A prospective study evaluating the accuracy of using combined clinical factors and candidate diagnostic markers to refine the accuracy of thyroid fine needle aspiration biopsy

Deep learning for the diagnosis of suspicious thyroid nodules based on multimodal ultrasound images

OBJECTIVES

This study aimed to differentially diagnose thyroid nodules (TNs) of Thyroid Imaging Reporting and Data System (TI-RADS) 3-5 categories using a deep learning (DL) model based on multimodal ultrasound (US) images and explore its auxiliary role for radiologists with varying degrees of experience.

METHODS

Preoperative multimodal US images of 1,138 TNs of TI-RADS 3-5 categories were randomly divided into a training set (n = 728), a validation set (n = 182), and a test set (n = 228) in a 4:1:1.25 ratio. Grayscale US (GSU), color Doppler flow imaging (CDFI), strain elastography (SE), and region of interest mask (Mask) images were acquired in both transverse and longitudinal sections, all of which were confirmed by pathology. In this study, fivefold cross-validation was used to evaluate the performance of the proposed DL model. The diagnostic performance of the mature DL model and radiologists in the test set was compared, and whether DL could assist radiologists in improving diagnostic performance was verified. Specificity, sensitivity, accuracy, positive predictive value, negative predictive value, and area under the receiver operating characteristics curves (AUC) were obtained.

RESULTS

The AUCs of DL in the differentiation of TNs were 0.858 based on (GSU + SE), 0.909 based on (GSU + CDFI), 0.906 based on (GSU + CDFI + SE), and 0.881 based (GSU + Mask), which were superior to that of 0.825-based single GSU (p = 0.014, p< 0.001, p< 0.001, and p = 0.002, respectively). The highest AUC of 0.928 was achieved by DL based on (G + C + E + M)US, the highest specificity of 89.5% was achieved by (G + C + E)US, and the highest accuracy of 86.2% and sensitivity of 86.9% were achieved by DL based on (G + C + M)US. With DL assistance, the AUC of junior radiologists increased from 0.720 to 0.796 (p< 0.001), which was slightly higher than that of senior radiologists without DL assistance (0.796 vs. 0.794, p > 0.05). Senior radiologists with DL assistance exhibited higher accuracy and comparable AUC than that of DL based on GSU (83.4% vs. 78.9%, p = 0.041; 0.822 vs. 0.825, p = 0.512). However, the AUC of DL based on multimodal US images was significantly higher than that based on visual diagnosis by radiologists (p< 0.05).

CONCLUSION

The DL models based on multimodal US images showed exceptional performance in the differential diagnosis of suspicious TNs, effectively increased the diagnostic efficacy of TN evaluations by junior radiologists, and provided an objective assessment for the clinical and surgical management phases that follow.

Implementation of the gut microbiota prevents anastomotic leaks in laparoscopic colorectal surgery for cancer:the results of the MIRACLe study

The aim of this pilot study was to evaluate the effects of a novel perioperative treatment for the implementation of the gut microbiota, to prevent anastomotic fistula and leakage (AL) in patients undergoing laparoscopic colorectal resections for cancer. A series of 60 patients who underwent elective colorectal surgery at S. Eugenio Hospital (Rome-Italy) between December 1, 2020 and November 30, 2021 and received a novel perioperative preparation following the MIRACLe (Microbiota Implementation to Reduce Anastomotic Colorectal Leaks) protocol (oral antibiotics, mechanical bowel preparation and perioperative probiotics), was compared to a group of 500 patients (control group) operated on between March 2015 and November 30, 2020, who received a standard ERAS protocol. In the MIRACLe Group only 1 anastomotic leak was registered. In this group the incidence of AL was just 1.7% vs. 6.4% in the control group (p = 0.238) and the incidence of surgical site infections (1.7% vs. 3.6%; p = 0.686), reoperations (1.7% vs. 4.2%; p = 0.547) and postoperative mortality (0% vs. 2.2%; p = 0.504) were lower. The postoperative outcomes were also better: the times to first flatus, to first stool and to oral feeding were shorter (1 vs. 2, 2 vs. 3 and 2 vs. 3 days, respectively; p < 0.001). Additionally, the postoperative recovery was faster, with a shorter time to discharge (4 vs. 6 days; p < 0.001). In this pilot study, the MIRACLe protocol appeared to be safe and considerably reduced anastomotic leaks in elective laparoscopic colorectal surgery for cancer, even if not statistically significant, due to the small number of cases.

Do ACR TI-RADS scores demonstrate unique thyroid molecular profiles?

Purpose

The present study aimed to examine the molecular profiles of cytologically indeterminate thyroid nodules stratified by American College of Radiology Thyroid Imaging Reporting and Data System (TI-RADS) categories and to determine whether certain ultrasonographic features display particular molecular alterations.

Methods

A retrospective review was conducted of cases from January 1, 2016 to April 1, 2018. Cases with in-house ultrasonography, fine-needle aspiration Bethesda System for Reporting Thyroid Cytopathology (TBSRTC) diagnoses, molecular testing, and surgery were included. All cases were diagnosed as TBSRTC indeterminate categories. The ultrasound studies were retrospectively reviewed and assigned TI-RADS scores (TR1-TR5) by board-certified radiologists. The final diagnoses were determined based on the surgical resection pathology. Binary logistic regression analysis was used to study whether demographic characteristics, TI-RADS levels, and TBSRTC diagnoses were associated with ThyroSeq molecular results.

Results

Eighty-one cases met the inclusion criteria. RAS mutations were the most common alteration across all TI-RADS categories (TR2 2/2; TR3 10/19, TR4 13/44, and TR5 8/16), and did not stratify with any particular TI-RADS category. Only TR4 and TR5 categories displayed more aggressive mutations such as BRAF^V600E; and TERT. ThyroSeq results were positively correlated with thyroid malignancy when non-invasive follicular thyroid neoplasm with papillary-like nuclear features (NIFTP) was categorized in the malignant category (odds ratio [OR], 6.859; P<0.01), but not when NIFTP was removed from the malignancy category. Echogenicity scores were found to be negatively correlated with ThyroSeq results in thyroid nodules (OR, 0.162; P<0.01).

Conclusion

Higher-risk molecular alterations tended to stratify with the higher TI-RADS categories.

Increased gene expression of TIMP1 and CHI3L1 in fine-needle aspiration biopsy samples from papillary thyroid cancer as compared to benign nodules

BACKGROUND

Thyroid nodules are common ultrasound findings with malignancy rate 7%-15%. Our objective was to assess the relative expression of the tissue inhibitor of metalloproteinase-1 gene (TIMP1) and chitinase-3-like protein 1 gene (CHI3L1) in fine-needle aspiration biopsy (FNAB) washouts and the serum levels of their protein products (TIMP-1 and chitinase-3-like protein 1 known as YKL-40) in patients with papillary thyroid cancer (PTC) and patients with benign nodules. Furthermore, the correlation between gene expression and circulating protein product was evaluated.

METHODS

Eighty patients who underwent FNAB in one tertiary center were recruited in the study. Forty with Bethesda V and VI nodules were operated and PTC was confirmed. The other 40 patients were with Bethesda II nodules. TIMP-1 and YKL-40 serum levels were measured in all subjects. The TIMP1 and CHI3L1 expression was assessed in FNAB washouts from 20 PTC patients and 20 benign cases using quantitative PCR.

RESULTS

The relative expression of TIMP1 and CHI3L1 was significantly higher in the PTC group than in the benign group (p < .001 for TIMP1; p = .018 for CHI3L1). The PTC patients had higher serum TIMP-1 than the patients with benign nodules (p = .036). We did not find significant difference in the YKL-40 level between the two groups. TIMP1 and CHI3L1 expression did not correlate with the serum levels of their protein products.

CONCLUSION

FNAB washouts could be used for identification of diagnostic markers. The increased TIMP1 and CHI3L1 expression implies a role of these genes in the PTC carcinogenesis.

Heterogeneity in Positive Predictive Value of RAS Mutations in Cytologically Indeterminate Thyroid Nodules

BACKGROUND

RAS mutations are common in the available mutational analysis of cytologically indeterminate (Cyto-I) thyroid nodules. However, their reported positive predictive value (PPV) for cancer is widely variable. The reason for this variability is unknown, and it causes clinical management uncertainty. A systematic review was performed, evaluating the PPV for cancer in RAS mutation positive Cyto-I nodules, and variables that might affect residual heterogeneity across the different studies were considered.

METHODS

PubMed was searched through February 22, 2017, including studies that evaluated at least one type of RAS mutation in Cyto-I nodules, including any (or all) of the Bethesda III/IV/V categories or their equivalents and where the histological diagnosis was available. The PPV residual heterogeneity was investigated after accounting for Bethesda classification, blindedness of the histopathologist to the RAS mutational status, Bethesda category-specific cancer prevalence for each study, and which RAS genes and codons were tested. This was studied using five meta-regression models fit to different sets of Bethesda classification categories: Bethesda III, IV, or V (III/IV/V); Bethesda III or IV (III/IV); Bethesda III only; Bethesda IV only; and Bethesda V only.

RESULTS

Of 1831 studies, 23 were eligible for data inclusion. Wide ranges of PPV were found at 0-100%, 28-100%, and 0-100% in Bethesda III, IV, and V, respectively. Residual heterogeneity remained moderately high for PPV after accounting for the above moderators for Bethesda III/IV/V (21 studies; I² = 59.5%) and Bethesda III/IV (19 studies; I² = 66.0%), with significant Cochran's Q-test for residual heterogeneity (p < 0.001). Among individual Bethesda categories, residual heterogeneity was: Bethesda III (eight studies; I² = 89.0%), IV (12 studies; I² = 53.5%), and V (10 studies; I² = 34.4%), with significant Cochran's Q-test for Bethesda III (p < 0.001) and IV (p = 0.04).

CONCLUSION

The PPV of RAS mutations in Bethesda III and IV categories is quite heterogeneous across different studies, creating low confidence in the accuracy of a single estimate of PPV. Clinicians must appreciate this wide variability when managing a RAS-mutated Cyto-I nodule. Future studies should seek to resolve this unexplained variability.

Triage of the indeterminate thyroid aspirate: What are the options for the practicing cytopathologist?

Fine-needle aspiration (FNA) plays a key role in the early evaluation of patients with thyroid nodules; however, from 15% to 30% of FNA specimens are cytologically indeterminate. Molecular testing has proven useful when applied to indeterminate thyroid FNAs, and its use has been endorsed in the American Thyroid Association guidelines. In addition to the noncommercial ("in-house") application of v-Raf murine sarcoma viral oncogene homolog B1 (BRAF), rat sarcoma (RAS), rearranged in transformation/papillary thyroid carcinoma (RET/PTC), and peroxisome proliferator-activated receptor γ/paired box gene 8 (PPARγ/PAX8) testing, there are currently 3 commercially available molecular panels that vary in their relative reported performances, strengths, and limitations. Here, we discuss the role of molecular testing for indeterminate thyroid aspirates, taking into consideration the recent reclassification of the encapsulated follicular variant of papillary thyroid carcinoma (PTC) as "noninvasive follicular neoplasm with papillary-like nuclear features (NIFTP)." Cancer Cytopathol 2017;125(6 suppl):477-85. © 2017 American Cancer Society.

A 10-Gene Classifier for Indeterminate Thyroid Nodules: Development and Multicenter Accuracy Study

BACKGROUND

In most of the world, diagnostic surgery remains the most frequent approach for indeterminate thyroid cytology. Although several molecular tests are available for testing in centralized commercial laboratories in the United States, there are no available kits for local laboratory testing. The aim of this study was to develop a prototype in vitro diagnostic (IVD) gene classifier for the further characterization of nodules with an indeterminate thyroid cytology.

METHODS

In a first stage, the expression of 18 genes was determined by quantitative polymerase chain reaction (qPCR) in a broad histopathological spectrum of 114 fresh-tissue biopsies. Expression data were used to train several classifiers by supervised machine learning approaches. Classifiers were tested in an independent set of 139 samples. In a second stage, the best classifier was chosen as a model to develop a multiplexed-qPCR IVD prototype assay, which was tested in a prospective multicenter cohort of fine-needle aspiration biopsies.

RESULTS

In tissue biopsies, the best classifier, using only 10 genes, reached an optimal and consistent performance in the ninefold cross-validated testing set (sensitivity 93% and specificity 81%). In the multicenter cohort of fine-needle aspiration biopsy samples, the 10-gene signature, built into a multiplexed-qPCR IVD prototype, showed an area under the curve of 0.97, a positive predictive value of 78%, and a negative predictive value of 98%. By Bayes' theorem, the IVD prototype is expected to achieve a positive predictive value of 64-82% and a negative predictive value of 97-99% in patients with a cancer prevalence range of 20-40%.

CONCLUSIONS

A new multiplexed-qPCR IVD prototype is reported that accurately classifies thyroid nodules and may provide a future solution suitable for local reference laboratory testing.

Diagnostic Value of RAS Mutations in Indeterminate Thyroid Nodules

Objectives To determine the diagnostic value of HRAS, KRAS, and NRAS mutations in fine-needle aspiration biopsies of thyroid nodules that are nondiagnostic on cytology. Data Sources PubMed, Scopus, Embase, CINAHL. Review Methods Two authors independently searched the data sources. To be included, studies reported the RAS mutational status and postoperative histopathologic diagnosis of nodules that exhibited indeterminate cytology after fine-needle aspiration biopsy. Data were extracted to calculate sensitivity, specificity, and positive/negative predictive values of any HRAS, KRAS, or NRAS mutation. A meta-analysis was performed to generate pooled values for each parameter. Results A total of 7 studies with a combined 1025 patients met inclusion criteria. The pooled sensitivity of a RAS mutation for detecting cancer was 0.343 (95% confidence interval [95% CI], 0.198-0.506), while the pooled specificity was 0.935 (95% CI, 0.882-0.973). The weighted averages for positive predictive value and negative predictive value were 78.0% and 64.0%, respectively, with 68.0% accuracy. The positive likelihood ratio was 4.235 (95% CI, 1.506-11.910), and the negative likelihood ratio was 0.775 (95% CI, 0.630-0.953). Conclusion Our data suggest that testing for any RAS mutation is unlikely to change the clinical management of thyroid nodules that have indeterminate cytology. While a RAS mutation may rule in malignancy, the sensitivity of testing is low enough to merit further mutational analysis, repeat fine-needle aspiration, or surgical excision, even in the presence of a negative test.

First-Line Use of Core Needle Biopsy for High-Yield Preliminary Diagnosis of Thyroid Nodules

BACKGROUND AND PURPOSE

Although core needle biopsy was introduced as a diagnostic alternative to fine-needle aspiration, the utility and safety of core needle biopsy for thyroid nodules in a large population has yet to be studied comprehensively. We evaluate core needle biopsy yields on a large-scale basis to investigate its potential in the preliminary diagnosis of thyroid nodules.

MATERIALS AND METHODS

Between March 2005 and December 2013, 2448 initially detected thyroid nodules from 2120 consecutive patients who underwent core needle biopsy were retrospectively evaluated. Of these, 72 thyroid nodules from 63 patients were excluded due to prior fine-needle aspiration attempts. The inconclusive and conclusive result rates, diagnostic accuracy, sensitivity, specificity, positive predictive value, negative predictive value, and unnecessary surgery rate of core needle biopsy were evaluated.

RESULTS

With core needle biopsy as the first-line method, the inconclusive result rate was 11.9% (283/2376) and the conclusive result rate was 88.1% (2093/2376). The diagnostic accuracy, sensitivity, specificity, positive predictive value, and negative predictive value of core needle biopsy for the diagnosis of malignancy were 96.7% (1160/1200), 89.7% (347/387), 100% (813/813), 100% (347/347), and 95.3% (813/853), respectively. There were no major complications and 12 minor complications.

CONCLUSIONS

We have demonstrated that first-line use of core needle biopsy may well improve diagnostic accuracy in thyroid nodules, reducing inconclusive or false-negative results and unnecessary operations. Such benefits underscore the promising role of core needle biopsy in managing thyroid nodules and optimizing related surgical decision-making.

Detection of Circulating BRAF(V600E) in Patients with Papillary Thyroid Carcinoma

BRAF(V600E) is a common mutation in papillary thyroid carcinoma (PTC) correlated with aggressive features. Our objective was to assess the feasibility and accuracy of a novel RNA-based blood assay to identify individuals with a high-risk tumor mutation in patients with PTC. Patients with benign or malignant thyroid disorders were included between September 2013 and July 2014 before either thyroidectomy (n = 62) or treatment of recurrent or metastatic PTC (n = 8). RNA was isolated from peripheral blood lymphocytes and reverse transcribed and followed by two rounds of nested PCR amplification with a restriction digest specific for wild-type BRAF. BRAF(V600E) levels were quantified with standardization curves. Circulating BRAF(V600E) levels were compared with BRAF mutation status from surgical pathologic DNA-based tissue assays. Testing characteristics and receiving-operator curve using tissue results as the gold standard were assessed. Matched blood and tissue assays for BRAF(V600E) were performed on 70 patients with PTC (stages I to IV, n = 48) or other (n = 22) thyroid tumors. Sixty-three percent of PTC patients tested positive for BRAF(V600E) with conventional tissue assays on surgical specimens. The correlation between the RNA-based blood assay and tissue BRAF status was 0.71. PTC patients harbor detectable BRAF(V600E) circulating tumor cells. This blood assay is feasible and has potential as a biomarker for prognosis, surveillance, clinical decision making, and assessment of treatment response to BRAF-targeted therapies.

High expression of metadherin correlates with malignant pathological features and poor prognostic significance in papillary thyroid carcinoma

BACKGROUND

Metadherin (MTDH) protein, also called astrocyte elevated gene-1 (AEG-1) is over expressed in a variety of malignant tumours, and is closely related to tumour invasion and the poor prognosis.

OBJECTIVE

This study tries to explore the clinical pathological significance of MTDH expression in a large cohort of patients with PTC.

DESIGN AND PATIENTS

Immunohistochemistry was used to detect MTDH expression in 156 cases of PTC, 6 cases of anaplastic thyroid carcinoma (ATC), 10 cases of multinodular goitre (MNG) and 10 cases of thyroid adenoma tissues who received a thyroid operation between June 2003 and July 2008.

MEASUREMENTS

Clinical pathological data of 156 cases of PTC were analysed according to MTDH expression. The Kaplan-Meier method was used to plot survival curves and log-rank test to compare the postoperative survival results. The prognostic meaning of MTDH expression in PTC was evaluated by Cox regression analysis.

RESULTS

The positive expression rates of MTDH in PTC and ATC tissues were 37·2% (58/156) and 50% (3/6), respectively, and MTDH positive expression rates were both 10% (1/10) in MNG and thyroid adenoma tissues. High MTDH expression in PTC was associated with larger tumour size (P = 0·030), high rates of lymph node (P = 0·041) and distant metastasis (P = 0·028), but no relation with the patient age, gender, tumour multicenter, extrathyroid invasion and tumour grade. High MTDH expression was associated with recurrence-free survival (RFS) and disease-specific survival rate (DSS) (P = 0·014, P = 0·001, respectively). Cox regression analysis showed that high MTDH expression was independent prognostic indicators for RFS and DSS in patients with PTC (P = 0·023 and P = 0·035, respectively).

CONCLUSION

High MTDH expression in PTC might play an important role in tumour growth and metastasis, and targeting MTDH treatment might have potential therapeutic value for patients with PTC.

BRAFV600E mutation in papillary thyroid microcarcinoma: a meta-analysis

The prognostic value of the BRAFV600E mutation, resulting in poor clinical outcomes of papillary thyroid carcinoma, has been generally confirmed. However, the association of BRAFV600E with aggressive clinical behaviors of papillary thyroid microcarcinoma (PTMC) has not been firmly established in individual studies. We performed this meta-analysis to examine the relationship between BRAFV600E mutation and the clinicopathological features of PTMC. We conducted a systematic search in PubMed, EMBASE, and the Cochrane library for relevant studies. We selected all the studies that reported clinicopathological features of PTMC patients with information available on BRAFV600E mutation status. Nineteen studies involving a total of 3437 patients met these selection criteria and were included in the analyses. The average prevalence of the BRAFV600E mutation was 47.48%, with no significant difference with respect to patient sex (male versus female) and age (younger than 45 years versus 45 years or older). Compared with the WT BRAF gene, the BRAFV600E mutation was associated with tumor multifocality (odds ratio (OR) 1.38; 95% CI, 1.04-1.82), extrathyroidal extension (OR 3.09; 95% CI, 2.24-4.26), lymph node metastases (OR 2.43; 95% CI, 1.28-4.60), and advanced stage (OR 2.39; 95% CI, 1.38-4.15) of PTMC. Thus, our findings from this large meta-analysis definitively demonstrate that BRAFV600E-mutation-positive PTMC are more likely to manifest with aggressive clinicopathological characteristics. In appropriate clinical settings, testing for the BRAFV600E mutation is likely to be useful in assisting the risk stratification and management of PTMC.

Utilization and impact of repeat biopsy for follicular lesion/atypia of undetermined significance

BACKGROUND

The Bethesda System for Reporting Thyroid Cytopathology (BSRTC) created a new diagnostic category,follicular lesion/atypia of undetermined significance(FLUS/AUS). The recommended management of FLUS/AUS lesions is repeat biopsy to re-classify the lesion and guide therapy. Prior surgical studies suggest a higher than expected malignancy rate for FLUS/AUS. The present study evaluates a large institutional experience with all FLUS/AUS lesions analyzing use and impact of repeat biopsy.

METHODS

A total of 322 patients with FLUS/AUS cytology have been retrospectively identified since adoption of the BSRTC (2/2009–6/2012). Patient demographics, the results of clinical follow-up, repeat biopsy, or surgical pathology results were evaluated.

RESULTS

Among the 322 patients, 16 had concurrent cytology of higher acuity and were excluded. For the remaining 306 patients, 101 (33 %) underwent repeat biopsy, yielding 49 (48.5 %) with FLUS/AUS, 43 (42.5 %)with benign cytology, and 9 (9 %) with higher acuity cytology. Among the 205 patients without repeat biopsy,117 (57 %) chose thyroidectomy, and 88 (43 %) are being observed. Overall, 170/306 (55.6 %) patients underwent surgery to remove the index lesion, yielding a malignancy rate of 16.5 %. In contrast, the malignancy rate for the entire cohort was 28/306 (9 %).

CONCLUSIONS

Repeat biopsy was underutilized in FLUS/AUS cases. Repeat biopsy allows a significant proportion of FLUS/AUS patients without other indications for surgery to move to surveillance. In patients who have indications for thyroidectomy regardless of FLUS/AUS results,repeat biopsy does not appear necessary. Malignancy and thyroidectomy rates were similar among patients who did or did not have a repeat biopsy. Further data must be obtained to determine the long-term outcomes for surveillance of FLUS/AUS lesions in patients who do not undergo surgical removal.

The prognostic implication and potential role of BRAF mutation in the decision to perform elective neck dissection for thyroid cancer

The BRAF V600E mutation is the most common genetic change in patients with papillary thyroid cancer (PTC). Many studies have shown that detection of the BRAF V600E mutation is useful for confirming or establishing the preoperative diagnosis of PTC. Moreover, the mutation is associated with aggressive tumor characteristics or poor prognostic factors in most. However, whether preoperative detection of this mutation changes the treatment strategy or surgical extent, including prophylactic central neck dissection (CND), remains controversial. In this paper, we review the currently available literature regarding the potential role of the BRAF V600E mutation in the decision to perform elective neck dissection for PTC.

Role of ancillary testing in thyroid fine needle aspiration: Review and update

Thyroid nodules are common, and ultrasound-guided fine needle aspiration identifies 70-75% as benign, and 4% as malignant. The remainder falls into categories of "indeterminate" with a widely ranging malignancy rate from 10-75%. The diagnosis and clinical management of indeterminate lesions is evolving, and we will review ancillary testing as an aid to diagnosis.

Clinical application of molecular testing of fine-needle aspiration specimens in thyroid nodules

Thyroid cancer is the most common endocrine malignancy, and its incidence is increasing. Thyroid cancer is typically diagnosed during the evaluation of thyroid nodules. Although most thyroid nodules are benign, the challenge is to accurately and effectively identify malignant nodules. Understanding of genetic pathways involved in thyroid carcinogenesis has improved, and molecular testing techniques have become widespread and cost-efficient. Routine testing for somatic mutations and rearrangements that are commonly found in thyroid cancer can augment current diagnostic testing algorithms for thyroid nodules, and can provide preoperative prognostic information that helps to optimize initial patient management.

The use of core needle biopsy as first-line in diagnosis of thyroid nodules reduces false negative and inconclusive data reported by fine-needle aspiration

BACKGROUND

The reported reliability of core needle biopsy (CNB) is high in assessing thyroid nodules after inconclusive fine-needle aspiration (FNA) attempts. However, first-line use of CNB for nodules considered at risk by ultrasonography (US) has yet to be studied. The aim of this study were: 1) to evaluate the potential merit of using CNB first-line instead of conventional FNA in thyroid nodules with suspicious ultrasonographic features; 2) to compare CNB and FNA as a first-line diagnostic procedure in thyroid lesions at higher risk of cancer.

METHODS

Seventy-seven patients with a suspicious-appearing, recently discovered solid thyroid nodule were initially enrolled as study participants. No patients had undergone prior thyroid fine-needle aspiration/biopsy. Based on study design, all patients were proposed to undergo CNB as first-line diagnostic aspiration, while those patients refusing to do so underwent conventional FNA.

RESULTS

Five patients refused the study, and a total of 31 and 41 thyroid nodules were subjected to CNB and FNA, respectively. At follow-up, the overall rate of malignancy was of 80% (CNB, 77%; FNA, 83%). However, the diagnostic accuracy of CNB (97%) was significantly (P < 0.05) higher than that of FNA (78%). In one benign lesion, CNB was inconclusive. Four (12%) of the 34 cancers of the FNA group were not initially diagnosed because of false negative (N = 1), indeterminate (N = 2) or not adequate (N = 1) samples.

CONCLUSIONS

CNB can reduce the false negative and inconclusive results of conventional FNA and should be considered a first-line method in assessing solid thyroid nodules at high risk of malignancy.

The nightmare of indeterminate follicular proliferations: when liquid-based cytology and ancillary techniques are not a moon landing but a realistic plan

OBJECTIVE

Thyroid nodules are a common finding in the general population, including both nonneoplastic and neoplastic entities. Fine-needle aspiration cytology (FNAC) is the first tool for evaluating thyroid nodules. In spite of its high diagnostic accuracy, 25% of nodules result in the category of follicular neoplasms (FN), with varying risk of malignancy and different management strategies.

STUDY DESIGN

The use of ancillary techniques is reshaping the practice of FNAC. These tools can significantly empower the morphological diagnosis and prognosis of thyroid nodules, allowing a more accurate prediction of the nature of the lesion. Several studies have underlined the role of single or multiple testing for the category of FN as strong indicators of cancer. Every cytological preparation can be used for the application of ancillary techniques but the introduction of liquid-based cytology (LBC) might facilitate the application.

RESULTS

Our experience involving an immunocytochemical panel made up of HBME-1 and galectin-3 pointed to an 81% overall diagnostic accuracy in discriminating between low and high risk of malignancy in FN.

CONCLUSIONS

The application of these techniques on LBC represents an adjunct to the morphological evaluation of FN. They represent a critical and challenging, but also a feasible, tool in the preoperative diagnoses, allowing specific prognostic and predictive details regardless of the cytological preparation. © 2014 S. Karger AG, Basel.

Pre-analytic steps for molecular testing on thyroid fine-needle aspirations: The goal of good results

Fine-needle aspiration cytology (FNAC) represents a valid alternative to biopsy in a variety of clinical settings mainly based on its simplicity and less invasive clinical approach. In some cases, morphology evaluation alone is not sufficient to manage the patients, so that the application of ancillary techniques can contribute to diagnosis, prognosis and prediction of tumor behavior. These techniques include polymerase chain reaction (PCR), fluorescence in situ hybridization (FISH), in situ PCR, direct Sequencing, microarrays and proteomic methodologies. Although several recent experiences underline the superior value of deoxyribonucleic acid (DNA) quality mainly for advanced genomic high throughput platforms, very scant literature studied the role of the pre-analytical or analytical phases. Despite the high specificity of molecular techniques as a support for diagnosis, there is a need for an increased standardization of pre-analytical/analytical steps such as providing appropriate clinical history, proper collection of laboratory specimens and proper preparation of samples, adequate fixative/reagent concentrations and technical equipments. All these requirements are crucial according to the results from 42 American laboratories, which reported 0.33% of significant molecular errors with 60% of them in the pre-analytical phase. The most common error is to forget that cytological preparation requires specific molecular variables, which are different from histological specimens. Cytological samples offer the advantage of a well preserved DNA, readily extractable and reasonably stable (from 6 months to 5 years) avoiding pitfalls due to formalin-fixation. Freshly prepared, unstained direct, alcohol-fixed papanicolaou, air-dried diff-quick smears are all suitable for DNA extraction and preservation. In the specific field of thyroid FNAC, molecular analysis has been supported by the growing evidence that papillary thyroid carcinoma (PTC), the most common thyroid cancer, frequently is a diploid lesion and can display non-overlapping mutations of the v-Raf murine sarcoma viral oncogene homolog B1 (BRAF) in 46% to 70%, cases, ret proto-oncogene (RET) in 3 to 85% and Rat Sarcoma oncogene (RAS) in 0-21% cases. Recently, several cytological papers demonstrated that the combination of morphology and molecular analysis can increase the diagnostic accuracy allowing more precise prediction of malignancy regardless of the diagnostic categories. In conclusion, the correct use of the pre-analytical-analytical steps might lead to optimal results on cytology and empower the prognostic value of molecular techniques as strong indicators of cancer for their high specificity and positive predictive value.

Prediction of occult central lymph node metastasis in papillary thyroid carcinoma by preoperative BRAF analysis using fine-needle aspiration biopsy: a prospective study

CONTEXT

Few reports have determined whether preoperative detection of the BRAF V600E mutation in fine-needle aspiration biopsy (FNAB) may influence determination of surgical extent such as prophylactic central lymph node dissection (CLND) in patients with papillary thyroid carcinoma (PTC).

OBJECTIVES

Our objectives were to investigate whether preoperative BRAF analysis may assist determination of surgical extent, including prophylactic CLND with variable clinicopathological risk factors for central lymph node metastasis, in patients with PTC and clinically node-negative neck.

PATIENTS AND METHODS

From July 2009 to May 2011, we prospectively enrolled 148 PTC patients with clinically node-negative neck who received a total thyroidectomy and prophylactic CLND. BRAF mutation by pyrosequencing was tested on preoperative FNAB specimens. The relationships between occult central lymph node metastasis and preoperative BRAF mutation or clinicopathological factors were analyzed. Additionally, we assessed the associations between preoperative BRAF mutation status and various clinicopathological characteristics of PTC revealed postoperatively.

RESULTS

The prevalence of the BRAF V600E mutation was 53.4%, and the rate of occult central lymph node metastasis was 25.7%. Multivariate analysis showed that tumor size over 1 cm [P = 0.006; odds ratio (OR) = 3.559], perithyroidal invasion (P = 0.023; OR = 2.893), and preoperative positive BRAF mutation (P = 0.029; OR = 2.727) were independent risk factors for the presence of occult central lymph node metastasis. BRAF mutation examined in FNAB specimens, compared with the wild-type allele, strongly predicted perithyroidal invasion (48 vs. 29%; P = 0.017), extracapsular spread (65 vs. 45%; P = 0.017), occult central lymph node metastasis (35 vs. 15%; P = 0.004), and advanced TNM stage (44 vs. 28%; P = 0.035). In the multivariate analysis, patients with preoperative positive BRAF mutation were significantly more likely (P = 0.023; OR = 2.848) to have occult central lymph node metastasis.

CONCLUSION

Preoperative BRAF analysis by FNAB and primary tumor size based on ultrasonography may assist in predicting occult central lymph node metastasis in patients with PTC and clinically node-negative neck.

Use of molecular biomarkers in FNA specimens to personalize treatment for thyroid surgery

BACKGROUND

Accurate preoperative assessment of thyroid nodules with fine-needle aspiration biopsy (FNAB) continues to be a challenge, often resulting in unnecessary diagnostic surgical intervention. The detection of several novel gene mutations in differentiated thyroid cancer (DTC) over the last decade has led to the diagnostic use of these oncogenic alterations to improve FNAB sensitivity and specificity.

METHODS AND RESULTS

Thyroid oncogene mutations including BRAF, RAS, and RET/PTC are reviewed. The potential benefit of using this panel on fine-needle aspiration (FNA) cytology samples will be described.

CONCLUSION

Our use of ''reflexive'' molecular testing demonstrates its clinical value in conjunction with FNAB cytology, representing an application of personalized molecular medicine to guide appropriate surgical therapy.

The impact of atypia/follicular lesion of undetermined significance on the rate of malignancy in thyroid fine-needle aspiration: evaluation of the Bethesda System for Reporting Thyroid Cytopathology

BACKGROUND

The Bethesda System for Reporting Thyroid Cytopathology (BSRTC) was developed to refine definitions and improve clinical communication and management. This study evaluates the impact of the BSRTC in a large cohort of patients undergoing thyroidectomy before and after its adoption at a single institution.

METHODS

The records from 469 patients in the pre-BSRTC (n = 187) and post-BSRTC (n = 282) periods were reviewed. Cytologic categories in group 1 included nondiagnostic, benign, follicular/Hürthle neoplasm, suspicious for malignancy, and malignant. Atypia/follicular lesion of undetermined significance (AUS/FLUS) was included in group 2. The percentage of each fine-needle aspiration (FNA) category, malignancy rate per category, and rate of AUS/FLUS utilization were calculated.

RESULTS

Group 1 FNA results included 3% (n = 6) nondiagnostic, 48% (n = 89) benign, 17% (n = 32) follicular/Hürthle, 13% (n = 25) suspicious for malignancy, and 19% (n = 35) malignant. Group 2 results included 4% (n = 11) nondiagnostic, 34% (n = 96) benign, 29% (n = 82) AUS/FLUS, 12% (n = 33) follicular/Hürthle, 10% (n = 29) suspicious for malignancy, and 11% (n = 31) malignant. The rate of cancer changed from 25% to 36% for follicular/Hürthle lesions. AUS/FLUS was utilized in 154 of 1095(14%) FNAs reviewed with a malignancy rate of 20%.

CONCLUSION

The new AUS/FLUS category was used more often than recommended (14%) with a higher than expected rate of malignancy (20%). Rigorous cytopathology to histopathology correlation is needed to accurately reflect the malignancy rates of the different BSRTC categories at each individual institution. Clinical management should be tailored based on such institutional findings.

Expression profiling of difficult-to-diagnose thyroid histologic subtypes shows distinct expression profiles and identify candidate diagnostic microRNAs

BACKGROUND

The incidence of thyroid cancer is increasing worldwide. The findings of up to 30% of thyroid fine-needle aspiration biopsies (FNAB) are inconclusive, primarily as a result of several thyroid histologic subtypes with overlapping cytologic features. MicroRNAs (miRNAs) are small noncoding RNAs and have been implicated in carcinogenesis. We hypothesized that there are miRNAs that are differentially expressed between benign and malignant thyroid tumors that are difficult to distinguish by FNAB.

METHODS

The expression of 1263 human miRNAs was profiled in 47 tumor samples representing difficult to diagnose histologic subtypes of thyroid neoplasm (21 benign, 26 malignant). Differentially expressed miRNAs were validated by quantitative real-time reverse transcriptase-polymerase chain reaction. The area under the receiver operating characteristic curve (AUC) was used to determine the diagnostic accuracy of differentially expressed miRNAs.

RESULTS

Supervised hierarchical cluster analysis demonstrated grouping of 2 histologies (papillary and follicular thyroid carcinoma). A total of 34 miRNAs were differentially expressed in malignant compared to benign thyroid neoplasms (P<0.05). A total of 25 of the 34 nonproprietary miRNAs were selected for validation, and 15 of the 25 miRNAs were differentially expressed between benign and malignant samples with P-value<0.05. Seven miRNAs had AUC values of >0.7. miR-7 and miR-126 had the highest diagnostic accuracy with AUCs values of 0.81 and 0.77, respectively.

CONCLUSION

To our knowledge, this is the first study to evaluate the diagnostic accuracy of miRNAs in thyroid histologies that are difficult to distinguish as benign or malignant by FNAB. miR-126 and miR-7 had high diagnostic accuracy and could be helpful adjuncts to thyroid FNAB.

Molecular genetics and diagnosis of thyroid cancer

Thyroid cancer is a common type of endocrine malignancy, and its incidence has been steadily increasing in many regions of the world. Initiation and progression of thyroid cancer involves multiple genetic and epigenetic alterations, of which mutations leading to the activation of the MAPK and PI3K-AKT signaling pathways are crucial. Common mutations found in thyroid cancer are point mutation of the BRAF and RAS genes as well as RET/PTC and PAX8/PPARγ chromosomal rearrangements. The mutational mechanisms seem to be linked to specific etiologic factors. Chromosomal rearrangements have a strong association with exposure to ionizing radiation and possibly with DNA fragility, whereas point mutations probably arise as a result of chemical mutagenesis. A potential role of dietary iodine excess in the generation of BRAF point mutations has also been proposed. Somatic mutations and other molecular alterations have been recognized as helpful diagnostic and prognostic markers for thyroid cancer and are beginning to be introduced into clinical practice, to offer a valuable tool for the management of patients with thyroid nodules.

The atypical thyroid fine-needle aspiration: past, present, and future

Thyroid fine-needle aspiration has developed into a key test in the evaluation of thyroid nodules. Although the interpretation of thyroid aspirates containing mild abnormalities is problematic, the introduction of the atypia of undetermined significance/follicular lesion of undetermined significance (AUS/FLUS) category in The Bethesda System for Reporting Thyroid Cytopathology (TBSRTC) has helped to delineate such cases in a systematic and clinically meaningful manner. Herein the authors review the cytomorphologic features associated with the AUS/FLUS interpretation and summarize the results of studies conducted since the implementation of TBSRTC.