Thyroid Nodule Molecular Testing: Is It Ready for Prime Time?

Performance of Thyroid Fine-Needle Aspiration Biopsy in a Low- and Middle-Income Country

INTRODUCTION

The 6 categories of the Bethesda System for Reporting Thyroid Cytology (TBSRTC) with associated risk of malignancy (ROM) provide evidence-based clinical management guidelines. This study aimed to determine the ROM and accuracy of FNAB in South Africa (SA).

METHODS

Thyroid specimens from 3 pathology laboratories registered between January 2015 and December 2019 were considered for inclusion. ROM was obtained per TBSRTC category by cytohistological correlation and dividing the total number of specimens with malignant histology by the total number of cases operated. Accuracy was calculated based on the Bethesda category and eventual malignant histology.

RESULTS

Seventeen thousand seven hundred and seventy-three histology and 4,791 cytology cases were identified. Of the 4,791 cytology cases, 931 (19%) underwent surgery. More than a third (333, 35.8%) of cases were confirmed as malignant following histological assessment, with the majority being benign (584, 62.7%). The ROM for the nondiagnostic and benign categories was 24.3% and 20.5%. The highest ROM was for category VI (91.5%), followed by categories V (69.5%), IV (51.9%), and III (38.8%). Thyroid FNAB had a sensitivity of 73%, specificity of 74%, and overall accuracy of 74%.

CONCLUSION

Bethesda categories II and IV have a relatively higher ROM in SA compared to findings from other developed countries. The diagnostic accuracy of thyroid FNAB in SA and the high rate of nondiagnostic diagnoses (38%) require further investigation. A national thyroid registry could provide location-specific data to aid the implementation of appropriate local policies and national guidelines for practicing thyroid surgeons.

Clinicopathological analysis of thyroid carcinomas with the RET and NTRK fusion genes: characterization for genetic analysis

Thyroid carcinomas exhibit various genetic alterations, including the RET and NTRK fusion genes that are targets for molecular therapies. Thus, detecting fusion genes is crucial for devising effective treatment plans. This study characterized the pathological findings associated with these genes to identify the specimens suitable for genetic analysis. Thyroid carcinoma cases positive for the fusion genes were analyzed using the Oncomine Dx Target Test. Clinicopathological data were collected and assessed. Among the 74 patients tested, 8 had RET and 1 had NTRK3 fusion gene. Specifically, of the RET fusion gene cases, 6 exhibited "BRAF-like" atypia and 2 showed "RAS-like" atypia, while the single case with an NTRK3 fusion gene presented "RAS-like" atypia. Apart from one poorly differentiated thyroid carcinoma, most cases involved papillary thyroid carcinomas (PTCs). Primary tumors showed varied structural patterns and exhibited a high proportion of non-papillary structures. Dysmorphic clear cells were frequently observed. BRAF V600E immunoreactivity was negative in all cases. Interestingly, some cases exhibited similarities to diffuse sclerosing variant of PTC characteristics. While calcification in lymph node metastases was mild, primary tumors typically required hydrochloric acid-based decalcification for tissue preparation. This study highlights the benefits of combining morphological and immunohistochemical analyses for gene detection and posits that lymph node metastases are more suitable for genetic analysis owing to their mild calcification. Our results emphasize the importance of accurate sample processing in diagnosing and treating thyroid carcinomas.

Assessment of the risk of malignancy in Bethesda III thyroid nodules: a comprehensive review

The increasing prevalence of thyroid cancer emphasizes the need for a thorough assessment of risk of malignancy in Bethesda III nodules. Various methods ranging commercial platforms of molecular genetic testing (including Afirma® GEC, Afirma® GSC, ThyroSeq® V3, RosettaGX®, ThyGeNEXT®/ThyraMIR®, ThyroidPRINT®) to radionuclide scans and ultrasonography have been investigated to provide a more nuanced comprehension of risk estimation. The integration of molecular studies and imaging techniques into clinical practice may provide clinicians with improved and personalized risk assessment. This integrated approach we feel may enable clinicians to carefully tailor interventions, thereby minimizing the likelihood of unnecessary thyroid surgeries and overall crafting the optimal treatment. By aligning with the evolving landscape of personalized healthcare, this comprehensive strategy ensures a patient-centric approach to thyroid nodule and thyroid cancer management.

Role of Genetic Testing in the Management of Indeterminate Thyroid Nodules in the Indian Setting

The increased detection of thyroid nodules in the human population has led to an increase in the number of thyroid surgeries without an improvement in survival outcomes. Though the choice for surgery is straightforward in malignant thyroid nodules, the decision is far more complex in those nodules that get categorized into indeterminate thyroid nodules (ITN) by fine needle aspiration. Therefore, there is a pressing need to develop a tool that will aid in decision-making among the ITN. In this context, the development of various molecular testing (MT) panels has helped to confirm or rule out malignancy, reducing unnecessary surgeries and potentially guiding the extent of surgery as well. Currently, such tests are widely used among the Western population but these MT panels are not used by the South Asian population because of non-availability of validated panels and the high cost involved. There is a need to develop a suitable panel which is population-specific and validate the same. In this review, we would focus on current trends in the management of ITN among the South Asian population and how to develop a novel MT panel which is cost-effective, with high diagnostic accuracy obviating the need for expensive panels that already exist.

Diagnostic Accuracy of the Bethesda System for Reporting Thyroid Cytopathology (TBSRTC): An Institution Experience

The Bethesda System for Reporting Thyroid Cytopathology (TBSRTC) is a standardized system which is used to classify results of thyroid fine-needle aspiration (FNA). This system is used to evaluate and determine which patients should get thyroid surgery. It was created in order to reduce the number of patients requiring surgery. The question remains as to whether this reporting system is accurate in determining those nodules that have malignant potential and those that do not. This study is a retrospective analysis of patients in one institution who have undergone FNA and then thyroid surgery based on TBSRTC. The outcome of the pathology reports after surgery was analyzed to determine the accuracy of TBSRTC in our institution (Lourdes Hospital, Binghamton, NY). The results from our institution were compared with similar studies in other institutions to determine accuracy and reproducibility. Our results indicated that the risk of malignancy in each Bethesda category was similar to the risk percentages described for most categories in the 2017 TBSRTC update.

Genetic Considerations in the Tumorigenesis, Diagnosis, and Treatment of Differentiated Thyroid Cancer: Current State of the Science

Thyroid nodules remain a common diagnosis encountered in general and endocrine surgical practice, and thyroid cancer appears to be increasing in incidence in both the United States and worldwide. The understanding of the complex genetics surrounding thyroid neoplasia has increased substantially in recent years and, consequently, has become a consideration in risk stratification, diagnosis, prognosis, and treatment. Molecular genetic analysis of thyroid nodules is now a readily available technology for diagnostic purposes via analysis of fine-needle aspiration biopsy (FNAB) specimens. Although their routine use is controversial, they may aid in selecting which patients require surgery and those who may be safely observed. In the following review, the genetics of the tumorigenesis of thyroid cancer are reviewed, focusing on the most common and clinically relevant of the literally hundreds of known mutations. Following this, the current status of the use of genetic analysis and molecular diagnostics in the workup of thyroid nodules and the diagnosis of differentiated thyroid cancer is explored. Finally, evolving concepts relating to the use of thyroid cancer genetics in individualizing treatment planning, follow-up, and management of recurrent disease is discussed. The goal is to provide the general surgeon with a working knowledge of the most common genetic alterations present in differentiated thyroid cancer, their relevance in clinical practice, and how they impact prognosis and treatment.

Molecular testing for indeterminate thyroid nodules: past, present, and future

PURPOSE OF REVIEW

To examine the origin, current progress, and future directions of molecular testing in indeterminate Bethesda III and Bethesda IV thyroid nodules.

RECENT FINDINGS

The diagnostic performance of current genomic tests shows improved benign call rates, specificity and positive-predictive values over prior test versions. The choice of test platform for clinical use should consider test performance, institutional rate of malignancy, nodule cytology and the potential for prognostication to help guide decision-making. Current challenges include test reliability, defining the optimal duration of surveillance, and improving test performance in challenging cytology, such as oncocytic nodules and NIFTP. Opportunities also remain to optimize cost-effectiveness across multiple clinical and practice settings and to refine the use of molecular testing for dynamic risk stratification, such as with BRAF V600E mutation testing.

SUMMARY

Molecular testing of indeterminate thyroid nodules has helped to reduce the burden of diagnostic surgery, associated healthcare costs, and potential complications. Current-generation tests have demonstrated improvement in diagnostic performance, but challenges remain in improving test performance and refining the scope of testing in care. Decision-making for the management of indeterminate thyroid nodules should consider cytology, clinical and sonographic features, patient values and preferences and molecular testing results, whenever available.

Pilot Study on the Use of Untargeted Metabolomic Fingerprinting of Liquid-Cytology Fluids as a Diagnostic Tool of Malignancy for Thyroid Nodules

Although it is the gold standard for assessing the malignancy of thyroid nodules (TNs) preoperatively, the cytological analysis of fine-needle aspiration cytology (FNAC) samples results in 20-30% of cases in indeterminate lesions (ITNs). As two-thirds of these lesions will appear benign after diagnostic surgery, improved preoperative diagnostic methods need to be developed. In this pilot study, we evaluate if the metabolomic profiles of liquid-based (CytoRich^®) FNAC samples of benign and malignant nodules can allow the molecular diagnosis of TNs. We performed untargeted metabolomic analyses with CytoRich^® FNAC in a monocentric retrospective study. The cohort was composed of cytologically benign TNs, histologically benign or papillary thyroid carcinomas (PTCs) cytologically ITNs, and suspicious/malignant TNs histologically confirmed as PTCs. The diagnostic performance of the identified metabolomic signature was assessed using several supervised classification methods. Seventy-eight patients were enrolled in the study. We identified 7690 peaks, of which 2697 ions were included for further analysis. We selected a metabolomic signature composed of the top 15 metabolites. Among all the supervised classification methods, the supervised autoencoder deep neural network exhibited the best performance, with an accuracy of 0.957 (0.842-1), an AUC of 0.945 (0.833-1), and an F1 score of 0.947 (0.842-1). Here, we report a promising new ancillary molecular technique to differentiate PTCs from benign TNs (including among ITNs) based on the metabolomic signature of FNAC sample fluids. Further studies with larger cohorts are now needed to identify a larger number of biomarkers and obtain more robust signatures.

Molecular Testing Results for Indeterminate Thyroid Nodules and Social Habits

INTRODUCTION

The effects of smoking and alcohol use on the risk of thyroid cancer remain unclear. We sought to investigate the association between these social habits, molecular testing results, and the risk of thyroid cancer.

METHODS

We conducted a retrospective chart review of patients with indeterminate thyroid nodules (Bethesda III and IV) who underwent molecular testing. The frequency of abnormal molecular testing results was compared among patients with varying smoking and alcohol consumption habits.

RESULTS

Of 460 patients, median age was 51.8 y, 78.3% were female, 60.7% were White, and 79.8% presented with Bethesda III nodules. The rate of malignancy was 42.6% overall; 73.4% of molecular testing was performed with Afirma, 20.1% with ThyroSeq, and 5.0% with ThyGeNEXT. For social habits, 72.2% never smoked and 40.9% never drank alcohol. Never/rare drinkers were less likely to have abnormal results compared to routine drinkers when considering all types of molecular testing together (83.2% versus 91.3%, P = 0.046), as were those who underwent ThyroSeq molecular testing (71.8% versus 94.4%, P = 0.045). Multivariable analysis revealed that being a routine drinker (adjusted OR 2.19, 95% CI 1.08-4.88), having a larger lesion (adjusted OR 0.65, 95% CI 0.54-0.77), being tested by ThyroSeq (adjusted OR 0.41, 95% CI 0.22-0.76), and other commercial panels (adjusted OR 0.12, 95% CI 0.02-0.64) were independent predictors of abnormal molecular testing results.

CONCLUSIONS

Our patients' social habits may be associated with the molecular testing results of their indeterminate thyroid nodules but not with their surgical pathology results.

Construction and validation of BRAF mutation diagnostic model based on ultrasound examination and clinical features of patients with thyroid nodules

Introduction: Fine Needle Aspiration (FNA) is currently the most popular method for identifying benign and malignant thyroid nodules. However, its diagnostic sensitivity is sometimes limited, which makes it necessary to apply genetic testing and other modalities as a secondary diagnostic method. The diagnostic accuracy of thyroid nodule can be improved by combining mutations in the B-Raf proto-oncogene serine/threonine kinase (BRAF) with FNA. Thus, this study was conducted to create a nomogram diagnostic model based on the clinical and ultrasonic characteristics of patients with BRAF mutations to aid in the identification of benign and malignant thyroid nodules using FNA.

Methods: From April 2018 to December 2021, 275 patients with thyroid nodules who underwent ultrasonography and BRAF gene testing (137 positive and 138 negative) were included from Xianyang Central Hospital. The clinical and ultrasonic characteristics of the patients were used to develop a nomographic, diagnostic model of BRAF gene mutation, and to validate and evaluate the usefulness of the model.

Results: Independent risk factors for BRAF mutations included: focal strong echogenicity (microcalcifications, OR = 3.04, 95%CI = 1.41–6.58, p = 0.005), hypoechogenicity (OR = 3.8, 95%CI = 1.14–12.61, p = 0.029), lymph node metastases (OR = 3.54, 95%CI = 1.43–8.75, p = 0.006), margin (lobulated, OR = 3.7, 95%CI = 1.66–8.23, p = 0.001; extrathyroidal invasion, OR = 2.81, 95%CI = 1.11–7.06, p = 0.029), and shape (vertical position, OR = 2.7, 95%CI = 1.11–6.59, p = 0.029). The area under the curve (AUC) of the receiver operating characteristic (ROC) curve of the BRAF mutation diagnostic model constructed on these factors was 0.806 (95% CI = 0.754–0.851), and 39.5% was set as the threshold probability of making a clinical decision. The results of the validation and clinical utility evaluation showed that our model had good predictive performance and clinical application value.

Conclusion: Our nomogram diagnostic model based on clinical and ultrasound features of patients accurately predicted the possibility of BRAF gene mutations in patients with thyroid nodules.

The Effect Modification of Ultrasound Risk Classification on Molecular Testing in Predicting the Risk of Malignancy in Cytologically Indeterminate Thyroid Nodules

Background: Thyroid nodules with indeterminate cytology are increasingly subjected to molecular testing. We evaluated the diagnostic performances of Afirma Genomic Sequencing Classifier (GSC) and ThyroSeq v3 in thyroid nodules with high versus low/intermediate suspicion ultrasound classification. Methods: In this prospective cohort study, we analyzed all Bethesda III and IV thyroid nodules that underwent fine-needle aspiration biopsies in the University of California Los Angeles Health System from July 2017 to April 2020. All patients underwent molecular testing with Afirma GSC or ThyroSeq v3 as part of an institutional randomized trial (NCT02681328). Nodules were categorized according to the American Thyroid Association (ATA) ultrasound risk classification. The benign call rate and the positive predictive value of molecular testing were compared between ATA high suspicion versus all other categories. Results: A total of 343 patients with 375 indeterminate thyroid nodules were included. The malignancy rate in ATA high suspicion nodules was not significantly increased by a suspicious Afirma GSC result (77.8% for all ATA high suspicion nodules vs. 87.5% for nodules with ATA high suspicion and suspicious Afirma GSC results, positive likelihood ratio [LR] = 2.0, 95% confidence interval [CI 0.5-8.0], p = 1.0) or by a positive ThyroSeq v3 result (80.0% vs. 80.0%, positive LR = 1.0 [CI 1.0-1.0], p = 1.0). The rate of malignancy in ATA low/intermediate suspicion nodules increased from 21.0% to 56.3% with a suspicious Afirma GSC result (positive LR = 4.8 [CI 3.4-6.9], p < 0.0001) and decreased to 3.8% with a benign Afirma GSC result (negative LR = 0.1 [CI 0.07-0.3], p < 0.0001). Similarly, the rate of malignancy in ATA low/intermediate suspicion nodules increased from 24.3% to 66.7% with a positive ThyroSeq v3 result (positive LR = 6.2 [CI 4.0-9.7], p < 0.0001) and decreased to 2.1% with a negative ThyroSeq v3 result (negative LR = 0.07 [CI 0.02-0.3], p < 0.0001). Conclusions: Afirma GSC and ThyroSeq v3 performed well in ruling out malignancy in sonographically low/intermediate suspicion thyroid nodules but has limited diagnostic value in sonographically high suspicion nodules. Molecular testing can prognosticate more aggressive thyroid cancers, which can inform treatment decisions.

Circulating microRNAs and Clinicopathological Findings of Papillary Thyroid Cancer: A Systematic Review

BACKGROUND/AIM

Papillary thyroid cancer (PTC) is the most common endocrine malignancy with a rising incidence. There is a need for a non-invasive preoperative test to enable better patient counselling. The aim of this systematic review was to investigate the potential role of circulating microRNAs (miRNAs) in the diagnosis and prognosis of PTC.

MATERIALS AND METHODS

A systematic literature search was performed using MEDLINE, Cochrane, and Scopus databases (last search date was December 1, 2021). Studies investigating the expression of miRNAs in the serum or plasma of patients with PTC were deemed eligible for inclusion.

RESULTS

Among the 1,533 screened studies, 39 studies met the inclusion criteria. In total, 108 miRNAs candidates were identified in the serum, plasma, or exosomes of patients suffering from PTC. Furthermore, association of circulating miRNAs with thyroid cancer-specific clinicopathological features, such as tumor size (13 miRNAs), location (3 miRNAs), extrathyroidal extension (9 miRNAs), pre- vs. postoperative period (31 miRNAs), lymph node metastasis (17 miRNAs), TNM stage (9 miRNAs), BRAF V600E mutation (6 miRNAs), serum thyroglobulin levels (2 miRNAs), ¹³¹I avid metastases (13 miRNAs), and tumor recurrence (2 miRNAs) was also depicted in this study.

CONCLUSION

MiRNAs provide a potentially promising role in the diagnosis and prognosis of PTC. There is a correlation between miRNA expression profiles and specific clinicopathological features of PTC. However, to enable their use in clinical practice, further clinical studies are required to validate the predictive value and utility of miRNAs as biomarkers.

Systematic Review and Meta-Analysis to Identify the Immunocytochemical Markers Effective in Delineating Benign from Malignant Thyroid Lesions in FNAC Samples

Conventional cytology-based diagnosis for thyroid cancer is limited with more than 30-45% of nodules categorized as indeterminate, necessitating surgery for confirming or refuting the diagnosis. This systematic review and meta-analysis were aimed at identifying immunocytochemical markers effective in delineating benign from malignant thyroid lesions in fine needle aspiration cytology (FNAC) samples, thereby improving the accuracy of cytology diagnosis. A systematic review of relevant articles (2000-2021) from online databases was carried out and the search protocol registered in PROSPERO database (CRD42021229121). The quality of studies was assessed using QUADAS-2. Review Manager 5.4.1 from Cochrane collaboration and MetaDisc Version 1.4 was used to conduct the meta-analysis. Bias in the studies were visually analyzed using funnel plots, and statistical significance was evaluated by Egger's test. Systematic review identified 64 original articles, while meta-analysis in eligible articles (n = 41) identified a panel of 5 markers, Galectin-3, HBME-1, CK-19, CD-56, and TPO. Assessment of the diagnostic performance revealed that Gal-3 (sensitivity: 0.81; CI: 0.79-0.83; specificity: 0.84; CI: 0.82-0.85) and HBME-1 (sensitivity: 0.83; Cl: 0.81-0.86; specificity: 0.85; CI: 0.83-0.86) showed high accuracy in delineating benign from malignant thyroid nodules. Efficacy analysis in indeterminate nodules showed Gal-3 and HBME-1 have high specificity of 0.86 (CI 0.84-0.89) and 0.82 (CI 0.78-0.86), respectively, and low sensitivity of 0.76 (CI 0.72-0.80) and 0.75 (CI 0.70-0.80), respectively. Diagnostic odds ratio (DOR) of Galectin-3 and HBME-1 were 39.18 (CI 23.38-65.65) and 24.44 (CI 11.16-53.54), respectively. Significant publication bias was observed for the markers Galectin-3 and CK-19 (p < 0.05). The panel of 5 markers identified from this meta-analysis are high-confidence candidates that need to be validated in thyroid cytology to establish their efficacy and enable clinical applicability.

Diagnostic performance of the second-generation molecular tests in the assessment of indeterminate thyroid nodules: A systematic review and meta-analysis

OBJECTIVE

The objective of this systematic review and meta-analysis was to evaluate the diagnostic performance of the second-generation molecular tests in the diagnosis of thyroid nodules with indeterminate fine-needle aspiration biopsy results.

METHODS

We searched PubMed, Google Scholar, Scopus, and Cochrane Library for studies published between January 2017 and March 2021. Inclusion criteria were indeterminate thyroid results from fine-needle aspiration (FNA) that included Bethesda categories III and IV, use of Afirma GSC, Thyroseq v3, and ThyGeNext as an index test, and conclusive histopathological results. Studies with no post-surgical diagnoses were excluded. For each included study, sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) were obtained. Sensitivity and specificity were pooled jointly using a bivariate binomial random-effects model. Statistical significance was indicated at p-value less than 0.05.

RESULTS

Our search yielded 431 non-duplicate articles, of which 15 were included in the study (7 GSC, 6 Thyroseq v3, and 2 ThyGeNext). ThyGeNext studies were excluded from the meta-analysis due to the small sample size. Pooled data for GSC studies on 472 thyroid nodules showed a sensitivity of 96.6 (95% confidence interval: 89.7-98.9%), specificity of 52.9% (23.4-80.5%), PPV of 63% (51-74%), and NPV of 96% (94-98%). Pooled data for ThyroSeq studies on 530 thyroid nodules showed a sensitivity of 95.1% (91.1-97.4%), specificity of 49.6% (29.3-70.1%), PPV of 70% (55-83%), and NPV of 92% (86-97%). There was no statistically significant difference in diagnostic performances of the two tests (p-values for sensitivity = 0.89, specificity = 0.82, PPV = 0.43, NPV = 0.17).

CONCLUSION

High sensitivity and high NPV in GSC and Thyroseq v3 have potential to help rule out malignancy among thyroid nodules with indeterminate cytology results. There was no difference in diagnostic performances between the two molecular tests indicating that either test is appropriate to determine the malignancy of thyroid nodules. Further long-term outcome data are warranted to make a clear recommendation.

PAPPA Expression in Indeterminate Thyroid Nodules as Screening Test to Select Patients for Molecular Testing

Pregnancy-associated plasma protein A (PAPPA) acts as an oncogene, and its expression is increased in multiple malignancies, including thyroid cancer. Molecular tests represent a useful tool in the management of indeterminate thyroid nodules; however, they are not conducted in all centers, and they contribute to increase the per-patient cost of nodule evaluation. In this study, we examined whether PAPPA expression could represent a promising new screening test in the management of indeterminate thyroid nodules. Toward this aim, PAPPA expression was evaluated in 107 fine needle aspiration cytologies (FNAC) belonging to Bethesda III–IV categories that had been sent to molecular biology to discriminate the nature of the nodules. We found that the PAPPA expression increased and showed an elevated sensitivity (97.14%) and negative predictive value (98%) in indeterminate cytological samples positive for mutations. The enhanced expression was not linked to a specific oncogene. Our findings demonstrated that assessing the PAPPA expression in indeterminate thyroid cytologies could represent a useful screening tool to select all patients that effectively need to be sent to molecular testing, thereby, leading to a potential cost reduction in the management of patients.

Fluorescence Polarization Imaging of Methylene Blue Facilitates Quantitative Detection of Thyroid Cancer in Single Cells

Simple Summary

Accurate diagnosis of thyroid fine-needle aspiration cytology is a significant clinical challenge. A method to detect thyroid cancer at the cellular level would be invaluable to reduce diagnostic uncertainty and improve clinical decision making. We studied the ability of confocal fluorescence polarization imaging of an exogenous fluorophore, methylene blue, to provide quantitative discrimination of cancerous cells in human samples. Our results indicate that fluorescence polarization imaging provides a reliable biomarker of thyroid cancer and holds the potential to shift the paradigm of cellular level cancer diagnosis from subjective visual assessment to objective measurement.

Abstract

Background: Diagnostic accuracy of the standard of care fine-needle aspiration cytology (FNAC) remains a significant problem in thyroid oncology. Therefore, a robust and accurate method for reducing uncertainty of cytopathological evaluation would be invaluable. Methods: In this double-blind study, we employed fluorescence emission and quantitative fluorescence polarization (Fpol) confocal imaging for sorting thyroid cells into benign/malignant categories. Samples were collected from malignant tumors, benign nodules, and normal thyroid epithelial tissues. Results: A total of 32 samples, including 12 from cytologically indeterminate categories, were stained using aqueous methylene blue (MB) solution, imaged, and analyzed. Fluorescence emission images yielded diagnostically relevant information on cytomorphology. Significantly higher MB Fpol was measured in thyroid cancer as compared to benign and normal cells. The results obtained from 12 indeterminate samples revealed that MB Fpol accurately differentiated benign and malignant thyroid nodules. Conclusions: The developed imaging approach holds the potential to provide an accurate and objective biomarker for thyroid cancer, improve diagnostic accuracy of cytopathology, and decrease the number of lobectomy and near-total thyroidectomy procedures.

The Risk Stratification of Papillary Thyroid Cancer With Bethesda Category III (Atypia of Undetermined Significance/Follicular Lesion of Undetermined Significance) by Thyroid Fine-Needle Aspiration Could Be Assisted by Tumor Size for Precision Treatment

PURPOSE

To investigate the clinical characteristics of papillary thyroid cancer (PTC) classified as Bethesda category III [atypia of undetermined significance (AUS)/follicular lesion of undetermined significance (FLUS)] by fine-needle aspiration (FNA) for precision treatment.

METHODS

A total of 1,739 patients diagnosed with Bethesda category III (AUS/FLUS) by FNA were investigated, and 290 patients diagnosed with PTC were analyzed.

RESULTS

The rate of papillary thyroid microcarcinoma (PTMC) was 82.1% (238/290). The rates of lymph node metastases were 44.9% (22/49) and 25.2% (56/222) for PTC and PTMC, respectively (p = 0.006). The rates of extra-thyroid extension were 46.2% (24/52) and 19.8% (47/237) (p < 0.001). Compared with PTMC, PTC had significantly higher odds ratios (ORs) of 3.41 (1.81-6.44, p < 0.001), 2.19 (1.16-4.13, p = 0.016), and 2.51 (1.29-4.88, p = 0.007) for extra-thyroid extension, multifocality, and lymph node metastases, respectively, after adjustment for age and gender. The larger size and BRAF V600E mutation had a robust synergistic effect for invasive features. The rates of lymph node metastases, multifocality, and extra-thyroid extension were significantly increased with larger sizes harboring BRAF V600E mutation. Compared with PTMC harboring wild type (WT)-BRAF, PTC harboring BRAF V600E mutation had adjusted higher ORs of 3.01 (1.26-8.68, p = 0.015), 3.20 (1.22-8.42, p = 0.018), and 5.62 (2.25-14.01, p < 0.001) for lymph node metastases, multifocality, and extra-thyroid extension, respectively.

CONCLUSIONS

In this study, risk stratification was recommended for patients with Bethesda category III (AUS/FLUS) nodules with a size under 1 cm harboring WT-BRAF being regarded as low risk and should be recommended for active surveillance. Nodules with a size over 1 cm harboring WT-BRAF or those under 1 cm harboring BRAF V600E mutation could be regarded as moderate risk, and molecular testing should be recommended. However, those with a size over 1 cm harboring BRAF V600E mutation should be regarded as high risk, and a diagnostic surgery should be recommended.

2021 Korean Thyroid Imaging Reporting and Data System and Imaging-Based Management of Thyroid Nodules: Korean Society of Thyroid Radiology Consensus Statement and Recommendations

Incidental thyroid nodules are commonly detected on ultrasonography (US). This has contributed to the rapidly rising incidence of low-risk papillary thyroid carcinoma over the last 20 years. The appropriate diagnosis and management of these patients is based on the risk factors related to the patients as well as the thyroid nodules. The Korean Society of Thyroid Radiology (KSThR) published consensus recommendations for US-based management of thyroid nodules in 2011 and revised them in 2016. These guidelines have been used as the standard guidelines in Korea. However, recent advances in the diagnosis and management of thyroid nodules have necessitated the revision of the original recommendations. The task force of the KSThR has revised the Korean Thyroid Imaging Reporting and Data System and recommendations for US lexicon, biopsy criteria, US criteria of extrathyroidal extension, optimal thyroid computed tomography protocol, and US follow-up of thyroid nodules before and after biopsy. The biopsy criteria were revised to reduce unnecessary biopsies for benign nodules while maintaining an appropriate sensitivity for the detection of malignant tumors in small (1-2 cm) thyroid nodules. The goal of these recommendations is to provide the optimal scientific evidence and expert opinion consensus regarding US-based diagnosis and management of thyroid nodules.

Outcome of atypia of undetermined significance/follicular lesion of undetermined significance in thyroid fine-needle aspirations: A six-year institutional experience

BACKGROUND

Atypia of undetermined significance/follicular lesion of undetermined significance (AUS/FLUS) is one of six diagnostic categories of The Bethesda System for Reporting Thyroid Cytopathology (BSRTC). The goal of our study is to assess the outcome of cases classified as AUS/FLUS at our institution.

METHODS

AUS/FLUS cases were identified by computer searching of the thyroid fine-needle aspiration (FNA) cases performed between 2010 and 2016. Outcomes were categorized as: follow-up surgery, repeat FNA or no follow-up available. Demographics, ultrasound findings and FNA diagnostic criteria were reviewed for AUS/FLUS cases with follow-up surgical pathology diagnosis.

RESULTS

Our AUS/FLUS thyroid FNA rate was 6% (117 out of 1984 FNAs). Only 15% of the AUS/FLUS cases had repeat FNA, while 41% underwent surgery. The risk of malignancy (ROM) for cases with follow-up surgery was 17%. When considering all AUS/FLUS cases, the ROM was 7%. Statistically, benign neoplasms were more likely to be single lesions on ultrasound comparing to malignant neoplasms, and to exhibit architectural atypia as opposed to non-neoplastic lesions on FNA. The malignancy rates among patients that directly went to surgical resection (17%) and patients having repeat FNA after the first AUS/FLUS diagnosis followed by surgery (29%) was not significantly different. However, repeat FNA was able to reclassify the majority of cases into more definitive categories.

CONCLUSION

The outcome of the thyroid FNAs diagnosed as AUS/FLUS in our institution meets the benchmark statistics for AUS/FLUS rate and ROM. This study constitutes a valuable quality assurance measure and serves as a baseline for subsequent quality improvement.

Atypical de Quervain's thyroiditis diagnosed as atypia of undetermined significance by cytology and suspicious for cancer by Afirma Genomic Sequencing Classifier

We report a case of atypical de Quervain's thyroiditis diagnosed as atypia of undetermined significance by cytology and suspicious for cancer by Afirma Genomic Sequencing Classifier. A 71-year-old male underwent thyroid ultrasound for goiter and was found to have two American Thyroid Association (ATA) 2015 high-suspicion nodules. The larger, 2.2-cm nodule was biopsied and the cytology showed atypical follicular cells and histiocytes. The Afirma Genomic Sequencing Classifier (detecting mRNA expression profile) result was ''suspicious'' (risk of malignancy ~50%) but Afirma Xpression Atlas (detecting specific mutations) did not find mutations in BRAF V600E, RET/PTC1, or RET/PTC3. The patient saw two endocrine surgeons and two endocrinologists who each recommended hemithyroidectomy. The patient chose to monitor the nodules. A new diagnostic ultrasound performed 3 months after the first one showed that the thyroid was significantly smaller and the previously seen nodules were no longer found. Re-examination of the cellular smears confirmed that the cytological findings were also compatible with de Quervain's thyroiditis. This case illustrates that atypical de Quervain's thyroiditis should be in the differential diagnosis of thyroid nodules for cytologists, radiologists, and clinicians. Furthermore, this case demonstrates that atypical de Quervain's thyroiditis can generate false positive results of molecular tests for indeterminate thyroid nodules.

Thyroid Nodule Evaluation and Management in Older Adults: A Review of Practical Considerations for Clinical Endocrinologists

OBJECTIVE

Contextualizing the evaluation of older adults with thyroid nodules is necessary to fully understand which management strategy is the most appropriate. Our goal was to summarize available clinical evidence to provide guidance in the care of older adults with thyroid nodules and highlight special considerations for thyroid nodule evaluation and management in this population.

METHODS

We conducted a literature search of PubMed and Ovid MEDLINE from January 2000 to November 2020 to identify relevant peer-reviewed articles published in English. References from the included articles as well as articles identified by the authors were also reviewed.

RESULTS

The prevalence of thyroid nodules increases with age. Although thyroid nodules in older adults have a lower risk of malignancy, identified cancers are more likely to be of high-risk histology. The goals of thyroid nodule evaluation and the tools used for diagnosis are similar for older and younger patients with thyroid nodules. However, limited evidence exists regarding thyroid nodule evaluation and management to guide personalized decision making in the geriatric population.

CONCLUSION

Considering patient context is significant in the diagnosis and management of thyroid nodules in older adults. When making management decisions in this population, it is essential to carefully weigh the risks and benefits of thyroid nodule diagnosis and treatment, in view of older adults' higher prevalence of high-risk thyroid cancer as well as increased risk for multimorbidity, functional and cognitive decline, and treatment complications.

Molecular analysis of fine-needle aspiration cytology in thyroid disease: where are we?

PURPOSE OF REVIEW

The prevalence of thyroid nodules in the general population is high but only about 5% are malignant lesions. Cytology is usually appropriate to rule out malignancy in sonographically suspicious nodules but in many cases, reports are indeterminate. Molecular testing is a more recent approach to rule out malignancy and guide subsequent management.

RECENT FINDINGS

Although several different molecular testing approaches have proven useful in reducing unnecessary surgery, there are still several remaining issues, such as the possible occurrence of RAS mutations (which are difficult to interpret in clinical management) and the role of molecular analysis in specific histotypes, such as Hürthle cell carcinomas. Furthermore, conclusive evidence is lacking regarding the cost-effectiveness and appropriateness of surgical options following molecular tests.

SUMMARY

To be useful in clinical practice, molecular tests should be applied to appropriate candidates. In truly uncertain thyroid nodules in which diagnostic surgery may be considered, molecular testing may change the clinical approach and 'save' a number of thyroids.