Imaging Reporting and Data System ultrasound criteria, we observed a 2.5-fold decline in the rate of benign cytology and an increase in the proportion of atypia of undetermined significance/follicular lesion of undetermined significance results.

SFE-AFCE-SFMN 2022 Consensus on the management of thyroid nodules: Initial work-up for thyroid nodules

The SFE-AFCE-SFMN 2022 consensus deals with the management of thyroid nodules, a condition that is a frequent reason for consultation in endocrinology. In more than 90% of cases, patients are euthyroid, with benign non-progressive nodules that do not warrant specific treatment. The clinician's objective is to detect malignant thyroid nodules at risk of recurrence and death, toxic nodules responsible for hyperthyroidism or compressive nodules warranting treatment. The diagnosis and treatment of thyroid nodules requires close collaboration between endocrinologists, nuclear medicine physicians and surgeons, but also involves other specialists. Therefore, this consensus statement was established jointly by 3 societies: the French Society of Endocrinology (SFE), French Association of Endocrine Surgery (AFCE) and French Society of Nuclear Medicine (SFMN); the various working groups included experts from other specialties (pathologists, radiologists, pediatricians, biologists, etc.). This section deals with the initial work-up for thyroid nodules in adult patients, including clinical and biological evaluation, standardized ultrasound characterization and EU-TIRADS-based nodule selection for fine-needle aspiration biopsy. Indications for thyroid core-biopsies or open surgical biopsies and for cross-sectional imaging of the neck and upper chest are also mentioned.

Risk of malignancy in thyroid nodules with indeterminate (THY3f) cytology

BACKGROUND

Fine-needle aspiration cytology (FNAC) is an integral part of thyroid nodule assessment. Nodules with an indeterminate cytology (THY3a-f) require formal histological assessment to confirm benign or malignant pathology. This study aimed to provide data for an evidence-based approach for management of patients with THY3f nodules.

METHODS

Retrospective review of patients who had a thyroid FNAC reported as suspicious of follicular neoplasm (THY3f) or showing atypia (THY3a) were identified, and clinical, operative and outcomes data were analysed.

RESULTS

Between 2018 and 2020, 200 patients (167F:33M, median age 51 years (range:18-86 years)) had a THY3f cytology. Most presented with a palpable nodule (n=104; 68.4%). Overall, 152 (76.0%;130F:23M) underwent surgery and 31 (20.4%) were found to have a thyroid carcinoma (22 follicular carcinomas, 7 papillary carcinomas, 1 medullary thyroid carcinoma and 1 metastatic renal carcinoma). An additional incidental carcinoma (size: 0.7-13mm) was found in seven (4.6%). Among those with cancer, a completion thyroidectomy and radioactive iodine treatment was indicated in nine (<6% of the entire cohort). Previously suggested risk factors for malignancy, eg male gender, large tumour size (>4cm) or age, were not found to be associated with increased risk. During the same period, THY3a cytology was reported in 53 patients, of whom 29 underwent diagnostic surgery and 4 patients were found to have a thyroid cancer (follicular, n=3 and medullary, n=1).

CONCLUSION

One in five patients with features suspicious of a follicular neoplasm (THY3f) has a thyroid carcinoma. This risk is much lower for THY3a. This study reinforces the current recommendation for thyroid surgery in all patients with a reliable THY3f cytology, as no further stratifying risk factors could be identified.

Functional and molecular thyroid imaging

Nuclear medicine methods were introduced in the 1940s for thyroid disease diagnosis and therapy. They is still a crucial part of thyroid nodules work-up. Thyroid imaging with iodine or iodine-analog isotopes is widely employed in patients with thyrotoxicosis and remains the only examination able to prove the presence of autonomously functioning thyroid tissue, which excludes malignancy with a high probability. In addition, technetium-99m-methoxyisobutylisonitrile ([^99mTc]Tc-MIBI) scintigraphy and positron emission tomography/computed tomography (PET/CT) with ¹⁸F-fluoro-2-deoxy-d-glucose ([¹⁸F]FDG) are able to avoid unnecessary surgical procedures for cytologically inconclusive thyroid nodules, as confirmed by meta-analysis and cost-effectiveness studies. All considered thyroid molecular imaging allows functional characterization of different thyroid diseases, even before clinical symptoms become manifest, and remains integral to the management of such conditions. This paper summarizes main concepts of thyroid scintigraphy and its clinical use. In addition, it elaborates development of thyroid scintigraphy, as well as thyroid molecular imaging in patients with thyroid nodules and thyrotoxicosis.

Thyroid functional and molecular imaging

Radioiodine uptake (RAIU) test with iodine-123 (Na[¹²³I]I) or iodine-131 (Na[¹³¹I]I) enables accurate evaluation and quantification of iodine uptake and kinetics within thyroid cells. Thyroid Scintigraphy (TS) employing Na[¹²³I]I or ^99mTc-pertechnetate (Na[^99mTc]TcO₄) provides information regarding the function and topographical distribution of thyroid cells activity, including detection and localization of ectopic thyroid tissue. Destructive thyrotoxicosis is characterized by low RAIU with scintigraphically reduced radiotracer activity in the thyroid tissue, while productive thyrotoxicosis (i.e. hyperthyroidism "stricto sensu") is characterized by high RAIU with scintigraphically diffuse (i.e. Graves' Disease, GD and diffuse thyroid autonomy) or focal (i.e. autonomously functioning thyroid nodules, AFTN) overactivity. Accordingly, RAIU and/or TS are widely used to differentiate different causes of thyrotoxicosis. In addition, several radiopharmaceuticals are also available to help differentiate benign from malignant thyroid nodules and inform clinical decision-making: scintigraphic identification of AFTNs obviate fine-needle aspiration (FNA) biopsy, and [^99mTc]Tc-hexakis-(2‑methoxy-2-isobutyl isonitrile ([^99mTc]Tc-MIBI) and/or ¹⁸F-fluoro-d-glucose ([¹⁸F]FDG) may complement the work-up of cytologically indeterminate "cold" nodules for reducing the need for diagnostic lobectomies/thyroidectomies. Finally, RAIU studies are also useful for calculating the administered therapeutic activity of Na[¹³¹I]I to treat hyperthyroidism and euthyroid multinodular goiter. All considered, thyroid molecular imaging allows functional characterization of different thyroid diseases, even before clinical symptoms become manifest, and remains integral to the management of such conditions. Our present paper summarizes basic concepts, clinical applications, and potential developments of thyroid molecular imaging in patients affected by thyrotoxicosis and thyroid nodules.

US-Elastography With Different Techniques for Thyroid Nodule Characterization: Systematic Review and Meta-analysis

Background

Thyroid nodules are frequent in adult population and thyroid cancer incidence has increased dramatically over the past three decades. The aim of this systematic review and meta-analysis was to evaluate the US-Elastosonography (USE) diagnostic performance in assessing the thyroid nodules malignancy risk.

Methods

PubMed and Embase databases were searched from January 2011 to July 2021. We extracted data from selected studies and calculated the overall diagnostic accuracy of qualitative USE, semi-quantitative USE and quantitative USE. Summary receiver operating characteristic (ROC) curve was elaborated to show the results. All statistical tests were performed using Metadisc and Medcal software package.

Results

Finally 72 studies with 13,505 patients and 14,015 thyroid nodules (33% malignant) undergoing elastography were included. The pooled sensitivity, specificity and AUC were 84%, 81%, and 0.89 respectively for qualitative USE; 83%, 80%, and 0.93 for semi-quantitative USE and 78%, 81% and 0.87, for quantitative USE. The qualitative and semiquantitative USE present very similar diagnostic accuracy values and both better than the quantitative USE.

Conclusions

USE is a useful imaging tool for thyroid nodule characterization. In accordance with recent guidelines and meta-analyses, the USE could be used daily in thyroid nodule malignancy risk stratification.

Systematic Review Registration

PROSPERO: CRD42021279257.

Long-term efficacy and safety of percutaneous ethanol injection (PEI) in cystic thyroid nodules: A systematic review and meta-analysis

BACKGROUND

Percutaneous ethanol injection (PEI) is used for the treatment of benign cystic thyroid nodules. This systematic review and meta-analysis aimed to obtain strong evidence of its long-term efficacy and safety.

METHODS

PubMed, CENTRAL, Scopus and Web of Science databases were searched until November 2020 for studies reporting data on volume reduction rate (VRR), compressive symptoms and cosmetic concerns. Associated complications were assessed. A random-effects model was designed to pool the data.

RESULTS

Out of 385 papers, nine studies evaluating 1667 nodules were finally included. Overall, VRR at 6, 12, 24, 36, 60 and 120 months was 77%, 81%, 72%, 68%, 74% and 69%, respectively. Significant reductions in the compressive symptoms and cosmetic concerns were observed. No permanent complications were observed.

CONCLUSIONS

The present meta-analysis showed that PEI could significantly reduce the volume of benign cystic thyroid nodules. This reduction was already effective at 6 months post-treatment, and the effect was stable over time.

Risk Stratification of Thyroid Nodules: From Ultrasound Features to TIRADS

Simple Summary

Thyroid nodules are a frequent clinical issue. Their incidence has increased mainly due to the widespread use of neck ultrasound scans. Most thyroid nodules are asymptomatic, incidentally discovered, and benign at cytology. Thyroid ultrasound is the most sensitive diagnostic tool to evaluate patients with nodular thyroid disease. It is therefore important to use the ultrasound features to select nodules that require a fine-needle aspiration cytology.

Abstract

Thyroid nodules are common in iodine deficient areas, in females, and in patients undergoing neck irradiation. High-resolution ultrasonography (US) is important for detecting and evaluating thyroid nodules. US is used to determine the size and features of thyroid nodules, as well as the presence of neck lymph node metastasis. It also facilitates guided fine-needle aspiration (US-FNA). The most consistent US malignancy features of thyroid nodules are spiculated margins, microcalcifications, a taller-than-wide shape, and marked hypoechogenicity. Increased nodular vascularization is not identified as a predictor of malignancy. Thyroid elastosonography (USE) is also used to characterize thyroid nodules. In fact, a low elasticity of nodules at USE has been related to a higher risk of malignancy. According to their US features, thyroid nodules can be stratified into three categories: low-, intermediate-, and high-risk nodules. US-FNA is suggested for intermediate and high-risk nodules.

Accuracy of Ultrasound Diagnosis of Benign and Malignant Thyroid Nodules: A Systematic Review and Meta-Analysis

BACKGROUND

Distinguishing between benign and malignant thyroid nodules remains difficult. Ultrasound has been established as a non-invasive and relatively simple imaging technique for thyroid nodules. This study aimed to assess the diagnostic accuracy of conventional ultrasound and ultrasound elastography for the differentiation between benign and malignant thyroid nodules by meta-analyzing published studies.

METHODS

Literature was retrieved from the PubMed and Embase databases from inception to May 31, 2022. The literature was screened using inclusion and exclusion criteria. The Quality Assessment of Diagnostic Accuracy Studies (QUADAS2) scale was used to assess the quality of the included literature. Publication bias of the included studies was assessed by Deek's funnel plot. Heterogeneity tests were performed using Cochrane Q statistic and I² statistic.

RESULTS

Finally, 9 articles were included. The meta-analysis showed that the combined sensitivity and specificity of ultrasound for the diagnosis of thyroid nodules were 0.88 [95% CI (0.83-0.91)] and 0.86 [95% CI (0.79-0.90)], respectively. The area under the curve (AUC) of the summary receiver operating characteristic curve (SROC) was 0.92 [95% CI (0.90-0.94)]. There was no significant publication bias in this study. Discussion. Existing evidence shows that ultrasound has a certain accuracy in diagnosing benign and malignant thyroid nodules, providing a scientific basis for thyroid assessment and diagnosis.

Repeat thyroid FNAC: Inter-observer agreement among high- and low-volume centers in Naples metropolitan area and correlation with the EU-TIRADS

Our institution (University Hospital "L. Vanvitelli" - Naples, Italy) is a high-volume (HV) center in Naples metropolitan area and many patients are referred there to repeat thyroid fine-needle aspiration cytology (FNAC) after initial FNAC performed in low-volume institutions (LV). The aims of the study were to 1) examine the inter-observer agreement between HV and LV institutions according to the Italian thyroid cytology system, and 2) explore how the discordant FNAC reports were distributed in the European Thyroid Imaging and Reporting Data System (EU-TIRADS) categories. All consecutive cases of repeat FNAC performed at University Hospital "L. Vanvitelli" from January 2016 to December 2021 were retrospectively reviewed. Fleiss' kappa (κ) was used to assess the inter-observer agreement, and categorical variables were compared by chi-square testing. P < 0.05 was considered statistically significant. A total of 124 nodules from 124 adults (mean age 49 years; mean maximum diameter 19 mm) were evaluated. Initial FNAC reports at LV were: 4 (3.2%) TIR1c, 64 (51.6%) TIR2, 48 (38.7%) TIR3A, 8 (6.5%) TIR3B, 0 TIR4, 0 TIR5. The overall FNAC reports were significantly different between the LV and HV institutions. At repeated FNAC, cytological diagnosis was unchanged in 64 (51.6%) cases including TIR2 and TIR3A results. A downgraded FNAC diagnosis (i.e., TIR2 vs TIR3A, TIR2 vs TIR3B) was observed in 36 (29%) nodules. An upgraded FNAC diagnosis (i.e., TIR3B vs TIR2, TIR3B vs TIR3A, TIR4 vs TIR3A, TIR5 vs TIR2, TIR5 vs TIR3B) was recorded in 24 (19.4%) nodules. The weighted inter-observer agreement between LV and HV institutions was poor (κ=0.133). Changed FNAC results were significantly (p=0.0023) more frequent in nodules at intermediate/high-risk (i.e., EU-TIRADS 4/5) than in those at no/low risk (EU-TIRADS 2/3) [i.e., 32/48 (66.7%) and 28/76 (36.8%), respectively]. Downgraded FNAC results were significantly more frequent in EU-TIRADS 2/3 (p=0.001) while upgraded FNAC were present only in EU-TIRADS 4/5 (24/24, 100.0%). The inter-observer agreement among LV and HV thyroid services was poor. The EU-TIRADS 4 and 5 categories included all the malignant nodules with FNAC results reclassified as higher risk (i.e., TIR3B-TIR4-TIR5) by the high-volume cytology service.

Evaluation of the efficacy of EU-TIRADS and ACR-TIRADS in risk stratification of pediatric patients with thyroid nodules

BACKGROUND

Pediatric thyroid nodules have a lower prevalence but a higher rate of malignancy (ROM) than those in adults. Ultrasound features suspected of malignancy lead to fine needle aspiration biopsy (FNAB) and subsequent cytological determination, upon which management is decided. Based on the characteristics of ultrasound, to standardize clinician decisions and avoid unnecessary FNAB, the European Thyroid Association and the American Radiology College have established guidelines for Thyroid Imaging, Reporting and Data System (EU-TIRADS and ACR-TIRADS) for ROM stratification of thyroid nodules. The aim of this study is to evaluate the diagnostic performance of ACR-TIRADS and EU-TIRADS in pediatric age.

MATERIALS AND METHODS

Subjects younger than 18 years of age with thyroid nodules greater than 0.5 cm observed in the 2000-2020 period were included.

RESULTS

Data from 200 subjects were collected. The overall ROM was 13%, rising to 26% if nodules with a diameter >1 cm were considered. Patients with a malignant nodule were more likely to have a higher EU-TIRADS score (p=0.03). Missed cancer diagnoses were 26.9%. Using the EU-TIRADS system, 40% of FNABs could have been avoided, while this scoring system would have resulted in FNAB being performed in 12% of cases where the assessment of ultrasound features would not recommend FNAB. Sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) were 73.1%, 57.1%, 73.1%, and 50%, respectively. Even considering the ACR-TIRADS, a higher score correlated with a higher ROM (p<0.001). This system missed 6 diagnoses of cancer (23.1%). Using the ACR-TIRADS system, 45.3% of FNABs could have been avoided, while FNAB should have been performed in 12% of cases where it was not recommended by ultrasound characteristics. Sensitivity, specificity, PPV and NPV were 76.9%, 50%, 76.9%, and 42.9%, respectively.

CONCLUSION

The present study confirms the correspondence of the EU-TIRADS and ACR-TIRADS categories with respect to malignancy but indicates not entirely satisfactory performance compared to FNAB alone. However, the use of the two TIRADS systems should be encouraged in multicentre studies to increase their performance and establish paediatric-specific points in the scoring criteria.

Rare Metastasis of Gastric Cancer to the Thyroid Gland: A Case Report and Review of Literature

Background: It is common for patients with gastric cancer to develop distant metastases in the liver, lung, bone, and brain. Although the thyroid also has an abundant blood supply, gastric cancer metastasis to the thyroid is uncommon. Due to the rarity of such metastasis, its clinical features are not well understood. Here, we present the case of a patient with gastric cancer metastasis to the thyroid treated at our hospital.

Case Summary: We report the case of a 63-year-old female with a mass in the anterior neck and mild hoarseness for 6 months. The patient underwent proximal subtotal gastrectomy for Siewert III oesophagogastric junction cancer 6 years ago. Subsequently, she received 8 cycles of adjuvant chemotherapy. Her condition was stable until mild hoarseness developed for no apparent reason 6 months prior to presenting at our clinic. Both ultrasonography and computed tomography confirmed a heterogeneous mass in the right lobe of the thyroid gland. Blood thyroid function tests and tumor marker expression levels were normal. Thyroid malignancy was suspected, and the patient underwent a right thyroidectomy. During the surgery, a tumor was found that had invaded the right recurrent laryngeal nerve and trachea. H&E staining and immunohistochemistry results suggested that the cancer cells originated from gastric cancer. The patient was diagnosed with thyroid metastasis of gastric cancer. She refused further treatment and died within 6 months.

Conclusion: Metastasis of gastric cancer to the thyroid is rare and is associated with a poor prognosis. Immunohistochemical diagnosis is essential for a conclusive diagnosis. For patients with a history of malignant tumors, the possibility of metastatic thyroid nodules should be ruled out when diagnosing thyroid nodules.

The New Era of TIRADSs to Stratify the Risk of Malignancy of Thyroid Nodules: Strengths, Weaknesses and Pitfalls

Simple Summary

The aim of this review is to provide the reader with a comprehensive overview of thyroid imaging and reporting data systems used for thyroid nodules, so as to understand how nodules are scored with all existing systems. Both ultrasound based risk stratification systems and indications for fine-needle aspirations are described. Systems are compared by analyzing their strengths and weaknesses. Studies show satisfactory sensitivities and specificities for the diagnosis of malignancy for all systems, and none of them have shown a real significant advantage over the others in terms of raw diagnostic value. Interobserver agreement is also very similar for all systems, fairly adequate to robust. Dimensional cut-offs for fine-needle aspiration are quite similar and all RSSs seem to reduce effectively the number of unnecessary FNAs. Merging all existing systems in a common international one is desirable.

Abstract

Since 2009, thyroid imaging reporting and data systems (TI-RADS) have been playing an increasing role in the field of thyroid nodules (TN) imaging. Their common aims are to provide sonologists of varied medical specialties and clinicians with an ultrasound (US) based malignancy risk stratification score and to guide decision making of fine-needle aspiration (FNA). Schematically, all TI-RADSs scores can be classified as either pattern-based or point-based approaches. The main strengths of these systems are their ability (i) to homogenize US TN descriptions among operators, (ii) to facilitate and shorten communication on the malignancy risk of TN between sonologists and clinicians, (iii) to provide quantitative ranges of malignancy risk assessment with high sensitivity and negative predictive values, and (iv) to reduce the number of unnecessary FNAs. Their weaknesses are (i) the remaining inter-observer discrepancies and (ii) their insufficient sensitivity for the diagnosis of follicular cancers and follicular variant of papillary cancers. Most common pitfalls are degenerating shrinking nodules and confusion between individual and coalescent nodules. The benefits of all TI-RADSs far outweigh their shortcomings, explaining their rising use, but the necessity to improve and merge the different existing systems remains.

Thyroid Nodule Characterization: How to Assess the Malignancy Risk. Update of the Literature

Ultrasound (US) is the first imaging modality for thyroid parenchyma evaluation. In the last decades, the role of ultrasound has been improved with the introduction of new US software, such as contrast-enhanced ultrasound (CEUS) and US-elastography (USE). USE is nowadays recognized as an essential part of the multiparametric ultrasound (MPUS) examination, in particular for the indeterminate thyroid nodule with possible fine-needle aspiration cytology (FNAC) number reduction; even if further and larger studies are needed to validate it. More controversial is the role of CEUS in thyroid evaluation, due to its high variability in sensitivity and specificity. Semi-automatic US systems based on the computer-aided diagnosis (CAD) system are producing interesting results, especially as an aid to less experienced operators. New knowledge on the molecular mechanisms involved in thyroid cancer is allowing practitioners to identify new genomic thyroid markers that could reduce the number of "diagnostic" thyroidectomies. We have therefore drawn up an updated representation of the current evidence in the literature for thyroid nodule multiparametric ultrasound (MPUS) evaluation with particular regard to USE, the US CAD system and CEUS.

Molecular Imaging for Thyrotoxicosis and Thyroid Nodules

After exclusion of exogenous iodine overload, radioiodine uptake (RAIU) testing with ¹²³I or ¹³¹I enables the accurate evaluation and quantification of iodine uptake and kinetics within thyroid cells. In addition, scintigraphic evaluation with ¹²³I or ^99mTc-pertechnetate (^99mTc04-) provides the topographic distribution of thyroid cell activity and allows the detection and localization of ectopic thyroid tissue. Destructive thyrotoxicosis is characterized by abolished or reduced uptake whereas productive thyrotoxicosis (i.e., hyperthyroidism "sensu strictu") is characterized by high RAIU with scintigraphically diffuse (i.e., Graves disease and diffuse thyroid autonomy) or focal (i.e., autonomously functioning thyroid nodules [AFTN]) overactivity. Accordingly, RAIU or thyroid scintigraphy are widely used to differentiate different causes of thyrotoxicosis. In addition, several radiopharmaceuticals are also available to help in differentiating benign from malignant thyroid nodules and inform clinical decision making. In fact, AFTNs can be safely excluded from fine-needle aspiration biopsy while either ^99mTc-methoxyisobutylisonitrile (MIBI) and ¹⁸F-FDG may complement the work-up of cytologically indeterminate cold nodules and contribute to reducing the need for diagnostic lobectomies/thyroidectomies. Finally, RAIU studies are also useful for calculating the administered therapeutic activity of ¹³¹I to treat hyperthyroidism and euthyroid multinodular goiter. All considered, thyroid molecular imaging allows us to characterize molecular/functional aspects of different thyroid diseases, even before clinical symptoms become manifest and remains integral to properly managing such conditions. Our present paper summarizes basic concepts, clinical applications, and potential developments of thyroid molecular imaging in patients affected by thyrotoxicosis and thyroid nodules.

Ultrasound: The Extension of Our Hands to Improve the Management of Thyroid Patients

Ultrasonography (US) was introduced in the thyroid field in the 1980s to guide the biopsy of palpable, scintigraphically cold nodules [...].

Focal Thyroid Incidentalomas on 18F-FDG PET/CT: A Systematic Review and Meta-Analysis on Prevalence, Risk of Malignancy and Inconclusive Fine Needle Aspiration

BACKGROUND

The rising demand for ¹⁸F-fluorodeoxyglucose positron emission tomography with computed tomography (¹⁸F-FDG PET/CT) has led to an increase of thyroid incidentalomas. Current guidelines are restricted in giving options to tailor diagnostics and to suit the individual patient.

OBJECTIVES

We aimed at exploring the extent of potential overdiagnostics by performing a systematic review and meta-analysis of the literature on the prevalence, the risk of malignancy (ROM) and the risk of inconclusive FNAC (ROIF) of focal thyroid incidentalomas (FTI) on ¹⁸F-FDG PET/CT.

DATA SOURCES

A literature search in MEDLINE, Embase and Web of Science was performed to identify relevant studies.

STUDY SELECTION

Studies providing information on the prevalence and/or ROM of FTI on ¹⁸F-FDG PET/CT in patients with no prior history of thyroid disease were selected by two authors independently. Sixty-one studies met the inclusion criteria.

DATA ANALYSIS

A random effects meta-analysis on prevalence, ROM and ROIF with 95% confidence intervals (CIs) was performed. Heterogeneity and publication bias were tested. Risk of bias was assessed using the quality assessment of diagnostic accuracy studies (QUADAS-2) tool.

DATA SYNTHESIS

Fifty studies were suitable for prevalence analysis. In total, 12,943 FTI were identified in 640,616 patients. The pooled prevalence was 2.22% (95% CI = 1.90% - 2.54%, I² = 99%). 5151 FTI had cyto- or histopathology results available. The pooled ROM was 30.8% (95% CI = 28.1% - 33.4%, I² = 57%). 1308 (83%) of malignant nodules were papillary thyroid carcinoma (PTC). The pooled ROIF was 20.8% (95% CI = 13.7% - 27.9%, I² = 92%).

LIMITATIONS

The main limitations were the low to moderate methodological quality of the studies and the moderate to high heterogeneity of the results.

CONCLUSION

FTI are a common finding on ¹⁸F-FDG PET/CTs. Nodules are malignant in approximately one third of the cases, with the majority being PTC. Cytology results are non-diagnostic or indeterminate in one fifth of FNACs. These findings reveal the potential risk of overdiagnostics of FTI and emphasize that the workup of FTI should be performed within the context of the patient's disease and that guidelines should adopt this patient tailored approach.

Progression of incidence and estimate of net survival from papillary thyroid cancers diagnosed between 2008 and 2016 in France

BACKGROUND

After several decades of increasing incidence of papillary thyroid cancer (PTC), a change in this trend has been recently observed, particularly in the United States. This is attributed to the impact of new guidelines for the management of thyroid disease. The objective of this study was to describe the recent situation in France in terms of incidence and survival, taking account of tumor size.

METHODS

Data from the FRANCIM network cancer registries, covering around 25% of the French metropolitan population, were analyzed. Distribution according to tumor size was determined in terms of frequency, trends in incidence and spatial distribution for the period 2008-2016. Analysis of net survival considered gender, age and tumor size.

RESULTS

Cancers of size≤5mm were predominant in patients diagnosed between 55 and 74 years of age. Incidence of≤5mm tumors in women and of 5-10mm tumors in men began declining in the early 2010s. Incidence of 10-20mm and 20-40mm tumors in men increased significantly throughout the period 2008-2016. For both men and women, the incidence of the largest tumors (>40mm) also increased, but not significantly. The spatial distribution of incidence showed great heterogeneity. Net survival was generally high, although decreasing with age and tumor size.

CONCLUSION

The recent epidemiological situation in France is consistent with the hypothesis of recent progress in medical management of thyroid pathologies. Variations in incidence should be monitored for both small (<10mm) and larger tumors, and notably>40mm tumors. Net survival is generally high, although decreasing with age and tumor size.

S-Detect Software vs. EU-TIRADS Classification: A Dual-Center Validation of Diagnostic Performance in Differentiation of Thyroid Nodules

Computer-aided diagnosis (CAD) and other risk stratification systems may improve ultrasound image interpretation. This prospective study aimed to compare the diagnostic performance of CAD and the European Thyroid Imaging Reporting and Data System (EU-TIRADS) classification applied by physicians with S-Detect 2 software CAD based on Korean Thyroid Imaging Reporting and Data System (K-TIRADS) and combinations of both methods (MODELs 1 to 5). In all, 133 nodules from 88 patients referred to thyroidectomy with available histopathology or with unambiguous results of cytology were included. The S-Detect system, EU-TIRADS, and mixed MODELs 1–5 for the diagnosis of thyroid cancer showed a sensitivity of 89.4%, 90.9%, 84.9%, 95.5%, 93.9%, 78.9% and 93.9%; a specificity of 80.6%, 61.2%, 88.1%, 53.7%, 73.1%, 89.6% and 80.6%; a positive predictive value of 81.9%, 69.8%, 87.5%, 67%, 77.5%, 88.1% and 82.7%; a negative predictive value of 88.5%, 87.2%, 85.5%, 92.3%, 92.5%, 81.1% and 93.1%; and an accuracy of 85%, 75.9%, 86.5%, 74.4%, 83.5%, 84.2%, and 87.2%, respectively. Comparison showed superiority of the similar MODELs 1 and 5 over other mixed models as well as EU-TIRADS and S-Detect used alone (p-value < 0.05). S-Detect software is characterized with high sensitivity and good specificity, whereas EU-TIRADS has high sensitivity, but rather low specificity. The best diagnostic performance in malignant thyroid nodule (TN) risk stratification was obtained for the combined model of S-Detect (“possibly malignant” nodule) and simultaneously obtaining 4 or 5 points (MODEL 1) or exactly 5 points (MODEL 5) on the EU-TIRADS scale.