The KWAK TI-RADS and 2015 ATA guidelines for medullary thyroid carcinoma: Combined with cell block-assisted ultrasound-guided thyroid fine-needle aspiration

Diagnostic Performance of Six Ultrasound Risk Stratification Systems for Thyroid Nodules: A Systematic Review and Network Meta-Analysis

BACKGROUND. Risk stratification systems for evaluating thyroid nodules on ultrasound use varying approaches to classify levels of suspicion for malignancy, leading to variable performance. OBJECTIVE. The purpose of this study was to perform a network meta-analysis comparing six risk stratification systems used to evaluate thyroid nodules on ultrasound in terms of their diagnostic performance for the detection of thyroid cancer. EVIDENCE ACQUISITION. Five bibliometric databases were searched for studies published through August 31, 2022, that compared at least two of six ultrasound risk stratification systems (the American Association of Clinical Endocrinologists, American College of Endocrinology, and Associazione Medici Endocrinologi [AACE/ACE/AME] system; American College of Radiology Thyroid Imaging Reporting and Data System [ACR TI-RADS]; the American Thyroid Association [ATA] risk stratification system; European Thyroid Association Thyroid Imaging Reporting and Data System [EU-TIRADS]; the Korean Thyroid Imaging Reporting and Data System [K-TIRADS] endorsed by the Korean Thyroid Association and the Korean Society of Thyroid Radiology; and the Thyroid Imaging Reporting and Data System developed by Kwak et al. [Kwak TIRADS]) in terms of their diagnostic performance for the detection of thyroid cancer, with cytologic or histologic evaluation used as a reference standard. The studies' risk of bias was evaluated using the Newcastle-Ottawa Scale. A meta-analysis of each system was performed to identify the risk category threshold that had the highest accuracy as well as the highest sensitivity and specificity at this threshold. Network meta-analysis was used to perform hierarchic ranking and identify the systems having the highest sensitivities and specificities at each system's most accurate threshold. EVIDENCE SYNTHESIS. The analysis included 39 studies with 49,661 patients. All studies were of fair (n = 17) or good (n = 22) quality. The most accurate risk category thresholds were class 3 (high risk) for the AACE/ACE/AME system, TR5 (highly suspicious) for ACR TI-RADS, EU-TIRADS 5 (high risk) for EU-TIRADS, 4c (moderate concern but not classic for malignancy) for Kwak TIRADS, K-TIRADS 5 (high suspicion) for K-TIRADS, and high suspicion for the ATA system. At these thresholds, the systems had sensitivity of 64-77% and specificity of 82-90%. Network meta-analysis identified the highest sensitivity and highest specificity for ACR TI-RADS, followed by K-TIRADS. CONCLUSION. Of six risk stratification systems, ACR TI-RADS had the highest diagnostic performance for the detection of thyroid nodules on ultrasound. CLINICAL IMPACT. This network meta-analysis can inform decisions regarding implementation of the risk stratification systems and can aid future system updates.

Diagnostic Performance of Various Ultrasound Risk Stratification Systems for Benign and Malignant Thyroid Nodules: A Meta-Analysis

BACKGROUND

To evaluate the diagnostic performance of ultrasound risk-stratification systems for the discrimination of benign and malignant thyroid nodules and to determine the optimal cutoff values of individual risk-stratification systems.

METHODS

PubMed, Embase, SCOPUS, Web of Science, and Cochrane library databases were searched up to August 2022. Sensitivity and specificity data were collected along with the characteristics of each study related to ultrasound risk stratification systems.

RESULTS

Sixty-seven studies involving 76,512 thyroid nodules were included in this research. The sensitivity, specificity, diagnostic odds ratios, and area under the curves by K-TIRADS (4), ACR-TIRADS (TR5), ATA (high suspicion), EU-TIRADS (5), and Kwak-TIRADS (4b) for malignancy risk stratification of thyroid nodules were 92.5%, 63.5%, 69.8%, 70.6%, and 95.8%, respectively; 62.8%, 89.6%, 87.2%, 83.9%, and 63.8%, respectively; 20.7111, 16.8442, 15.7398, 12.2986, and 38.0578, respectively; and 0.792, 0.882, 0.859, 0.843, and 0.929, respectively.

CONCLUSION

All ultrasound-based risk-stratification systems had good diagnostic performance. Although this study determined the best cutoff values in individual risk-stratification systems based on statistical assessment, clinicians could adjust or alter cutoff values based on the clinical purpose of the ultrasound and the reciprocal changes in sensitivity and specificity.

Diagnostic efficiency of existing guidelines and the AI-SONIC™ artificial intelligence for ultrasound-based risk assessment of thyroid nodules

INTRODUCTION

The thyroid ultrasound guidelines include the American College of Radiology Thyroid Imaging Reporting and Data System, Chinese-Thyroid Imaging Reporting and Data System, Korean Society of Thyroid Radiology, European-Thyroid Imaging Reporting and Data System, American Thyroid Association, and American Association of Clinical Endocrinologists/American College of Endocrinology/Associazione Medici Endocrinologi guidelines. This study aimed to compare the efficiency of the six ultrasound guidelines vs. an artificial intelligence system (AI-SONICTM) in differentiating thyroid nodules, especially medullary thyroid carcinoma.

METHODS

This retrospective study included patients with medullary thyroid carcinoma, papillary thyroid carcinoma, or benign nodules who underwent nodule resection between May 2010 and April 2020 at one hospital. The diagnostic efficacy of the seven diagnostic tools was evaluated using the receiver operator characteristic curves.

RESULTS

Finally, 432 patients with 450 nodules were included for analysis. The American Association of Clinical Endocrinologists/American College of Endocrinology/Associazione Medici Endocrinologi guidelines had the best sensitivity (88.1%) and negative predictive value (78.6%) for differentiating papillary thyroid carcinoma or medullary thyroid carcinoma vs. benign nodules, while the Korean Society of Thyroid Radiology guidelines had the best specificity (85.6%) and positive predictive value (89.6%), and the American Thyroid Association guidelines had the best accuracy (83.7%). When assessing medullary thyroid carcinoma, the American Thyroid Association guidelines had the highest area under the curve (0.78), the American College of Radiology Thyroid Imaging Reporting and Data System guidelines had the best sensitivity (90.2%), and negative predictive value (91.8%), and AI-SONICTM had the best specificity (85.6%) and positive predictive value (67.5%). The Chinese-Thyroid Imaging Reporting and Data System guidelines had the best under the curve (0.86) in diagnosing malignant tumors vs. benign tumors, followed by the American Thyroid Association and Korean Society of Thyroid Radiology guidelines. The best positive likelihood ratios were achieved by the Korean Society of Thyroid Radiology guidelines and AI-SONICTM (both 5.37). The best negative likelihood ratio was achieved by the American Association of Clinical Endocrinologists/American College of Endocrinology/Associazione Medici Endocrinologi guidelines (0.17). The highest diagnostic odds ratio was achieved by the American Thyroid Association guidelines (24.78).

DISCUSSION

All six guidelines and the AI-SONICTM system had satisfactory value in differentiating benign vs. malignant thyroid nodules.

Diagnostic Performance of ACR and Kwak TI-RADS for Benign and Malignant Thyroid Nodules: An Update Systematic Review and Meta-Analysis

(1) Background: To determine the optimal cut-off values of two risk stratification systems to discriminate malignant thyroid nodules and to compare the diagnostic performance; (2) Methods: True and false positive and negative data were collected, and methodological quality was assessed for forty-six studies involving 39,085 patients; (3) Results: The highest area under the receiver operating characteristic (ROC) curve (AUC) of ACR and Kwak TI-RADS were 0.875 and 0.884. Based on the optimal sensitivity and specificity, the highest accuracy values of ROC curves or diagnostic odds ratios (DOR) were taken as the cut-off values for TR4 (moderate suspicious) and 4B. The sensitivity, specificity, DOR, and AUC by ACR (TR4) and Kwak TI-RADS (4B) for malignancy risk stratification of thyroid nodules were 94.3% and 96.4%; 52.2% and 53.7%; 17.5185 and 31.8051; 0.786 and 0.884, respectively. There were no significant differences in diagnostic accuracy in any of the direction comparisons of the two systems; (4) Conclusions: ACR and Kwak TI-RADS had good diagnostic performances (AUCs > 85%). Although we determined the best cut-off values in individual risk stratification systems based on statistical assessment, clinicians can adjust the optimal cut-off value according to the clinical purpose of the ultrasonography because raising or lowering cut-points leads to reciprocal changes in sensitivity and specificity.

Suboptimal accuracy of ultrasound and ultrasound-based risk stratification systems in detecting medullary thyroid carcinoma should not be overlooked. Findings from a systematic review with meta-analysis

OBJECTIVE

Ultrasound (US) is the pivotal procedure during the diagnostic work-up of thyroid nodule and several US-based risk stratification systems (RSSs) have been recently developed. Since the performance of RSSs in detecting medullary thyroid carcinoma (MTC) has been rarely investigated, the present systematic review aimed to achieve high evidence about (1) how MTC is classified according to RSSs; (2) if RSSs correctly classify MTC at high risk/suspicion, and (3) if MTC is classified as suspicious at US when RSSs are not used.

DESIGN

The review was performed according to MOOSE. The online search was performed by specific algorithm on January 2022. A random-effects model was used for statistical analysis.

RESULTS

Twenty-five papers were initially included and their risk of bias was generally low. According to ATA system, 65% of MTCs was assessed at high suspicion and 25% at intermediate suspicion. Considering all RSSs, a 54.8% of MTCs was put in a high-risk/suspicion category. Pooling data from studies without data of RSS the prevalence of ultrasonographically suspicious MTCs was 60%.

CONCLUSIONS

As conclusion, MTC presentation according to RSSs is partially known and it is classified in a high-risk/suspicion category of RSSs in just over a half of cases. This advises for further studies, ideally supported by international societies, to better define the US presentation of MTC.

Ultrasonographic features of cervical lymph node metastases from medullary thyroid cancer: a retrospective study

Background

To investigate sonographic features of cervical lymph node metastases from medullary thyroid cancer (LNM-MTC), as compared with lymph node metastases from papillary thyroid cancer (LNM-PTC).

Methods

A total of 42 MTC patients with 52 metastatic LNs and 222 PTC patients with 234 metastatic LNs who were confirmed by fine needle aspiration and post-operative pathology, were enrolled in this study. The clinical characteristics and sonographic features of LNs were compared between the two groups. Univariate analysis and multivariate logistic regression analysis were performed on the sonographic features of LNs, including short and long-axis diameter, long-axis diameter/short-axis, shape, border, hilum, echogenicity, calcifications, cystic change and vascularity pattern. The discriminating performance was assessed with the area under the receiver operating characteristic curve (AUC).

Results

The mean age of patients with LNM-MTC was older than that of patients with LNM-PTC (46.81 ± 13.05 vs 39.09 ± 12.05, P < 0.001). No differences were observed in gender, location, long-axis diameter/short-axis, shape, border, echogenicity, cystic change and vascularity pattern between LNM-MTC and LNM-PTC groups (P > 0.05, for all). However, long-axis and short-axis diameter, hilum and calcifications were statistically different between these two groups (P < 0.05, for all). The AUC of discriminate value between LNM-MTC and LNM-PTC was 0.808 (95% confidence interval 0.739–0.877).

Conclusion

Compared with LNM-PTC, LNM-MTC tended to have the sonographic characteristics of larger size, absence of hilum, and less calcifications, and awareness of these features might be helpful to in the diagnosis of LNM-MTC.

Clinical diagnostic value of American College of Radiology thyroid imaging report and data system in different kinds of thyroid nodules

BACKGROUND

To evaluate the diagnostic value of American College of Radiology (ACR) score and ACR Thyroid Imaging Report and Data System (TI-RADS) for benign nodules, medullary thyroid carcinoma (MTC) and papillary thyroid carcinoma (PTC) through comparing with Kwak TI-RADS.

METHODS

Five hundred nine patients diagnosed with PTC, MTC or benign thyroid nodules were included and classified into the benign thyroid nodules group (n = 264), the PTC group (n = 189) and the MTC group (n = 56). The area under the curve (AUC) values were analyzed and the receiver operator characteristic (ROC) curves were drawn to compare the diagnostic efficiencies of ACR score, ACR TI-RADS and KWAK TI-RADS on benign thyroid nodules, MTC and PTC.

RESULTS

The AUC values of ACR score, ACR TI-RADS and Kwak TI-RADS for distinguishing malignant nodules from benign nodules were 0.914 (95%CI: 0.886-0.937), 0.871 (95%CI: 0.839-0.899) and 0.885 (95%CI: 0.854-0.911), respectively. In distinguishing of patients with MTC from PTC, the AUC values of ACR score, ACR TI-RADS and Kwak TI-RADS were 0.650 (95%CI: 0.565-0.734), 0.596 (95%CI: 0.527-0.664), and 0.613 (95%CI: 0.545-0.681), respectively. The AUC values of ACR score, ACR TI-RADS and Kwak TI-RADS for the discrimination of patients with MTC, PTC or benign nodules from patients without MTC, PTC or benign nodules were 0.899 (95%CI: 0.882-0.915), 0.865 (95%CI: 0.846-0.885), and 0.873 (95%CI: 0.854-0.893), respectively.

CONCLUSION

The ACR score performed the best, followed ex aequo by the ACR and Kwak TI-RADS in discriminating patients with malignant nodules from benign nodules and patients with MTC from PTC.

Exploring the Performance of Ultrasound Risk Stratification Systems in Thyroid Nodules of Pediatric Patients

Neck ultrasound (nUS) is the cornerstone of clinical management of thyroid nodules in pediatric patients, as well as adults. The current study was carried out to explore and compare the diagnostic performance of the main US-based risk stratification systems (RSSs) (i.e., the American College of Radiology (ACR), European (EU), Korean (K) TI-RADSs and ATA US RSS criteria) for detecting malignant thyroid lesions in pediatric patients. We conducted a retrospective analysis of consecutive children and adolescents who received a diagnosis of thyroid nodule. We included subjects with age <19 years having thyroid nodules with benign cytology/histology or final histological diagnosis. We excluded subjects with (a) a previous malignancy, (b) a history of radiation exposure, (c) cancer genetic susceptibility syndromes, (d) lymph nodes suspicious for metastases of thyroid cancer at nUS, (e) a family history of thyroid cancer, or (f) cytologically indeterminate nodules without histology and nodules with inadequate cytology. We included 41 nodules in 36 patients with median age 15 years (11-17 years). Of the 41 thyroid nodules, 29 (70.7%) were benign and 12 (29.3%) were malignant. For both ACR TI-RADS and EU-TIRADS, we found a sensitivity of 41.7%. Instead, for both K-TIRADS and ATA US RSS, we found a sensitivity of 50%. The missed malignancy rate for ACR-TIRADS and EU-TIRADS was 58.3%, while that for K-TIRADS and ATA US RSS was 50%. The unnecessary FNA prevalence for ACR TI-RADS and EU-TIRADS was 58.3%, while that for K-TIRADS and ATA US RSS was 76%. Our findings suggest that the four US-based RSSs (i.e., ACR-TIRADS, EU-TIRADS, K-TIRADS, and ATA US RSS) have suboptimal performance in managing pediatric patients with thyroid nodules, with one-half of cancers without indication for FNA according to their recommendations.

Assessment of perinodular stiffness in differentiating malignant from benign thyroid nodules

OBJECTIVE

We evaluated the diagnostic accuracy of perinodular stiffness, four risk stratification systems (RSSs) (KWAK-TIRADS, ACR-TIRADS, EU-TIRADS, and C-TIRADS), and the combination of perinodular stiffness and the four RSSs in differentiating malignant from benign thyroid nodules (TNs).

METHODS

A total of 788 TNs in 726 patients were examined with conventional ultrasound (US) examination and sound touch elastography (STE). All TNs were classified by each of the four RSSs. The stiffness inside (E) the TNs was measured by STE. The stiffness of the 2.0-mm perinodular region (Eshell) was measured with the Shell measurement function of STE. The diagnostic performances of four RSSs, the E values, and the Eshell values were evaluated. All TNs were further divided into subgroups based on size (≤ 10 mm group and > 10 mm group).

RESULTS

Ninety-six TNs were classified as benign and 692 as malignant. Among the single-method approaches, ACR-TIRADS showed the highest AUC (0.77) for differentiating malignant from benign TNs for all TNs included. Eshell showed the highest AUC (0.75) in differentiating malignant from benign TNs for TNs with sizes ≤ 10 mm, and there were no significant differences in AUC among all single methods for diagnosis of TNs with sizes > 10 mm (P > 0.05). The combination of C-TIRADS and Eshell/E yielded the highest AUC for all TNs (0.83) and for TNs with size ≤ 10 mm (0.85) compared with other combinations.

CONCLUSIONS

Eshell/E combined with conventional US improves the diagnostic accuracy in TNs and may reduce unnecessary fine-needle aspiration.

Architectural aspects of cell-blocks as small biopsies

Cell-block preparations have become an essential part of integrated cytology diagnosis. They are essentially microbiopsies that are formalin fixed and embedded in paraffin. This has become more prevalent with greater sample procurement due to the advent of newer biopsy techniques and needles. Cell-blocks allow retrieval of small tissue fragments from cytology specimens that sometimes cannot be processed by alternate cytologic techniques. They represent concentrated, cell-enriched preparations that provide cytologists with the opportunity to evaluate cellular architecture, as well as to perform ancillary testing. A cell-block compatible sample may thus obviate the need for a more invasive procedure such as a tissue biopsy. Microscopic examination of cell-blocks is quick, avoids obscuring material, permits cells to be evaluated in one focal plane, and allows the histologic architecture such as glandular differentiation, papillary formations, and sometimes invasion to be easily identified. This new era of “cytohistology” accordingly requires practicing cytologists to become more familiar with histopathology. This review article discusses the benefit of various architectural patterns identifiable in cell-blocks employed as an adjunct to Pap tests, exfoliative fluid specimens, and fine-needle aspirations.

EU-TIRADS-Based Omission of Fine-Needle Aspiration and Cytology from Thyroid Nodules Overlooks a Substantial Number of Follicular Thyroid Cancers

BACKGROUND

The classification of nodules by Thyroid Imaging Reporting and Data Systems (TIRADS) is important in guiding management. Whether sensitivity in identifying thyroid cancers varies with thyroid cancer phenotype remains unclarified.

METHODS

The ultrasound (US) characteristics of nodules of 26,908 nodular goiter patients were recorded. Fine-needle aspiration cytology (FNA) was performed in all nodules >1 cm irrespective of US findings (n = 25,025) and in nodules between 5 mm and 10 mm with suspicious US characteristics (n = 1,883). Of the 3281 operated cases, 221, 30, and 23 were papillary (PTC), follicular (FTC), and medullary (MTC) cancers, respectively. The US-based indication of FNA, as defined by EU-TIRADS scores, combined with lesion size, was calculated. This study design is unique in avoiding the common selection bias when TIRADS' sensitivity is tested in a cohort selected for FNA and surgery based on the same US characteristics on which TIRADS is based.

RESULTS

The EU-TIRADS score influences decision of FNA in the 10-20 mm range. In such nodules (n = 118), the number of suspicious features (marked hypoechogenicity, microcalcifications, irregular shape, and irregular border) per lesion was lower in FTC (0.7 ± 0.6) than in PTC (1.7 ± 1.0) or MTC (1.8 ± 0.7; p < 0.02), resulting in EU-TIRADS scores of 4.1 ± 0.6, 4.8 ± 0.3, and 4.9 ± 0.2, respectively (p < 0.01). The EU-TIRADS-based FNA indication rate was lower in FTC (55.5%) compared to PTC (85.0%) and MTC (88.9%) (p=0.02).

CONCLUSIONS

EU-TIRADS-defined suspicious US features are less common in FTC than in PTC and MTC. Therefore, a substantial number of FTCs in the 10-20 mm range escape surgery.

Cytologic diagnosis of medullary thyroid carcinoma in the Asia-Pacific region

BACKGROUND

The accurate preoperative identification of medullary thyroid carcinoma (MTC) is challenging due to the rarity of tumor and variable cytologic appearance. The Asian experience with diagnosing MTC by fine-needle aspiration (FNA) was scarcely reported.

METHODS

Cases of MTC with available FNA slides were enrolled from 13 hospitals representing 8 Asia-Pacific countries. Clinicopathological information, including sample preparation technique, staining method, original cytologic diagnosis and review diagnosis were collected.

RESULTS

Of a total of 145 MTC cases retrospectively recruited, 99 (68.3%) were initially interpreted as MTC/suspicious for MTC (S-MTC). The distribution of original FNA diagnostic categories was not associated with the staining method or sample preparation technique. The staining methods used were Papanicolaou, hematoxylin-eosin and Romanowsky stains. Liquid-based cytology (LBC) was used only in three countries. After reviewing all cases, the diagnostic rate of MTC/S-MTC increased to 91.7% (133/145). Cases with initially unrecognized MTC had either marked pleomorphism or cytology mimicking papillary carcinoma or follicular neoplasm. Although LBC provided certain benefits, there was no significant difference in diagnostic accuracy between conventional smear and LBC. Immunocytochemistry was available in 38 cases (26.2%), all of which were correctly recognized as MTC.

CONCLUSION

Our report summarizes how MTC is handled in contemporary Asian thyroid FNA practice. Although the detection rate of MTC by cytology alone is less satisfactory, integration with ancillary tests could achieve an excellent performance. The recognition of constitutive cytomorphologic features is needed for each cytopreparatory method, which may result in a lower threshold to initiate further workup for MTC.