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

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.

Rates of Thy 1-non-diagnostic thyroid fine needle aspiration using the UK Royal College of Pathologists Thy Terminology. A systematic review of the literature comparing patients who undergo rapid on-site evaluation and those who do not

INTRODUCTION

The UK Royal College of Pathologists (RCPath) Thy terminology is an internationally recognised system for reporting thyroid fine needle aspiration. The terminology has been used throughout the UK and Ireland, in some parts of Italy and Switzerland, and elsewhere in the world. There is no systematic review of the literature specifically addressing the use of the non-diagnostic for cytological diagnosis-Thy1/Thy 1c category in the UK RCPath terminology.

METHODS

A comprehensive literature search of online databases was conducted in October 2019 specifically examining overall reported rates of Thy1 and Thy1c in aspirates classified according to the UK Thy terminology.

RESULTS

Twenty-five articles were identified showing a Thy1 rate of 13.4% (2540/18 920). The studies were then stratified according to whether or not the patients underwent rapid on-site evaluation (ROSE): 6.0% (353/5841; range 3.0%-10.9%) of ROSE aspirates were Thy1 whereas 18.5% (2072/11 204; range 7.9%-43.3%) of non-ROSE patients were Thy1; (P < .05). Three studies from 2016 reported Thy1c rates of 5.4%, 6.5% and 10.6%, respectively, implying Thy1 rates excluding Thy1c aspirates of 20.9%, 8.7% and 12.7%, respectively.

CONCLUSION

This systematic review of the literature shows relatively high rates of aspirates non-diagnostic for cytological diagnosis-Thy1 in the peer-reviewed published literature using the UK terminology. Utilisation of ROSE appears to produce lower rates of Thy1 aspirates and ROSE should be considered if rates of non-diagnostic for cytological diagnosis-Thy1/Thy 1c are high.

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.

Precise Detection of Gene Mutations in Fine-Needle Aspiration Specimens of the Papillary Thyroid Microcarcinoma Using Next-Generation Sequencing

PURPOSE

To assess the feasibility of next-generation sequencing (NGS) to detect mutations in BRAF, RAS, TERT promoter, and TP53 genes in ultrasound-guided fine-needle aspiration (FNA) biopsy samples of the papillary thyroid microcarcinoma (PTMC).

METHODS

A total of 135 FNA samples out of 135 patients with suspected PTMC were submitted for mutation testing using NGS. NGS was successfully performed in 114 specimens, while the remaining 21 samples were excluded due to insufficient amount/poor quality of DNA and sequencing failure. Of those 114 samples, 72 who were confirmed as having PTMC by postoperative histopathology were enrolled in our study, and the other 42 who had a follow-up with ultrasound were excluded. Mutations of genes including BRAF, NRAS, HRAS, KRAS, TERT promoter, and TP53 were evaluated using NGS. The associations of gene mutations and clinicopathological characteristics of PTMC were analyzed.

RESULTS

BRAF mutation was observed in 59 (81.94%) of 72 specimens. This mutation detected in BRAF was p.V600E (c.1799T>A) in exon 15 of all 59 specimens. NRAS mutation was identified in 1 (1.39%) specimen classified as Bethesda III and pathologically confirmed as a follicular variant PTMC. There were no mutations found in TERT promoter or TP53. The tumor with a maximum diameter (D _max) larger than 5 mm was shown to be significantly correlated with the BRAF mutation in a multivariate analysis (OR 5.52, 95% CI 1.51-26.42, P = 0.033). But the BRAF mutation was not found to be significantly associated with the gender or age of patients with PTMC (P > 0.05).

CONCLUSIONS

This study demonstrated that gene mutations in FNA specimens of PTMC could be successfully analyzed with a higher sensitivity using NGS compared to conventional methods for mutation detection. BRAF mutation of p.V600E was statistically associated with PTMC with a D _max larger than 5 mm.

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.

Utility of intraoperative frozen sections for thyroid nodules with prior fine needle aspiration cytology diagnosis

INTRODUCTION

The objective of this study was to evaluate the role of intraoperative frozen section (IFS) in determining the course of surgery in thyroid nodules with a prior fine needle aspiration (FNA) biopsy diagnosis. In addition, reliability of FNA interpretation to guide surgical management without IFS was investigated.

MATERIAL AND METHODS

This is a retrospective study of all patients who had a FNA biopsy, IFS, and final pathology performed on a thyroid nodule over a 9 month period. The extent of surgery at the time of the IFS was recorded. Subsequent change in surgical procedure following the IFS diagnosis was noted in each of the Bethesda diagnostic categories.

RESULTS

55% of the cases were deferred at IFS overall, with 68 and 86% in Bethesda III and IV categories, respectively. Overall, there was a change in management in 6% of cases.

CONCLUSIONS

Our study does not support the use of IFS for nodules with prior FNA interpretation of Bethesda II, III, IV and VI as management was not significantly changed. IFS is of value for nodules with prior FNA diagnosis of Bethesda I for interpretation of nodule, and Bethesda V for planning surgery. A confirmatory diagnosis could not be rendered at IFS for lesions with follicular architecture, which comprised most of the cases in Bethesda III and IV.

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.

Evaluation of the Clinical Usefulness of BRAFV600E Mutation Analysis of Core-Needle Biopsy Specimens in Thyroid Nodules with Previous Atypia of Undetermined Significance or Follicular Lesions of Undetermined Significance Results

BACKGROUND

The accurate diagnosis of thyroid nodules is important for making management decisions. The purpose of this study is to evaluate the clinical usefulness of BRAF(V600E) mutation analysis with core-needle biopsy (CNB+BRAF(V600E)) in thyroid nodules with previous atypia of undetermined significance (AUS) or follicular lesions of undetermined significance (FLUS) results.

MATERIALS AND METHODS

From January 2011 to December 2012, 590 CNB+BRAF(V600E) mutation analyses were performed. We analyzed 200 nodules from 200 patients with previous AUS/FLUS results (22 men, 178 women; mean age, 48.6 years). The clinical usefulness of CNB+BRAF(V600E) was assessed by comparing the rates of conclusive results, the additional value of BRAF(V600E) mutation analysis, diagnostic performances, and therapeutic/diagnostic surgery results with those of CNB alone. For the subgroup analysis, the study patients were divided into those with nodules with previous AUS results and those with previous FLUS results.

RESULTS

All CNB+BRAF(V600E) procedures were well-tolerated. CNB+BRAF(V600E) did not show significantly better diagnostic performance than CNB alone in thyroid nodules with previous AUS/FLUS results. However, the conclusive result rate of CNB+BRAF(V600E) was improved in thyroid nodules with previous AUS/FLUS results (76.5% vs. 73.0%, p=0.016), especially with previous AUS results (81.1% vs. 76.4%, p=0.031). Of the 56 previous AUS result thyroid nodules with surgical management, BRAF(V600E) mutation analysis led to therapeutic surgery in 5.4% by decreasing unnecessary diagnostic surgery.

CONCLUSIONS

In general, CNB+BRAF(V600E) did not show significantly higher diagnostic accuracy than CNB alone. Although CNB+BRAF(V600E) may add additional value in nodules with previous AUS results, routinely adding BRAF(V600E) mutation analysis to CNB is not recommended.

High-Resolution Melting Is a Sensitive, Cost-Effective, Time-Saving Technique for BRAF V600E Detection in Thyroid FNAB Washing Liquid: A Prospective Cohort Study

OBJECTIVE

The diagnostic accuracy of thyroid fine needle aspiration biopsy (FNAB) can be improved by the combination of cytological and molecular analysis. In this study, washing liquids of FNAB (wFNAB) were tested for the BRAF V600E mutation, using the sensitive and cost-effective technique called high-resolution melting (HRM). The aim was to demonstrate the feasibility of BRAF analysis in wFNAB and its diagnostic utility, combined with cytology.

DESIGN

Prospective cohort study.

METHODS

481 patients, corresponding to 648 FNAB samples, were subjected to both cytological (on cells smeared onto a glass slide) and molecular analysis (on fluids obtained washing the FNAB needle with 1 ml of saline) of the same aspiration. BRAF V600E analysis was performed by HRM after methodological validation for application to wFNAB (technique sensitivity: 5.4%).

RESULTS

The cytological results of the FNAB were: 136 (21%) nondiagnostic (THY1); 415 (64%) benign (THY2); 80 (12.4%) indeterminate (THY3); 9 (1.4%) suspicious for malignancy (THY4); 8 (1.2%) diagnostic of malignancy (THY5). The BRAF V600E mutation was found in 5 THY2, 2 THY3, 6 THY4 and 6 THY5 samples. Papillary carcinoma diagnosis was histologically confirmed in all BRAF+ thyroidectomized patients. BRAF combined with cytology improved the diagnostic value compared to cytology alone in a subgroup of 74 operated patients.

CONCLUSIONS

HRM was demonstrated to be a feasible method for BRAF analysis in wFNAB. Thanks to its sensitivity and cost-effectiveness, it might be routinely used on a large scale in clinical practice. In perspective, standby wFNAB samples could be analyzed a posteriori in case of indeterminate cytology and/or suspicious findings on ultrasound.

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.