Pilot of BRAF mutation analysis in indeterminate, suspicious and malignant thyroid FNA cytology

MRI-Based Texture Analysis for Preoperative Prediction of BRAF V600E Mutation in Papillary Thyroid Carcinoma

Purpose

BRAF V600E mutation can compensate for the low detection rate by fine-needle aspiration (FNA) and is related to aggressiveness and lymph node metastasis. This study aimed to investigate the relationship between texture analysis features based on magnetic resonance imaging (MRI) and mutations.

Methods

Retrospective analysis was performed on patients with postoperative pathology confirmed papillary thyroid carcinoma (PTC) from 2017 to 2021. One thousand one hundred and thirty-two texture features were extracted from T2-weighted imaging (T2WI) and contrast-enhanced T1-weighted imaging (CE-T1WI) separately by outlining the tumor volume of interest (VOI). Univariate, minimum redundancy maximum relevance (mRMR), and multivariate analyses were used for feature selection to construct 3 models (T2WI, CE-T1WI, and combined model) to predict mutation. The reproducibility between observers was evaluated by intraclass correlation coefficient (ICC). Receiver operating characteristic (ROC) analysis was used to assess the performance of models. The diagnostic performance of the optimal cut-off value of models were calculated and validated by 10-fold cross-validation.

Results

A total of 80 PTCs (22 BRAF V600E wild-type and 58 BRAF V600E mutant) were included in our study. Good interobserver agreement was found on texture features we selected (all ICCs >0.75). The area under the ROC curves (AUCs) for the T2WI model, CE-T1WI model, and combined model were 0.83 (95% CI: 0.75-0.91), 0.83 (95% CI: 0.73-0.90), and 0.88 (95% CI: 0.81-0.94), respectively. The accuracy, sensitivity, specificity, PPV, and NPV were 0.776, 0.679, 0.905, 0.905, and 0.679 for the T2WI model at a cut-off value of 0.674; 0.755, 0.750, 0.762, 0.808, and 0.696 for the CE-T1WI model at a cut-off value of 0.573; 0.816, 0.893, 0.714, 0.806, and 0.833 for the combined model at a cut-off value of 0.420.

Conclusion

MRI-based texture analysis could be a potential method for predicting BRAF V600E mutation in PTC preoperatively.

Yield and costs of molecular diagnostics on thyroid cytology slides in the Netherlands, adapting the Bethesda classification

Objective

To evaluate our institutional experience with molecular diagnostics (MD) on thyroid cytology smears, evaluate the costs and describe MD guided clinical management of indeterminate Bethesda III/V thyroid nodules.

Methods

We performed a retrospective review of 164 Bethesda III or V thyroid cytopathology reports subjected to MD from 2013 to 2020, that altered Bethesda classification or management. MD consisted of mutation and gene fusion analysis by next‐generation sequencing (NGS) of morphologically analysed and selected cytological slides. Findings were modelled to nationwide data on Bethesda incidences from ‘the Dutch Pathology Registry’ PALGA, and costs were estimated.

Results

82 of 164 cases received an upgrade in Bethesda class. Twenty cases changed from Bethesda III to IV/V, 62 from Bethesda III or V to VI, and 72 remained unaltered. We estimate net savings with implementing MD, by preventing 454 repeat cytology and 326 (diagnostic) hemithyroidectomies, to be at least 2 million Euro annually in the Netherlands. Per Bethesda III and V patient, net savings would be about 100 Euro and 4100 Euro, respectively.

Conclusion

NGS‐based MD on nucleic acids extracted directly from cytology slides is a feasible and cost saving tool for personalized management in indeterminate Bethesda III/V thyroid cytology. Based on the interpretation of our retrospective data, we assume that this approach results in less disease burden for the patient, reduced surgical interventions and complication risks, reduced sick leave, among others. Further evaluation of structural implementation of the presented approach in routine thyroid Bethesda III/V cytology in a prospective setting is warranted.

Serum Metabolomics Study of Papillary Thyroid Carcinoma Based on HPLC-Q-TOF-MS/MS

This study examined metabolite profile differences between serum samples of thyroid papillary carcinoma (PTC) patients and healthy controls, aiming to identify candidate biomarkers and pathogenesis pathways in this cancer type. Serum samples were collected from PTC patients (n = 80) and healthy controls (n = 80). Using principal component analysis (PCA), partial least squares discrimination analysis(PLS-DA), orthogonal partial least square discriminant analysis (OPLS-DA), t-tests, and the volcano plot, a model of abnormal metabolic pathways in PTC was constructed. PCA, PLS-DA, and OPLS-DA analysis revealed differences in serum metabolic profiles between the PTC and control group. OPLS-Loading plot analysis, combined with Variable importance in the projection (VIP)>1, Fold change (FC) > 1.5, and p < 0.05 were used to screen 64 candidate metabolites. Among them, 22 metabolites, including proline betaine, taurocholic acid, L-phenylalanine, retinyl beta-glucuronide, alpha-tocotrienol, and threonine acid were upregulated in the PTC group; meanwhile, L-tyrosine, L-tryptophan, 2-arachidonylglycerol, citric acid, and other 42 metabolites were downregulated in this group. There were eight abnormal metabolic pathways related to the differential metabolites, which may be involved in the pathophysiology of PTC. Six metabolites yielded an area under the receiver operating curve of >0.75, specifically, 3-hydroxy-cis-5-tetradecenoylcarnitine, aspartylphenylalanine, l-kynurenine, methylmalonic acid, phenylalanylphenylalanine, and l-glutamic acid. The Warburg effect was observed in PTC. The levels of 3-hydroxy-cis-5-tetradecenoylcarnitine, aspartylphenylalanine, l-kynurenine, methylmalonic acid, phenylalanine, and L-glutamic acid may help distinguish PTC patients from healthy controls. Aspartic acid metabolism, glutamic acid metabolism, urea cycle, and tricarboxylic acid cycle are involved in the mechanism of PTC.

Preoperative molecular testing in thyroid nodules with Bethesda VI cytology: Clinical experience and review of the literature

Risk assessment is critical to determine the timing of elective surgeries and preserve valuable resources in time of pandemic. This study was undertaken to better understand the potential value of molecular testing to risk‐stratify thyroid nodules with malignant cytology (Bethesda VI). Systematic review of the literature contributed 21 studies representing 2036 preoperative specimens. The BRAF p.V600E substitution was detected in 46% to 90% of cases with a pooled positivity rate of 70% (95% confidence intervals: 64%‐76%). None of the studies used comprehensive oncogene panels. Retrospective analysis of 531 clinical specimens evaluated with the next‐generation sequencing ThyGeNEXT Thyroid Oncogene Panel identified a total of 436 gene alterations. BRAF mutation rate was 64% in specimens tested as part of standard clinical care and 75% in specimens from cross‐sectional research studies (P = .022). Testing for additional actionable gene alterations such as TERT promoter mutations or RET and NTRK gene rearrangements further increased the diagnostic yield to 78%‐85% and up to 95% when including the ThyraMIR Thyroid miRNA Classifier. These data support the role of molecular cytopathology in surgical and therapeutic decision‐making and warrant additional studies.

The role of molecular genetics in the presurgical management of thyroid nodules

INTRODUCTION

Fine-needle aspiration (FNA) is an important diagnostic tool for the evaluation of thyroid nodules. However, in almost ¼ of all nodules submitted to FNA cytology is indeterminate. Since the majority of genetic alterations in thyroid cancer have been identified, the use of molecular testing platforms has been endorsed by American Thyroid Association for management of indeterminate nodules.

EVIDENCE ACQUISITION

Several commercial tests were based on mRNA expression of FNA samples (Afirma®, Veracyte, South San Francisco, CA, USA) while others detect DNA alterations (ThyroSeq, UPMC, Pittsburgh, PA, USA). Noncommercial tests detect limited number of point mutations or re-arrangements (gene panels). Literature study included a Pubmed research for adult original studies from 2003 to 2020, focusing on terms such as "molecular tests," "nodules with indeterminate AUS/FLUS and FN/SFN cytology."

EVIDENCE SYNTHESIS

Gene expression profile tests serve as "rule out" tests due to their high negative predictive value and perform better in a setting of low cancer pretest probability. Genetic alteration platforms display high positive predictive value and serve as rather "rule in" tests but their diagnostic accuracy is hampered either because a small proportion of nodules does not harbor any of these alterations targeted (gene panels) or because commonly identified RAS mutations can also be found in benign nodules.

CONCLUSIONS

Next generation sequencing development and incorporation of other genetic markers such as miRNA can improve diagnostic accuracy of molecular tests.

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.

Testing for BRAF (V600E) Mutation in Thyroid Nodules with Fine-Needle Aspiration (FNA) Read as Suspicious for Malignancy (Bethesda V, Thy4, TIR4): a Systematic Review and Meta-analysis

In patients with thyroid fine-needle aspiration (FNA) report of suspicious for malignancy (SFM), both lobectomy and thyroidectomy might be considered. BRAF mutation analysis could guide towards accurate surgical therapy. The primary outcome was the reliability of BRAF (V600E) in detecting malignancy in nodules with FNA reading of SFM. The secondary outcome was to analyze its positive predictive value (PPV) and negative predictive value (NPV) considering the surgical histology as gold standard. A literature search of online databases was performed in June 2019. BRAF prevalence among thyroid nodules with FNA read as SFM according to the most popular classification systems (i.e., Bethesda V, Thy4, TIR4 category) was searched. The random-effects model was used. Three hundred sixty original articles were identified and 34 were finally included in the study. There were 1428 thyroid nodules with FNA read as SFM and 1287 (90.1%) lesions underwent surgery with a cancer rate 89.6%. The pooled prevalence of BRAF (V600E) mutation among all nodules with SFM cytology was 47% (95% CI = 40 to 54, I2 = 85.5%). Pooled PPV and NPV of BRAF testing were 99% (95% CI, 97-99) and 24% (95% CI, 16-32), respectively. BRAF (V600E) mutation was found in about one in two nodules with thyroid FNA read as SFM, its PPV to detect cancers was excellent, and its NPV was very poor. The routine BRAF testing in FNA read as SFM cannot be recommended. BRAF (V600E) test may be useful to extend surgical approach in selected cases with further suspicious clinical/ultrasound features.

The Role of BRAF V600E in Reducing AUS/FLUS Diagnosis in Thyroid Fine Needle Aspiration

BRAF V600E mutations are common in papillary thyroid carcinoma (PTC) and some de-differentiated thyroid cancers. In this study, we summarize AUS/FLUS diagnosed cases from thyroid fine needle aspirations in our center from 2015 to 2017 to explore the impact of BRAF V600E detection on the cytopathological diagnosis of PTC. BRAF V600E detection could significantly reduce the AUS/FLUS diagnosis rates from 11.59 to 8.42% when all BRAF V600E-mutated AUS/FLUS cases were diagnosed as conforming to PTC (20.01 to 19.13% in 2016 and 10.92 to 7.93% in 2017, respectively). The AUS/M rates decreased from 0.67 to 0.64 in 2016 and from 0.33 to 0.23 in 2017. We further discuss a case with a single BRAF V600E cytological mutant lacking a postoperative PTC diagnosis and discuss the limitations of BRAF V600E detection using puncture elution fluid. Our findings support the notion that BRAF V600E detection can effectively reduce the diagnostic rates of AUS/FLUS and help clinicians decide both treatment strategies and patient prognosis.

Molecular Variants and Their Risks for Malignancy in Cytologically Indeterminate Thyroid Nodules

Background: Gene panels are routinely used to assess predisposition to hereditary cancers by simultaneously testing multiple susceptibility genes and/or variants. More recently, genetic panels have been implemented as part of solid tumor malignancy testing assessing somatic alterations. One example is targeted variant panels for thyroid nodules that are not conclusively malignant or benign upon fine-needle aspiration (FNA). We systematically reviewed published studies from 2009 to 2018 that contained genetic data from preoperative FNA specimens on cytologically indeterminate thyroid nodules (ITNs) that subsequently underwent surgical resection. Pooled prevalence estimates per gene and variant, along with their respective positive predictive values (PPVs) for malignancy, were calculated. Summary: Our systematic search identified 540 studies that were supplemented by 18 studies from bibliographies or personal files. Sixty-one studies met all inclusion criteria and included >4600 ITNs. Overall, 26% of nodules contained at least 1 variant or fusion. However, half of them did not include details on the specific gene, variant, and/or complete fusion pair reported for inclusion toward PPV calculations. The PPVs of genomic alterations reported at least 10 times were limited to BRAF^V600E (98%, 95% confidence interval [CI 96-99%]), PAX8/PPARG (55% [CI 34-78%]), HRAS^Q61R (45% [CI 22-72%]), BRAF^K601E (42% [CI 19-68%]), and NRAS^Q61R (38% [CI 23-55%]). Excluding BRAF^V600E, the pooled PPV for all other specified variants and fusions was 47%. Multiple variants within the same nodule were identified in ∼1% of ITN and carried a cumulative PPV of 77%. Conclusions: The chance that a genomic alteration predicts malignancy depends on the individual variant or fusion detected. Only five alterations were reported at least 10 times; BRAF^V600E had a PPV of 98%, while the remaining four had individual PPVs ranging from 38% to 55%. The small sample size of most variants and fusion pairs found among ITNs, however, limits confidence in their individual PPV point estimates. Better specific reporting of genomic alterations with cytological category, histological subtype, and cancer staging would facilitate better understanding of cancer prediction, and the independent contribution of the genomic profile to prognosis.

The mutational analysis in the diagnostic work-up of thyroid nodules: the real impact in a center with large experience in thyroid cytopathology

PURPOSE

Fine-needle aspiration (FNA) cytology is a mainstay in the evaluation of thyroid nodules, but fails to reach reliable results in 25-30% of cases. The role of molecular markers in helping clinical decisions has been investigated for the last years, but their clinical usefulness is still unsettled.

METHODS

Mutation analysis of BRAF, RAS genes and TERT promoter was performed in a series of 617 consecutive cytological specimens undergoing FNA.

RESULTS

The 617 nodules had the following cytological diagnosis: non diagnostic 22 (3.6%), benign 425 (68.9%), indeterminate 114 (18.5%), suspicious 11 (1.8%) and malignant 45 (7.3%). BRAF mutations were found in 31 cases (5.0%), all but two in suspicious and malignant nodules. RAS mutations were detected in 47 samples (7.6%): 25 benign (5.9%) and 19 indeterminate nodules (16.7%). TERT promoter mutation alone was detected in three samples. Histological outcome was available for 167 nodules, 81 of which proved malignant: all the 48 with suspicious or malignant cytology; 25 out of 56 (44.6%) with indeterminate and 8 out of 57 (14%) with benign cytology. BRAF mutations were associated with worse tumors pathological features. The presence of RAS mutations was indicative of follicular-patterned malignancies in 5 out of 8 benign nodules and 9 out of 11 indeterminate nodules.

CONCLUSIONS

Our study established mutational rates for BRAF and RAS genes in a large series of FNA specimens. BRAF mutations were confirmed as highly specific but not able to improve cytological diagnosis, while RAS testing proved effective in assessing malignancy in nodules with indeterminate and benign cytology.

Presurgical Screening of Fine Needle Aspirates from Thyroid Nodules for BRAF Mutations: A Prospective Single Center Experience

OBJECTIVE

Analysis of BRAF V600E mutation in thyroid fine needle aspirates (FNA) is an important adjunct to cytology, particularly among FNA placed in the "indeterminate category." However, such a prospective evaluation of FNA obtained from patients with thyroid nodules has been lacking from India.

MATERIAL AND METHODS

FNA from 277 patients were prospectively evaluated for BRAF mutations by Sanger's sequencing. A subset of 30 samples was also analyzed by pyrosequencing using the PyroMark BRAF mutation kit.

RESULTS

Overall, 27.2% of FNA samples were positive for mutations including 19 (35.8%) of the 53 histologically confirmed papillary thyroid carcinoma (PTC), 2 of the 25 follicular variants of PTC, and 1 anaplastic thyroid carcinoma. Only 1 (2.7%) of the 37 samples in the atypia of undetermined significance/follicular lesion of unknown significance category was BRAF positive. The sensitivity of cytology improved marginally from 67.1% to 68.3% when evaluated with BRAF. Further, a comparison of the clinicopathological characteristics of BRAF positive and negative PTCs showed a significant association (P = 0.05) between lymph node metastasis and BRAF positivity.

CONCLUSION

BRAF positivity was lower than that reported from East Asia with the test being useful in confirming malignancies among the suspicious of malignancy and malignant categories.

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.

Risk of malignancy in thyroid nodules classified as TIR-3A: What therapy?

BACKGROUND

The aim of the present study was to assess the clinical applicability of the TIR3A category in managing thyroid nodules, to examine the malignancy rates of TIR 3A and TIR 3B nodules, and to suggest management guidelines for these nodules.

MATERIALS AND METHODS

Thyroid cytologies performed in patients referred to our Department between January 2014 and August 2016 were classified according to the guidelines published by the SIAPEC. 102 cases were included in this retrospective study and were divided into two groups: 19 TIR3A were included in group A and 83 TIR3B in group B.

RESULTS

In group A, malignancy was diagnosed in 4 (21.1%) cases, papillary thyroid cancer was found in 3 patients and follicular thyroid cancer in 1; one case was classified as microcarcinoma, in two cancer was multicentric and bilateral and in one central node metastases were observed. In Group B malignancy was diagnosed in 48 (57.8%) patients, papillary thyroid cancer was found in 36 patients and follicular cancer in 12; microcarcinoma was observed in 25 cases, 12 were unilateral multicentric and 7 bilateral multicentric; in 3 cases central node metastases were present.

CONCLUSION

Thyroid nodules with TIR3A cytology have a lower risk of malignancy than TIR3B cases, for which the new SIAPEC classification has proved accurate and effective. Malignancy rates in nodules with TIR3A cytology are higher than expected, although the real and accurate definition of the risk is extremely difficult. The recommendation to perform an accurate follow-up and repeat the fine-needle aspiration still appears the best option. For better management of patients with TIR3A cytology a careful assessment of risk factors and ultrasound characteristics is always needed. Further multicenter studies with longer follow-up are needed to better define the efficacy of this classification, the actual cancer risk, and the best management of these lesions.

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.

BRAF-mutated carcinomas among thyroid nodules with prior indeterminate FNA report: a systematic review and meta-analysis

BACKGROUND

Several molecular analyses have been investigated for risk stratification of thyroid nodules, with a particular focus on the V600E mutation of the BRAF gene [BRAF(V600E)]. To date, there is no high-level evidence supporting or refuting a role for BRAF analysis in thyroid nodules with prior indeterminate cytology. To obtain more robust evidence, we reviewed and meta-analysed data from published articles.

RESEARCH DESIGN AND METHODS

A comprehensive literature search of the PubMed/MEDLINE, Embase and Scopus databases was conducted using the terms 'BRAF', 'thyroid' and 'indeterminate'. The search was updated until March 2015, and references of the retrieved articles were also screened. Only original articles reporting BRAF mutation testing within nodules with indeterminate FNA were eligible for inclusion.

RESULTS

The literature search revealed 82 articles, of which 8 were eligible for the study. Five studies were prospective and three retrospective. The majority of authors analysed BRAF mutations in FNA samples which were classified by the British or Bethesda system. Of the initial series of studies, a pooled number of 1361 cases were achieved of which 43 were BRAF mutated. Overall, the BRAF mutation rate was 4·6% (95% CI: 1-10·8%), ranging from 0 to 22·9%. When we included only histological series, 978 thyroid nodules were found. Of these, 245 were cancers.

CONCLUSIONS

A very low rate of lesions with indeterminate cytology are BRAF mutated. Thus, the role of this biomarker to detect or exclude cancers in patients with such FNA reports is marginal and should be reconsidered in guidelines.

The utility of molecular markers in pre-operative assessment of thyroid nodules

The pre-operative diagnosis of thyroid tumors is determined by gold standard fine needle aspiration (FNA) biopsy. This has been widely accepted and offers the most cost-effective approach for evaluation of thyroid nodules. However, its diagnostic accuracy can pose a challenging scenario to surgeons. These diagnostic difficulties may subject patients to unnecessary thyroidectomies for benign thyroid nodules. Thus, additional molecular tests are needed to improve the sensitivity and specificity of FNA. The role of molecular markers is being proposed to predict the type and risk of malignancy to abate the need for diagnostic thyroidectomies. This review discusses their utility and validity in pre-operative diagnosis of thyroid nodules and how these markers can enhance the accuracy of FNA cytology.

Cytomorphologic features in thyroid nodules read as "suspicious for malignancy" on cytology may predict thyroid cancers with the BRAF mutation

Some morphologic parameters have been studied to help predict the BRAF(V600E) mutation using cytopathologic specimens, which can indicate which nodules should undergo further testing. The aim of this study was to investigate the value of cytomorphologic parameters to predict the BRAF(V600E) mutation in nodules read as "suspicious for malignancy" on cytology. This study included 142 resected nodules which were diagnosed as "suspicious for malignancy" on cytology in 142 patients. At our institution, BRAF(V600E) mutation analysis was performed at the request of the referring clinicians based on the clinical features of the patients, or the judgment of the radiologists performing US-FNA because suspicious US features were observed on the targeted nodule during this study period. Cytology smears were re-reviewed to assess the presence and amount of polygonal eosinophilic (plump) cells and microfollicles, and the presence of intranuclear pseudoinclusions, irregular nuclear membranes, nuclear grooves, sickles cells, psammoma bodies, and cystic changes. We evaluated the diagnostic performances of the cytomorphologic features to predict the BRAF(V600E) mutation. Polygonal eosinophilic (plump) cells, microfollicles, intranuclear pseudoinclusions, sickle cells, and cystic changes were significantly associated with the BRAF(V600E) mutation. The mutation was not present in all 6 thyroid nodules with microfollicles larger than 20% on cytology. Additionally, polygonal eosinophilic (plump) cells larger than 20%, cystic changes, and sickle cells on cytology had a high specificity of 95%, 96.7%, and 81.7%, respectively. Excluding 6 nodules with microfollicles larger than 20% on cytology, there were 82 (60.3%) nodules with the BRAF(V600E) mutation among the 136 nodules. Among the 136 nodules, there were 95 nodules with polygonal eosinophilic (plump) cells larger than 20%, cystic changes, or sickle cells on cytology. Of the 95 nodules, 69 (72.6%) had the mutation. Cytomorphologic features can help select nodules for the BRAF(V600E) mutation test among nodules read as "suspicious for malignancy" on cytology.

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 indeterminate thyroid cytology by second-opinion diagnosis or repeat fine-needle aspiration: which is the best approach?

OBJECTIVE

This study investigated a published series evaluating the role of second-opinion diagnosis (SOD) or repeat fine-needle aspiration cytology (RFNA) for indeterminate thyroid aspirates.

STUDY DESIGN

Twenty-three studies were selected and the following parameters were analyzed: disagreement between SOD or RFNA and the original diagnosis (OD), reclassification of OD according to the Bethesda system for reporting thyroid cytopathology, the rate of definitive diagnosis and the diagnostic performance of SOD and RFNA.

RESULTS

7,154 thyroid FNAs were retrieved from 9 studies that investigated the role of SOD, including 1,048 (14.6%) cases originally reported as indeterminate. The 14 studies that analyzed the role of thyroid RFNA comprised 67,581 FNAs and included 7,246 (10.7%) indeterminate cases. A definitive diagnosis was achieved by SOD in 450 cases (42.9%) and RFNA in 1,645 cases (57.2%, p=0.0001). Based on cases with histological follow-up, SOD demonstrated significantly higher rates of positive predictive value and accuracy than RFNA (55.8 vs. 37.7%, p=0.0001; 67.4 vs. 56.0%, p=0.0034, respectively).

CONCLUSIONS

Both SOD and RFNA demonstrated an improvement in the diagnosis of initially indeterminate thyroid FNAs. RFNA achieved a definitive diagnosis for the majority of indeterminate cases. Regarding histological follow-up, SOD was shown to be more accurate than RFNA.

Application of metabolomics in thyroid cancer research

Thyroid cancer is the most common endocrine malignancy with four major types distinguished on the basis of histopathological features: papillary, follicular, medullary, and anaplastic. Classification of thyroid cancer is the primary step in the assessment of prognosis and selection of the treatment. However, in some cases, cytological and histological patterns are inconclusive; hence, classification based on histopathology could be supported by molecular biomarkers, including markers identified with the use of high-throughput "omics" techniques. Beside genomics, transcriptomics, and proteomics, metabolomic approach emerges as the most downstream attitude reflecting phenotypic changes and alterations in pathophysiological states of biological systems. Metabolomics using mass spectrometry and magnetic resonance spectroscopy techniques allows qualitative and quantitative profiling of small molecules present in biological systems. This approach can be applied to reveal metabolic differences between different types of thyroid cancer and to identify new potential candidates for molecular biomarkers. In this review, we consider current results concerning application of metabolomics in the field of thyroid cancer research. Recent studies show that metabolomics can provide significant information about the discrimination between different types of thyroid lesions. In the near future, one could expect a further progress in thyroid cancer metabolomics leading to development of molecular markers and improvement of the tumor types classification and diagnosis.

Laser capture microdissection is a valuable tool in the preoperative molecular screening of follicular lesions of the thyroid: an institutional experience

OBJECTIVES

The application of molecular tests to thyroid fine needle aspiration (FNA) has been shown to be a valuable tool to better refine the pre-operative malignant risk of patients with indeterminate cytology results. In this study, we investigated the feasibility of using the laser capture microdissection (LCM) technique to obtain DNA and RNA for molecular tests in routine thyroid FNA smears.

METHODS

Nine coupled FNA and histological retrospective cases and 31 prospective FNA cases with a follicular neoplasm/suspicious for a follicular neoplasm (FN/SFN) diagnosis were included in this study. Both cytological and histological specimens were investigated by direct sequencing and reverse transcription-polymerase chain reaction (RT-PCR) for BRAF and RAS mutations and for PAX8/PPARG and RET/PTC rearrangements, respectively.

RESULTS

LCM yielded good DNA and RNA quality in all cases (100%) in both series, irrespective of the staining used (Giemsa, Papanicolaou, immunostain for thyroglobulin) and the cytology technique (conventional or liquid-based preparations). Total mutations found in the FNA and in the corresponding histological specimen in both series were: one PAX8/PPARG rearrangement in a follicular carcinoma (FC), four NRAS mutations [in two FCs, one papillary carcinoma and one follicular adenoma (FA)] and one HRAS mutation in one FA. The sensitivity was 67% and the specificity was 91%.

CONCLUSIONS

LCM is a valuable tool to obtain good quality DNA and RNA for molecular tests in cytological material from thyroid FNA, and can be a useful option in the management of patients with an FN/SFN FNA diagnosis.

BRAF mutation analysis in thyroid nodules with indeterminate cytology: our experience on surgical management of patients with thyroid nodules from an area of borderline iodine deficiency

PURPOSE

Fine-needle aspiration (FNA) with cytologic evaluation is the most reliable tool for malignancy prediction in thyroid nodules, but cytologic diagnosis remains indeterminate for 12-18 % of nodules. BRAF V600E mutation has been reported to show a high specificity for malignant thyroid nodules and the use of this marker to refine indeterminate FNA cytology results may be a useful diagnostic adjunctive tool in the pre-operative evaluation of thyroid nodules. The aim of this study was to estimate the prevalence of BRAF exon 15 mutation (V600E) and its clinical value as a diagnostic tool in a series of thyroid nodules with indeterminate cytology from an area of borderline iodine deficiency.

SUBJECTS AND METHODS

One hundred and fifty-three thyroid samples obtained by FNA of thyroid nodules from 151 patients were subjected to the analysis of BRAF V600E mutation by direct sequencing. In the study 54 nodules with indeterminate cytology, 56 benign and 43 malignant thyroid nodules were included.

RESULTS

V600E BRAF gene mutation was demonstrated in 19/43 malignant nodules, in 0/56 benign nodules and in only 1/54 indeterminate nodules that, after histology, turned out to be at a papillary thyroid carcinoma.

CONCLUSIONS

The application of BRAF exon 15 analysis showed limitations when applied to discriminate thyroid nodules with indeterminate cytology if wild-type BRAF is found, and there is no role for avoiding diagnostic thyroid surgery.

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.

BRAF V600 co-testing in thyroid FNA cytology: short-term experience in a large cancer centre in the UK

AIMS

To ascertain whether BRAF V600 mutational analysis is useful for diagnosis of thyroid cancer in thyroid fine needle aspirate (FNA).

METHODS

Over 8 months thyroid FNAs reported as Thy 3F (neoplasm possible/suggestive of follicular neoplasm), Thy4 (suspicious of malignancy) and Thy 5 (malignant) were tested for BRAF V600 mutation and managed as malignant if mutations were present.

RESULTS

Of 207 FNAs from 176 patients, 5 were Thy 5, 19 Thy 4, 36 Thy 3f, 13 Thy 3a, 84 Thy 2 and 50 Thy 1. 11 Thy 3f, 15 Thy 4 and 3 Thy 5 FNAs were tested for BRAF V600 mutation. 0 Thy 3F cases, 6 Thy 4 and 1 Thy 5 (24% of the total tested) showed evidence of mutation. Four patients with BRAF V600 mutation underwent surgery to remove all thyroid tissue, two patients received a lobectomy and one patient is awaiting thyroidectomy. All patients with BRAF V600 mutation were found to have malignancy on final histology, with a diagnostic sensitivity for malignancy excluding coincidental microcarcinoma of 43% and specificity of 100%.

CONCLUSIONS

BRAF V600 mutational analysis can enable single-stage total thyroidectomy for carcinoma if gene mutation is present in preoperative FNA. BRAF V600 co-testing may reduce the need for completion thyroidectomy with implied cost savings and lower patient morbidity associated with completion thyroidectomy when the cytology is inconclusive but where BRAF V600 mutation is identified in preoperative thyroid FNA.