Comparison of Korean vs. American Thyroid Imaging Reporting and Data System in Malignancy Risk Assessment of Indeterminate Thyroid Nodules

Is the nodule location a predictive risk factor for cancer in AUS/FLUS thyroid nodules? A retrospective cohort study

BACKGROUND

Atypia of undetermined significance/follicular lesion of undetermined significance (AUS/FLUS) is a heterogeneous category of thyroid nodules with uncertain cytology and controversial management. This study aimed to assess the association between nodule location and malignancy risk and whether the location can be used as a predictive risk factor for cancer in AUS/FLUS nodules.

METHODS

A cohort of 102 patients (79 [77.5%] women, 23 [22.5%] men) was retrospectively analyzed. Only patients with a final histopathology of benign or well-differentiated thyroid cancer and an available nodule location were included. Sociodemographic, histopathological, and sonographic data were statistically evaluated and correlated.

RESULTS

Based on pathology findings, 54 (52.9%) and 48 (47.1%) nodules were benign and malignant, respectively. Most nodules were right-sided (54.9%). Considering the nodule location, 41.2% of nodules occupied the whole lobe, 20.6% only the lower pole, 15.7% only the upper pole, and 2.9% the isthmus. Cases with nodules occupying only the upper, middle, or lower pole showed significant associations with cancer risk (odds ratio, [95% confidence interval]: 2.6, [1.1-5.7]; 2.0, [1.0-4.7]; and 1.9, [1.0-3.9], respectively). Male sex and the presence of a peripheral halo were significantly associated with malignancy risk (3.3, [1.2-9.1], P = 0.014; and 2.7, [1.0-9.5], P = 0.049, respectively). Isthmic nodules had the highest malignancy level (66.7%).

CONCLUSIONS

Nodule location is a promising predictor of malignancy in AUS/FLUS nodules. Furthermore, isthmic nodules had the highest malignancy level, emphasizing the significance of careful evaluation of these nodules. Further large prospective studies are required to confirm these findings.

Comparison of diagnostic performance of two ultrasound risk stratification systems for thyroid nodules: a systematic review and meta-analysis

OBJECTIVES

To assume the ideal cut-off values and diagnostic performance of two thyroid imaging reporting and data systems published by the Korean Thyroid Association/Korean Society of Thyroid Radiology (Korean TI-RADS) and the American Thyroid Association (ATA TI-RADS).

METHODS

Eighteen studies with 25,422 patients from PubMed, SCOPUS, Embase, Web of Science, and Cochrane Library databases up to August 2022. True and false positive and negative values with characteristics were extracted.

RESULTS

The highest area under the receiver operating characteristic curve (AUC) was 0.893 and 0.887 for Korean and ATA TI-RADS. High suspicion was judged as the best cut-off value with the highest AUC based on optimal sensitivity and specificity. In determining the risk of malignant thyroid nodules, high suspicion in Korean and ATA TI-RADS showed sensitivity as 71.3% and 73.5%, specificity as 7.9% and 86.4%, diagnostic odds ratios as 20.0289 and 20.9076, AUC as 0.893 and 0.887. There was no significant difference when directly comparing the diagnostic accuracy of both TI-RADS.

CONCLUSION

The two risk stratification systems had good diagnostic performance with high AUC and no significant differences. The ideal cut-off can depend on the medical condition or thyroid nodules, because the changes of cut-off point may reciprocally alter sensitivity and specificity.

Diagnostic efficiency among Eu-/C-/ACR-TIRADS and S-Detect for thyroid nodules: a systematic review and network meta-analysis

Background

The performance in evaluating thyroid nodules on ultrasound varies across different risk stratification systems, leading to inconsistency and uncertainty regarding diagnostic sensitivity, specificity, and accuracy.

Objective

Comparing diagnostic performance of detecting thyroid cancer among distinct ultrasound risk stratification systems proposed in the last five years.

Evidence acquisition

Systematic search was conducted on PubMed, EMBASE, and Web of Science databases to find relevant research up to December 8, 2022, whose study contents contained elucidation of diagnostic performance of any one of the above ultrasound risk stratification systems (European Thyroid Imaging Reporting and Data System[Eu-TIRADS]; American College of Radiology TIRADS [ACR TIRADS]; Chinese version of TIRADS [C-TIRADS]; Computer-aided diagnosis system based on deep learning [S-Detect]). Based on golden diagnostic standard in histopathology and cytology, single meta-analysis was performed to obtain the optimal cut-off value for each system, and then network meta-analysis was conducted on the best risk stratification category in each system.

Evidence synthesis

This network meta-analysis included 88 studies with a total of 59,304 nodules. The most accurate risk category thresholds were TR5 for Eu-TIRADS, TR5 for ACR TIRADS, TR4b and above for C-TIRADS, and possible malignancy for S-Detect. At the best thresholds, sensitivity of these systems ranged from 68% to 82% and specificity ranged from 71% to 81%. It identified the highest sensitivity for C-TIRADS TR4b and the highest specificity for ACR TIRADS TR5. However, sensitivity for ACR TIRADS TR5 was the lowest. The diagnostic odds ratio (DOR) and area under curve (AUC) were ranked first in C-TIRADS.

Conclusion

Among four ultrasound risk stratification options, this systemic review preliminarily proved that C-TIRADS possessed favorable diagnostic performance for thyroid nodules.

Systematic review registration

https://www.crd.york.ac.uk/prospero, CRD42022382818.

Current controversies in the management of patients with indeterminate thyroid nodules

The management of cytologically indeterminate thyroid nodules remains debatable as their malignancy is difficult to establish. Most nodules have benign postoperative histology, but an accurate assessment of their proclivity for malignant transformation is crucial. Numerous studies have investigated the effects of various tools, including clinical, radiological, and cytological features, as well as biochemical and molecular markers, on the management of these heterogeneous nodules. Collectively, strategies aim to treat malignant nodules and avoid unnecessary surgery for asymptomatic benign nodules. Currently, no clear guidelines for the optimal management of cytologically indeterminate thyroid nodules exist to determine whether a conservative approach with long-term observation or surgical intervention should be selected. Thus, personalized approaches have been recommended. Large-scale multicenter prospective studies are needed to elucidate controversial issues. As this topic has not been comprehensively covered based on publications from the Gulf region, this review aims to shed light on remaining controversies.

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 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.

The impact of thyroid imaging reporting and data system on the management of Bethesda III thyroid nodules

Objectives

Atypia of undetermined significance (AUS) or follicular lesion of undetermined significance (FLUS) is a heterogeneous category of fine needle aspiration cytology (FNAC); the management of this condition remains controversial. The clinical significance of such patients relies on the exclusion of malignancy. In this study, we aimed to determine the validity of the American College of Radiology Thyroid Imaging Reporting and Data System (ACR TI-RADS) (2017) for predicting malignancy in this specific category of patients.

Methods

In this study, we analysed a cohort of patients from our previous retrospective study. This four-year retrospective cohort study included all cases undergoing surgery with a cytological diagnosis of AUS/FLUS. We enrolled 110 cases with documented final histopathological diagnoses and ultrasound examinations.

Results

The study included 83 females (75.5%) and 27 males (24.5%). The overall risk of malignancy (ROM) for AUS/FLUS thyroid nodules was 47.3%. The ROMs of TI-RADS 3 (TR3), TI-RADS 4 (TR4), and TI-RADS 5 (TR5) were 43.5%, 49.4% and 40%, respectively. There was no significant association between TI-RADS and final pathological analysis.

Conclusions

Repeated FNAC with initial AUS/FLUS nodules is crucial. Our findings showed that ACR TI-RADS did not contribute to the cancer risk stratification of AUS/FLUS nodules. A large prospective multi-institutional study is now required to determine the validity of ACR TI-RADS and whether other adjunct clinical, cytological, molecular, or biochemical tools could facilitate the management of patients with these heterogeneous nodules.