Impact of Molecular Testing on the Management of Indeterminate Thyroid Nodules Among Western and Asian Countries: a Systematic Review and Meta-analysis

Molecular testing has a potential to improve the management of patients with indeterminate thyroid nodules considered for surgery. This study examined the influence of molecular tests on the treatment of indeterminate nodules, particularly the differences between Western and Asian countries. Electronic databases including PubMed and Web of Science were searched for relevant articles from 2010 to March 2019. We computed meta-analysis of proportion and their 95% confidence intervals (CIs) utilizing the random-effect model. We used independent samples t test to compare the resection rate (RR), rate of malignancy (ROM), rate of preoperative molecular testing (RMT), and rate of positive test (RP) between subgroups. We included a total of 34 studies with 7976 indeterminate nodules. The multigene panel testing methods were exclusively used in the USA. Compared with the non-molecular era, molecular testing was associated with a significantly increased ROM (47.9% versus 32.1%; p = 0.001). The ROM of indeterminate nodules in Asian institutes was significantly higher than that in Western countries (75.3% versus 36.6%; p < 0.001, respectively). Institutes employing single-gene tests achieved a higher ROM (59.8% versus 37.9%; p = 0.013). Molecular testing is a promising method to tailor the clinical management for indeterminate thyroid FNA. Certain differences in routine thyroid cytopathology practice among the West and the East are still present. The combination of molecular testing and active surveillance enhances the accuracy of case selection for surgery in Asian countries.

Standardisation of thyroid cytology terminology and practice: are modifications necessary?-a narrative review

Universally accepted guidelines for diagnosis and management of any disease are desirable. Standardization of thyroid cytology reporting is aimed at guiding and improving clinical decision-making and management. However, socio-economic, and local factors and differences in disease prevalence and patterns require modification to suit local settings. 'One size fit all' approach is not possible for any disease diagnosis or management. The same concept is applicable in diagnosis and management of thyroid nodules. An additional special issue is the well-known high inter and intra-observer variability in the histological and cytological diagnosis of thyroid neoplasms. Despite this, thyroid cytology has a very significant influence in the management of thyroid diseases. An approach based on common principals with appropriate modifications that suits countries or continents is desirable and sustainable. The principals of TBSRTC have served as a framework for similar tiered classifications for reporting thyroid cytopathology. This article discusses globally available professional guidelines based on a common framework with appropriate modifications, with the universal aim of risk stratification of thyroid nodules.

The diversities in thyroid cytopathology practices among Asian countries using the Bethesda system for reporting thyroid cytopathology

Background

The Bethesda System for Reporting Thyroid Cytopathology (TBSRTC) has been adopted and widely used among Asian countries. This study aims to investigate the application of TBSRTC in thyroid cytology practice among Asian countries.

Methods

We searched electronic databases including PubMed and Web of Science from 2010 to 2019. Meta-analysis of proportion and their 95% confidence intervals (CIs) were calculated using the random-effect model. Meta-regression and subgroup analysis were used to search for heterogeneity origins.

Results

We included 42 Asian studies with 84.953 fine-needle aspirations. Among six categories, benign was the most commonly diagnosed category. The resection rate (RR) and risk of malignancy (ROM) were highest in malignant and SM categories, and lowest among benign nodules. Thyroid cytology practice in Asia was characterized by a low RR and high ROM in patients with indeterminate thyroid nodules. There was a significant amount of heterogeneities of TBSRTC outputs (frequency, resection rate, and malignancy risk) among Asian countries. Meta-regression showed that the sources of heterogeneity might stem from the differences in study origin and the application of molecular testing. We highlighted the usefulness of preoperative molecular testing to select patients for surgery.

Conclusions

Our study provided insight regarding thyroid cytology practice among Asian countries. Active surveillance is commonly used in Asian practice resulting in a low RR and high ROM for indeterminate nodules. There are still variations in general thyroid cytology practice in Asia. Future guidelines and consensus regarding the application of TBSRTC in thyroid cytology practice among Asian countries are required.

Molecular markers for the classification of cytologically indeterminate thyroid nodules

BACKGROUND

The diagnosis of indeterminate lesions of the thyroid is a challenge in cytopathology practice. Indeed, up to 30% of cases lack the morphological features needed to provide definitive classification. Molecular tests have been developed to assist in the diagnosis of these indeterminate cases. The first studies dealing with the preoperative molecular evaluation of FNA samples focused on the analysis of BRAF^V600E or on the combined evaluation of two or three genetic alterations. The sensitivity of molecular testing was then improved through the introduction of gene panels, which became available for clinical use in the late 2000s. Two different categories of molecular tests have been developed, the 'rule-out' methods, which aim to reduce the avoidable treatment of benign nodules, and the 'rule-in' tests that have the purpose to optimize surgical management. The genetic evaluation of indeterminate thyroid nodules is predicted to improve patient care, particularly if molecular tests are used appropriately and with the awareness of their advantages and weaknesses. The main disadvantage of these tests is the cost, which makes them rarely used in Europe. To overcome this limitation, customized panels have been set up, which are able to detect the most frequent genetic alterations of thyroid cancer.

CONCLUSIONS

In the present review, the most recent available versions of commercial molecular tests and of custom, non-commercial panels are described. Their characteristics and accuracy in the differential diagnosis of indeterminate nodules, namely Bethesda classes III (Atypical follicular lesion of undetermined significance, AUS/FLUS) and IV (Suspicious for follicular neoplasm, FN/SFN) are fully analyzed and discussed.

Value of rapid on-site evaluation for ultrasound-guided thyroid fine needle aspiration

Objective

Application of rapid on-site evaluation (ROSE) for thyroid fine needle aspiration (FNA) is controversial. Therefore, ROSE has not been universally applied. This study aimed to evaluate the value of ROSE for ultrasound-guided thyroid FNA.

Methods

A total of 997 patients with 1103 suspicious thyroid nodules had ultrasound-guided FNA performed from January 2016 to February 2018. There were 513 nodules with ROSE and 590 nodules without ROSE. The cytological nondiagnostic rate, needle passes, and procedural times of thyroid FNA with or without ROSE were compared. The nondiagnostic rates of subsets of suspicious thyroid nodules were further compared.

Results

There was no significant effect of ROSE on the nondiagnostic rate of FNA. However, FNA with ROSE significantly reduced the numbers of sub-centimeter, mixed solid-cystic, macrocalcified, and hypervascular nodules. There was a significantly smaller number of needle passes and less procedural times with ROSE than without ROSE. There was no significant difference in the complication rate of FNA with and without ROSE.

Conclusion

ROSE for thyroid FNA reduces the number of needle passes and procedural times. ROSE has a higher clinical application value in subsets of thyroid nodules, which tend to be difficult to diagnose with FNA.

Diagnostic Utility of Molecular and Imaging Biomarkers in Cytological Indeterminate Thyroid Nodules

Indeterminate thyroid cytology (Bethesda III and IV) corresponds to follicular-patterned benign and malignant lesions, which are particularly difficult to differentiate on cytology alone. As ~25% of these nodules harbor malignancy, diagnostic hemithyroidectomy is still custom. However, advanced preoperative diagnostics are rapidly evolving.This review provides an overview of additional molecular and imaging diagnostics for indeterminate thyroid nodules in a preoperative clinical setting, including considerations regarding cost-effectiveness, availability, and feasibility of combining techniques. Addressed diagnostics include gene mutation analysis, microRNA, immunocytochemistry, ultrasonography, elastosonography, computed tomography, sestamibi scintigraphy, [18F]-2-fluoro-2-deoxy-d-glucose positron emission tomography (FDG-PET), and diffusion-weighted magnetic resonance imaging.The best rule-out tests for malignancy were the Afirma® gene expression classifier and FDG-PET. The most accurate rule-in test was sole BRAF mutation analysis. No diagnostic had both near-perfect sensitivity and specificity, and estimated cost-effectiveness. Molecular techniques are rapidly advancing. However, given the currently available techniques, a multimodality stepwise approach likely offers the most accurate diagnosis, sequentially applying one sensitive rule-out test and one specific rule-in test. Geographical variations in cytology (e.g., Hürthle cell neoplasms) and tumor genetics strongly influence local test performance and clinical utility. Multidisciplinary collaboration and implementation studies can aid the local decision for one or more eligible diagnostics.

The largest CAP-certified Chinese reference laboratory experience with the Bethesda system for reporting thyroid cytopathology: correlation with histologic and BRAF data

INTRODUCTION

Thyroid fine needle aspiration biopsy (FNAB) has not been widely used in most areas of China. We investigated a large cohort of thyroid FNAB using the Bethesda system for reporting thyroid cytopathology (TBSRTC) from the largest College of American Pathology (CAP)-certified reference laboratory in China.

MATERIALS AND METHODS

Patients with thyroid FNAB between 2014 and 2016 from Guangzhou Kingmed Diagnostics were retrospectively retrieved and the histologic follow-up results and BRAF results were collected and analyzed.

RESULTS

A total of 7355 thyroid FNAB cases were identified. The average age of these patients was 48.03 years (range: 5-90 years). A total of 875 cases (11.9%) were reported as nondiagnostic, 4041 (54.9%) cases were benign, 736 cases (10.0%) were atypia of undetermined significance/follicular lesion of undetermined significance (AUS/FLUS), 53 cases (0.7%) were suspicious for follicular neoplasm, 615 cases (8.4%) were suspicious for malignancy, and 1035 cases (14.1%) were positive for malignancy. Histologic follow-up was available on 552 patients. Among 13 cases of AUS/FLUS, 8 (61.5%) had malignancy on histology; 195 (92.0%) of the suspicious for malignancy cases had malignancies on histology, and 320 (98.5%) of the positive for malignancy cases had malignancies on histology. BRAF analysis was performed on 578 cases. Sixty cases with BRAF data had histologic follow-up, all 4 benign cases had negative BRAF, one follicular adenoma had negative BRAF, and 37 of the 55 PTC cases (67.3%) had positive BRAF. BRAF mutation has a 100% positive predictive value of malignancy for the indeterminate thyroid FNABs.

CONCLUSIONS

This is the largest cohort of thyroid FNA reported using TBSRTC in China and the data are helpful for better understanding the status of thyroid FNA in China.

Comparative analysis of diagnostic performance, feasibility and cost of different test-methods for thyroid nodules with indeterminate cytology

Since it is impossible to recognize malignancy at fine needle aspiration (FNA) cytology in indeterminate thyroid nodules, surgery is recommended for all of them. However, cancer rate at final histology is <30%. Many different test-methods have been proposed to increase diagnostic accuracy in such lesions, including Galectin-3-ICC (GAL-3-ICC), BRAF mutation analysis (BRAF), Gene Expression Classifier (GEC) alone and GEC+BRAF, mutation/fusion (M/F) panel, alone, M/F panel+miRNA GEC, and M/F panel by next generation sequencing (NGS), FDG-PET/CT, MIBI-Scan and TSHR mRNA blood assay.We performed systematic reviews and meta-analyses to compare their features, feasibility, diagnostic performance and cost. GEC, GEC+BRAF, M/F panel+miRNA GEC and M/F panel by NGS were the best in ruling-out malignancy (sensitivity = 90%, 89%, 89% and 90% respectively). BRAF and M/F panel alone and by NGS were the best in ruling-in malignancy (specificity = 100%, 93% and 93%). The M/F by NGS showed the highest accuracy (92%) and BRAF the highest diagnostic odds ratio (DOR) (247). GAL-3-ICC performed well as rule-out (sensitivity = 83%) and rule-in test (specificity = 85%), with good accuracy (84%) and high DOR (27) and is one of the cheapest (113 USD) and easiest one to be performed in different clinical settings.In conclusion, the more accurate molecular-based test-methods are still expensive and restricted to few, highly specialized and centralized laboratories. GAL-3-ICC, although limited by some false negatives, represents the most suitable screening test-method to be applied on a large-scale basis in the diagnostic algorithm of indeterminate thyroid lesions.

BRAFV600E mutation as a predictor of thyroid malignancy in indeterminate nodules: A systematic review and meta-analysis

BACKGROUND

Thyroid nodules are usually diagnosed using fine-needle aspiration (FNA). The sensitivity limitations of FNA result in 10-30% of nodules being classified as "indeterminate". The BRAF^V600E mutation is associated with papillary thyroid carcinoma (PTC). We conducted a systemic review and meta-analysis to evaluate the diagnostic utility of the BRAF^V600E mutation in indeterminate nodules.

METHOD

PUBMED and EMBASE were searched for studies testing for the BRAF^V600E involving indeterminate nodules (Thy3a, Thy3f, Thy4) and containing information on final surgical histopathology. Thirty two studies involving 3150 indeterminate nodules were included in the analysis.

RESULTS

The overall sensitivity and specificity for BRAF^V600E for the diagnosis of thyroid malignancy was 0.40 (95% CI: 0.32-0.48) and 1.00 (95% CI: 0.98-1.00) respectively. The diagnostic odds ratio (DOR) was 205.4 (95% CI: 40.1-1052). With a Fagan plot, the post-test probability of thyroid cancer, given a negative mutation was 6%, but this rose to 92% with a positive result. On subgroup analysis, for Thy3a nodules, the pooled sensitivity and specificity for thyroid malignancy was 0.21 (95% CI: 0.13-0.34) and 1.00 (95% CI: 0.98-1.00). For Thy3f nodules, the pooled sensitivity and specificity was 0.09 (95% CI: 0.03-0.20) and 1.00 (95% CI: 0.05-1.00) respectively. For Thy4 nodules, the corresponding sensitivity and specificity was 0.58 (95% CI: 0.5-0.64) and 0.99 (95% CI: 0.95-1.00) respectively.

CONCLUSIONS

Despite a high specificity for thyroid cancer, BRAF^V600E mutation has a low overall sensitivity and therefore has a limited diagnostic value as a single screening test.

Diagnostic value of BRAF (V600E)-mutation analysis in fine-needle aspiration of thyroid nodules: a meta-analysis

Fine-needle aspiration (FNA) is a reliable method for preoperative diagnosis of thyroid nodules; however, about 10%–40% nodules are classified as indeterminate. The BRAF^V600E mutation is the most promising marker for thyroid FNA. This meta-analysis was conducted to investigate the diagnostic value of BRAF^V600E analysis in thyroid FNA, especially the indeterminate cases. Systematic searches were performed in PubMed, Web of Science, Scopus, Ovid, Elsevier, and the Cochrane Library databases for relevant studies prior to June 2015, and a total of 88 studies were ultimately included in this meta-analysis. Compared with FNA cytology, the synergism of BRAF^V600E testing increased the diagnostic sensitivity from 81.4% to 87.4% and decreased the false-negative rate from 8% to 5.2%. In the indeterminate group, the mutation rate of BRAF^V600E was 23% and varied in different subcategories (43.2% in suspicious for malignant cells [SMC], 13.77% in atypia of undetermined significance/follicular lesion of undetermined significance [AUS/FLUS], and 4.43% in follicular neoplasm/suspicious for follicular neoplasm [FN/SFN]). The sensitivity of BRAF^V600E analysis was higher in SMC than that in AUS/FLUS and FN/SFN cases (59.4% vs 40.1% vs 19.5% respectively), while specificity was opposite (86.1% vs 99.5% vs 99.7% respectively). The areas under the summary receiver-operating characteristic curve also confirmed the diagnostic value of BRAF^V600E testing in SMC and AUS/FLUS rather than FN/SFN cases. Therefore, BRAF^V600E analysis can improve the diagnostic accuracy of thyroid FNA, especially indeterminate cases classified as SMC, and select malignancy to guide the extent of surgery.

Clinical impact of BRAF mutation on the diagnosis and prognosis of papillary thyroid carcinoma: a systematic review and meta-analysis

BACKGROUND

The possible role of BRAF(V) (600E) mutation in the diagnosis and prognosis of papillary thyroid carcinoma (PTC) remains controversial. A systematic review to investigate the diagnostic and prognostic role of BRAF(V) (600E) mutation in patients with PTC is urgently needed.

METHODS

A systematic review of relevant literatures was performed in PubMed, EMBASE and CENTRAL. The incremental accuracy (IA) of fine needle aspiration biopsy plus BRAF(V) (600E) mutation analysis over fine needle aspiration biopsy alone, and the statistical data about the association of BRAF(V) (600E) mutation and the prognosis of PTC (risk ratios (RR) for dichotomous data, standard mean differences for continuous data and hazard ratios (HRs) for disease-free survival (DFS) were pooled. Subgroup analysis was performed to explain the heterogeneities.

RESULTS

A total of 67 studies were included. The pooled IA was 2% (95% confidence interval (CI): 0·5-4%). The pooled RR for gender, multifocality, lymph node metastasis, extrathyroidal invasion and pathological stage was 1·11 (95% CI: 0·98-1·25), 1·17 (95% CI: 1·09-1·24), 1·36 (95% CI: 1·20-1·53), 1·60 (95% CI: 1·41-1·82), and 1·49 (95% CI: 1·33-1·68), respectively. The pooled standard mean differences for age and tumour size were 0·14 (95% CI: 0·04-0·23) and 0·21 (95% CI: 0·1-0·32), respectively. The pooled HR for DFS was 1·96 (95% CI: 1·62-2·37). Subgroup analysis showed that these statistical results were affected by the geographical background of patients, study design and detection methods.

CONCLUSIONS

BRAF(V) (600E) mutation analysis can not only be used in the diagnosis of PTC, but can also predict its prognosis.

RAS Mutations in AUS/FLUS Cytology: Does it Have an Additional Role in BRAFV600E Mutation-Negative Nodules?

The object of this study is to evaluate the additional role of RAS mutation in detecting thyroid malignancy among BRAF mutation-negative nodules diagnosed as atypia of undetermined significance/follicular lesion of undetermined significance (AUS/FLUS) on cytology.From December 2009 to December 2011, 202 BRAF mutation-negative thyroid nodules diagnosed as AUS/FLUS cytology in 201 patients were included in this study. RAS mutation analysis was performed using residual material from ultrasonography-guided fine needle aspiration (US-FNA) cytology testing for K-RAS, N-RAS, and H-RAS codons 12/13 and 61 point mutations. The authors evaluated the association between RAS mutation status and cytopathologic characteristics.Of the 202 BRAF mutation-negative thyroid nodules with AUS/FLUS cytology, 4 were considered insufficient for mutation analysis. Of the 198 thyroid nodules, 148 (74.7%) were confirmed as benign and 50 (25.3%) as malignant. Thirty-one (15.7%) of the 198 thyroid nodules were positive for any RAS mutation, 4 positive for K-RAS 12/13, 26 for N-RAS 61, and 1 positive for H-RAS 61. Seven (22.6%) of the RAS mutation positive nodules were malignant, 1 with K-RAS 12/13, 6 with N-RAS 61. Twenty-four (77.4%) of the 31 nodules positive for K-RAS 12/13 (N = 3), N-RAS 61 (N = 20), or H-RAS 61 (N = 1) mutations were proven benign. None of the 198 thyroid nodules were positive for K-RAS 61, N-RAS 12/13, or H-RAS 12/13 mutations.N-RAS 61 mutation is the most common mutation detected among BRAF mutation-negative nodules with AUS/FLUS cytology. RAS mutation has limited value in predicting malignancy among BRAF mutation-negative thyroid nodules with AUS/FLUS cytology and further, investigation is anticipated to evaluate the true role of RAS mutation in thyroid malignancy.

Evaluation of the Real-Q BRAF V600E Detection Assay in Fine-Needle Aspiration Samples of Thyroid Nodules

Recently, several molecular assays for detecting the BRAF V600E mutation in fine-needle aspiration (FNA) specimens have been developed. Herein, we tested 294 consecutive FNA samples from patients with thyroid nodules with the Real-Q BRAF V600E detection assay (Real-Q). These results were compared with an allele-specific PCR-based kit using dual-priming oligonucleotides (AS-PCR). Any discordant results between the two tests were also analyzed by mutant enrichment with 3'-modified oligonucleotide sequencing. A total of 128 cases were confirmed histologically; of these, 121 were diagnosed as papillary thyroid carcinoma (PTC). The BRAF mutation was detected by Real-Q and AS-PCR testing in 80.2% (95% CI, 71.9%-86.9%) and 76.9% (95% CI, 68.3%-84.0%), respectively, of FNA specimens with PTC. Combining the BRAF V600E molecular assays (Real-Q and AS-PCR) with cytological diagnoses of malignant and suspicious for malignant cells, the detection rates (sensitivity) of Real-Q and AS-PCR for diagnosis of PTC increased to 94.2% (95% CI, 88.4%-97.6%) and 92.6% (95% CI, 86.4%-96.5%), respectively. In conclusion, the detection of BRAF V600E mutations in PTC by Real-Q is compatible to that of AS-PCR.

Clinical Implication of Highly Sensitive Detection of the BRAFV600E Mutation in Fine-Needle Aspirations According to the Thyroid Bethesda System in Patients With Conventional Papillary Thyroid Carcinoma

BACKGROUND

We investigated the additional diagnostic yield of the mutation test and evaluated the frequency of the BRAF mutation in conventional PTC (cPTC) according to ultrasound (US) features and the Bethesda System for Reporting Thyroid Cytopathology (BSRTC) based on the BRAFV600E mutation status.

MATERIALS AND METHODS

During the study period, 279 patients who underwent FNA with an additional BRAFV600E mutation test were diagnosed as cPTC after surgery. We analyzed the association between the mutation and several clinical factors.

RESULTS

Of the 279 cPTCs, 250 (89.6%) had the BRAFV600E mutation. The BRAF mutation test was helpful in diagnosing an additional 19% (53/279) of cPTCs. The frequency of the BRAF mutation in cPTCs with suspicious US features was higher than that of cPTCs with negative US features regardless of the BSRTC.

CONCLUSIONS

Suspicious US features may be helpful in deciding whether an additional BRAFV600E mutation test should be done in thyroid nodules with indeterminate cytology.

Additional BRAF mutation analysis may have additional diagnostic value in thyroid nodules with "suspicious for malignant" cytology alone even when the nodules do not show suspicious US features

The BRAF(V600E) mutation test has been more effective in thyroid nodules with suspicious US features than ones without suspicious features. Therefore, we investigated the role of the BRAF(V600E) mutation as an additional study to cytology in diagnosing a thyroid nodule without suspicious US features. This study was performed at Severance hospital from December 2010 through February 2012. During this period, 2,650 patients with 2,918 nodules underwent FNA with an additional BRAF(V600E) mutation test. Among them, we excluded thyroid nodules with suspicious US features. Finally, 485 thyroid nodules in 466 patients (mean age 50.3 years; range 9-80 years) were included in this study. We compared the differences between patients with malignant and benign thyroid nodules. We evaluated the detection rates of the BRAF(V600E) mutation according to the Bethesda System for Reporting Thyroid Cytopathology (BSRTC). There were 60 (60/485, 12.4 %) malignant and 425 (425/485, 87.6 %) benign nodules. The detection rate of the BRAF(V600E) mutation in thyroid nodules without suspicious US features was only 6.6 % (32/485). Most had malignant cytology (62.5 %, 20/32). For nodules without malignant cytology, only 12 nodules (2.6 %, 12/462) had the BRAF mutation. Among the 12 nodules, nine nodules were suspicious for malignancy on cytology. Additional BRAF mutation analysis shows additional diagnostic value in thyroid nodules with "suspicious for malignant" cytology alone even when the nodules do not show suspicious US features. Therefore, the test should be selectively performed in thyroid nodules without suspicious US features, considering cost-effectiveness as well as diagnostic accuracy.

Role of BRAF molecular analysis in the management of papillary thyroid carcinoma: analysis of cytological and histological samples

BACKGROUND

Although fine needle aspiration (FNA) is the standard diagnostic test for the characterization of a suspicious thyroid nodule, in some cases cytological evaluation is inconclusive. The aim of this study was to determine the role of BRAF mutation in aiding diagnosis and to verify whether archival cytological samples could be suitable for molecular analysis.

METHODS

Eighty-five patients with suspicious (Thy4) or follicular (Thy3) lesions on cytology were resubmitted to a second FNA for BRAF mutation analysis. Of these, 56 subsequently underwent surgery. The usefulness of archival samples for molecular analysis was also studied in a second cohort of 42 patients with a confirmed diagnosis of papillary thyroid carcinoma for whom both archived paraffin-embedded histological samples and cytological smears were available. A further 15 patients with paired fresh FNA and archived cytological and histological samples were recruited.

RESULTS

BRAF mutation was found in the fresh FNA samples from 10 of 56 patients who had surgery with previous inconclusive cytology (4/45, 9%, Thy3 and 6/11, 55%, Thy4). The BRAF test showed a specificity and positive predictive value of 100% (26/26 and 10/10, respectively), sensitivity of 33% (10/30) and negative predictive value of 57% (26/46). There was absolute concordance between the BRAF results obtained with 42 histological and cytological archived samples. BRAF analysis on 15 archived cytological samples showed absolute concordance with histology, whereas there was one false negative on the matched fresh FNA.

CONCLUSION

BRAF analysis is a highly specific test that can facilitate cytological diagnosis in some cases and can also be performed on archived cytological samples.

The prediction of malignant risk in the category "atypia of undetermined significance/follicular lesion of undetermined significance" of the Bethesda System for Reporting Thyroid Cytopathology using subcategorization and BRAF mutation results

BACKGROUND

The "atypia of undetermined significance/follicular lesion of undetermined significance" (AUS/FLUS) category in the Bethesda System for Reporting Thyroid Cytopathology is a heterogeneous category of cases that are not clearly benign or malignant.

METHODS

We conducted an analysis of cytologic and histologic evaluations of thyroid nodules that had been interpreted as AUS/FLUS on fine-needle aspiration (FNA) at a single institution from April 2011 to April 2012. Those cases were classified into 2 subgroups according to the predominance of nuclear atypia (AUS) or microfollicular architecture (FLUS). In addition, for a number of these cases, BRAF gene mutation analyses were performed.

RESULTS

Of 6402 thyroid FNAs performed, 431 cases were diagnosed as AUS and 120 as FLUS. Follow-up cytologic or histologic outcome data were available for 315 AUS cases and 73 FLUS cases. Among AUS cases, 52.7% were malignant on repeat FNA or histologic diagnosis. In contrast, for FLUS, 6.8% were malignant on repeat FNA or histologic diagnosis. Among AUS/FLUS cases, 147 had adequate BRAF mutation analysis, which accompanied the histologic diagnosis. BRAF mutations were found in 87 AUS cases, 86 of which were papillary carcinoma. In contrast, there was only 1 case of BRAF mutation in FLUS. Correlating molecular results with histologic outcome revealed a 98.9% cancer probability for AUS cases with BRAF mutation.

CONCLUSIONS

The AUS subcategory indicates a higher risk of malignancy than the FLUS subcategory. Furthermore, BRAF molecular testing is helpful in stratifying the malignant risk of AUS cases into high-risk and low-risk groups.

Diagnostic value of B-RAF(V600E) in difficult-to-diagnose thyroid nodules using fine-needle aspiration: systematic review and meta-analysis

Fine-needle aspiration (FNA) is routinely used in the preoperative evaluation of thyroid nodules. However, approximately 5-20% of thyroid nodules are considered indeterminate or suspicious cases that do not meet clinical standards. The B-RAF(V600E) mutation has been reported in FNA specimens. We conducted a systematic review to evaluate the diagnostic value of testing for B-RAF(V600E) in thyroid nodules that are difficult to diagnose by FNA. A systematic literature search was performed from January 1, 2002 to June 30, 2012. Articles were obtained by searching two electronic databases (MEDLINE and EMBASE), hand searching selected journals, and contacting authors. Article quality was assessed using the Quality Assessment of Diagnostic Accuracy Studies (QUADAS) tool. Sensitivity, specificity, and other measures of accuracy were pooled using random effects models. Summary receiver operating characteristic (SROC) curves were used to summarize overall diagnostic accuracy. A total of 16 studies incorporating 1131 patients were included in a meta-analysis on diagnostic accuracy of B-RAF(V600E) tests. Pooled sensitivity was 0.60 (95% confidence interval [CI]: 0.556-0.634), pooled specificity was 0.99 (95% CI 0.976-0.997), and the area under the curve of the SROC curve was 0.8376. Q index value was 0.7696. Our data suggest a potentially useful adjunct to evaluating thyroid nodules that are difficult to diagnose. The B-RAF(V600E) test has a high positive predictive value and could help clinicians formulate a more individualized treatment schedule. When supplemented with other noninvasive test methods, the B-RAF(V600E) test could be a powerful adjunct with extensive clinical applications.

Rapid onsite evaluation improves the adequacy of fine-needle aspiration for thyroid lesions: a systematic review and meta-analysis

BACKGROUND

Fine-needle aspiration (FNA) with ultrasonography guidance is one of the optimal techniques for the diagnostic evaluation of thyroid nodules. A significant subset of thyroid FNAs continues to be inadequate for interpretation, which potentially leads to increased costs from repeat aspirations. Numerous studies have been published regarding the influence of rapid onsite evaluation (ROSE) by cytopathologists on thyroid FNAs, some indicating that FNA is more likely to be adequate for interpretation with ROSE, while others refute this idea. To our knowledge, no meta-analysis of the literature on this subject has been undertaken.

METHODS

We searched MEDLINE and EMBASE using the following search string: (needle biopsy) AND (assessment or onsite OR onsite or immediate or rapid)/title or abstract. There were no restrictions on study design, language, anatomic site, or time period. Only studies comparing two arms (with/without ROSE) at a single site were eligible for inclusion. Potentially relevant studies were subjected to a citation search (forward search) and reference search (backward search) using SCOPUS. Statistical calculations were performed using Stata Release 12. Meta-analysis was completed using a random-effect model as implemented in the metan routine in Stata.

RESULTS

An initial search obtained 2179 studies from MEDLINE and EMBASE, and screening yielded 71 potentially relevant studies. A focused review of this subset resulted in seven full studies and one abstract that met our inclusion criteria. Our citation search using SCOPUS yielded no new studies. Overall, the average adequacy rate was 83% without ROSE compared to 92% with ROSE. Visual inspection of the data suggested that the improvement in adequacy due to ROSE may be related to the adequacy rate without ROSE. Metaregression analysis showed that the change in the adequacy rate was strongly correlated (t=-12.7, p<0.001) with the non-ROSE adequacy rate. In addition, the non-ROSE adequacy rate explained all, but 10% of the residual between study variability in the change in the adequacy rates due to ROSE.

CONCLUSIONS

ROSE is generally associated with an improvement in adequacy, but the impact of ROSE depends heavily on the initial adequacy rate. Sites with lower initial adequacy rates can benefit the most from the implementation of ROSE.

BRAF test and cytological diagnosis with a single fine needle cytology sample

OBJECTIVE

Recently, fine needle cytology (FNC) of the thyroid has been combined with biomolecular analysis. In particular, there has been detailed study of the V600E-BRAF mutation. The aim of our study is to demonstrate that with a single thyroid sample it is possible to obtain enough cellular material for both cytological diagnosis and a V600E-BRAF molecular test.

STUDY DESIGN

FNC was carried out under ultrasound guidance aided by an echographist and cytopathologist. We acquired one biopsy for each nodule with a 23-gauge needle without suction. The preparations were smeared by the pathologist onto one glass slide, air dried and stained with Diff-Quick. Cell adequacy was evaluated for each patient. The needle was washed by aspirating 2 ml of physiologic solution which was collected into a tube. The material was collected for molecular testing.

RESULTS

The following cytological diagnoses were made: not neoplastic, Tir2 (n = 227); indeterminate, Tir3 (n = 15); suspicious, Tir4 (n = 4), and malignancy, Tir5 (n = 12). The V600E-BRAF mutation was found in 0 of 227 Tir2 specimens, 2 of 15 (13.3%) Tir3 specimens, 2 of 4 (50%) Tir4 specimens and 9 of 12 (75%) Tir5 specimens.

CONCLUSIONS

Our data showed that, in a routine clinical setting, FNC specimens can be handled properly to provide both morphological and molecular information. In fact, our tests show that with a single specimen it is possible to set up a slide for the cytological diagnosis and to obtain enough residual cellular material for DNA extraction (>70 ng) and for the identification of the V600E-BRAF mutation.

Employing genetic markers to improve diagnosis of thyroid tumor fine needle biopsy

Fine-Needle Aspiration (FNA) is the most widely used and cost-effective preoperative test for the initial evaluation of a thyroid nodule, although it has limited diagnostic accuracy for several types of tumors. Patients will often receive cytological report of indeterminate cytology and are referred to surgery for a more accurate diagnosis. An improved test would help physicians rapidly focus treatment on true malignancies and avoid some unnecessary treatment of benign tumors. This review will discuss current molecular markers that may improve thyroid nodule diagnosis.

BRAF mutation detection in indeterminate thyroid cytology specimens: underlying cytologic, molecular, and pathologic characteristics of papillary thyroid carcinoma

BACKGROUND

BRAF mutations are highly specific for papillary thyroid carcinoma (PTC) and many cytology specimens with BRAF mutations are expected to demonstrate cytologic features typical of PTC. However, indeterminate thyroid cytology cases are inevitable and understanding the significance of the BRAF mutation within the context of the Bethesda System for Reporting Thyroid Cytopathology would be valuable.

METHODS

Thyroid cytology cases submitted for conventional cytomorphologic evaluation and BRAF mutational analyses were selected from the authors' cytopathology files from April 2007 to October 2011. From this group, the diagnostic usefulness of BRAF mutations in indeterminate and malignant cases was assessed and analyses of cytologic and histopathologic features associated with the mutations in this gene were performed.

RESULTS

A total of 131 cases with a BRAF mutation were identified. Of these, 119 underwent surgical pathology resection follow-up and demonstrated PTC. Approximately 75% of the cases were cytologically diagnosed as being positive for malignancy and these cases were associated with both the classic and tall cell variants of PTC at the time of resection, a greater likelihood of extrathyroidal extension, and the V600E type of BRAF mutation. In contrast, BRAF-mutated cases with diagnoses of atypia of undetermined significance/follicular lesion of undetermined significance (AUS/FLUS) and follicular neoplasm/suspicious for follicular neoplasm were found to be more strongly associated with the follicular variant of PTC, a K601E BRAF mutation, and a lower likelihood of extrathyroidal extension. However, a subset of AUS/FLUS cases with the V600E BRAF mutation appeared to represent sampling variability of the classic or tall cell variants of PTC.

CONCLUSIONS

Bethesda thyroid diagnoses in the setting of a BRAF mutation reflect differences in PTC subtypes, the nature of cytology specimens, and molecular characteristics.

Thyroid nodule management: clinical, ultrasound and cytopathological parameters for predicting malignancy

Although fine-needle aspiration cytology is considered to be the reference method for evaluating thyroid nodules, the results are inaccurate in approximately 10-30% of cases. Several studies have attempted to predict the risk of malignancy in thyroid nodules based on age, nodularity, thyrotropin values, thyroid autoimmune disease, hot/cold nodule status, and ultrasound parameters. However, no consensus has been found, and none of these parameters has significantly affected patient management. The management of indeterminate thyroid nodules and re-biopsies of nodules with initially benign cytological results remain important and controversial topics of discussion. The Bethesda cytological system and several studies on the use of molecular markers to predict malignancy from cytological samples of thyroid nodules need further clarification. More in-depth discussions among and continuous education of the specialists involved in treating thyroid disease are necessary to improve the management of these patients. This review aims to examine the clinical, laboratory, ultrasound, and scintigraphic parameters that can be used for thyroid nodule management.

Clinical implication of highly sensitive detection of the BRAF V600E mutation in fine-needle aspirations of thyroid nodules: a comparative analysis of three molecular assays in 4585 consecutive cases in a BRAF V600E mutation-prevalent area

CONTEXT

Detection of the BRAF V600E mutation in fine-needle aspiration cytology (FNAC) specimens may increase the value of FNAC.

OBJECTIVE

The objectives of the study was to compare the diagnostic performance of BRAF assays that differ in sensitivity and to examine the associations between the BRAF V600E mutation status and the clinicopathological features in papillary thyroid carcinoma (PTC).

DESIGN AND SETTING

Three molecular assays were performed in all subjects and compared with regard to FNAC and histology results.

PARTICIPANTS

We evaluated 4585 consecutive patients who were found to have malignant or indeterminate thyroid nodules by ultrasonography.

OUTCOME MEASURES

All FNAC samples were tested for the BRAF V600E mutation using conventional Sanger sequencing, dual-priming oligonucleotide-PCR, and mutant enrichment with 3'-modified oligonucleotide (MEMO) sequencing.

RESULTS

The detection sensitivities of the three molecular assays for the BRAF V600E mutation were 20, 2, and 0.1%, respectively. Compared with conventional Sanger sequencing (n = 673), dual-priming oligonucleotide-PCR and MEMO sequencing detected more tumors with the BRAF V600E mutation (n = 919 and n = 1044, respectively), especially tumors with a benign, indeterminate, or nondiagnostic cytology. All BRAF-positive tumors that were histologically examined were shown to be PTC, regardless of cytology results. The clinical sensitivities of the three assays for detecting PTC were 54.8, 74.4, and 79.7%, respectively. BRAF V600E mutations in microcarcinomas (≤ 10 mm) were detected more efficiently as the detection sensitivity of the assay increased (P < 0.001). Tumor size correlated significantly with multifocality, extrathyroidal extension, and lymph node metastasis (P = 0.003, P < 0.001 and P < 0.001, respectively), but the BRAF V600E mutation status was not associated with any of those features.

CONCLUSION

Highly sensitive and specific molecular assays such as MEMO sequencing are optimal for detecting the BRAF mutations in thyroid FNAC because these techniques can detect PTC that might be missed by cytology or less sensitive molecular assays.