Histopathology of telomerase reverse transcriptase promoter (TERT) mutated indeterminate thyroid nodules

Objective

The objective of this study was to analyze the risk of malignancy and the histopathology of telomerase reverse transcriptase promoter (TERT) mutated cytologically indeterminate thyroid nodules (ITN).

Methods

A PUBMED search of molecularly tested ITN was conducted and data on TERT mutated ITN with histopathology correlation were extracted.

Results

Twenty-six manuscripts (published between 2014 and 2022) reported on 77 TERT mutated ITN. Sixty-five nodules were malignant (84 %), with 16 (25 %) described with high-risk histopathology, 5 (8 %) described as low-risk, and most without any description. Isolated TERT mutations were malignant in 26/30 ITNs (87 %) with 9 (35 %) described as high risk and none described as low risk. TERT + RAS mutated ITNs were malignant in 29/34 ITNs (85 %) with 3 (10 %) described as high risk and 4 (14 %) described as low risk. Finally, all 5 TERT + BRAFV600E mutated nodules were malignant and 3/5 (60 %) were described as high risk.

Conclusion

TERT mutated ITNs have a high risk of malignancy (84 %), and the current data does not show a difference in malignancy rate between isolated TERT mutations and TERT + RAS co-mutated ITNs. When described, TERT + RAS co-mutated ITNs did not have a higher rate of high-risk histopathology as compared to isolated TERT mutated lesions. Most TERT mutated ITNs did not have a description of histopathology risk and the oncologic outcomes, including rate of recurrence, metastases, and disease specific survival, are unknown. Further data is needed to determine if TERT mutated ITNs should be subjected to aggressive initial treatment.

Improving the TIR3B oncological stratification: try to bridge the gap through a comprehensive presurgical algorithm

PURPOSE

Indeterminate cytology still puzzles clinicians, due to its wide range of oncological risks. According to the Italian SIAPEC-IAP classification, TIR3B cytology holds up to 30% of thyroid cancer, which justifies the surgical indication, even if more than half of cases do not result in a positive histology. The study aim is to identify potential clinical, ultrasound or cytological features able to improve the surgical indication.

METHODS

Retrospective analysis. A consecutive series of TIR3B nodules referred to the Endocrine Unit of Careggi Hospital from 1st May 2014 to 31st December 2021 was considered for the exploratory analysis (Phase 1). Thereafter, a smaller confirmatory sample of consecutive TIR3B diagnosed and referred to surgery from 1st January 2022 to 31st June 2022 was considered to verify the algorithm (Phase 2). The main clinical, ultrasound and cytological features have been collected. A comprehensive stepwise logistic regression was applied to build a prediction algorithm. The histological results represented the final outcome.

RESULTS

Of 599 TIR3B nodules referred to surgery, 451 cases were included in the exploratory analysis. A final score > 14.5 corresponded to an OR = 4.98 (95% CI 3.24-7.65, p < 0.0001) and showed a PPV and NPV of 57% and 79%, respectively. The Phase 2 analysis on a confirmatory sample of 58 TIR3B cytology confirmed that a threshold of 14.5 points has a comparable PPV and NPV of 53% and 80%, respectively.

CONCLUSIONS

A predictive algorithm which considers the main clinical, US and cytological features can significantly improve the oncological stratification of TIR3B cytology.

Molecular testing for thyroid nodules: Where are we now?

Approximately 25% of the fine needle aspiration samples (FNAB) of thyroid nodules are classified as "indeterminate samples", that means, Bethesda III and IV categories. Until the last decade, most of these cases underwent diagnostic surgery, although only a minority (13-34%) confirmed malignancy postoperatively. In view of this, with the objective of improving the preoperative diagnosis in these cases, the molecular tests emerged, which are validated from the diagnostic point of view, presenting good performance, with good diagnostic accuracy, being able to avoid diagnostic surgeries. With the advancement of knowledge of the role of each of the mutations and gene rearrangements in thyroid oncogenesis, molecular markers have left to play only a diagnostic role and have been gaining more and more space both in defining the prognostic role of the tumor, as well as in the indication of target therapy. Thus, the objective of this review is to show how to use the tool of molecular tests, now commercially available in the world, in the management of indeterminate cytological nodules, assessing the pre-test malignancy risk of the nodule, through clinical, ultrasonographic and cytological characteristics, and decide on the benefit of molecular testing for each patient. In addition, to discuss its new and promising prognostic and therapeutic role in thyroid cancer.

Performance of multigene testing in cytologically indeterminate thyroid nodules and molecular risk stratification

Objective

Thyroid cancer is the third most prevalent cancer among females. Genetic testing based on next-generation sequencing may provide an auxiliary diagnosis to reduce cytologically diagnostic uncertainty. However, commercial multigene tests are not widely available and are not well-tested in the Chinese population.

Methods

In this study, we designed a multigene testing panel and evaluated its performance in 529 cytologically indeterminate thyroid nodules (Bethesda III, IV and V). The molecular data of the DNA mutations and RNA fusions of fine needle aspiration samples were reviewed in conjunction with a clinical diagnosis, pathological reports, and definitive surgery for retrospective analysis. Then, the molecular risk stratification was investigated for its accuracy in malignant risk prediction.

Results

The overall combined consistency revealed substantial agreement (Kappa = 0.726) with the sensitivity, specificity, positive predictive value, and negative predictive values of 97.80%, 82.14%, 98.99%, and 67.65%, respectively. The most common aberration was BRAFV600E (82.59%), followed by NRAS mutants (4.07%), RET fusions (3.70%), and KRAS mutants (3.15%). Two cases (0.44%) were categorized into a high-risk group, 426 cases (94.67%) were categorized into a BRAF-like group with totally histopathologic papillary patterned tumors, and 22 cases (4.89%) were categorized into a RAS-like group with 14 papillary and eight follicular patterned tumors when the cohort concurrent aberrations were excluded. Potentially aggressive features may be related to concurrent molecular alterations of BRAFV600E with TERTQ302R, and AKT1L52R, NRASG12C, NRASQ61R, and CCDC6-RET fusions.

Conclusions

This study provided a multigene panel for identifying benign nodules from cytologically indeterminate thyroid nodules to avoid unnecessary surgery. We provide further evidence for using molecular risk stratification as a promising predictor of disease outcomes. The results of this study may be limited by the extremely high prevalence of cancer in the cohort for clinical reference.

Malignancy risk in Bethesda class IV thyroid nodules in an iodine deficient region

Background

According to the latest guidelines, in patients with high-risk nodules with indeterminate cytology, diagnostic lobectomy should be the preferable surgical approach in the absence of factors that suggest a total thyroidectomy.

Methods

This retrospective observational study has as its main aim the evaluation of the cases that underwent surgery, for Bethesda class IV nodules in our iodocarent geographical area. Particular attention was paid to carcinoma incidence, preoperative nodule size, histological characteristics of the neoplasm, surgical approach and eventual need of radiometabolic treatment. A total of 320 patients were included that underwent surgery for Bethesda IV nodules, between January 2010 and December 2020, at the General Surgical Clinic of the University Hospital of Parma, Italy.

Results

A total of 230 total thyroidectomies (71.9%) and 90 lobectomies (28.1%) were performed. Our data showed a strong impact of the 2015 ATA Guidelines on the surgical approach choice, with a progressive propensity towards a conservative approach and an increase of lobectomies from 7.2% to 41.5% after the new guidelines introduction. However, in our sample the percentage of lobectomies remains below 50%; this data is certainly influenced by the number of cases of multinodular pathology, often bilateral, in our geographical area. The nodules malignancy rate resulted 28.8%. Our data showed that increasing size correlated with an increasing malignancy rate (P<0.01), and follicular carcinomas were found to be larger than papillary carcinomas (P<0.001). A statistically significant correlation also emerged between nodule size increase and local/lymphovascular invasion (P<0.05). On the other hand, there was no statistically significant correlation between nodule size and multifocality, and between nodule size and presence of lymph node metastases. Out of the patients where it was possible to find this data, 66% underwent radioiodiometabolic treatment: 59% with papillary carcinoma, and 85% with follicular carcinoma.

Conclusions

In patients with Bethesda IV thyroid nodules, diagnostic lobectomy should be the preferable surgical approach in absence of factors that suggest total thyroidectomy. In our opinion, total thyroidectomy remains the first choice in large nodules (≥4 cm) as these nodules have a high malignancy rate, greater local/lymphovascular invasion and a consequent frequent indication for post-operative radiometabolic treatment.

Thyroglobulin is a poor predictor of differentiated thyroid cancer in patients who undergo surgery for thyroid nodular diseases

OBJECTIVES

Thyroglobulin, produced exclusively by thyroid follicular cells, serves as a specific tumor marker for the follow-up of differentiated thyroid cancer (DTC) patients after thyroidectomy. However, its role as a predictor of malignancy in patients with thyroid nodules is controversial. We assessed the potential role of preoperative serum thyroglobulin concentration to predict DTC in patients without a preoperative diagnosis of malignancy who underwent partial or total thyroidectomy.

METHODS

This retrospective study included patients with a preoperative diagnosis of benign multinodular goiter (MNG) or a thyroid nodule with indeterminate cytology (INC) (Bethesda system categories III/IV) who underwent partial or total thyroidectomy between January 2014 and May 2019. We compared the patients' demographic, clinical, imaging, and biochemical data according to their final diagnosis: DTC or benign thyroid nodular disease. Further statistical analysis included odds ratio calculation and receiver operating characteristic (ROC) curve analysis.

RESULTS

Of 131 patients who met inclusion and exclusion criteria, the indication for surgery was benign MNG in 69 patients and a thyroid nodule with INC in 62 patients. A final diagnosis of DTC was reported in 18 of the 69 benign MNG patients (26%) and in 30 of the 62 thyroid nodule with INC patients (48%). The preoperative measurements of nodule diameter and serum thyroid-stimulating hormone and thyroglobulin concentrations did not significantly differ between patients with a final diagnosis of DTC and those with benign histology.

CONCLUSIONS

Preoperative serum thyroglobulin alone is insufficient to differentiate between malignant and benign thyroid nodular disease.

SFE-AFCE-SFMN 2022 Consensus on the management of thyroid nodules : Role of molecular tests for cytologically indeterminate 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.). Because of the emerging role of molecular fine-needle cytology diagnostics, the French Endocrine Society convened a panel of experts to review the evidence for the diagnostic value of molecular tests performed on cytologically indeterminate thyroid nodules.

Real-life use of BRAF-V600E mutation analysis in thyroid nodule fine needle aspiration: consequences on clinical decision-making

PURPOSE

This study aimed to evaluate the real-life use of BRAF-V600E mutation analysis in washout liquid from thyroid nodule fine needle aspiration (FNA), and the consequences of genetic result on clinical decision-making.

METHODS

We retrospectively considered subjects tested for BRAF-V600E among those attending the Endocrinology Unit of Modena for FNA between 2014 and 2018. Washing fluid was collected together with cytological sample and stored at -20 °C. If the clinician deemed it necessary, the sample was thawed, DNA extracted, and genetic test performed by high-resolution melting technique. We collected data on cytology according to the Italian Consensus for the cytological classification of thyroid nodules, type of surgery (when performed), histology, and adverse events.

RESULTS

Out of 7112 subjects submitted to FNA, BRAF analysis was requested for 683 (9.6%). Overall, 896 nodules were analyzed: 74% were indeterminate at cytology, mainly TIR3A (low risk). Twenty-two nodules were mutant (BRAF+). Only 2% of indeterminate, mainly TIR3B, were BRAF+. Based on final histological diagnosis, BRAF test had high specificity (100%) but poor sensitivity (21%), also in indeterminate nodules. Mutant subjects underwent more extensive surgery compared to wild type (p = 0.000), with frequent prophylactic central lymph node dissection. One third had local metastases. Higher prevalence of hypoparathyroidism was found in BRAF+ compared to wild type (p = 0.018).

CONCLUSIONS

The analysis of BRAF-V600E outside of gene panels has low sensitivity, especially in indeterminate nodules, and a positive result could lead to more extensive surgery with greater risk of hypoparathyroidism and questionable clinical utility.

Performance of afirma gene sequencing classifier versus gene expression classifier in thyroid nodules with indeterminate cytology

INTRODUCTION

About 15% to 30% of thyroid fine-needle aspiration (FNA) nodules have indeterminate cytology. The Afirma (Veracyte Inc, South San Francisco, CA) Gene Expression Classifier (GEC)/Gene Sequencing Classifier (GSC) tests were designed to improve risk stratification of the indeterminate thyroid nodules. This study aimed to evaluate and compare the performance of the Afirma GEC and GSC tests in the indeterminate thyroid lesions.

METHODS

Thyroid FNA cases with indeterminate cytology were searched in the pathology database and only those with available Afirma results were selected for this study. Each patient's demographic, sonographic, cytologic, molecular, and subsequent surgical follow-up results were collected and analyzed.

RESULTS

There were 100 cases with indeterminate thyroid FNA results, including 49 cases tested by GEC and 51 cases by GSC. In the GEC group, benign call rate (BCR) was 53% (26 of 49) and the calculated negative predictive value (NPV) and positive predictive value (PPV) were 88% and 47% respectively. In the GSC group, the BCR was 63% (32 of 51) and the calculated NPV and PPV were 100% and 64%, respectively. Whereas only 17% (1 of 6) of benign oncocytic lesions were tested benign by the GEC, 60% (3 of 5) of benign oncocytic nodules were tested benign by the GSC.

CONCLUSION

We demonstrated in this study that a little more than half of the indeterminate thyroid nodules had negative Afirma GEC/GSC results and the BCR using the Afirma GSC test was higher than GEC. The Afirma GSC showed higher NPV and PPV than GEC. In addition, the Afirma GSC appeared to be superior for differentiating benign and malignant oncocytic thyroid lesions.

Retrospective analysis of cancer-specific gene expression panel for thyroid fine needle aspiration specimens

BACKGROUND

While molecular testing is a promising strategy for preoperative assessment of cytologically indeterminate thyroid nodules, thyroid fine needle aspiration biopsy (FNA) presents unique challenges for molecular assays, including contaminating peripheral blood mononuclear cells (PBMC) and variable numbers of evaluable epithelial thyroid cells. Moreover, the newly recognized entity, noninvasive follicular thyroid neoplasm with papillary-like nuclear features (NIFTP), has added an additional challenge to the currently available molecular diagnostic platforms. New diagnostic tools are still needed to correctly distinguish benign and malignant thyroid nodules preoperatively.

METHODS

Twenty-two transcript splice variants from 12 genes we previously identified as discriminating benign from malignant thyroid nodules were characterized in 80 frozen thyroid tumors from 8 histological subtypes. Isoforms detectable in PBMC were excluded, and the 5 most discriminating isoforms were further validated by real-time quantitative PCR (qPCR) on intraoperative FNA samples from 59 malignant tumors, 55 benign nodules, and 23 NIFTP samples. The qPCR threshold cycle values for each transcript were normalized to the thyrocyte-specific thyroid peroxidase isoform 1 (TPO1) and z-transformed. Receiver operating characteristic (ROC) analyses of the composite transcript scores were used to evaluate classification of thyroid FNAs by the 5-gene isoform expression panel.

RESULTS

A molecular signature was developed by combining expression levels of specific isoforms of CDH3, FNDC4, HMGA2, KLK7, and PLAG1. FNAs containing at least 12-36 thyrocytes were sufficient for this assay. The 5-gene composite score achieved an area under the ROC curve (AUC) of 0.86 for distinguishing malignant from benign nodules, with a specificity of 91%, sensitivity of 75%, negative predictive value of 91%, and positive predictive value of 74%.

CONCLUSION

Our newly developed 5-gene isoform expression panel distinguishes benign from malignant thyroid tumors and, may help distinguish benign from malignant thyroid nodules in the context of the new NIFTP subtype.

Multiparametric Ultrasound Evaluation of the Thyroid: Elastography as a Key Tool in the Risk Prediction of Undetermined Nodules (Bethesda III and IV)-Histopathological Correlation

The purpose of this study was to select thyroid nodules most at risk for malignancy among those cytologically undetermined by fine-needle aspiration biopsy (FNAB), using B-mode, color duplex Doppler and 2-D shear wave shear wave elastography (2-D-SWE). This was a prospective diagnostic accuracy study with 62 Bethesda III/IV nodules according to FNAB (atypia/follicular lesion of undetermined significance or follicular neoplasia/Hürthle cell neoplasm). Ultrasonography (US) data were compared with resection histologic results, revealing 35 of 62 benign nodules (56.4%) and 27 of 62 carcinomas (43.6%). Conventional US was uses to evaluate nodule echogenicity, dimensions, contours, presence of halo and microcalcifications. Doppler US was used to assess the vascularization (exclusively or predominantly peripheral or central) and mean resistance index of three nodule arteries. Elastography was used to evaluate the nodule elastographic pattern; mean nodule deformation index; deformation ratio between nodule and adjacent thyroid parenchyma; and mean deformation ratio between nodule and pre-thyroid musculature (MDR). Statistical analysis included χ², Fisher's exact, Student's t, Mann-Whitney tests and multivariable analysis by multiple logistic regression. Areas under the receiver operating characteristic curves (AUC-ROCs) were used for accuracy analysis. Fifty-eight participants (54.7 ± 14.0 y, 51 women) were studied. The parameters that were statistically significant to the univariate analysis were hypo-echogenicity, nodule diameter greater than width and all parameters analyzed from Doppler and elastography. Multivariate analysis revealed that the MDR (in kPa) was the best parameter for risk analysis of indeterminate nodules. Nodules with MDRs >1.53 exhibited a greater chance of malignancy (AUC-ROC = 0.98). We conclude that 2-D-SWE is able to select malignant nodules among those cytologically indeterminate, thus avoiding unnecessary surgery in these cytologic groups.

Adherence to Active Surveillance and Clinical Outcomes in Patients with Indeterminate Thyroid Nodules Not Referred for Thyroidectomy

OBJECTIVE

Outcomes of patients with cytologically indeterminate thyroid nodules not referred for thyroidectomy have hardly been investigated. We previously reported outcomes of 322 patients with thyroid nodules classified according to the Bethesda System of Reporting Thyroid Cytology (BSRTC) as indeterminate (B3/B4), of whom 123 (38.2%) underwent thyroidectomy. In the present extension study, we investigated adherence and outcomes in the remaining unoperated 199 patients.

METHODS

We conducted a file review of 189/199 patients with thyroid nodules cytologically diagnosed as B3 (n = 174) or B4 (n = 15) in 2011-2012 who were conservatively followed at our institution until 2019.

RESULTS

Among 174 patients with B3 nodules, 140 (80.4%) underwent repeated ultrasound. Nodular growth was detected in 23 (16.4%), and findings remained stable in 105 (75%). Fine-needle aspiration was repeated in 88/174 patients (50.6%), with B2 results in 62 (70.4%) and B3/B4/B5 in 20 (22.7%). Thyroidectomy was performed in 14/174 patients (8%) in the B3 and 5/15 patients (33%) in the B4 group at a median of 5 years' follow-up; thyroid cancer was diagnosed in 4/14 patients (28.5%) and 3/5 patients (60%), respectively. For B3 patients who remained unoperated, none had evidence of thyroid cancer at last follow-up. A reason for avoiding surgery was documented in 6/10 unoperated B4 patients (1 thyroid lymphoma, 3 died of unrelated causes, 2 were considered inoperable due to advanced age).

CONCLUSIONS

Most patients with initially unoperated B3/B4 nodules adhere, at least partially, to active surveillance. For B3 nodules, subsequent thyroidectomy and thyroid cancer detection are rare events, and patients may be safely managed without using molecular markers. Thyroid cancer is diagnosed in most B4 patients who undergo thyroidectomy in our institution.

Performance of a dual-component molecular assay in cytologically indeterminate thyroid nodules

PURPOSE

Deciding whether patients with a cytologically indeterminate thyroid nodule should be referred for surgery or for active surveillance is an important challenge for clinicians. The aim of this study was to evaluate the performance of a novel dual-component molecular assay as an ancillary molecular method for resolving indeterminate thyroid nodule cytology.

METHODS

We selected 156 thyroid nodules from those that had undergone fine-needle aspiration processed by liquid-based cytology and surgical resection between June 2016 and December 2017. The sample set included 63 nodules cytologically classified as indeterminate, and 93 other nodules randomly selected from those with non-diagnostic, benign, suspicious, or malignant cytology. Nucleic acids from each nodule were subjected to next-generation sequencing analysis for mutation detection in 23 genes and to digital polymerase chain reaction (PCR) evaluation for miR-146b-5p expression levels.

RESULTS

Used alone, mutation analysis in the indeterminate subset (cancer prevalence: 22.5%) displayed high sensitivity (89%) and NPV (96%). In contrast, the miR-146b-5p assay offered high specificity (93%) and PPV (93%). Combined use of both analyses improved panel performance by eliminating false-negative results.

CONCLUSIONS

These preliminary data suggest that a dual-component molecular test can increase the diagnostic accuracy of thyroid cytology alone by reducing the number of nodules that will be classified as indeterminate and increasing those that can be reliably classified as benign. If these findings are confirmed, this test can be considered for use in clinical practice and is expected to reduce diagnostic surgery and health care costs, and to improve patient quality of life.

Quantifying the differences in surgical management of patients with definitive and indeterminate thyroid nodule cytology

INTRODUCTION

Thyroid nodules are increasingly common. Despite being an essential pre-operative diagnostic tool, up to 30% of fine needle aspirate cytology (FNAC) yields a non-definitive diagnosis. This study aimed to quantify differences in surgical management of patients with definitive and indeterminate thyroid nodule cytology, and determine if clinical factors can improve cytological diagnosis.

MATERIALS AND METHODS

Patients who underwent thyroidectomy for nodules from 2001 to 2015 were recruited. Those with benign and malignant preoperative cytology were included in the "definitive diagnosis" (DC) group; patients with all other preoperative cytology results were included in the "indeterminate diagnosis" (IC) group. We compared demographics and procedures between these groups. Clinical factors and demographics were also compared between patients with benign and malignant histology in the IC group.

RESULTS

A total of 3821 cases were included. A significantly larger proportion of the IC patients had a hemithyroidectomy (IC 69% vs. DC 39%, p < 0.001) initially, and also had a significantly higher rate of two-stage surgery compared to the DC group (IC 17% vs. DC 11%, p < 0.001). Patients in the DC group were twice as likely to undergo concurrent central lymph node dissection for papillary and medullary cancers than the IC group (p < 0.001). Overall, up to 60% of IC patients had been over- or under-treated at initial surgery. The clinical factors examined were not significantly associated with higher risk of malignancy in IC patients.

CONCLUSION

This study highlights the potential for improved preoperative diagnosis to streamline decision making for surgical management of patients with thyroid nodules.

The Malignancy Risk Assessment of Cytologically Indeterminate Thyroid Nodules Improves Markedly by Using a Predictive Model

OBJECTIVES

The majority of thyroid nodules are discovered incidentally, and the management may be a challenge if the fine needle aspiration specimen yields indeterminate findings. Our aim was to develop an individualized risk prediction model to provide an accurate estimate of cancer risk in patients with cytologically indeterminate thyroid nodules.

MATERIALS AND METHODS

Clinical records, ultrasound images, and cytopathology reports of patients who underwent thyroidectomy were retrospectively reviewed. Logistic regression analysis was used to identify the predictive ability of each variable for malignancy, and a nomogram was built by integrating patients' age, multiplicity of nodules, cytology results, and suspicious ultrasound features, such as microcalcifications and irregular margins.

RESULTS

For the 233 indeterminate nodules according to the Bethesda System for Reporting Thyroid Cytopathology, the malignancy rates of the subgroups "atypia of undetermined significance," "suspicious follicular neoplasia," and "suspicious for malignancy" were 44.3, 47.7, and 88.0%, respectively. It was found that the Bethesda category "suspicious for malignancy," microcalcifications, and irregular margins were independent risk factors for malignancy. The area under the receiver operating characteristics curve was 0.784, which suggested that the presented nomogram had considerable discriminative performance.

CONCLUSIONS

The nomogram developed in our study accurately predicts the malignancy risk of thyroid nodules with indeterminate cytology by using clinical, cytological, and ultrasonographic features.

Evaluation of 167 Gene Expression Classifier (GEC) and ThyroSeq v2 Diagnostic Accuracy in the Preoperative Assessment of Indeterminate Thyroid Nodules: Bivariate/HROC Meta-analysis

The objective of this meta-analysis was to evaluate the performance of the Gene Expression Classifier (GEC) and ThyroSeq v2 (ThyroSeq) in the preoperative diagnosis of thyroid nodules with indeterminate fine-needle aspiration biopsy results. We searched literature databases from January 2001 to April 2018. The bivariate model analysis was performed to estimate pooled sensitivity, specificity, positive likelihood ratio (LR+), negative likelihood ratio (LR-), positive predictive value (PPV), and negative predictive value (NPV). Pooled data from 1086 nodules with histopathologic confirmation from 16 GEC studies enabled calculation of diagnostic parameters (95% confidence interval): sensitivity 98% (96-99%), specificity 12% (8-20%), PPV 45% (37-53%), and NPV 91% (85-96%). Pooled data from five ThyroSeq studies assessing 459 nodules showed sensitivity of 84% (74-91%), specificity 78% (50-92%), PPV 58% (31-81%), and NPV 93% (89-97%). When both tools were compared, GEC had a significantly higher sensitivity (p = 0.003), while ThyroSeq had a significantly higher specificity (p < 0.001) and accuracy (p = 0.015). Pooled LR+ was higher for ThyroSeq: 3.79 (1.40-10.27) vs. 1.12 (1.05-1.20). Pooled LR- was higher for GEC, 0.20 (0.10-0.39) vs. 0.13 (0.05-0.31). The bivariate summary estimates of sensitivity and specificity for GEC and ThyroSeq and their pooled accuracy showed a superiority of the ThyroSeq test. The GEC with a high sensitivity and NPV may be helpful in ruling out malignancy in cases of indeterminate thyroid nodule cytology. ThyroSeq has a significantly higher specificity and accuracy with an acceptable sensitivity so that it has the potential for use as an all-round test of malignancy of thyroid nodules.

Molecular Diagnostic Evaluation of Thyroid Nodules

The historical management approach for many patients with indeterminate thyroid nodule fine needle aspiration cytology is a diagnostic lobectomy or thyroidectomy. However, the majority of patients undergo surgery unnecessarily, because most are proven to have benign disease on histology. Molecular testing is a diagnostic tool that can be used to help guide the clinical management of thyroid nodules with indeterminate cytology results. Testing has evolved substantially over the last decade with significant advances in testing methodology and improvements in our understanding of the genetic basis of thyroid cancer.

Updates in Thyroid Cytology

Genomic, clinical, and pathologic studies have prompted a more risk-stratified approach to the management of patients with thyroid nodules. The recent nomenclature change concerning noninvasive follicular thyroid neoplasm with papillary-like nuclear features reflects the clinical trend toward conservative treatment choices for carefully selected low-risk thyroid neoplasms. These developments have occurred in parallel with a growing array of molecular tests intended to improve clinical triage for patients with indeterminate fine needle aspiration diagnoses. This review discusses the implications of the nomenclature revision on the interpretation of thyroid fine needle aspiration and updates available ancillary molecular tests for thyroid fine needle aspirations.

Diagnosis of post-surgical fine-needle aspiration biopsies of thyroid lesions with indeterminate cytology using HRMAS NMR-based metabolomics

INTRODUCTION

Ultrasound examination coupled with fine-needle aspiration (FNA) cytology is the gold standard for the diagnosis of thyroid cancer. However, about 10-40% of these analyses cannot be conclusive on the malignancy of the lesions and lead to surgery. The cytological indeterminate FNA biopsies are mainly constituted of follicular-patterned lesions, which are benign in 80% of the cases.

OBJECTIVES

The development of a FNAB classification approach based on the metabolic phenotype of the lesions, complementary to cytology and other molecular tests in order to limit the number of patients undergoing unnecessary thyroidectomy.

METHODS

We explored the potential of a NMR-based metabolomics approach to improve the quality of the diagnosis from FNABs, using thyroid tissues collected post-surgically.

RESULTS

The NMR-detected metabolites were used to produce a robust OPLSDA model to discriminate between benign and malignant tumours. Malignancy was correlated with amino acids such as tyrosine, serine, alanine, leucine and phenylalanine and anti-correlated with myo-inositol, scyllo-inositol and citrate. Diagnosis accuracy was of 84.8% when only indeterminate lesions were considered.

CONCLUSION

These results on model FNAB indicate that there is a clear interest in exploring the possibility to export NMR metabolomics to pre-surgical diagnostics.

The contemporary utility of intraoperative frozen sections in thyroid surgery

PURPOSE

To determine the accuracy of intraoperative frozen section analysis on thyroidectomy specimens stratified by the Bethesda classification scheme and its utility for intraoperative decision-making.

STUDY DESIGN

Retrospective chart review.

METHODS

A retrospective review was performed on all patients who underwent thyroidectomy or thyroid lobectomy with intraoperative frozen sections at a tertiary care academic center from 2009 to 2015.

RESULTS

There were 74 total patients who underwent partial or total thyroidectomy with intraoperative frozen section analysis of a thyroid nodule whom had previously undergone a thyroid fine needle aspiration of the nodule. The sensitivity, specificity, positive predictive value, and negative predictive value for a thyroid frozen section with respect to its prediction for malignancy was 81%, 95%, 98%, and 66%, respectively, with a diagnostic accuracy of 85%. For 37 patients with an indeterminate cytologic diagnosis on fine needle aspiration (Bethesda categories III-V), the sensitivity, specificity, positive predictive value, and negative predictive value for a thyroid frozen section was 81%, 91%, 95%, and 67%, respectively, with a diagnostic accuracy of 84%. False positives and false negatives resulted in 1 completion thyroidectomy for benign pathology and 3 reoperations for malignancy not discovered on frozen section.

CONCLUSION

While intraoperative frozen sections on thyroid specimens may be helpful if positive, the false negative rate remains high. There appears to be limited value in routine frozen sections to guide clinical management and decision-making in the era of the Bethesda system.

Molecular Genetics of Thyroid Cancer in Children and Adolescents

There has been a steady incorporation of powerful new molecular tools into the evaluation and management of thyroid nodules and thyroid cancer. With an increasing incidence of nodules and differentiated thyroid cancer (DTC) being diagnosed in children and adolescents, oncogene data are providing insight into the clinical differences between pediatric and adult patients with histologically similar DTC. However, additional investment and efforts are needed to define the genomic landscape for pediatric DTC with the goal of improving preoperative diagnostic accuracy as well as stratifying treatment in an effort to reduce complications of therapy.

Thyroglobulin antibodies as a potential predictive marker of papillary thyroid carcinoma in patients with indeterminate cytology

BACKROUND

We investigated the efficacy of thyroglobulin antibodies (TgAb) in detecting malignancy in indeterminate thyroid nodules and evaluated the possible association between TgAb and autoimmunity in papillary thyroid carcinoma (PTC).

METHODS

This retrospective, nonrandomized study included 1,646 patients who had undergone preoperative fine-needle aspiration biopsy to evaluate their thyroid nodules, and then standard total thyroidectomy. Of 194 patients (11.8%) with indeterminate nodules, 61 (31.4%) had PTC and 133 (68.6%) had benign nodules at the final histologic examination.

RESULTS

Univariate analysis showed that multifocality (P = .002), bilaterality (P = .003), lymph-node metastasis (P = .030), and capsule penetration (P = .003) were significantly associated with positive TgAb in patients with indeterminate cytology and histopathologic diagnosis of PTC. The multivariate analysis showed that TgAb positivity (P < .001) and preoperative thyroid-stimulating hormone levels (P = .022) were independent predictive factor for PTC diagnosis in patients with indeterminate cytology.

CONCLUSIONS

Preoperative TgAb could be a marker for PTC in patients with indeterminate thyroid nodules, increasing diagnostic accuracy. TgAb positivity could also influence the clinical assessment and subsequent selection of total thyroidectomy.

Strain ratio ultrasound elastography increases the accuracy of colour-Doppler ultrasound in the evaluation of Thy-3 nodules. A bi-centre university experience

OBJECTIVES

To assess whether ultrasound elastography (USE) with strain ratio increases diagnostic accuracy of Doppler ultrasound in further characterisation of cytologically Thy3 thyroid nodules.

METHODS

In two different university diagnostic centres, 315 patients with indeterminate cytology (Thy3) in thyroid nodules aspirates were prospectively evaluated with Doppler ultrasound and strain ratio USE before surgery. Ultrasonographic features were analysed separately and together as ultrasound score, to assess sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV). Receiver operating characteristic (ROC) curves to identify optimal cut-off value of the strain ratio were also provided. Diagnosis on a surgical specimen was considered the standard of reference.

RESULTS

Higher strain ratio values were found in malignant nodules, with an optimum strain ratio cut-off of 2.09 at ROC analysis. USE with strain ratio showed 90.6% sensitivity, 93% specificity, 82.8% PPV, 96.4% NPV, while US score yielded a sensitivity of 52.9%, specificity of 84.3%, PPV 55.6% and NPV 82.9%. The diagnostic gain with strain ratio was statistically significant as proved by ROC areas, which was 0.9182 for strain ratio and 0.6864 for US score.

CONCLUSIONS

USE with strain ratio should be considered a useful additional tool to colour-Doppler US, since it improves characterisation of thyroid nodules with indeterminate cytology.

KEY POINTS

• Strain ratio measurements improve differentiation of thyroid nodules with indeterminate cytology • Elastography with strain ratio is more reliable than ultrasound features and ultrasound score • Strain ratio may help to better select patients with Thy 3 nodules candidate for surgery.

The use of semi-quantitative ultrasound elastosonography in combination with conventional ultrasonography and contrast-enhanced ultrasonography in the assessment of malignancy risk of thyroid nodules with indeterminate cytology

Background

The pre-surgical selection of thyroid nodules with indeterminate cytology (Thy 3 according to British Thyroid Association) after fine-needle aspiration biopsy (FNAB) is currently required in order to reduce unnecessary total thyroidectomy. The objective of our study was to use a surgical series of Thy 3 nodules to evaluate the predictive role of ultrasound elastosonography (USE) and contrast-enhanced ultrasonography (CEUS) in pre-surgical diagnoses of malignancy.

Subjects and methods

We enrolled 63 patients with Thy 3 nodules in which cytological–histological correlation was available. The ELX 2/1 strain index was obtained by means of semi-quantitative USE, which was performed before surgery in addition to conventional ultrasonography (US) and contrast-enhanced US (CEUS) on the Thy 3 nodules. The ELX 2/1 strain index, a five-item US score and both peak (P) index and time to peak (TTP) index from CEUS were correlated with the histological results. After surgical diagnosis, the data were analysed by using a receiver-operating characteristic (ROC) curve.

Results

Histology was benign in 50 and malignant in 13 Thy 3 nodules. No difference in maximal diameter was noted between benign (22.8 ± 1.6 mm) and malignant (18.9 ± 2.9 mm) nodules. Significant correlations were found between histology and cumulative US findings (p=0.005), ELX 2/1 index (p=0.002), P index (p=0.01) and TTP index (p=0.02). On analysing data from US, USE and CEUS, significant ROC areas under the curve were observed (p<0.0001). A cut-off value was set for US (>2), ELX 2/1 (>0.95), P index (<0.99) and TTP index (>0.98) scores. The diagnostic power of the cumulative pre-surgical analysis of Thy 3 nodules with US, USE and CEUS, considering the experimental cut-off points obtained from the ROC curves was: sensitivity 64%, specificity 92%, PPV 75% and accuracy 84%.

Conclusion

The ELX 2/1 index in conjunction with the US score can be useful in orienting surgical strategies in Thy 3 nodules. The information added by CEUS is less sensitive than that provided by US and USE. The use of a cut-off based on histology can reduce thyroidectomy. Observation should be the first choice when not all instrumental results are suspect.

Carbonic anhydrase 4 and crystallin α-B immunoreactivity may distinguish benign from malignant thyroid nodules in patients with indeterminate thyroid cytology

BACKGROUND

Thyroid nodules are present in 19%-67% of the population and carry a 5%-10% risk of malignancy. Unfortunately, fine-needle aspiration biopsies are indeterminate in 20%-30% of patients, often necessitating thyroid surgery for diagnosis. Numerous DNA microarray studies including a recently commercialized molecular classifier have helped to better distinguish benign from malignant thyroid nodules. Unfortunately, these assays often require probes for >100 genes, are expensive, and only available at a few laboratories. We sought to validate these DNA microarray assays at the protein level and determine whether simple and widely available immunohistochemical biomarkers alone could distinguish benign from malignant thyroid nodules.

METHODS

A tissue microarray (TMA) composed of 26 follicular thyroid carcinomas (FTCs) and 53 follicular adenomas (FAs) from patients with indeterminate thyroid nodules was stained with 17 immunohistochemical biomarkers selected based on prior DNA microarray studies. Antibodies used included galectin 3, growth and differentiation factor 15, protein convertase 2, cluster of differentiation 44 (CD44), glutamic oxaloacetic transaminase 1 (GOT1), trefoil factor 3 (TFF3), Friedreich Ataxia gene (X123), fibroblast growth factor 13 (FGF13), carbonic anhydrase 4 (CA4), crystallin alpha-B (CRYAB), peptidylprolyl isomerase F (PPIF), asparagine synthase (ASNS), sodium channel, non-voltage gated, 1 alpha subunit (SCNN1A), frizzled homolog 1 (FZD1), tyrosine related protein 1 (TYRP1), E cadherin, type 1 (ECAD), and thyroid hormone receptor associated protein 220 (TRAP220). Of note, two of these biomarkers (GOT1 and CD44) are now used in the Afirma classifier assay. We chose to compare specifically FTC versus FA rather than include all histologic categories to create a more uniform immunohistochemical comparison. In addition, we have found that most papillary thyroid carcinoma could often be reasonably distinguished from benign disease by morphological cytology findings alone.

RESULTS

Increased immunoreactivity of CRYAB was associated with thyroid malignancy (c-statistic, 0.644; negative predictive value [NPV], 0.90) and loss of immunoreactivity of CA4 was also associated with malignancy (c-statistic, 0.715; NPV, 0.90) in indeterminate thyroid specimens. The combination of CA4 and CRYAB for discriminating FTC from FA resulted in a better c-statistic of 0.75, sensitivity of 0.76, specificity of 0.59, positive predictive value (PPV) of 0.32, and NPV of 0.91. When comparing widely angioinvasive FTC from FA, the resultant c-statistic improved to 0.84, sensitivity of 0.75, specificity of 0.76, PPV of 0.11, and NPV of 0.99.

CONCLUSIONS

Loss of CA4 and increase in CRYAB immunoreactivity distinguish FTC from FA in indeterminate thyroid nodules on a thyroid TMA with an NPV of 91%. Further studies in preoperative patient fine needle aspiration (FNAs) are needed to validate these results.