Changing Trends in Thyroid Practice: Understanding Nodular Thyroid Disease

Progress in Thyroid Cancer Genomics: A 40-Year Journey

Background: Very little was known about the molecular pathogenesis of thyroid cancer until the late 1980s. As part of the Centennial celebration of the American Thyroid Association, we review the historical discoveries that contributed to our current understanding of the genetic underpinnings of thyroid cancer. Summary: The pace of discovery was heavily dependent on scientific breakthroughs in nucleic acid sequencing technology, cancer biology, thyroid development, thyroid cell signaling, and growth regulation. Accordingly, we attempt to link the primary observations on thyroid cancer molecular genetics with the methodological and scientific advances that made them possible. Conclusions: The major genetic drivers of the common forms of thyroid cancer are now quite well established and contribute to a significant extent to how we diagnose and treat the disease. However, many challenges remain. Future work will need to unravel the complexity of thyroid cancer ecosystems, which is likely to be a major determinant of their biological behavior and on how they respond to therapy.

Research Review of Thermal Ablation in the Treatment of Papillary Thyroid Carcinoma

Background

Minimally invasive treatment of thyroid tumors has become increasingly common, but has mainly focused on benign thyroid tumors, whereas thermal ablation of thyroid cancer remains controversial. Clinical studies analyzing the efficacy of thermal ablation of papillary thyroid carcinoma (PTC) have been conducted in several countries to verify its safety. Here, we screened and reviewed recent studies on the efficacy and safety of thermal ablation of PTC as well as psychological assessment, patient prognosis, recurrence, and factors affecting ablation.

Summary

The most significant controversy surrounding ablative treatment of PTC centers on its effectiveness and safety, and >40 studies have been conducted to address this issue. The studies include papillary thyroid microcarcinoma (PTMC) and non-PTMC, single PTC and multiple PTC, and controlled studies of ablative therapy and surgical treatment. In general, ablation techniques can be carefully performed and promoted under certain conditions and with active follow-up of postoperative patients. Ablation is a promising alternative treatment especially in patients who are inoperable.

Conclusions

Clinical studies on PTC ablation have provided new perspectives on local treatment. However, because PTC grows very slowly, it is an indolent tumor; therefore, studies with larger sample sizes and extended post-procedure follow-ups are necessary to confirm the investigators’ hypotheses.

Diagnostic utility of conventional and liquid-based cytology in the management of thyroid lesions; an institutional experience

Objectives:

Liquid-based cytology (LBC) is becoming a useful method in evaluating both gynecological and nongynecological preparations. Many studies have been conducted these days to see the quality of LBC in diagnosing thyroid lesions and its role is yet to be standardized. This study has been done to pick the cytomorphological features of thyroid lesions on LBC and to compare them with the conventional cytology of these lesions.The objective of the study is to evaluate the efficacy of thyroid fine-needle aspiration cytology processed by LBC as compared to conventional smears.

Material and Methods:

A prospective study has been done on 53 cases of thyroid lesions using standard conventional and LBC techniques.

Results:

In most of the cases, the cytological features are similar in conventional cytology smears and LBC, but the colloid film and the lymphocytic component show a clear picture on direct smears, whereas nuclear and cytoplasmic details are better evaluated in LBC slides. The preservative solution used in LBC could be efficiently used for the application of immunocytochemical and molecular techniques.

Conclusion:

LBC does not represent as a valid alternative to conventional cytology but it can be considered as a diagnostic utility process especially due to the possibility of applying additional techniques which enhance the efficacy of the cytological diagnosis of thyroid lesions.

Radiofrequency ablation and thyroid cancer: review of the current literature

BACKGROUND

Thyroid nodules are commonly being diagnosed in general population and have a potential for malignant transformation. Historically, surgery has been considered as the first line treatment for these tumors. However, with passage of time newer minimally invasive techniques such as RFA (radiofrequency ablation) has been adapted. Though, RFA for thyroid tumors has been performed more commonly in Asian and European countries, it is a fairly new technique in North America. The aim of the review is to assess the current data and conclude that whether RFA is likely a valuable option when compared to surgery for treatment of thyroid tumors.

MATERIALS AND METHODS

A Comprehensive PubMed/MEDLINE, Embase and Web of Science search was performed. To expand our search, references of the retrieved articles were also screened for additional data. After selecting the studies that fulfilled the initial screening, authors independently reviewed the selected studies and screened the full texts to identify those that met the inclusion criteria.

RESULTS

The comprehensive literature search from PubMed/MEDLINE, Web of Science, and EMBASE databases revealed 1094 studies (Embase 870, PubMed 200, and Web of Science 24). References were imported for screening. Amongst 1094 studies, 138 duplicates removed, and 956 studies were screened against title and abstract. After these 777 studies were excluded the remaining 179 studies were assessed for full-text eligibility. Amongst them 127 studies excluded due to wrong design or setting. Finally, 18 studies were included in the review.

CONCLUSION

RFA appears to be a safe alternative to surgery in selected cases. However, it is not widely used and there are few randomized controlled trials. Furthermore, it is associated with a low risk profile and has shown promising results in patients who are difficult surgery candidates. Currently large-scale prospective studies are needed in North America to establish the efficacy of RFA and its use as an alternative to surgery for thyroid tumors.

Combination of ultrasound and molecular testing in malignancy risk estimate of Bethesda category IV thyroid nodules: results from a single-institution prospective study

PURPOSE

Malignancy prediction in indeterminate thyroid nodules is still challenging. We prospectively evaluated whether the combination of ultrasound (US) risk stratification and molecular testing improves the assessment of malignancy risk in Bethesda Category IV thyroid nodules.

METHODS

Ninety-one consecutively diagnosed Bethesda Category IV thyroid nodules were prospectively evaluated before surgery by both ACR- and EU-TIRADS US risk-stratification systems and by a further US-guided fine-needle aspiration cytology (FNAC) for the following molecular testing: BRAFV600E, N-RAS codons 12/13, N-RAS codon 61, H-RAS codons 12/13, H-RAS codon 61, K-RAS codons 12/13, and K-RAS codon 61 point-mutations, as well as PAX8/PPARγ, RET/PC1, and RET/PTC 3 rearrangements.

RESULTS

At histology, 37% of nodules were malignant. No significant association was found between malignancy and either EU- or ACR-TIRADS. In total, 58 somatic mutations were identified, including 3 BRAFV600E (5%), 5 N-RAS 12/13 (9%), 13 N-RAS 61 (22%), 7 H-RAS 12/13 (12%), 11 H-RAS 61 (19%), 6 K-RAS 12/13 (10%), 8 K-RAS 61 (14%) mutations and 2 RET/PTC1 (4%), 0 RET/PTC 3 (0%), 3 PAX8/PPARγ (5%) rearrangements. At least one somatic mutation was found in 28% and 44% of benign and malignant nodules, respectively, although malignancy was not statistically associated with the outcome of the mutational test. However, the combination of ACR-, but not EU-, TIRADS with the presence of at least one somatic mutation, was significantly associated with malignant histology (P = 0.03).

CONCLUSION

US risk stratification and FNAC molecular testing may synergistically contribute to improve malignancy risk estimate of Bethesda category IV thyroid nodules.

Evaluation of LMR, NLR and PLR as predictors of malignancy in indeterminate thyroid nodules

Objective

Thyroid nodules with indeterminate cytology represent 20% of all thyroid nodules. Inflammation plays an important role in cancer. Lymphocyte-to-monocyte ratio (LMR), neutrophil-to-lymphocyte ratio (NLR) and platelet-to-lymphocyte ratio (PLR) are independent prognostic scores in numerous cancers, although no study has documented their role in cytology indeterminate nodules. The aim of this study is to evaluate the role of LMR, NLR and PLR values as predictors of malignancy in patients with cytology indeterminate nodules.

Methods

This retrospective study analysed data from 298 patients with indeterminate thyroid nodule. Anatomopathological and haematological data were analysed, dividing the population into two groups. LMR, NLR and PLR values were determined using ROC curve and data were analysed using independent samples t-test, test of proportions, Fisher’s exact test and univariate and multivariate logistic regression.

Results

We found that a baseline LMR value ≥ 4.09 was indicative of benignity of indeterminate nodule. The probability of malignancy in patients with LMR < 4.09 was 26 times higher than patients with a LMR value ≥ 4.09.

Conclusions

This study showed that only LMR has shown a concrete probability to find a thyroid cancer in patients with indeterminate nodules. Further studies are necessary to implement tailored treatment.

Reporting Thyroid Cytology in a Globalized World

The Italian SIAPEC-AIT 2014 classification, the 2017 Bethesda System for Reporting Thyroid Cytology (TBSRTC), the 2016 UK Royal College of Pathologists (RCPath) thyroid reporting system, and the 2019 Japanese reporting system for thyroid aspiration cytology (JRSTAC2019) represent the most widely used reporting systems among clinicians and pathologists for the purpose of cytologically diagnosing, estimating the potential risk of malignancy (ROM), and defining the most appropriate treatment for a patient with a thyroid nodule. Although all the systems use overlapping diagnostic categories and morphologic criteria, they differ on the basis of the criteria for inclusion in the cytologic categories, which may, in turn, affect the ROM of a given category and the clinical management of the patient, particularly with regard to the “indeterminate” categories. The aim of this review is to analyze the main differences that emerge between the systems and to propose possible solutions for a comprehensive reporting system that integrates and harmonizes all the criteria of the Italian classification and the Bethesda system, also taking into account the impact that the new tumor entity NIFTP (non-invasive follicular tumor with papillary-like nuclear features) that has, in many instances, replaced the non-invasive form of the follicular variant of papillary carcinoma, has had on the modification of malignancy risks.

Comparison of Afirma Gene Expression Classifier with Gene Sequencing Classifier in indeterminate thyroid nodules: A single-institutional experience

INTRODUCTION

The Afirma test has been used in the diagnosis of cytologically indeterminate thyroid nodules to reduce diagnostic uncertainty and unnecessary surgeries. Gene Sequencing Classifier (GSC) was developed to improve the positive predictive value and overall test performance of Gene Expression Classifier (GEC). Here we present our experience comparing the performance of first-generation assay of Afirma (GEC) with the new assay (GSC).

METHODS

Retrospective analysis was performed on all Bethesda III and IV cytology thyroid nodules tested with GEC and GSC. Test performance was evaluated by surgical pathology outcomes.

RESULTS

In total, 167 cases were tested with GEC, of which 49% were reported as benign. Fourteen cases had surgical follow-up with 11 benign, one non-invasive follicular thyroid neoplasm with papillary-like nuclear features (NIFTP) and two malignant diagnoses. Of the 167 cases, 51% had suspicious GEC result. Fifty-seven of these suspicious GEC cases had surgical follow-up with 28 benign, nine NIFTP and 20 malignant histology. There 133 cases tested with GSC, of which 61% were reported as benign. Ten cases had surgical follow-up, all of which showed benign results and 32% of the cases were tested as suspicious. Thirty-six cases with suspicious GSC had surgical follow-up. Fourteen of them had benign, five NIFTP, and 17 malignant surgical pathology. Based on molecular testing, surgical resection could have been be prevented 61% with GSC, compared to 49% with GEC test.

CONCLUSION

Our experience shows that GSC has a better test performance than GEC. Also, our data support that GSC identify more cases as benign and reduces the number of unnecessary surgeries compared to GEC.

ThyroSeq v3 for Bethesda III and IV: An institutional experience

BACKGROUND

The ThyroSeq v3 genomic classifier is a commercial molecular test that examines a wide spectrum of genomic alterations in a thyroid fine-needle aspiration (FNA) sample and reports test results as either negative or positive. The authors report their institutional experience with ThyroSeq v3.

METHODS

Thyroid FNA specimens diagnosed as either atypia of undetermined significance or follicular lesion of undetermined significance (AUS/FLUS) (Bethesda category III [Bethesda III] according to The Bethesda System for Reporting Thyroid Cytopathology) or follicular neoplasm/suspicious for follicular neoplasm (FN/SFN) (Bethesda IV) that had ThyroSeq v3 results available from December 2017 through October 2019 were retrieved for analysis. FNA diagnoses were correlated with ThyroSeq v3 results and follow-up histopathology.

RESULTS

In total, 415 cases (AUS/FLUS, n = 251; FN/SFN, n = 164) were retrieved: 294 (71%) were reported as ThyroSeq v3-negative, and 121 (29%) were reported as ThyroSeq v3-positive. The benign call rate (BCR) of ThyroSeq v3 for AUS/FLUS (82%; 206 of 251 cases) was significantly higher (P < .001) than that for FN/SFN (BCR, 54%; 88 of 164 cases). Histopathologic follow-up was available for 127 cases (ThyroSeq v3-positive, 96; ThyroSeq v3-negative, 31), of which 57 were benign and 70 were malignant (including noninvasive follicular thyroid neoplasm with papillary-like nuclear features). The negative predictive value of ThyroSeq v3 was significantly higher for AUS/FLUS (99.5%) than for FN/SFN (95.4%; P < .0294), given malignancy rates of 10% for AUS/FLUS and 30% for FN/SFN. Forty-five unique combinations of genetic alterations were detected in the operated ThyroSeq-positive cases, and there were only 5 false-negative cases, comprised of 4 low-risk neoplasms.

CONCLUSIONS

The high BCR of ThyroSeq v3 for AUS/FLUS prevents surgery in a majority of patients. The ThyroSeq v3 genomic classifier reveals the complexity of the genetic signature of indeterminate nodules.

Efficacy and safety of radiofrequency, microwave and laser ablation for treating papillary thyroid microcarcinoma: a systematic review and meta-analysis

Background: To evaluate the efficacy and safety of radiofrequency ablation (RFA), microwave ablation (MWA) and laser ablation (LA) for treating papillary thyroid microcarcinoma (PTMC).Materials and methods: PUBMED and EMBASE were searched for studies on the efficacy and safety of RFA, MWA and LA for treating PTMC. The standard mean difference of the tumor volume before and after therapy and the proportion of complete disappearance, local recurrence, distant metastasis and complications were assessed using both fixed or random-effects modeling. Heterogeneity among studies was determined using the Q statistic for the pooled estimates and the inconsistency index I².Results: A total of 12 eligible studies, including a sample size of 1187 patients and 1284 PTMCs, were used. RFA, MWA and LA all showed a significant reduction in tumor volume of PTMCs (p < 0.05). Though MWA demonstrated superior efficacy over the other two therapies for volume reduction, the differences were not statistically significant. Additionally, the pooled proportion of complete disappearance after RFA was the highest (76.2%), and the pooled proportion of recurrence for RFA was the lowest (0.01%) among the three therapeutic methods, but no significant difference was detected. There was no event of distant metastasis during the follow-up in all of these studies. Few major complications were encountered; the pooled proportion of complications for RFA (1.73%), MWA (6.0%) and LA (0.92%) was low, revealing no significant differences (p > 0.05).Conclusion: RFA, MWA and LA are acceptable treatments to manage PTMCs in terms of efficacy and safety for non-surgical candidates.

Clinical performance of multiplatform mutation panel and microRNA risk classifier in indeterminate thyroid nodules

INTRODUCTION

We evaluated the clinical performance of an expanded mutation panel in combination with microRNA classification (MPTX) for the management of indeterminate thyroid nodules.

MATERIALS AND METHODS

MPTX included testing of fine-needle aspirates from multiple centers with a combination of ThyGeNEXT mutation panel for strong and weak driver oncogenic changes and ThyraMIR microRNA risk classifier (both from Interpace Diagnostics; Pittsburgh, PA). MPTX test status (positive or negative) and MPTX clinical risk classifications (low, moderate, or high risk) were determined blind to patient outcomes. Surgical pathology and clinical follow-up records of patients from multiple centers were used to determine patient outcomes. MPTX performance was assessed by Kaplan Meier analysis for cancer-free survival of patients, with risk of malignancy determined by hazard ratio (HR).

RESULTS

Our study included 140 patients with AUS/FLUS or FN/SFN nodules, of which 13% had malignancy. MPTX negative test status and MPTX low risk results conferred a high probability (94%) that patients would remain cancer-free. MPTX positive test status (HR 11.2, P < 0.001) and MPTX moderate-risk results (HR 8.5, P = 0.001) were significant risk factors for malignancy, each conferring a 53% probability of malignancy. MPTX high-risk results elevated risk of malignancy even more so, conferring a 70% probability of malignancy (HR 38.5, P < 0.001).

CONCLUSIONS

MPTX test status accurately stratifies patients for risk of malignancy. Further classification using MPTX clinical risk categories enhances utility by accurately identifying patients at low, moderate, or high risk of malignancy at the low rate of malignancy encountered when clinically managing patients with indeterminate thyroid nodules.

Novel three-dimensional cultures provide insights into thyroid cancer behavior

Thyroid cancer has the fastest growing incidence of any cancer in the United States, as measured by the number of new cases per year. Despite advances in tissue culture techniques, a robust model for thyroid cancer spheroid culture is yet to be developed. Using eight established thyroid cancer cell lines, we created an efficient and cost-effective 3D culture system that can enhance our understanding of in vivo treatment response. We found that all eight cell lines readily form spheroids in culture with unique morphology, size, and cytoskeletal organization. In addition, we developed a high-throughput workflow that allows for drug screening of spheroids. Using this approach, we found that spheroids from K1 and TPC1 cells demonstrate significant differences in their sensitivities to dabrafenib treatment that closely model expected patient drug response. In addition, K1 spheroids have increased sensitivity to dabrafenib when compared to monolayer K1 cultures. Utilizing traditional 2D cultures of these cell lines, we evaluated the mechanisms of this drug response, showing dramatic and acute changes in their actin cytoskeleton as well as inhibition of migratory behavior in response to dabrafenib treatment. Our study is the first to describe the development of a robust spheroid system from established cultured thyroid cancer cell lines and adaptation to a high-throughput format. We show that combining 3D culture with traditional 2D methods provides a complementary and powerful approach to uncover drug sensitivity and mechanisms of inhibition in thyroid cancer.

European perspective on the use of molecular tests in the diagnosis and therapy of thyroid neoplasms

Thyroid nodules are frequently observed, particularly in individuals of over 60 years of age. On the other hand, most of the detected changes are benign and they do not require surgery. Therefore, differentiation between benign and malignant lesions in preoperative diagnosis is of crucial importance. Currently, the use of fine-needle aspiration biopsy (FNAB) and cytological assessment are the gold standard in the diagnosis of thyroid nodules. This procedure significantly reduces the need for diagnostic surgical intervention. However, approximately 15-30% of cytological results are classified as indeterminate. This is mainly due to the lack of specific cytomorphologic features that would facilitate the diagnosis based on cell evaluation under microscopic assessment. For the diagnoses of atypia of undetermined significance/follicular lesion of undetermined significance (AUS/FLUS), the assessment of invasion is crucial. Such an evaluation is not possible in cytology. Recently, molecular tests have been developed. They improve cytological diagnosis, particularly in the case of indeterminate results. Commercially available tests are developed based on the North American population. It is important to assess whether such tests can be used in the evaluation of e.g., European population.

Quality of Life in Papillary Thyroid Microcarcinoma Patients Undergoing Radiofrequency Ablation or Surgery: A Comparative Study

Objective: Papillary thyroid microcarcinoma (PTMC) has a good prognosis and a long survival time. Health-related quality of life (HRQoL) is vital for PTMC patients during their survivorship. Ultrasound (US)-guided radiofrequency ablation (RFA), which has high efficacy and safety, is recommended as an alternative treatment to surgery for the patients with low-risk PTMC. However, the assessment of QoL of patients with PTMC has not been specially reported. The purpose of our study was to compare the HRQoL of patients with PTMC who underwent RFA and those who underwent surgery. Methods: From October 2019 to December 2019, 88 PTMC patients were enrolled in our study, including 54 in RFA group and 34 in surgery group. We used three questionnaires which included the 36-item short form health survey (SF-36), thyroid cancer-specific quality of life (THYCA-QOL), and Fear of Progression Questionnaire-Short Form (FoP-Q-SF) for each patient to evaluate their scores of HRQoL. The scores were compared after adjusting for age, sex, medical expense, and follow-up time. Results: According to the SF-36, the scores of the domain for the role limitation due to physical problems and emotional problems (RP, RE) as well as Physical Component Summary (PCS) showed a significant negative linear association between the RFA group and surgery group: RP coefficient [coef]-22.613 [confidence interval (CI) -33.504 to -11.723], p < 0.001, RE (coef: -21.901 [CI -36.737 to -7.064], p = 0.004), and PCS (coef: -8.312 [CI -13.694 to -2.930], p = 0.003). The THYCA-QOL showed that the scores of the surgery group were higher than that of the RFA group regarding scars (coef: 10.246 [CI 1.330 to 19.162], p = 0.025 according to the multivariate analysis), suggesting a higher level of complaint in the surgery group. There was no statistically significant difference in the scores of FoP-Q-SF between the two groups. Conclusions: In patients with PTMC, US-guided RFA offers advantage over surgery in terms of HRQoL, which supports the role of RFA as an alternative strategy to surgery.

Incremental utility of expanded mutation panel when used in combination with microRNA classification in indeterminate thyroid nodules

INTRODUCTION

Focused and expanded mutation panels were assessed for the incremental utility of using an expanded panel in combination with microRNA risk classification.

METHODS

Molecular results were reviewed for patients who underwent either a focused mutation panel (ThyGenX®) or an expanded mutation panel (ThyGeNEXT®) for strong and weak oncogenic driver mutations and fusions. microRNA results (ThyraMIR®) predictive of malignancy, including strong positive results highly specific for malignancy, were examined.

RESULTS

Results of 12 993 consecutive patients were reviewed (focused panel = 8619, expanded panel = 4374). The expanded panel increased detection of strong drivers by 8% (P < .001), with BRAFV600E and TERT promoters being the most common. Strong drivers were highly correlated with positive microRNA results of which 90% were strongly positive. The expanded panel increased detection of coexisting drivers by 4% (P < .001), with TERT being the most common partner often paired with RAS. It increased the detection of weak drivers, with RAS and GNAS being the most common. 49% of nodules with weak drivers had positive microRNA results of which 33% were strongly positive. The expanded panel also decreased the number of nodules lacking mutations and fusions by 15% (P < .001), with 8% of nodules having positive microRNA results of which 22% were strongly positive.

CONCLUSIONS

Using expanded mutation panels that include less common mutations and fusions can offer increased utility when used in combination with microRNA classification, which helps to identify high risk of malignancy in the cases where risk is otherwise uncertain due to the presence of only weak drivers or the absence of all drivers.

Clinical impact of testing for mutations and microRNAs in thyroid nodules

Background

We report results of a multicenter clinical experience study examining the likelihood of patients with indeterminate thyroid nodules to undergo surgery or have malignant outcome based on multiplatform combination mutation and microRNA testing (MPT).

Methods

MPT assessed mutations in BRAF, HRAS, KRAS, NRAS, and PIK3CA genes, PAX8/PPARγ, RET/PTC1, and RET/PTC3 gene rearrangements, and the expression of 10 microRNAs. Baseline clinical information at the time of MPT and clinical follow‐up records were reviewed for 337 patients, of which 80% had negative MPT results. Kaplan Meier analysis for cumulative probability of survival without having a surgical procedure or malignant diagnosis over the course of patient follow‐up was determined for MPT results of 180 patients, among which only 14% had malignancy.

Results

A negative MPT result in nodules with Bethesda III or IV cytology (2009) conferred a high probability of non‐surgical treatment, with only 11% expected to undergo surgery and a high probability of survival without malignancy (92%) for up to 2 years follow up. A positive MPT result conferred a 57% probability of malignancy and was an independent risk factor for undergoing surgical treatment (Hazard Ratio [HR] 9.2, 95% confidence intervals 5.4‐15.9, P < .0001) and for malignancy (HR 13.4, 95% confidence intervals 4.8‐37.2, P < .0001). For nodules with weak driver mutations, positive microRNA test results supported high risk of cancer while negative results downgraded cancer risk.

Conclusion

MPT results are predictive of real‐world decisions to surgically treat indeterminate thyroid nodules, with those decisions being appropriately aligned with a patient's risk of malignancy over time.

Update on Molecular Testing for Cytologically Indeterminate Thyroid Nodules

Fine needle aspiration biopsy (FNAB) and ultrasonography are the most common modalities for the diagnosis and follow up of thyroid nodules. FNAB is able to distinguish benign from malignant nodules with high sensitivity and specificity; however, 20% to 30% of nodules are diagnosed as indeterminate with a risk of malignancy varying from 10% to 75% based on the 2017 revision of the Bethesda System for Reporting Thyroid Cytopathology. Molecular tests are being increasingly used to triage this group of nodules. Several molecular tests are commercially available and newer upgrades are being developed to either "rule in" or "rule out" malignancy with greater accuracy. The Afirma gene expression classifier and its recent upgrade (the Afirma gene sequencing classifier), Thryoseq v2, a next generation sequencing test and its recent upgrade (the v3), RosettaGX Reveal based on microRNA alterations, and ThyGenX/ThyraMIR, a combination test, are currently on the market. Familiarity with these tests, their performance, and postvalidation publications will enable appropriate test selection and improve triage of patients for appropriate therapy. The underlying rate of malignancy at different institutions and the interobserver variability in cytologic and histologic diagnosis of thyroid lesions are important factors that impact the performance of the various molecular tests.

Expression of SLC5A5 in Circulating Tumor Cells May Distinguish Follicular Thyroid Carcinomas from Adenomas: Implications for Blood-Based Preoperative Diagnosis

Preoperative diagnosis of thyroid nodules reduces unnecessary surgery. Circulating tumor cells (CTCs) may contain information of primary tumor(s). We asked whether the peripheral blood expression of genes specific for circulating tumor cells (CTCs) differentiates benign thyroid nodules from malignant nodules. Peripheral blood mononuclear cells from thyroid nodule patients (n = 20) were isolated preoperatively and the expression of seven CTC-associated genes was measured in patients with thyroid nodule(s) (n = 20). Among the tested genes, the expression of SLC5A5 and LGALS3 were validated in a larger number of patients (n = 64) and our results show that SLC5A5 expression differentiated follicular adenomas from follicular carcinomas (area under the curve (AUC) = 0.831). The expression of SLC5A5 in CTCs may preoperatively distinguish thyroid follicular adenomas from follicular carcinomas.

Centrifuged supernatants from FNA provide a liquid biopsy option for clinical next-generation sequencing of thyroid nodules

BACKGROUND

Molecular testing is recommended as an adjunct to improve the preoperative diagnosis of fine-needle aspiration (FNA) of thyroid nodules. Centrifuged supernatants from FNA samples, which are typically discarded, have recently emerged as a novel liquid-based biopsy for molecular testing. This study evaluates the use of thyroid FNA supernatants for detecting clinically relevant mutations.

METHODS

Supernatants from thyroid FNA samples (n = 156) were evaluated. A 50-gene next-generation sequencing (NGS) assay was used, and mutation analysis results from a subset of samples were further compared with those of paired FNA smears and/or cell blocks.

RESULTS

All 156 samples yielded adequate DNA (median, 135 ng; range, 11-3180 ng), and 129 of these samples (83%) were successfully sequenced by NGS. The most frequently detected somatic mutations included BRAF and RAS mutations, which were followed by RET, TP53, PTEN, CDKN2A, and PIK3CA mutations. Eleven of 31 cases with an indeterminate cytologic diagnosis and 9 of 12 cases that were suspicious for malignancy had somatic mutations, including the BRAF V600E mutation, which is highly definitive for papillary thyroid carcinoma (PTC). Seven of the 9 indeterminate and suspicious cases with the BRAF V600E mutation had surgical follow-up, and they were all confirmed to be PTC. A comparison of the mutation profiles derived from supernatants with those of paired smears and/or cell blocks in a small subset of cases (n = 8) showed 100% concordance.

CONCLUSIONS

This study provides evidence that FNA supernatants can be used as a surrogate for thyroid molecular testing to improve diagnostic accuracy in indeterminate nodules, provide prognostic/predictive information, and improve overall patient management.

Gene expression differences between thyroid carcinoma, thyroid adenoma and normal thyroid tissue

To identify differences in gene expression profiles of infected cells between thyroid carcinoma (C), thyroid adenoma (A) and normal thyroid (N) epithelial cells, differentially expressed genes were identified using three pairwise comparisons with the GEO2R online tool. Gene ontology and Kyoto Encyclopedia of Genes and Genomes pathway enrichment analysis were used to classify them at the functional level. The most significant cluster in the N vs. A pairwise comparison had four hub genes: Insulin-like growth factor 2, Von Willebrand factor (VWF), multimerin 1 (MMRN1) and complement factor D (CFD). In N vs. C, the most significant cluster had 19 genes: IGF2, early growth response 2, transcription factor 3, KIT proto‑oncogene receptor tyrosine kinase, SMAD family member 9, MLLT3 super elongation complex subunit, runt related transcription factor 1, CFD, actinin α 1, SWI/SNF related matrix associated actin dependent regulator of chromatin subfamily a member 4, JunD proto‑oncogene AP‑1 transcription factor subunit, serum response factor (SRF), FosB proto‑oncogene, AP‑1 transcription factor subunit, connective tissue growth factor (CTGF), SRC proto‑oncogene, non‑receptor tyrosine kinase, MMRN1, SRY‑box 9, early growth response 3 and ETS variant 4. In A vs. C, the most significant cluster had 14 genes: BCL2-like 1, galectin 3, MCL1 BCL2 family apoptosis regulator, DNA damage inducible transcript 3, BCL2 apoptosis regulator, CTGF, matrix metallopeptidase 7, early growth response 1, kinase insert domain receptor, TIMP metallopeptidase inhibitor 1, apolipoprotein E, VWF, cyclin D1 and placental growth factor. Histological evidence was presented to confirm the makeup of the hubs prior to logistic regression analysis to differentiate benign and malignant neoplasms. The results of the present study may aid in the search for novel potential biomarkers for the differential diagnosis, prognosis and development of drug targets of thyroid neoplasm.

Complications Following Radiofrequency Ablation of Benign Thyroid Nodules: A Systematic Review

Objective:

This systematic review examined whether radiofrequency ablation (RFA) is a safe treatment modality for benign thyroid nodules (BTNs).

Data Sources:

PubMed, Embase, and the Cochrane Library database were searched for articles that (a) targeted human beings and (b) had a study population with BTNs that were confirmed by fine-needle aspiration cytology and/or core needle biopsy.

Study Selection:

Thirty-two studies relating to 3409 patients were included in this systematic review.

Results:

Based on literatures, no deaths were associated with the procedure, serious complications were rare, and RFA appears to be a safe and well-tolerated treatment modality. However, a broad spectrum of complications offers insights into some undesirable complications, such as track needle seeding and Horner syndrome.

Conclusions:

RFA appears to be a safe and well-tolerated treatment modality for BTNs. More research is needed to characterize the complications of RFA for thyroid nodules.

Preoperative Molecular Markers in Thyroid Nodules

The need for distinguishing benign from malignant thyroid nodules has led to the pursuit of differentiating molecular markers. The most common molecular tests in clinical use are Afirma^® Gene Expression Classifier (GEC) and Thyroseq^® V2. Despite the rapidly developing field of molecular markers, several limitations exist. These challenges include the recent introduction of the histopathological diagnosis "Non-Invasive Follicular Thyroid neoplasm with Papillary-like nuclear features", the correlation of genetic mutations within both benign and malignant pathologic diagnoses, the lack of follow-up of molecular marker negative nodules, and the cost-effectiveness of molecular markers. In this manuscript, we review the current published literature surrounding the diagnostic value of Afirma^® GEC and Thyroseq^® V2. Among Afirma^® GEC studies, sensitivity (Se), specificity (Sp), positive predictive value (PPV), and negative predictive value (NPV) ranged from 75 to 100%, 5 to 53%, 13 to 100%, and 20 to 100%, respectively. Among Thyroseq^® V2 studies, Se, Sp, PPV, and NPV ranged from 40 to 100%, 56 to 93%, 13 to 90%, and 48 to 97%, respectively. We also discuss current challenges to Afirma^® GEC and Thyroseq^® V2 utility and clinical application, and preview the future directions of these rapidly developing technologies.

Radiofrequency ablation of small follicular neoplasms: initial clinical outcomes

BACKGROUND

In thyroid gland, radiofrequency ablation (RFA) has been applied to both recurrent cancers and benign nodules, although, according to the American Thyroid Association (ATA) and the Korean Society of Thyroid Radiology (KSThR) guidelines, surgery is the first-line treatment for follicular neoplasm. However, it has been argued that follicular neoplasm with lower risk of malignancy can be managed by close follow-up. In this study, we evaluated the effectiveness of RFA of small follicular neoplasms, examining reductions in volume and related clinical problems, and making observations over long-term follow-up.

METHODS

We evaluated 10 follicular neoplasms in 10 patients who were treated with RF ablation between 2009 and 2011. A RF generator and an 18-gauge internally cooled electrode were used to perform complete ablation of the whole nodules. Changes in nodules or ablated zones on follow-up ultrasound, and complications during and after RF ablation were evaluated.

RESULTS

The mean follow-up period was 66.4 ± 5.1 months (range: 60-76 months). In eight patients, single session of RF ablation was sufficient, while two patients required two sessions. There was a significant reduction in the mean volume (99.5 ± 1.0%) of lesions, with eight ablated lesions (8/10, 80%) disappearing completely on follow-up. No recurrences were found in any ablated zones at last follow-up. Transient mild neck pain (n = 6) occurred during the procedure without requiring any medication.

CONCLUSION

In addition to active surveillance, RF ablation may be an effective and safe alternative for the management of patients with small (<2 cm) follicular neoplasm suspected on thyroid biopsy and who strongly refuse surgery.

Next-generation sequencing in thyroid cancer

Next-generation sequencing (NGS) in thyroid cancer allows for simultaneous high-throughput sequencing analysis of variable genetic alterations and provides a comprehensive understanding of tumor biology. In thyroid cancer, NGS offers diagnostic improvements for fine needle aspiration (FNA) cytology of thyroid with indeterminate features. It also contributes to patient management, providing risk stratification of patients based on the risk of malignancy. Furthermore, NGS has been adopted in cancer research. It is used in molecular tumor classification, and molecular prediction of recurrence and metastasis in papillary thyroid carcinoma. This review covers previous NGS analyses in variable types of thyroid cancer, where samples including FNA cytology, fresh frozen tissue, and formalin-fixed, paraffin-embedded tissues were used. This review also focuses on the clinical and research implications of using NGS to study and treat thyroid cancer.

Efficacy and Safety of Ultrasound-Guided Radiofrequency Ablation for Treating Low-Risk Papillary Thyroid Microcarcinoma: A Prospective Study

BACKGROUND

Papillary thyroid microcarcinoma (PTMC) has a high incidence and a good prognosis. Surgical operation for all PTMC might be an overtreatment. The objective of this study was to evaluate the efficacy and safety of ultrasound (US)-guided radiofrequency ablation (RFA) for treating low-risk PTMC.

METHODS

Ninety-eight PTMC in 92 patients were included in this study. US and contrast-enhanced ultrasound (CEUS) examinations were performed before ablation. RFA was performed using the moving-shot technique. The ablation area exceeded the tumor edge to prevent marginal residue and recurrence. Patients were followed at 1, 3, 6, and 12 months and every six months thereafter. US and CEUS examinations were used to evaluate the ablation area. At three months after ablation, US-guided core-needle biopsy (CNB) was performed in the center, at the edge of the ablation area, and in the surrounding thyroid parenchyma to exclude recurrence.

RESULTS

The mean tumor volume was 118.8 ± 106.9 mm³. The mean volume reduction ratio (VRR) was 0.47 ± 0.27, 0.19 ± 0.16, 0.08 ± 0.11, 0.04 ± 0.10, and 0 at 1, 3, 6, 12, and 18 months after RFA, respectively. Significant differences in the VRR were found between every two follow-up times before six months (p < 0.01), and no significant differences in the VRR were found between six months and after 12 months (p = 0.42). Of all the nodules, 10 (41.7%) resolved in six months, and 23 (95.8%) resolved in 12 months. No residual or recurrent tumor tissue was detected in RFA area or in residual thyroid tissue during follow-up. No suspicious metastatic lymph nodes were detected. The histological pathology results of US-guided CNB confirmed the absence of residual or recurrent tumor. No major complications were encountered.

CONCLUSIONS

RFA can effectively eliminate low-risk PTMC with a very small complication rate. RFA may be an alternative strategy for the treatment of PTMC.

Plasma exosomal miR-21 and miR-181a differentiates follicular from papillary thyroid cancer

Thyroid cancer (TC) is the most common endocrine malignancy and its incidence has increased over the last few decades. As has been revealed by a number of studies, TC tissue's micro-RNA (miRNA) profile may reflect histological features and the clinical behavior of tumor. However, alteration of the miRNA profile of plasma exosomes associated with TC development has to date not been explored. We isolated exosomes from plasma and assayed their characteristics using laser diffraction particle size analysis, atomic force microscopy, and western blotting. Next, we profiled cancer-associated miRNAs in plasma exosomes obtained from papillary TC patients, before and after surgical removal of the tumor. The diagnostic value of selected miRNAs was evaluated in a large cohort of patients displaying different statuses of thyroid nodule disease. MiRNA assessment was performed by RT-qPCR. In total, 60 patients with different types of thyroid nodal pathology were included in the study. Our results revealed that the development of papillary TC is associated with specific changes in exosomal miRNA profiles; this phenomenon can be used for differential diagnostics. MiRNA-31 was found to be over-represented in the plasma exosomes of patients with papillary TC vs. benign tumors, while miRNA-21 helped to distinguish between benign tumors and follicular TC. MiRNA-21 and MiRNA-181a-5p were found to be expressed reciprocally in the exosomes of patients with papillary and follicular TC, and their comparative assessment may help to distinguish between these types of TC with 100 % sensitivity and 77 % specificity.

Clinical Next Generation Sequencing for Precision Medicine in Cancer

Rapid adoption of next generation sequencing (NGS) in genomic medicine has been driven by low cost, high throughput sequencing and rapid advances in our understanding of the genetic bases of human diseases. Today, the NGS method has dominated sequencing space in genomic research, and quickly entered clinical practice. Because unique features of NGS perfectly meet the clinical reality (need to do more with less), the NGS technology is becoming a driving force to realize the dream of precision medicine. This article describes the strengths of NGS, NGS panels used in precision medicine, current applications of NGS in cytology, and its challenges and future directions for routine clinical use.

Outcome of thyroid gene expression classifier testing in clinical practice

OBJECTIVES/HYPOTHESIS

Gene expression classifiers can safely reduce diagnostic thyroid surgery for fine-needle aspiration cytology (FNAC) indeterminate thyroid nodules.

STUDY DESIGN

Retrospective review, single-institution, single-practice surgeon.

METHODS

Three-year retrospective review of indeterminate FNAC that went on to gene expression classifier testing.

RESULTS

A total of 520 patients met American Thyroid Association guideline criteria for surgeon-performed ultrasound-guided FNAC for a thyroid nodule with on-site cytopathology. The indeterminate (Bethesda III or IV) FNAC rate was 9%. Prevalence of malignancy in FNAC indeterminate was 21%. Thirty-two cases went on to gene expression classifier testing. Fourteen were benign, 15 suspicious, and three with no result.

CONCLUSIONS

Benign gene expression classifier testing had an estimated negative predictive value of 100% during the study period. These patients have been observed for a mean and median duration of 14 and 7 months, respectively. In this small series, 14 of 29 patients with indeterminate FNAC were spared diagnostic surgery.

LEVEL OF EVIDENCE

4.

Highly accurate diagnosis of cancer in thyroid nodules with follicular neoplasm/suspicious for a follicular neoplasm cytology by ThyroSeq v2 next-generation sequencing assay

BACKGROUND

Fine-needle aspiration (FNA) cytology is a common approach to evaluating thyroid nodules, although 20% to 30% of FNAs have indeterminate cytology, which hampers the appropriate management of these patients. Follicular (or oncocytic) neoplasm/suspicious for a follicular (or oncocytic) neoplasm (FN/SFN) is a common indeterminate diagnosis with a cancer risk of approximately 15% to 30%. In this study, the authors tested whether the most complete next-generation sequencing (NGS) panel of genetic markers could significantly improve cancer diagnosis in these nodules.

METHODS

The evaluation of 143 consecutive FNA samples with a cytologic diagnosis of FN/SFN from patients with known surgical outcomes included 91 retrospective samples and 52 prospective samples. Analyses were performed on a proprietary sequencer using the targeted ThyroSeq v2 NGS panel, which simultaneously tests for point mutations in 13 genes and for 42 types of gene fusions that occur in thyroid cancer. The expression of 8 genes was used to assess the cellular composition of FNA samples.

RESULTS

In the entire cohort, histologic analysis revealed 104 benign nodules and 39 malignant nodules. The most common point mutations involved the neuroblastoma RAS viral oncogene homolog (NRAS), followed by the Kirsten rat sarcoma viral oncogene homolog (KRAS), the telomerase reverse transcriptase (TERT) gene, and the thyroid-stimulating hormone receptor (TSHR) gene. The identified fusions involved the thyroid adenoma associated (THADA) gene; the peroxisome proliferator-activated receptor γ (PPARG) gene; and the neurotrophic tyrosine kinase, receptor, type 3 (NTRK3) gene. Performance characteristics were similar in the retrospective and prospective groups. Among all FN/SFN nodules, preoperative ThyroSeq v2 performed with 90% sensitivity (95% confidence interval [CI], 80%-99%), 93% specificity (95% CI, 88%-98%), a positive predictive value of 83% (95% CI, 72%-95%), a negative predictive value of 96% (95% CI, 92%-100%), and 92% accuracy (95% CI, 88%-97%).

CONCLUSIONS

The current results indicate that comprehensive genotyping of thyroid nodules using a broad NGS panel provides a highly accurate diagnosis for nodules with FN/SFN cytology and should facilitate the optimal management of these patients.

PAX8/PPARγ rearrangement in thyroid nodules predicts follicular-pattern carcinomas, in particular the encapsulated follicular variant of papillary carcinoma

BACKGROUND

PAX8/PPARγ rearrangement is a common genetic alteration in follicular thyroid carcinoma (FTC) and has been reported with variable frequency in papillary thyroid carcinoma (PTC). The diagnostic and phenotypic features of thyroid nodules positive for PAX8/PPARγ on preoperative examination are not well understood.

METHODS

The prevalence of PAX8/PPARγ rearrangement was analyzed in a series of 2015 consecutive thyroid nodules that underwent molecular analysis on cytology specimens and in 446 surgically removed PTCs. For all PAX8/PPARγ positive cases, cytology and surgical pathology slides were examined and the available clinical records were reviewed.

RESULTS

Twenty-two PAX8/PPARγ rearrangements were identified, including 16 detected preoperatively and 6 postoperatively. The incidence of PAX8/PPARγ in PTC was 1.1%. Cytologically, most of these nodules were diagnosed as a follicular neoplasm (73%), followed by the diagnosis of atypia of undetermined significance (19%), and none of the cases was diagnosed as cytologically malignant. All nodules with PAX8/PPARγ detected preoperatively and surgical follow-up available were found to be malignant, among which the most common diagnosis was the encapsulated follicular variant of PTC. Overall, among 20 PAX8/PPARγ-positive tumors that were surgically excised, 17 (85%) were PTC and 3 (15%) were FTC. On follow-up available for 17 patients (mean, 22.4 months), 16 PAX8/PPARγ-positive cancers showed no evidence of biochemical or structural recurrence, whereas 1 patient with FTC developed bone metastasis.

CONCLUSIONS

In this series, PAX8/PPARγ rearrangement found in thyroid nodules had a 100% predictive value for differentiated thyroid cancer, and was more predictive of PTC than FTC. However, almost all PTC carrying PAX8/PPARγ were encapsulated follicular-pattern tumors, distinguished from FTC only by nuclear features. Although most tumors carrying this mutation appear to be clinically indolent, at least on short-term follow-up, distant metastasis can develop from FTC positive for PAX8/PPARγ.

Role of molecular diagnostic markers in the management of indeterminate and suspicious thyroid nodules

Incidental thyroid nodules are commonly found during routine neck examination. Fine needle aspiration (FNA) followed by cytological examination is currently considered as the most reliable method for evaluation of thyroid nodules. However, 10–40% of FNA results are inconclusive, and are reported as indeterminate or suspicious. Approximately 20% of indeterminate or suspicious nodules are malignant. Therefore, there has been an increasing trend in use of molecular markers as an adjunctive measure for more accurate preoperative diagnosis of indeterminate or suspicious nodules. Molecular markers can be used alone or as a part of molecular panels. Although some investigations revealed promising findings regarding the potential use of molecular markers in the management of thyroid nodules, their true impact on management of patients with indeterminate nodules is still unclear.

Current role and value of fine-needle aspiration in nodular goitre

Thyroid nodules are common and, depending on the detection technique used, can affect 50% or greater of the population. The primary diagnostic test to assess the nature of these nodules is fine-needle aspiration cytology. Most thyroid nodules are benign and often are multiple. However, the morphology of these nodules may mimic neoplasms showing features such as papillary growth, micro-follicles and even oncocytic metaplasia. Lesions with these features may be considered indeterminate for neoplasm or malignancy, and often require surgical excision to define their nature. The role of cytopathology in this area is to screen those definitely benign nodules, thus preventing surgery and reassuring both the patient and the clinician. In this review, we demonstrate many of the morphological manifestations of nodular goiter and stress the necessity of careful preparatory techniques. Although the past several years have witnessed the development of molecular testing to refine diagnostic cytology in the thyroid, it is still the role of the cytopathologist to identify those "indeterminant" nodules which should be tested. Thus, the cytopathologist contributes both an essential diagnostic and an important cost saving role which hopefully will continue in the future.

Deregulation of microRNA expression in thyroid tumors

MicroRNAs (miRNAs or miRs) are endogenous non-coding RNAs that negatively regulate gene expression by binding to the 3' non-coding regions of target mRNAs, resulting in their cleavage or blocking their translation. miRNAs may have an impact on cell differentiation, proliferation, and survival, and their deregulation can be inclined to diseases and cancers, including thyroid tumors. The purpose of this review is to summarize the existing findings of deregulated miRNAs in different types of thyroid tumors and to exhibit their potential target genes, especially to demonstrate those involved in tumor invasion and metastasis. In addition, new findings of circulating miRNA expression profiles, single nucleotide polymorphism (SNP) in thyroid tumors, and the correlation of somatic mutations with deregulated miRNA expression in thyroid tumors were all included in this review.

A model to discriminate malignant from benign thyroid nodules using artificial neural network

Objective

This study aimed to construct a model for using in differentiating benign and malignant nodules with the artificial neural network and to increase the objective diagnostic accuracy of US.

Materials and methods

618 consecutive patients (528 women, 161 men) with 689 thyroid nodules (425 malignant and 264 benign nodules) were enrolled in the present study. The presence and absence of each sonographic feature was assessed for each nodule - shape, margin, echogenicity, internal composition, presence of calcifications, peripheral halo and vascularity on color Doppler. The variables meet the following criteria: important sonographic features and statistically significant difference were selected as the input layer to build the ANN for predicting the malignancy of nodules.

Results

Six sonographic features including shape (Taller than wide, p<0.001), margin (Not Well-circumscribed, p<0.001), echogenicity (Hypoechogenicity, p<0.001), internal composition (Solid, p<0.001), presence of calcifications (Microcalcification, p<0.001) and peripheral halo (Absent, p<0.001) were significantly associated with malignant nodules. A three-layer 6-8-1 feed-forward ANN model was built. In the training cohort, the accuracy of the ANN in predicting malignancy of thyroid nodules was 82.3% (AUROC = 0.818), the sensitivity and specificity was 84.5% and 79.1%, respectively. In the validation cohort, the accuracy, sensitivity and specificity was 83.1%, 83.8% and 81.8%, respectively. The AUROC was 0.828.

Conclusion

ANN constructed by sonographic features can discriminate benign and malignant thyroid nodules with high diagnostic accuracy.

Targeted next-generation sequencing panel (ThyroSeq) for detection of mutations in thyroid cancer

OBJECTIVES

Next-generation sequencing (NGS) allows for high-throughput sequencing analysis of large regions of the human genome. We explored the use of targeted NGS for simultaneous testing for multiple mutations in thyroid cancer.

DESIGN

A custom panel (ThyroSeq) was designed to target 12 cancer genes with 284 mutational hot spots. Sequencing was performed to analyze DNA from 228 thyroid neoplastic and nonneoplastic samples including 105 frozen, 72 formalin-fixed, and 51 fine-needle aspiration samples representing all major types of thyroid cancer.

RESULTS

Only 5-10 ng of input DNA was sufficient for successful analysis of 99.6% of samples. The analytical accuracy for mutation detection was 100% with the sensitivity of 3%-5% of mutant allele. ThyroSeq DNA assay identified mutations in 19 of 27 of classic papillary thyroid carcinomas (PTCs) (70%), 25 of 30 follicular variant PTCs (83%), 14 of 18 conventional (78%) and 7 of 18 oncocytic follicular carcinomas (39%), 3 of 10 poorly differentiated carcinomas (30%), 20 of 27 anaplastic (ATCs) (74%), and 11 of 15 medullary thyroid carcinomas (73%). In contrast, 5 of 83 benign nodules (6%) were positive for mutations. Most tumors had a single mutation, whereas several ATCs and PTCs demonstrated two or three mutations. The most common mutations detected were BRAF and RAS followed by PIK3CA, TP53, TSHR, PTEN, GNAS, CTNNB1, and RET. The BRAF mutant allele frequency was 18%-48% in PTCs and was lower in ATCs.

CONCLUSIONS

The ThyroSeq NGS panel allows simultaneous testing for multiple mutations with high accuracy and sensitivity, requires a small amount of DNA and can be performed in a variety of thyroid tissue and fine-needle aspiration samples, and provides quantitative assessment of mutant alleles. Using this approach, the point mutations were detected in 30%-83% of specific types of thyroid cancer and in only 6% of benign thyroid nodules and were shown to be present in the majority of cells within the cancer nodule.

Molecular diagnosis for indeterminate thyroid nodules on fine needle aspiration: advances and limitations

Indeterminate thyroid lesions are diagnosed in up to 30% of fine needle aspirations. These nodules harbor malignancy in more than 25% of cases, and hemithyroidectomy or total thyroidectomy has therefore been advocated in order to achieve definitive diagnosis. Recently, many molecular markers have been investigated in an attempt to increase diagnostic accuracy of indeterminate fine needle aspiration cytology and thereby avoid unnecessary complications and costs associated with thyroid surgery. Somatic mutation testing, mRNA gene expression platforms, protein immunocytochemistry and miRNA panels have improved the diagnostic accuracy of indeterminate thyroid nodules, and although no test is perfectly accurate, in the authors' opinion, these methods will most certainly become an important part of the diagnostic tools for clinicians and cytopathologists in the future.

Hashimoto's thyroiditis, microcalcification and raised thyrotropin levels within normal range are associated with thyroid cancer

BACKGROUND

To confirm whether clinical and biochemical parameters or Hashimoto's thyroiditis (HT) could predict the risks of malignancy among subjects who underwent thyroidectomy, as well as to determine the influence of HT on the biological behavior of papillary thyroid cancer (PTC).

METHODS

A total of 2,052 patients who underwent initial thyroidectomy were enrolled between June 2006 and August 2008. Serum free T4, free T3, thyrotropin (TSH), thyroglobulin, thyroglobulin antibody, antimicrosomal antibody, tumor-associated status, and thyroid disorders were documented.

RESULTS

Binary logistic regression analysis was performed to define the risk predictors for thyroid cancer. Finally, calcification, HT, TSH, and age, were entered into the multivariate model. Multivariate logistic regression analysis revealed the risk of thyroid cancer increases in parallel with TSH concentration within normal range, and the risk for malignancy significantly increased with serum TSH 1.97-4.94 mIU/L, compared with TSH less than 0.35 mIU/L (OR = 1.951, 95% CI = 1.201-3.171, P = 0.007). Increased risks of thyroid cancer were also detected among the patients with HT (OR = 3.732, 95% CI = 2.563-5.435), and microcalcification (OR = 14.486, 95% CI = 11.374-18.449). The effects of HT on the aggressiveness of PTC were not observed in extrathyroidal invasion (P = 0.347), capsular infiltration (P = 0.345), angioinvasion (P = 0.512), and lymph node metastases (P = 0.634).

CONCLUSIONS

The risk of malignancy increases in patients with higher level TSH within normal range, as well as the presence of HT and microcalcification. No evidence suggests that coexistent HT alleviates the aggressiveness of PTC.

New strategies in diagnosing cancer in thyroid nodules: impact of molecular markers

Thyroid cancer is the most common type of endocrine malignancy, with approximately 55,000 new cases diagnosed in the United States in 2012. However, thyroid nodules are much more prevalent, particularly with increased age, and only a small fraction of those are malignant. Therefore, the major clinical challenge is to reliably differentiate those nodules that are malignant and need to be treated surgically from the majority of nodules that are benign and do not require surgery. The traditional diagnostic approach to this clinical situation is ultrasound-guided fine-needle aspiration (FNA) of the thyroid nodule followed by cytologic examination, which together reliably establish the diagnosis in 70% to 80% of cases. However, in the rest of nodules the presence of cancer cannot be ruled out by FNA cytology, hampering appropriate surgical management and frequently resulting in unnecessary surgical interventions. New approaches to diagnosis of cancer in thyroid nodules are based on mutational and other molecular markers, which can be reliably detected in cells aspirated during the FNA procedure. These markers offer significant improvement in the diagnostic accuracy of FNA cytology and are poised to make a profound effect on the management of patients with thyroid nodules. In addition to the molecular markers that have recently become available for clinical use, rapid development of new sequencing techniques is expected to further improve the accuracy of cancer diagnosis in thyroid nodules and allow for a fully individualized approach to the management of patients with thyroid nodules.

Fine-Needle Aspiration, Touch Imprint, and Crush Preparation Cytology for Diagnosing Thyroid Malignancies in Thyroid Nodules

Several methods are used to evaluate the thyroid nodules. The aim of this study was to determine the sensitivity, specificity, false positive and negative rates, positive predictive value (PPV), and negative predictive value (NPV) of touch imprint, crush preparation, and fine-needle aspiration (FNA) methods. This cross-sectional study was done in Shohada-ye Ashayer University Hospital in Khorramabad. All the patients who underwent thyroid surgery due to thyroid nodules in this hospital between March and September 2011 were evaluated. The thyroid nodules of all the patients were evaluated by touch imprint, crush preparation, FNA, and permanent pathology methods. Finally, the results of the first three methods were compared with the result of permanent pathology method. The mean age of 104 patients who underwent thyroid surgery was 42.6 ± 11.9 years old. Based on permanent pathology, touch imprint, crush preparation, and FNA methods, 15.3, 6.25, 6.25, and 4.4 % of thyroid nodules were malignant, respectively. Sensitivity, specificity, false positive rate, false negative rate, PPV, and NPV of FNA biopsy were 62.5, 100, 0, 37.5, 100, and 95.3 %, respectively. Also, sensitivity, specificity, false positive rate, false negative rate, PPV, and NPV of touch imprint and crush preparation were equal and were 80, 100, 0, 20, 100, and 96.7 %, respectively. Using touch imprint and crush preparation in evaluation of thyroid nodules for rapid evaluation of these nodules in operating rooms seems to be logical, and it can prevent further surgeries.

Diagnosis and management of differentiated thyroid cancer using molecular biology

OBJECTIVES/HYPOTHESIS

To define molecular biology in clinical practice for diagnosis, surgical management, and prognostication of differentiated thyroid cancer.

DATA SOURCES

Ovid Medline 2006-2012

REVIEW METHODS

Manuscripts with clinical correlates.

RESULTS

Papillary thyroid carcinomas harbor point mutations of the BRAF and RAS genes or RET/PTC rearrangements, all of which activate the mitogen-activated protein kinase pathway. These mutually exclusive mutations are found in 70% of PTC. BRAF mutation is found in 45% of papillary thyroid cancer and is highly specific. Follicular carcinomas are known to harbor RAS mutation or PAX8/PPARγ rearrangement. These mutations are also mutually exclusive and identified in 70% of follicular carcinomas. Molecular classifiers measure the expression of a large number of genes on a microarray chip providing a substantial negative predictive value pending further validation.

CONCLUSIONS

1) 20% to 30% of cytologically classified Follicular Neoplasms and Follicular Lesion of Undetermined Significance collectively are malignant on final pathology. Approximately 70% to 80% of thyroid lobectomies performed solely for diagnostic purposes are benign. Molecular alteration testing may reduce the number of unnecessary thyroid procedures, 2) may reduce the number of completion thyroidectomies, and 3) may lead to more individualized operative and postoperative management. Molecular testing for BRAF, RAS, RET/PTC, and PAX8/PPARγ for follicular lesion of undetermined significance and follicular neoplasm improve specificity, whereas molecular classifiers may add negative predictive value to fine needle aspiration diagnosis.

Use of radiofrequency ablation in benign thyroid nodules: a literature review and updates

Successful thermal ablation using radiofrequency has been reported in various tumors including liver or kidney tumors. Nonsurgical minimally invasive ablative therapy such as radiofrequency ablation (RFA) has been reported to be a safe and efficient treatment option in managing symptomatic cold thyroid nodules or hyperfunctioning thyroid nodules. Pressure and cosmetic symptoms have been shown to be significantly improved both in the short and long terms after RFA. For hyperfunctioning thyroid nodules, RFA is indicated for whom surgery or radioiodine are not indicated or ineffective or for those who refuse surgery or radio-iodine. Improvement of thyroid function with decreased need for antithyroid medications has been reported. Complication rate is relatively low. By reviewing the current literature, we reported its efficacy and complications and compared the efficacy of RFA relative to other ablative options such as ethanol ablation and laser ablation.

Differentiating benign from malignant thyroid nodules using micro ribonucleic acid amplification in residual cells obtained by fine needle aspiration biopsy

BACKGROUND

Fine needle aspiration biopsy (FNAB) is the most commonly used diagnostic tool to differentiate benign from malignant thyroid nodules. Nevertheless, some FNAB cytology results are not definite. In such cases diagnostic thyroid lobectomy is performed with malignancy rate on final histopathology ranging at 15%-75%. The aim of this study was to improve on the accuracy of FNAB-based cytology by amplification of microRNAs (micro ribonucleic acids [miRs]) from the residual cells left in the FNAB needle after submission for cytology.

METHODS

Residual cells were collected from the needle cup after FNAB cytology of 77 consecutive patients with thyroid nodules. miR-enriched RNA was extracted for all patients with cytology showing either follicular lesion or suspicion for malignancy (n=11). The expression of miR-21, -31, -146b, -187, -221, and -222 was determined using real-time polymerase chain reaction. Results were compared with final surgical histopathology.

RESULTS

RNA was successfully extracted from all FNAB specimens. Five patients had FNAB cytology suspicious for malignancy. The miR panel was positive in all five (100%). Six patients had follicular lesions on FNAB. The miR panel was positive in three of four patients (75%) with confirmed malignancy and was negative in two of two (0%) patients with benign pathology results. This corresponded to a specificity of 100%, sensitivity of 88%, and accuracy of 90%.

CONCLUSIONS

RNA extraction from FNAB residual cells is feasible, and a miR panel amplified from the extracted RNA seems like a promising diagnostic tool in this limited number of patients.

A panel of four miRNAs accurately differentiates malignant from benign indeterminate thyroid lesions on fine needle aspiration

PURPOSE

Indeterminate thyroid lesions on fine needle aspiration (FNA) harbor malignancy in about 25% of cases. Hemi- or total thyroidectomy has, therefore, been routinely advocated for definitive diagnosis. In this study, we analyzed miRNA expression in indeterminate FNA samples and determined its prognostic effects on final pathologic diagnosis.

EXPERIMENTAL DESIGN

A predictive model was derived using 29 ex vivo indeterminate thyroid lesions on FNA to differentiate malignant from benign tumors at a tertiary referral center and validated on an independent set of 72 prospectively collected in vivo FNA samples. Expression levels of miR-222, miR-328, miR-197, miR-21, miR-181a, and miR-146b were determined using reverse transcriptase PCR. A statistical model was developed using the support vector machine (SVM) approach.

RESULTS

A SVM model with four miRNAs (miR-222, miR-328, miR-197, and miR-21) was initially estimated to have 86% predictive accuracy using cross-validation. When applied to the 72 independent in vivo validation samples, performance was actually better than predicted with a sensitivity of 100% and specificity of 86%, for a predictive accuracy of 90% in differentiating malignant from benign indeterminate lesions. When Hurthle cell lesions were excluded, overall accuracy improved to 97% with 100% sensitivity and 95% specificity.

CONCLUSIONS

This study shows that that the expression of miR-222, miR-328, miR-197, and miR-21 combined in a predictive model is accurate at differentiating malignant from benign indeterminate thyroid lesions on FNA. These findings suggest that FNA miRNA analysis could be a useful adjunct in the management algorithm of patients with thyroid nodules.