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

Histology-based and cytology-based needle sampling for targeted next-generation sequencing in the indeterminate thyroid tumors

PURPOSE

To establish the optimal and minimally invasive diagnostic approach for targeted next-generation sequencing (NGS) in the indeterminate thyroid tumors.

METHODS

The patients with indeterminate thyroid tumors were prospectively recruited and analyzed in a single tertiary medical center. We performed FNA and core needle biopsy (CNB) at the surgical specimens to confirm the quality of each sampling procedure. Cytological diagnosis by FNA, histological diagnosis by CNB and confirmed diagnosis by final surgery were compared to demonstrate the agreement among these approaches for the indeterminate thyroid tumors. The quality of the samples from FNA and CNB was evaluated, respectively to determine the optimal approach for targeted NGS. Finally, we performed ultrasound-guided CNB and FNA (US-CNB and US-FNA) on one case to confirm the clinical feasibility of being a pre-operative minimally invasive diagnostic approach.

RESULTS

A total of 6 female patients (average age: 50.83 ± 15.18 years) with indeterminate thyroid tumors (average size: 1.79 ± 0.91 cm) were recruited for further analyses. The pathological diagnoses could be obtained by CNB in the first five cases, and the sample quality of CNB for targeted NGS was better than that of FNA, even after 10X dilution. The gene mutations associated with thyroid malignancy could be detected by NGS. In the case treated with US-CNB, the pathological and targeted NGS results were successfully obtained, which suggested the possibility of thyroid malignancy to facilitate immediate decision of subsequent treatment.

CONCLUSION

CNB could serve as a minimally invasive diagnostic approach in the indeterminate thyroid tumors by providing pathological diagnoses and qualified samples for detection of mutated genes, which facilitates appropriate and immediate management.

Serum TSH Level as a Simple Efficient Tool to Assess the Risk of Thyroid Malignancy in Euthyroid Patients with Indeterminate Cytology - A Cohort Study

Context

A significant number of fine-needle aspiration cytology (FNAC) for thyroid nodules is reported as indeterminate. Expensive molecular testing can give a clue to the possibility of malignancy in this group. The effectiveness of serum thyroid-stimulating hormone (TSH) levels as a diagnostic tool in euthyroid patients with indeterminate cytology has not been previously studied, especially in the Indian population.

Aims

This study was conducted to evaluate the predictive efficacy of serum TSH in the early diagnosis and treatment of malignancy.

Settings and Design

This is a retrospective cross-sectional study on a cohort of patients who presented to our department with complaints of thyroid swelling and underwent thyroidectomy.

Methods and Material

Euthyroid patients who underwent thyroid surgery for newly diagnosed thyroid nodules with FNAC reported as indeterminate cytology were included in our study. Based on the histopathological report, the patients were divided into two groups and into quartiles based on TSH values.

Statistical Analysis Used

The mean difference in the numerical variables between groups was compared using the independent two-sample 't' test for parametric data and Mann-Whitney 'u' test for non-parametric data. A logistic regression analysis was done with age, sex, TSH level and nodule size as dependant variables and malignancy as the independent variable.

Results

There were 211 patients in group A and 93 in group B. Patients with malignancy confirmed on final histopathology showed higher serum TSH levels compared to benign nodules (2.93 ± 1.067 vs 1.73 ± 1.051, P = <0.001). The mean TSH levels of all types of malignant nodules correlated with our test model (>2.185 mIU/L).

Conclusions

Serum TSH above 2.185 mIU/mL is a good predictor of malignancy in indeterminate nodules. It is an inexpensive, safe and reliable diagnostic screening test for the risk of malignancy in an indeterminate nodule.

Non-invasive Follicular Thyroid Neoplasm with Papillary-Like Nuclear Features (NIFTP) lowers the risk of malignancy in the bethesda system for reporting thyroid cytopathology diagnostic categories

Background:

The introduction of non-invasive follicular thyroid neoplasm with papillary-like nuclear features (NIFTP) has been shown to decrease the risk of malignancy (ROM) in The Bethesda System for Reporting Thyroid Cytopathology. This knowledge may alter the management of patients with thyroid nodules.

Objectives:

To correlate cytological diagnosis with histological diagnosis for establishing the ROM of all Bethesda system categories after the introduction of NIFTP.

Methods:

This was a retrospective cohort study. All consecutive fine-needle aspiration cytology (FNAC) specimens collected from January 1, 2013, to December 31, 2017, at King Abdullah Medical City, Jeddah, Saudi Arabia, were assessed, and patients who underwent surgical excision of thyroid nodules were further analyzed. The ROM and overall ROM for each Bethesda category were calculated with and without considering NIFTP as a malignant tumor.

Results:

Overall, 1066 FNAC specimens were collected, of which 281 had a surgical correlation. Our cases included 18 (6.4%) non-diagnostic (ND), 109 (38.8%) benign, 28 (9.9%) atypia/follicular lesion of undetermined significance (AUS/FLUS), 39 (13.8%) follicular neoplasm or suspicion for follicular neoplasm (FN/SFN), 20 (7.1%) suspicion for malignancy (SM), and 67 (23.8%) malignant (POM) cases. After considering NIFTP diagnosis on resection specimens, the ROM decreased as follows: ND, 38.8% to 27.7% (P = 0.2388); benign, 21.1% to 11.9% (P = 0.0343); AUS/FLUS, 50% to 39.2% (P = 0.2089); FN/SFN, 53.8% to 33.3% (P = 0.0336); SM, 85% to 75% (P = 0.2147); POM, 95.5% to 88% (P = 0.0582).

Conclusion:

The introduction of NIFTP would significantly decrease the ROM of thyroid FNAC in both benign and FN/SFN categories of the Bethesda system.

Next-Generation Sequencing Enhances the Diagnosis Efficiency in Thyroid Nodules

BACKGROUND

Though fine-needle aspiration (FNA) improved the diagnostic methods of thyroid nodules, there are still parts of nodules that cannot be determined according to cytology. In the Bethesda system for reporting thyroid cytopathology, there are two uncertain cytology results. Thanks to the development of next-generation sequencing technology, it is possible to gain the genetic background of pathological tissue efficiently. Therefore, a combination of the cytology and genetic background may enhance the accuracy of diagnosis in thyroid nodules.

METHODS

DNA from 73 FNA samples of thyroid nodules belonging to different cytology types was extracted and exome sequencing was performed by the ThyroLead panel. Test for BRAF mutation was also performed by ARMS-qPCR. Information including age, sex, preoperative cytology, BRAF mutation status tested by ARMS-qPCR, and surgical pathology was collected in electronic medical record system.

RESULTS

A total of 71 single nucleotide variants, three fusion gene, and two microsatellite instability-high status were detected in 73 FNA samples. BRAF V600E mutation is the most common mutation in these malignant thyroid nodules. After combining the cytology and genetic background detected by next-generation sequencing, the diagnosis sensitivity was increased from 0.582 (95% CI: 0.441-0.711) to 0.855 (95% CI: 0.728-0.930) (P < 0.001) in our group, while the specificity, 1,000 (95% CI: 0.732-1.000) compared to 0.857 (95% CI: 0.562-0.975) (P = 0.25), did not get affected.

CONCLUSIONS

Next-generation sequencing in thyroid nodules can enhance the preoperative diagnosis sensitivity by fine-needle aspiration alone. It can also provide genetic background for direction of medication. It is possible for clinicians to combine cytology with genetic alterations for a more precise diagnosis strategy of thyroid nodules.

Preoperative Role of RAS or BRAF K601E in the Guidance of Surgery for Indeterminate Thyroid Nodules

BACKGROUND

RAS and K601E BRAF mutations are not a reliable indicator of malignancy in fine-needle aspirations (FNA) of thyroid indeterminate cytologic nodules. We aimed to evaluate the histologic characteristics, the risk of malignancy associated with such mutations in FNA and their potential interest for preoperative clinical management of nodules.

METHODS

We evaluated 69 indeterminate thyroid nodules with RAS or K601E BRAF mutations with available histopathologic follow-up. All FNA specimens were indeterminate according to the thyroid Bethesda system. Diagnosis of malignant, benign or indolent neoplasms was classified according to 2017 WHO classification. Carcinoma, NIFTP (noninvasive follicular thyroid neoplasm with papillary-like features) and WDTUMP (well-differentiated tumor of uncertain malignant potential) were considered "surgical," as they require surgical excision. Adenoma was considered "non-surgical." The risk of malignancy and the risk of "surgical disease" were evaluated.

RESULTS

Pathologic evaluation of the 69 mutated nodules demonstrated benign, indolent and malignant histology in 17 cases (25%), 21 cases (30%) and 31 cases (45%), respectively. The risk of malignancy was 45%, and the risk of surgical disease was 75%. The majority of carcinomas were a follicular variant of papillary thyroid carcinoma. On follow-up, there have been no recurrences to date.

CONCLUSION

Preoperative RAS or BRAF K601E mutations detection in cytologic indeterminate thyroid nodules carries a high risk of surgical disease and may benefit from surgical management. Most surgical lesions harboring those mutations are low-risk tumors, which may be in favor of an initial lobectomy.

Cost effectiveness of intraoperative pathology in the management of indeterminate thyroid nodules

Objective This study aims to determine the cost effectiveness of rapid frozen section (RFS) for indeterminate thyroid nodules. Materials and methods A retrospective chart review was conducted between January 2009 and June 2013 at a tertiary care institution. Main outcomes were number needed to treat, RFS efficacy, and cost-savings of avoiding second completion thyroidectomy. Cost-effectiveness was estimated using 2015 Medicare reimbursement rate. Results Out of 1,114 patients undergoing thyroid surgery, 314 had preoperative AUS/FLUS cytopathology and subsequent thyroid lobectomy with RFS. RFS identified 13 of the 32 patients with malignancy resulting in a total thyroidectomy. 19 of the 29 malignancies not detected by RFS were papillary microcarcinomas. Conclusions Completion thyroidectomy was avoided in 1 out of every 24 patients resulting in cost-savings of $ 80.04 per patient. In the era of outpatient thyroid surgery, intraoperative RFS for indeterminate thyroid nodules is cost-effective.

Developing a tool that could reliably refute total thyroidectomy for solitary Bethesda IV thyroid nodules

PURPOSE

To assess the reliability of a simple, accessible, cost-effective rule-out tool, for use in triaging patients with Bethesda IV nodules to appropriate surgery.

METHODS

The diagnostic tool was assembled by combining the negativity for suspicious ultrasound features (irregular margins, microcalcification, and a taller-than-wide orientation), and mutational marker negativity (BRAF and NRAS). The tool, (US^-/mutation^-), was tested on 167 patients with solitary Bethesda IV nodules. The primary outcome was its negative predictive value (NPV) for lesions requiring total thyroidectomy (TT). The impact of mutational marker negativity, as part of the tool, was evaluated by comparing the NPV of (US^-/mutation^-) to that of (US^-/mutation⁺).

RESULTS

10 out of 167 lesions were positive for a mutational marker. These underwent TT, and only 2/10 (20%) were benign, on final histology. In 6/8 malignant lesions, TT was concordant with current clinical guidelines. 157 patients comprised the negative study cohort, for both mutational markers and suspicious US features. These underwent thyroid lobectomy, and 17 cases resulted in malignancy, only 8 of which required completion thyroidectomy. Accordingly, the NPV of (US^-/mutation^-) for malignancy was 89% (140/157), and 95% (149/157) for malignancy requiring TT. However, the NPV of (US^-/mutation⁺) was 20% for malignancy, and 40% for malignancy requiring TT. These differences were statistically significant (89% vs. 20%; p < 0.0001, and 95% vs. 40%; p < 0.0001).

CONCLUSION

US^-/mutation^- is a reliable rule-out tool, with sufficient diagnostic accuracy to spare patients, with Bethesda IV nodules, an overly radical TT.

TSH Level and Risk of Malignancy in Patients with Bethesda Category IV Thyroid Nodules

Fine needle aspiration biopsy does not permit to distinguish between benign and malignant follicular thyroid lesions (category IV in the Bethesda Cytopathology System). Some reports have suggested an association between increased serum TSH levels and thyroid cancer, so the aim of this study was to investigate the association between TSH levels and malignancy in patients with follicular thyroid nodules. Therefore, we conducted a retrospective study of all subjects who underwent surgical treatment for Bethesda IV thyroid nodules in a single center (years 2012-2017). A total of 127 patients were analyzed, and malignancy was present in 38.6% of the patients. Using ROC analysis, the best TSH cut-off point to differentiate benign from malignant disease was 2.1 mU/l and the age cut-off with better sensitivity and specificity was 47 years. The proportion of subjects with TSH ≥ 2.1 mU/l was greater among subjects with cancer than in those with benign diseases (65.3 vs 44.9%, P = 0.029). The concurrence of both cut-off points (TSH ≥ 2.1 mU/l and age ≥ 47 years) showed a higher diagnostic accuracy than either of the two variables separately. Therefore, the present study supports an association between serum concentrations of TSH and risk of malignancy among subjects with Bethesda IV thyroid nodules. TSH levels could modify the diagnostic and therapeutic approach of patients with Bethesda IV nodules.

Positive central lymph-nodes are underdiagnosed in patients with Bethesda V cytology in an endemic goiter region

Background

Fine needle aspiration (FNA) is a significant diagnostic procedure for detecting malignancy in patients with nodular thyroid disease. A high proportion of patients with cytological diagnosed follicular neoplasia (Bethesda IV and V) ultimately have thyroid cancer. The aim of this study was to evaluate the incidence of preoperatively undiagnosed central lymph node metastasis in patients with multinodular goiter (MNG).

Methods

Patients who underwent FNA and were classified as Bethesda IV/V were included. Applying a radical approach, all patients underwent (hemi)thyroidectomy and prophylactic unilateral central neck dissection.

Results

During our study period 2009-2013, 60 patients (19.7%) were classified as Bethesda IV and 21 (6.9%) Bethesda V. Final histopathological results revealed malignancy in 35 (43.2%) of 81 Bethesda IV/V nodules. Of the nodules classified as Bethesda IV, 20 (33.3%) showed malignancy in the final histology. Ten patients (16.7%) had papillary micro-carcinoma (mPTC, <10 mm), 4 (6.6%) PTC and 6 (10%) follicular thyroid cancer. Fifteen of 21 (71.4%) Bethesda V nodules were revealed as PTC of whom seven (33.3%) patients also had lymph-node metastases.

Conclusions

While 33.3% of the patients with PTC, preoperatively classified as Bethesda V, had previously undetected positive lymph-nodes, only one patient with Bethesda IV had lymph-node metastasis.

Impact of ultrasonographic features, cytomorphology and mutational testing on malignant and indeterminate thyroid nodules on diagnostic accuracy of fine needle cytology samples: A prospective analysis of 141 patients

OBJECTIVE

Fine needle cytology (FNC) is the first-line diagnostic method to determine the benign or malignant nature of thyroid nodules. The gray zone of cytological classifications remains, however, a crucial and challenging area for cytopathologists.

DESIGN, PATIENTS AND MEASUREMENTS

In the present study, 141 thyroid cytological samples, with ultrasonographic suspicious features, have been prospectively analysed. Molecular analyses were performed by an innovative technology using two multiplex PCRs for the amplification of BRAF, N-H-K-RAS and RET exon genes. RNA samples were studied for RET/PTC1 and RET/PTC3 rearrangements by PCR amplification, and the conditions were set-up to study, with a single experiment, both wild-type PAX8 and PAX8/PPARɣ rearrangements. In total, 111 samples were examined for BRAF, N-H-KRAS and RET genes. An ultrasonographic, cytological and molecular correlation was also carried out in an attempt to suggest a possible way to manage the patients with thyroid nodules. Cyto-histological correlation was available in 115 cases, and it was used to verify the global diagnostic accuracy of this combined approach.

RESULTS

According to the histopathological diagnosis, FNC accuracy was 100% for TIR5 and metastases; 89% for TIR4; 84% for TIR3A and 58% for TIR3B. About 11% of the studied samples showed either RET-PTC1 or RET/PTC3 chromosomal rearrangements, and only one sample simultaneously presented RET/PTC1 and RET/PTC3 rearrangements. PAX8/PPARɣ rearrangement was found in 6% of the samples.

CONCLUSIONS

A multidisciplinary approach to the thyroid is therefore necessary to develop innovative methods suitable for an improved diagnostic and prognostic definition of thyroid cancer.

The surgical dilemma of primary surgery for follicular thyroid neoplasms

Follicular thyroid carcinoma is the second most prevalent form of differentiated thyroid carcinoma, following papillary thyroid carcinoma. Preoperative diagnosis is hampered by the fact that fine-needle aspiration cytology as well as supplemental molecular analysis cannot unambiguously distinguish between follicular thyroid carcinoma and benign follicular thyroid adenoma. The 2017 WHO classification defines three histological subtypes of follicular thyroid carcinoma: minimally invasive (excellent prognosis), encapsulated angioinvasive, and widely invasive type (higher risk of recurrence and metastatic spread). The fact that definite characterization of follicular neoplasms is predominantly a postoperative histological diagnosis (core criteria: capsular, vascular and adjacent tissue invasion) translates into the challenge for the thyroid surgeon to plan preoperatively for presence of malignancy and, if required, to adapt the surgical strategy according to intraoperative (frozen section) or postoperative histological findings. Until improved tools for pre-/intraoperative diagnosis are available, the malignant potential of a follicular thyroid lesion can be assessed by stratifying the patient according to clinical risk factors (presence of metastases, advanced patient age, tumor size). A stepwise, escalating surgical approach with restricted primary resection (hemithyroidectomy) and completion surgery based on the definite histopathology is another option to solve this dilemma. The currently recommended surgical treatment strategies for FTCs as published by ATA, BTA, CAEK and ESES are discussed. There is consensus that prophylactic lymphadenectomy is not required for FTCs and that hemithyroidectomy is sufficient in low-risk FTCs (capsular invasion only) whereas thyroidectomy with postoperative radioiodine therapy is indicated in high-risk FTCs (angioinvasion; widely invasive FTC).

A single nuclear polymorphism in let-7g binding site affects the doubling time of thyroid nodule by regulating KRAS-induced cell proliferation

As an indicator for the malignancy of thyroid nodules (TN), the doubling time of TN was studied in this study to evaluate the effect of rs712 polymorphism on the progression of TN. In addition, we aimed to study the potential molecular mechanisms underlying the pathological effect of rs712 polymorphism upon TN. A Taqman method was used to genotype the patients according to their rs712 polymorphism. Real-time polymerase chain reaction, western blot, Terminal deoxynucleotidyl transferase dUTP nick end labeling assay and 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium (MTT) assay was conducted to study the correlation between KRAS expression and the pathological effect of rs712 polymorphism. In-silicon analysis and luciferase assay were utilized to establish the regulatory relationship between let-7g and KRAS. KRAS messenger RNA (mRNA)/protein levels in the GG group were upregulated with a decreased apoptosis index. KRAS mRNA was validated to be a virtual target of let-7g. In addition, the mRNA/protein level of KRAS as well as cell proliferation index was decreased in primary thyroid cancer cells genotyped as TT/TG and transfected with KRAS small interfering RNA (siRNA)/let-7g precursors. The cell apoptosis index was evidently elevated in the KRAS siRNA/let-7g precursors group compared with that in the scramble controls. Moreover, KRAS mRNA/protein only showed slight reduction when GG-genotyped primary thyroid cancer cells were transfected by let-7g precursors. Additionally, let-7g precursors exhibited no significant effect on cell proliferation index or cell apoptosis in GG cells. Rs712 polymorphism T>G in the 3'-untranslated region of KRAS interrupts the interactions between let-7g and KRAS mRNA, leading to a higher cell proliferation index and reduced doubling time of TN.

Preoperative detection of TERT promoter and BRAFV600E mutations in papillary thyroid carcinoma in high-risk thyroid nodules

OBJECTIVES

This observational study analyzed telomerase reverse transcriptase (pTERT) mutations in 45 fine-needle aspiration (FNA) specimens obtained from thyroid nodules followed by postoperatively confirmation of papillary thyroid cancer (PTC) diagnosis, examining their relationship with clinicopathologic aspects and the BRAFV600E mutation.

SUBJECTS AND METHODS

Clinical information was collected from patients who presented to Ribeirao Preto University Hospital for surgical consultation regarding a thyroid nodule and who underwent molecular testing between January 2010 to October 2012. Tests included a DNA-based somatic detection of BRAFV600E and pTERT mutations.

RESULTS

We found coexistence of pTERTC228T and BRAFV600E mutations in 8.9% (4/45) of thyroid nodules. All nodules positive for pTERT mutations were BRAFV600E positives. There was a significant association between pTERTC228T/BRAFV600E with older age and advanced stage compared with the group negative for either mutation.

CONCLUSIONS

This series provides evidence that FNA is a reliable method for preoperative diagnosis of high-risk thyroid nodules. pTERTC228T/BRAFV600E mutations could be a marker of poor prognosis. Its use as a personalized molecular medicine tool to individualize treatment decisions and follow-up design needs to be further studied.

Lymph Node Metastases Papillary Thyroid Carcinoma and their Importance in Recurrence of Disease

Background

The purpose of this study is to establish whether the lymph node metastases of the papillary thyroid carcinoma are a significant factor in recurrence of the disease by analyzing the time until recurrence of the disease and frequency of recurrence of the disease.

Methods

From 1 January 1995 until 30 June 2017, 102 patients were treated at the Public Health Institute Hospital “Sveti Vracevi” in Bijeljina for PTC. In all patients, surgery of the thyroid gland and/or lymph nodes of the neck was performed. Total thyroidectomy (TT) was performed in 20 patients and near-total thyroidectomy leaving <1 g thyroid tissue adjacent to the recurrent laryngeal nerve in 7 patients. TT and lymph nodes dissection were performed in 71 patients. Palliative surgery and biopsy due to locally advanced disease were performed in 3 patients.

Results

In our study, 102 patients with PTC were analyzed. 82 patients experienced pure PTC (80.4%), the other 20 patients (19.6%) experienced other variants of PTC. 24 patients (23.5%) experienced multi centric or bilateral tumors. 71 patients (69.6%) experienced histologically verified metastases in the lymph nodes of the neck. 7 patients (6.8%) experienced distant metastases. 20 patients underwent total thyroidectomy (TT), and 7 near-total thyroidectomy. Total thyroidectomy + dissection of central and lower jugular lymph nodes with frozen section histopathology verification was performed in 71 patients (69.6%). Out of these 71 patients, in 50 patients (70.4%) metastases were verified in the lower jugular lymph nodes. A modified lymph node dissection (MRND) was also performed in these patients.

Conclusion

Lymph node metastases of the papillary thyroid carcinoma are a plausible prognostic factor. They are important for recurrence of the disease, but not for survival.

Transcriptomic signature associated with carcinogenesis and aggressiveness of papillary thyroid carcinoma

Papillary thyroid carcinoma (PTC) is the fastest-growing disease caused by numerous molecular alterations in addition to previously reported DNA mutations. There is a compelling need to identify novel transcriptomic alterations that are associated with the pathogenesis of PTC with potential diagnostic and prognostic implications. Methods: We gathered and compared 242 expression profiles between paired PTC and adjacent normal tissues and identified and validated the coding and long non-coding RNAs (lncRNAs) associated with the extrathyroidal extension (ETE) of 655 PTC patients in two independent cohorts, followed by predicting their interactions with drugs. Co-expression, RNA interaction, Kaplan-Meier survival and multivariate Cox proportional regression analyses were performed to identify dysregulated lncRNAs and genes that correlated with clinical outcomes of PTC. Alternative splicing (AS), RNA circularization, and editing were also compared between transcriptomes to expand the repertoire of molecular alterations in PTC. Results: Numerous genes related to cellular microenvironment and steroid hormone response were associated with the ETE of PTC. Drug susceptibility predictions of the expression signature revealed two highly ranked compounds, 6-bromoindirubin-3'-oxime and lovastatin. Co-expression and RNA interaction analysis revealed the essential role of lncRNAs in PTC pathogenesis by modulating extracellular matrix and cell adhesion. Eight genes and two novel lncRNAs were identified that correlated with the aggressive nature and disease-free survival of PTC. Furthermore, this study provided the transcriptome-wide landscape of circRNAs in PTC and uncovered dissimilar expression profiles among circRNAs originating from the same host gene, suggesting the functional complexity of circRNAs in PTC carcinogenesis. The newly identified AS events in the SERPINA1 and FN1 genes may improve the sensitivity and specificity of these diagnostic biomarkers. Conclusions: Our study uncovered a comprehensive transcriptomic signature associated with the carcinogenesis and aggressive behavior of PTC, as well as presents a catalog of 10 potential biomarkers, which would facilitate PTC prognosis and development of new therapeutic strategies for this cancer.

Multiplex PCR approach to simultaneously identify several mutations in fine needle cytology thyroid samples

The most frequent initial manifestation of thyroid cancer is the appearance of a nodule. More than 20% of the general population has a palpable thyroid nodule and the percentage rises to 70% based on ultrasound identification. In 95% of cases the nodule is simply a hyperplastic or benign lesion. The most reliable diagnostic test for thyroid nodules is fine needle aspiration (FNA), but cytological discrimination between malignant and benign follicular neoplasms remains difficult. Cytological analysis is now, almost routinely, being combined with molecular genetics to enable the pathologist to make a more objective diagnosis. In this study, we performed the molecular analysis using a new simplified procedure that involves a panel of BRAF, RAS, RET and RET/PTC gene mutations in easily obtainable FNA samples, in the attempt to improve the efficacy of the FNA diagnosis of thyroid nodules and thus patient management. In this new procedure, PCR and sequencing analysis are used to detect point mutations, and, in parallel, RT-PCR is used to detect the chimeric RET/PTC1 and RET/PTC3 transcripts in RNA extracted from FNA.

Rapid methods to create a positive control and identify the PAX8/PPARγ rearrangement in FNA thyroid samples by molecular biology

Thyroid cancer is the most common malignancy of the endocrine system and includes well-differentiated forms, namely papillary and follicular carcinomas, and the poorly differentiated and undifferentiated forms that result from the transformation of thyroid follicular cells (anaplastic carcinomas). Notably, 5–10% of all thyroid cancers are medullary thyroid cancers that arise from parafollicular cells also known as C cells. The most common genetic mutations in papillary and follicular thyroid cancers are point mutations of the BRAF or RAS genes, while the most common chromosomal alterations are RET/PTC and PAX8/PPARγ rearrangements. The most frequent initial manifestation of thyroid cancer is the appearance of a nodule most of which are benign; indeed, less than 5% are malignant. However, some cases are misdiagnosed, and many patients undergo unnecessary surgery. Therefore, an accurate pre-surgery evaluation is crucial. The most reliable diagnostic test for thyroid nodules is fine needle aspiration (FNA) cytology, which accurately distinguishes between a benign and malignant lesion in most cases. However, cytological discrimination between malignant and benign follicular cancer is often difficult because of poor quality samples. Here we describe rapid methods to create a positive control and identify the PAX8/PPARγ rearrangement in FNA thyroid samples by molecular biology.

Thyroid Cancer: Risk-Stratified Management and Individualized Therapy

Thyroid cancer is the most common endocrine malignancy. Differentiated thyroid cancer (DTC) with the two subtypes, papillary thyroid cancer (PTC) and follicular thyroid cancer (FTC), is the most frequent subtype of thyroid cancer; more rare subtypes are medullary thyroid cancer (MTC) and anaplastic thyroid cancer (ATC). The incidence of DTC has increased rapidly in recent years due to the more frequent use of imaging methods such as ultrasound of the neck and fine-needle aspiration (FNA) of thyroid nodules. After total thyroidectomy and radioiodine treatment, DTC remains an indolent and curable disease in most patients, whereas the cure rate in MTC is lower and depends on early diagnosis. Most ATCs are incurable. In recent years, there has been great progress in identifying genetic changes in thyroid cancer, and genetic testing of FNA samples or blood samples provides useful information for clinical decision making. Tumor staging, either postoperatively or by imaging, and measuring the tumor markers thyroglobulin for DTC and calcitonin for MTC, allow for dynamic risk-adapted stratification for follow-up procedures. In advanced metastatic thyroid cancer, molecular targeted therapy using tyrosine kinase receptor inhibitors, including sorafenib, lenvantinib, vandetanib, and cabozantinib, helps control tumor progression and prolongs progression-free survival. Using a dynamic risk-stratified approach to manage thyroid cancer, the outcomes for most thyroid cancer patients are excellent compared with those for other cancers. The major challenge in the future is to identify high-risk patients and to treat and monitor them appropriately. Clin Cancer Res; 22(20); 5012-21. ©2016 AACR SEE ALL ARTICLES IN THIS CCR FOCUS SECTION, "ENDOCRINE CANCERS REVISING PARADIGMS".

Clinical Significance of Thyroid-Stimulating Hormone Receptor Gene Mutations and/or Sodium-Iodine Symporter Gene Overexpression in Indeterminate Thyroid Fine Needle Biopsies

Objectives: To examine the prevalence of genetic alterations of thyroid-stimulating hormone receptor (TSHR) gene and sodium-iodine symporter (NIS) in a series of thyroid fine needle biopsy (FNB) specimens with indeterminate cytology, and to assess the correlation of the type of genetic changes with clinical features and follow-up results in the target thyroid nodule. Methods: Between February 2015 and September 2017, 388 consecutive FNBs with indeterminate cytology were evaluated for TSHR mutations and NIS gene overexpression using ThyroSeqV.2 next-generation sequencing (NGS) panel. Medical records were reviewed for target nodules. Results: Among 388 indeterminate FNBs, TSHR mutations and/or NIS overexpression were detected in 25 (6.4%) nodules. Ten nodules (2.6%) harbored TSHR mutations only, 7 nodules (1.8%) over-expressed NIS gene only, and 8 nodules (2.1%) had both alterations. The TSHR mutations were located between codons 281 and 640, with codon 453 being the most frequently affected. The allelic frequency of the mutated TSHR ranged from 6 to 36%. One nodule with NIS overexpression was simultaneously detected EIF1AX mutation and GNAS mutation. Nodules with TSHR mutations and/or NIS overexpression presented hyperfunctioning (n = 4), hypofunctioning (n = 5), and isofunctioning (n = 3) on the available thyroid scintigraphies. Eight cases accompanied with hyperthyroidism in which only 1 was caused by the target nodule. Evidence of co-existing autoimmune thyroid disease (AITD) and multinodular goiter were found in 52% and 52% of cases, respectively. Seven nodules underwent surgeries and all were benign on final pathology. None of 9 nodules with follow-up by ultrasound (3~33 mon, median 12 mon) showed grow in size. Conclusions: TSHR mutations and/or NIS overexpression can be detected in pre-operative FNB specimens using the NGS approach. These genetic alterations occurred in 6.4% thyroid nodules in this consecutive series with indeterminate cytology. They present not only in hyperfunctioning nodules but also in hypo- or iso-functional nodules, indicating their prevalence may be higher than previously expected. Co-existing AITD was common in cases with these molecular alterations. None of our patients with TSHR mutations and/or NIS overexpression manifested malignant outcomes. How to use these two molecular markers in thyroid FNBs to guide our clinical practice warrants further investigation.

Serum TSH levels as a predictor of malignancy in thyroid nodules: A prospective study

BACKGROUND

The role of serum TSH concentrations as a predictor of malignancy of thyroid nodule remains unclear.

OBJECTIVE

To prospectively evaluate the usefulness of serum TSH levels as a predictor of malignancy in thyroid nodules.

METHODS

Patients with thyroid nodule(s) who underwent fine-needle aspiration biopsy under ultrasonographic guidance in a tertiary, university-based hospital were consecutively evaluated. Patients with known thyroid cancer and/or patients receiving thyroid medication were excluded. Serum TSH levels were measured by two differents methodologies, chemiluminescent (CLIA) and electrochemiluminscent immunoassay (ECLIA). Anatomopathological exam of tissue samples obtained at thyroidectomy was considered the gold standard for the diagnosis of thyroid cancer.

RESULTS

A total of 615 patients participated in the study. The mean age was 55.9±14.7 years, and 544(88.5%) were female. The median TSH values were 1.48 and 1.55 μU/mL, using CLIA and ECLIA, respectively. One-hundred-sixty patients underwent thyroidectomy and the final diagnoses were malignant in 47(29.4%) patients. TSH levels were higher in patients with malignant than in those with benign nodules in both TSH assays: 2.25 vs. 1.50; P = 0.04 (CLIA) and 2.33 vs. 1.27; P = 0.03 (ECLIA). Further analysis using binary logistic regression identified elevated TSH levels, a family history of thyroid cancer, the presence of microcalcifications, and solitary nodule on US as independent risk factors for malignancy in patients with thyroid nodules. Additional analyses using TSH levels as a categorical variable, defined by ROC curve analysis, showed that the risk of malignancy was approximately 3-fold higher in patients with TSH levels ≥2.26 μU/mL than in patients with lower TSH levels (P = 0.00).

CONCLUSIONS

Higher serum TSH levels are associated with an increased risk of thyroid cancer in patients with thyroid nodules. Using TSH levels as an adjunctive diagnostic test for stratifying the risk of malignancy associated with a thyroid nodule may help on defining the best therapeutic approaches.

Thyroid nodule recognition in computed tomography using first order statistics

Background

Computed tomography (CT) is one of the popular tools for early detection of thyroid nodule. The pixel intensity of thyroid in CT image is very important information to distinguish nodule from normal thyroid tissue. The pixel intensity in normal thyroid tissues is homogeneous and smooth. In the benign or malignant nodules, the pixel intensity is heterogeneous. Several studies have shown that the first order features in ultrasound image can be used as imaging biomarkers in nodule recognition.

Methods

In this paper, we investigate the feasibility of utilizing the first order texture features to identify nodule from normal thyroid tissue in CT image. A total of 284 thyroid CT images from 113 patients were collected in this study. We used 150 healthy controlled thyroid CT images from 55 patients and 134 nodule images (50 malignant and 84 benign nodules) from 58 patients who have undergone thyroid surgery. The final diagnosis was confirmed by histopathological examinations. In the presented method, first, regions of interest (ROIs) from axial non-enhancement CT images were delineated manually by a radiologist. Second, average, median, and wiener filter were applied to reduce photon noise before feature extraction. The first-order texture features, including entropy, uniformity, average intensity, standard deviation, kurtosis and skewness were calculated from each ROI. Third, support vector machine analysis was applied for classification. Several statistical values were calculated to evaluate the performance of the presented method, which includes accuracy, sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and area of under receiver operating characteristic curve (AUC).

Results

The entropy, uniformity, mean intensity, standard deviation, skewness (P < 0.05), except kurtosis (P = 0.104) of thyroid tissue with nodules have a significant difference from those of normal thyroid tissue. The optimal classification was obtained from the presented method. The accuracy, sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) are 0.880, 0.821, 0.933, 0.917, 0.854, and 0.953 respectively.

Conclusion

First order texture features can be used as imaging biomarkers, and the presented system can be used to assist radiologists to recognize the nodules in CT image.

Characterization of Thyroid Nodules by 4-Dimensional Computed Tomography: Initial Experience

OBJECTIVE

We aimed to evaluate the use of 4-dimensional computed tomography (4DCT) for characterization of thyroid nodules.

METHODS

Our study drew from 100 consecutive patients with primary hyperparathyroidism who underwent 4D parathyroid CT imaging for adenoma localization. Included subjects had tissue sampling of a thyroid nodule within 3 months of 4DCT.

RESULTS

Twenty subjects (18 women and 2 men) had thyroid nodules that were pathologically confirmed. Precontrast nodule attenuation was significantly lower in malignant nodules when compared with benign nodules (36 vs 61 HU, P = 0.05). Arterial phase and delayed phase nodule attenuations were not significantly different in malignant and benign nodules (128 vs 144 HU, P = 0.7; 74 vs 98 HU, P = 0.3).

CONCLUSIONS

Our initial experience with a small group of patients was unable to support the use of 4DCT for characterizing thyroid nodules; however, precontrast nodule attenuation was significantly lower in malignant nodules when compared with benign nodules.

Molecular perspectives in differentiated thyroid cancer

Progress in understanding the molecular genetics of thyroid cancer in the last 20 years has accelerated recently with the advent of high-throughput sequencing technologies known as Next-Generation Sequencing. Besides classical molecular abnormalities involving the MAPK (Mitogen Activated Protein Kinase) and PI3K (PhosphoInositide 3-Kinase) pathways that play a key role in follicular-derived thyroid tumorigenesis, new molecular abnormalities have been discovered. The major advances in recent years have been the discovery of new somatic driver gene point mutations (such as RASAL1 [RAS protein activator Like 1] mutations in follicular cancer) and/or mutations that have prognostic value (such as TERT [Telomerase reverse transcriptase] promoter mutations); new chromosomal rearrangements, usually having close connection with exposure to ionizing radiation (such as ALK [Anaplastic Lymphoma Kinase] rearrangements); and deregulation of some gene or microRNA expression representing a molecular signature. Progress made in understanding the molecular mechanisms of thyroid cancer offers new perspectives for the diagnosis of the benign or malignant status of a thyroid nodule, to refine prognosis and offer new perspectives of targeted therapy for radioiodine-refractory cancers.

Current status and diagnostic values of the Bethesda system for reporting thyroid cytopathology in a papillary thyroid carcinoma-prevalent area

BACKGROUND

Most studies validating the Bethesda system for reporting thyroid cytopathology (TBSRTC) have been conducted in Western countries. We explored the current status of TBSRTC in an area where most thyroid malignancies are papillary carcinomas.

METHODS

Fine-needle aspirations (FNAs) of thyroid nodules performed in 2013 were retrospectively analyzed and the results were compared to final pathology on resection.

RESULTS

Of 1947 FNAs, 1925 (98.9%) were reported using TBSRTC. Among 381 resected lesions, 27.3% of nondiagnostic, 19.6% of benign, 56.0% of atypia of undetermined significance/follicular lesion of undetermined significance (AUS/FLUS), 33.3% of follicular neoplasm/suspicious for a follicular neoplasm (FN/SFN), 97.7% of suspicious for malignancy, and 100.0% of malignant lesions were malignant on pathology. The sensitivity and specificity of FNA using TBSRTC were 96.7% and 84.1%, respectively.

CONCLUSION

TBSRTC works well in an area in which papillary thyroid cancer is prevalent; however, it may underestimate malignancy rates in AUS/FLUS, benign, and nondiagnostic categories. © 2016 Wiley Periodicals, Inc. Head Neck 39: 269-274, 2017.

The Spectrum of Clinical Utilities in Molecular Pathology Testing Procedures for Inherited Conditions and Cancer: A Report of the Association for Molecular Pathology

Clinical utility describes the benefits of each laboratory test for that patient. Many stakeholders have adopted narrow definitions for the clinical utility of molecular testing as applied to targeted pharmacotherapy in oncology, regardless of the population tested or the purpose of the testing. This definition does not address all of the important applications of molecular diagnostic testing. Definitions consistent with a patient-centered approach emphasize and recognize that a clinical test result's utility depends on the context in which it is used and are particularly relevant to molecular diagnostic testing because of the nature of the information they provide. Debates surrounding levels and types of evidence needed to properly evaluate the clinical value of molecular diagnostics are increasingly important because the growing body of knowledge, stemming from the increase of genomic medicine, provides many new opportunities for molecular testing to improve health care. We address the challenges in defining the clinical utility of molecular diagnostics for inherited diseases or cancer and provide assessment recommendations. Starting with a modified analytic validity, clinical validity, clinical utility, and ethical, legal, and social implications model for addressing clinical utility of molecular diagnostics with a variety of testing purposes, we recommend promotion of patient-centered definitions of clinical utility that appropriately recognize the valuable contribution of molecular diagnostic testing to improve patient care.

Intraoperative Frozen Section in “Suspicious for Papillary Thyroid Carcinoma” after Adoption of the Bethesda System

Objective

To evaluate the accuracy and utility of intraoperative frozen section examination (iFSE) in patients with a preoperative fine-needle aspiration (FNA) cytology of “suspicious for malignancy” (SFM)–Bethesda V, after the adoption of the Bethesda System for Reporting Thyroid Cytopathology.

Study Design

Case series with chart review.

Setting

Tertiary medical center.

Subjects and Methods

All patients with SFM–Bethesda V who underwent thyroid surgery with iFSE between 2010 and 2015 were included. In cases where the iFSE was reported to be malignant, a total thyroidectomy was performed; otherwise, thyroid lobectomy (hemithyroidectomy) was performed.

Results

The current series included 47 patients diagnosed preoperatively with FNA cytology of SFM–Bethesda V. The malignancy rate was 74.5% (35 of 47). Twenty-four patients with nonmalignant iFSE results underwent lobectomy during their initial surgery: 12 were subsequently found with benign final histology and did not undergo completion thyroidectomy; the other 12 patients had malignant results on final histology, but only 4 of them underwent completion thyroidectomy. iFSE resulted in a sensitivity and specificity of 65.7% and 100%, respectively, with a positive predictive value of 100% (23 of 23) and a negative predictive value of 50% (12 of 24). Accuracy of the iFSE methodology was 74.5% (35 of 47).

Conclusions

With no significant preoperative clinical or sonographic predictors for thyroid malignancy and given the high specificity of iFSE, our results support the use of iFSE for patients with preoperative FNA cytology of SFM–Bethesda V who are undergoing thyroid surgery, to determine the extent of required surgery.

Evolutionary features of thyroid cancer in patients with thyroidectomies from 2008 to 2013 in China

To evaluate the characteristics of thyroid carcinoma over time, we carried out a retrospective study to illustrate the evolutionary features of thyroid carcinoma. All records of thyroidectomies from the First Affiliated Hospital of Nanjing Medical University from 2008 to 2013 were obtained focusing on pathological diagnosis, size, local lymph node metastasis (LNM) of the tumors. The thyroid cancer detection rate increased from 24.6% to 41.5% significantly (P < 0.05). Papillary thyroid carcinoma (PTC) remained to be the most common type counting 86.4% of all thyroid carcinomas. In all 1,704 PTCs, microPTC (mPTC) with maximum diameter less than or equal to 10 mm has become the dominant form taking up 56.5% of all PTCs in 2013 while only 43.1% in 2008. The mean maximum tumor size has decreased from 17.8 mm to 12.2 mm significantly (P < 0.05). However, the average age, female dominance, and local LNM remained similarly in the past six years. Logistic regression test showed that the determinants for local LNM were age, gender and tumor size. mPTC has become the most common form of thyroid carcinoma detected during thyroidectomies in China while other features of thyroid carcinoma remained similarly in the recent years.

Indeterminate Single Thyroid Nodule: Synergistic Impact of Mutational Markers and Sonographic Features in Triaging Patients to Appropriate Surgery

BACKGROUND

Patients labeled as having indeterminate thyroid nodular disease following fine-needle aspiration cytology are at risk of non-optimal initial surgery: an overly radical total thyroidectomy, or an unnecessary two-stage operation. The objective of this study was to assess the impact of combining mutational markers and ultrasonographic (US) features preoperatively on predicting the risk of malignancy in patients with indeterminate nodules, thereby offering them a tailored initial surgical intervention.

METHODS

The records of 258 patients who underwent conventional total thyroidectomy for single nodules reported as suspicious for a follicular neoplasm (Bethesda category IV) in a four-year period were reviewed. Main issues addressed included: certain US findings (individually and in combination), mutational markers (BRAF and NRAS), and combinations of both. Correlation of these with malignancy was assessed, as was their ability to predict malignancy. The usefulness of combining the absence of suspicious sonographic features and the absence of mutational markers was also evaluated.

RESULTS

Among the 258 patients with an indeterminate diagnosis, only 90 lesions were found to be malignant. The sonographic features that correlated significantly with malignancy were irregular margins, microcalcifications, and a "taller than wide" shape. The presence of irregular margins was the feature with the highest positive predictive value. Combinations of two or more features were always associated with predictivity in excess of 90%, and at times at 100%. NRAS mutation was the most common gene alteration. Both BRAF and NRAS mutations were mutually exclusive and correlated significantly with malignancy. Their predictivity of malignancy was high, particularly when combined with suspicious sonographic features (100%). The major limitation of both suspicious sonographic features and/or mutational markers was their low occurrence in malignancy. The absence of both mutational markers and suspicious sonographic features proved extremely useful in tailoring surgical strategy, as it could have ultimately spared 143/258 patients (55%) an overly radical thyroidectomy.

CONCLUSION

The preoperative utility of mutational markers and sonographic features in combination has a synergistic impact. It can predict the risk of malignancy with high accuracy, properly triaging patients to appropriate surgery.

LONG-TERM NONOPERATIVE RATE OF THYROID NODULES WITH BENIGN RESULTS ON THE AFIRMA GENE EXPRESSION CLASSIFIER

OBJECTIVE

The primary objective was to assess the operative rate in patients with a benign result from the Afirma gene expression classifier (GEC) during long-term follow-up at nonacademic medical facilities. The secondary endpoint of this study was the treating physician's opinion regarding the safety of GEC use compared to the hypothetical situation of providing thyroid nodule management without the GEC.

METHODS

This was a retrospective study of nonacademic medical practices utilizing the GEC. Those clinicians utilizing the GEC testing who had three or more 'benign' results during the data collection period (September 2010 through June 2014) were invited to participate. Operative status and patient demographics were documented for patients with GEC testing at least 36 months (± 3 months) prior to the date of data collection. A survey also was administered to the treating physicians to assess their perceived safety of using the GEC in patient care.

RESULTS

During 36 months (± 3 months) of follow-up, 17 of 98 patients (17.3%) with a 'benign' GEC result underwent surgery. Within the first 2 years after a 'benign' GEC, 88% of surgeries were performed. Regarding safety of the GEC, the treating physicians reported that patient safety was improved by using the GEC compared to not using the GEC in 78 of 91 cases (86%).

CONCLUSION

It appears that a 'benign' result on the GEC is associated with a reduction in the rate of thyroid surgeries compared to published data when patients are followed for 36 months after testing. A nonoperative approach to follow-up was felt to be a safe alternative to diagnostic surgery by the majority of responsible physicians in the study.

ABBREVIATIONS

AUS = atypia of undetermined significance FLUS = follicular lesion of undetermined significance FN = follicular neoplasm FNA = fine-needle aspiration GEC = gene expression classifier.

Tumor genotype determines phenotype and disease-related outcomes in thyroid cancer: a study of 1510 patients

OBJECTIVES

To correlate thyroid cancer genotype with histology and outcomes.

BACKGROUND

The prognostic significance of molecular signature in thyroid cancer (TC) is undefined but can potentially change surgical management.

METHODS

We reviewed a consecutive series of 1510 patients who had initial thyroidectomy for TC with routine testing for BRAF, RAS, RET/PTC, and PAX8/PPARG alterations. Histologic metastatic or recurrent TC was tracked for 6 or more months after oncologic thyroidectomy.

RESULTS

Papillary thyroid cancer (PTC) was diagnosed in 97% of patients and poorly differentiated/anaplastic TC in 1.1%. Genetic alterations were detected in 1039 (70%); the most common mutations were BRAFV600E (644/1039, 62%), and RAS isoforms (323/1039, 31%). BRAFV600E-positive PTC was often conventional or tall cell variant (58%), with frequent extrathyroidal extension (51%) and lymph node metastasis (46%). Conversely, RAS-positive PTC was commonly follicular variant (87%), with infrequent extrathyroidal extension (4.6%) and lymph node metastasis (5.6%). BRAFV600E and RET/PTC-positive PTCs were histologically similar. Analogously, RAS and PAX8/PPARG-positive PTCs were histologically similar. Compared with RAS or PAX8/PPARG-positive TCs, BRAFV600E or RET/PTC-positive TCs were more often associated with stage III/IV disease (40% vs 15%, P < 0.001) and recurrence (10% vs 0.7%, P < 0.001; mean follow-up 33 ± 21 mo). Distant metastasis was highest in patients with RET/PTC-positive TC (10.8%, P = 0.02).

CONCLUSIONS

In this large study of prospective mutation testing in unselected patients with TC, molecular signature was associated with distinctive phenotypes including cancers, with higher risks of both distant metastasis and early recurrence. Preoperative genotype provides valuable prognostic data to appropriately inform surgery.

Impact of reclassifying noninvasive follicular variant of papillary thyroid carcinoma on the risk of malignancy in The Bethesda System for Reporting Thyroid Cytopathology

BACKGROUND

Recent discussions have focused on redefining noninvasive follicular variant of papillary thyroid carcinoma (NI-FVPTC) as a neoplasm rather than a carcinoma. This study assesses the potential impact of such a reclassification on the implied risk of malignancy (ROM) for the diagnostic categories of The Bethesda System for Reporting Thyroid Cytopathology (TBSRTC).

METHODS

The study consisted of consecutive fine-needle aspiration biopsy (FNAB) cases collected between January 1, 2013 and June 30, 2014 from 5 academic institutions. Demographic information, cytology diagnoses, and surgical pathology follow-up were recorded. The ROM was calculated with and without NI-FVPTC and was presented as a range: all cases (ie, overall risk of malignancy [OROM]) versus those with surgical follow-up only.

RESULTS

The FNAB cohort consisted of 6943 thyroid nodules representing 5179 women and 1409 men with an average age of 54 years (range, 9-94 years). The combined average ROM and OROM for the diagnostic categories of TBSRTC were as follows: nondiagnostic, 4.4% to 25.3%; benign, 0.9% to 9.3%; atypia of undetermined significance/follicular lesion of undetermined significance (AUS/FLUS), 12.1% to 31.2%; follicular neoplasm (FN), 21.8% to 33.2%; suspicious for malignancy (SM), 62.1% to 82.6%; and malignant, 75.9% to 99.1%. The impact of reclassifying NI-FVPTC on the ROM and OROM was most pronounced and statistically significant in the 3 indeterminate categories: the AUS/FLUS category had a decrease of 5.2% to 13.6%, the FN category had a decrease of 9.9% to 15.1%, and the SM category had a decrease of 17.6% to 23.4% (P < .05), whereas the benign and malignant categories had decreases of 0.3% to 3.5% and 2.5% to 3.3%, respectfully. The trend of the effect on the ROM and OROM was similar for all 5 institutions.

CONCLUSIONS

The results from this multi-institutional cohort indicate that the reclassification of NI-FVPTC will have a significant impact on the ROM for the 3 indeterminate categories of TBSRTC.

FNA needle rinses preserved in Cytolyt are acceptable specimen type for mutation testing of thyroid nodules

INTRODUCTION

This study investigated the application of molecular testing to residual thyroid fine-needle aspiration material from needle rinses collected in Cytolyt.

MATERIALS AND METHODS

Two thyroid needle rinses from 135 patients were collected in Cytolyt during routine diagnostic workup in our institution. Molecular testing was performed to detect 14 genetic alterations in BRAF, K-, H-, N-RAS genes as well as RET/PTC1, RET/PTC3, and PAX8/PPARγ and verified by next generation sequencing and correlated with cytologic diagnoses.

RESULTS

Molecular testing revealed a total of 17 mutations across specimens with benign nodule (n = 5; HRAS, NRAS), Hürthle cell neoplasm (n = 2; BRAF, HRAS) and Papillary thyroid carcinoma (n = 10, 9 BRAF, 1 KRAS) cytology. No RNA gene rearrangements were detected.

CONCLUSIONS

Mutations and translocations associated with thyroid cancer can be detected in thyroid fine-needle aspiration needle rinses preserved in Cytolyt specimens collected during routine patient management, which are typically discarded when a diagnosis is attained.

BRAF(V600E) Mutation, RET/PTC1 and PAX8-PPAR Gamma Rearrangements in Follicular Epithelium Derived Thyroid Lesions - Institutional Experience and Literature Review

BACKGROUND

Thyroid cancers are the most frequently occurring endocrine malignancy worldwide. In Turkey, thyroid cancers are ranked 2(nd) on the incidence list in women, with a rate of 16.2%, but they are not included among the top 10 cancer types in men.

AIMS

To identify the contribution of the BRAF(V600E) mutation, and the RET/PTC1 and PAX8-PPARγ rearrangements in the diagnosis and differential diagnosis of follicular epithelial-derived thyroid lesions.

STUDY DESIGN

Retrospective clinical and molecular genetic study.

METHODS

A total of 86 thyroid cases diagnosed between 2001 and 2012 at the Department of Pathology were included in the retrospective study group. Samples best representing the lesion and comprising capsules were chosen in the selection of paraffin blocks pertaining to the cases. The BRAF(V600E) mutation, and the RET/PTC1 and PAX8-PPARγ rearrangements were investigated in all cases.

RESULTS

The BRAF(V600E) mutation was observed in 12 out of 37 papillary carcinoma cases (32.4%), in 1 out of 15 follicular carcinoma cases (6.6%), and in 1 out of 7 undifferentiated carcinoma cases (14.3%). No mutation was detected in benign lesions. The RET/PTC1 rearrangement was detected in 2 out of 7 undifferentiated carcinoma cases (28.6%), and in 1 out of 15 follicular carcinoma cases (6.6%). No gene rearrangement was detected in benign lesions. The PAX8-PPARγ rearrangement was detected in 5 out of 15 follicular thyroid carcinoma cases (33.3%) and in 1 out of 15 follicular adenoma cases (6.6%).

CONCLUSION

The BRAF(V600E) mutation and RET/PTC1 rearrangement were effective in distinguishing the follicular epithelium-derived benign and malignant lesions of the thyroid in the resection materials. The BRAF(V600E) mutation was rather specific to papillary carcinoma in the thyroid, and in cases where the BRAF(V600E) mutation was detected, multi-centricity, lymph node metastasis and capsular invasion findings were observed more frequently compared to cases in which no mutation was observed. The PAX8-PPARγ rearrangement was observed to be more effective in the differentiation of adenomas and carcinomas in follicular neoplasms of the thyroid, whereas the RET/PTC1 analysis contributed to the differential diagnosis of papillary carcinoma histogenesis at a frequency of 29% in undifferentiated thyroid carcinomas.

Integrated genomic characterization of papillary thyroid carcinoma

Papillary thyroid carcinoma (PTC) is the most common type of thyroid cancer. Here, we describe the genomic landscape of 496 PTCs. We observed a low frequency of somatic alterations (relative to other carcinomas) and extended the set of known PTC driver alterations to include EIF1AX, PPM1D, and CHEK2 and diverse gene fusions. These discoveries reduced the fraction of PTC cases with unknown oncogenic driver from 25% to 3.5%. Combined analyses of genomic variants, gene expression, and methylation demonstrated that different driver groups lead to different pathologies with distinct signaling and differentiation characteristics. Similarly, we identified distinct molecular subgroups of BRAF-mutant tumors, and multidimensional analyses highlighted a potential involvement of oncomiRs in less-differentiated subgroups. Our results propose a reclassification of thyroid cancers into molecular subtypes that better reflect their underlying signaling and differentiation properties, which has the potential to improve their pathological classification and better inform the management of the disease.

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

OBJECTIVES

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

A risk model to determine surgical treatment in patients with thyroid nodules with indeterminate cytology

BACKGROUND

Thyroid nodules are present in 19-67 % of the population and have a 5-10 % risk of malignancy. Fine needle aspiration biopsies are indeterminate in 20-30 % of patients, often necessitating thyroid surgery for diagnosis. We hypothesized that developing a risk model incorporating factors associated with malignancy could help predict the risk of malignancy in patients with indeterminate thyroid nodules.

METHODS

We identified 151 patients with a cytologic diagnosis of follicular neoplasm (Bethesda IV) who progressed to surgery. We retrospectively analyzed demographic, clinical, sonographic, and cytological variables in relation to thyroid carcinoma.

RESULTS

Of 151 patients, 51 (33.8 %) had a final diagnosis of thyroid carcinoma. Papillary carcinoma was diagnosed in 34 patients (66.7 %), follicular carcinoma in 15 (29.4 %), and Hürthle cell carcinoma in 2 (3.9 %). On univariate analysis, younger age, male gender, tobacco use, larger nodule size, and calcifications on ultrasound, nuclear atypia on cytology, and suspicious frozen section were associated with the presence of malignancy. When determining odds ratios, four factors were most predictive of malignancy: nodule calcification [odds ratio (OR) 6.37, 95 % confidence interval (CI) 1.62-25.1, p < 0.01] and nodule size (OR 1.75, 95 % CI 1.19-2.57, p < 0.01) on ultrasound, nuclear atypia on cytology (OR 4.91, 95 % CI 1.90-12.66, p < 0.01), and tobacco use (OR 4.59, 95 % CI 1.30-16.27, p < 0.02). A multivariable model based on these four factors resulted in a c-statistic of 0.82.

CONCLUSIONS

A multivariable model based on calcification, nodule size, nuclear atypia, and tobacco use may predict the risk of thyroid cancer requiring a total thyroidectomy in patients with thyroid nodules of indeterminate cytology.

Multiplatform comparison of molecular oncology tests performed on cytology specimens and formalin-fixed, paraffin-embedded tissue

BACKGROUND

Molecular oncology testing is important for patient management, and requests for the molecular analysis of cytology specimens are increasingly being made. Formalin-fixed, paraffin-embedded (FFPE) cell blocks of such specimens have been routinely used for molecular diagnosis. However, the inability to assess cellularity before cell block preparation is a pitfall of their use. In this study, various cytologic preparations were tested with several molecular test platforms, and the results were compared with paired FFPE tissue.

METHODS

Seventy-seven cytology cases, including fine-needle aspiration smears, touch preparations, and SurePath thin-layer preparations, were selected from the archives. Areas of interest were removed from the slide with a matrix capture solution. DNA extracted from the cells was evaluated by mutation analysis for BRAF, epidermal growth factor receptor (EGFR), RAS, and a 50-gene panel with various testing platforms (single-nucleotide primer extension assay, Sanger sequencing, and next-generation sequencing). Thirty-eight tumors with available FFPE tissue were tested in parallel.

RESULTS

The average DNA concentration was 299 ng/µL for the cytology specimens and 171 ng/µg for the paired FFPE tissue. Point mutations and large deletions were detected in BRAF, KRAS, NRAS, HRAS, and EGFR genes. In comparison with FFPE tissue, 5- to 8-fold less input DNA was needed when cytology preparations were used. The concordance between cytology specimens and FFPE tissue was 100%.

CONCLUSIONS

Cytologic preparations were found to be a reliable source for molecular oncology testing. DNA derived from cytology specimens performed well on multiple platforms, and 100% concordance was observed between cytology specimens and FFPE tissue.

Annual financial impact of thyroidectomies for nodular thyroid disease in China

A large proportion of patients with thyroid nodules in China undergo thyroidectomy in order to get confirmatory histology diagnosis. The financial impact of this modality remains to be investigated. To evaluate rationality of performing thyroidectomy without a routine FNA preoperatively from the economic perspective, we conducted a retrospective, observational study of all archival thyroidectomies with records of cost per stay (CPS), cost per day (CPD) and length of stay (LOS) from 2008 to 2013 in the First Affiliated Hospital of Nanjing Medical University. We compared all the parameters between cancer and non-cancer thyroidectomies. We recruited 6, 140 thyroidectomies with valid records of CPS, CPD and LOS in this period. The CPS of cancer thyroidectomy was significantly higher than non-cancer thyroidectomy. The percentage of cancer thyroidectomy increased from 26.5% to 41.6%. The percentage of annual cost of cancer thyroidectomies rose from 30.2% to 45.2%. The LOS for cancer and non-cancer thyroidectomy decreased while the CPD increased in the past six years. The estimated national cost in 2012 for all thyroidectomies would be USD 1.86 billion with USD 1.09 billion for non-cancer thyroidectomies. We have witnessed great improvement in the healthcare for patients with thyroid nodules in China. However, given limited healthcare resources, currently thyroid FNA for more precise preoperative diagnosis may help to curb the rapidly increasing demand in healthcare costs in the future for nodular thyroid disease in China.

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.

Diagnostic value of immunohistochemistry for the detection of the BRAF(V600E) mutation in papillary thyroid carcinoma: comparative analysis with three DNA-based assays

BACKGROUND

The aim of this study was to compare the detection of BRAF(V600E) by immunohistochemistry (IHC) using a mutation-specific antibody with molecular biology methods for evaluation of papillary thyroid carcinoma (PTC) patients.

PATIENTS AND METHODS

This study concerned 198 consecutive conventional PTC patients, of which the majority were women (133/198; 67%), with a mean age of 56 years (range 19-79 years). BRAF mutation analysis was performed using DNA-based (direct sequencing, pyrosequencing, and SNaPshot) and IHC (VE1 antibody) methods. The sensitivity and specificity of IHC for BRAF(V600E) was compared with the molecular biology data.

RESULTS

A BRAF mutational result was obtained in 194 cases. A BRAF(V600E) mutation was detected in 153/194 (79%) cases of PTC when using at least one molecular method, and in 151/194 (78%) cases with IHC. No false positive results were noted using IHC to detect the BRAF(V600E) mutation. Besides this mutation, other rare BRAF mutations (BRAF(V600K) and BRAF(K601E)), used as negative controls, were consistently negative with IHC. The sensitivity and specificity of IHC for the detection of this mutation were 98.7% and 100% respectively. The IHC test demonstrated excellent performance at a level equivalent to two DNA-based counterparts (pyrosequencing and SNaPshot). Failure to achieve a result was more frequent with the direct sequencing method than with the three other methods.

CONCLUSION

IHC using the VE1 antibody is a specific and sensitive method for the detection of the BRAF(V600E) mutation in PTC. IHC may be an alternative to molecular biology approaches for the routine detection of this mutation in PTC patients.

Update on the molecular diagnosis and targeted therapy of thyroid cancer

Thyroid cancer (TC) is the most common endocrine malignancy with steadily increasing incidence over the past few decades. Although standard strategies for the management of TC offer optimal outcomes in TC patients with favorable histological types at early stage, challenges arising from diagnosis and therapy still exist during clinical practice. A number of genetic alterations have been described in thyroid cancer, which provides an unprecedented opportunity for the identification of novel diagnostic and prognostic molecular markers as well as novel therapeutic targets. Molecular-targeted therapies, which have been investigated recently with increasing success, may prove to be a breakthrough in patients with advanced, radioiodine-refractory thyroid cancers. This review summarizes the latest progression in molecular diagnosis and targeted therapy of TC.

Clinical characteristics as predictors of malignancy in patients with indeterminate thyroid cytology: a meta-analysis

Indeterminate thyroid nodules (ITN) constitute the gray zone of thyroid fine-needle aspiration cytology (FNAC). About 70-80 % of ITN are later diagnosed as benign; therefore, it is very important to identify the predictors of malignancy. Aim of the study was to summarize published data about clinical risk factors for malignancy in patients with ITN and thereby provide more robust estimates of the effect of these risk factors. Sources comprised studies published through December 2012. Original articles that investigated clinical parameters as potential predictors of malignancy in ITN were identified. Two authors performed the data extraction independently. A meta-analysis of 19 relevant studies was conducted that included 3,494 patients with ITN according to FNAC. The pooled prevalence of malignancy was 28 % (95 % CI 23-33), 26 % in females and 34 % in males. The pooled OR was 1.51 (95 % CI 1.2-1.83) for males and 0.68 (95 % CI 0.53-0.88) for females. Regarding the nodule's size, the pooled OR was 2.10 (95 % CI 1.26-3.50) for nodules >4 cm in diameter. Analysis of the patient age as a risk factor was not feasible because of marked difference found between the studies. In patients with indeterminate thyroid nodules diagnosed at FNAC, the pooled rate of malignancy from 19 studies was 28 %. Patients that are male and have ITN greater than 4 cm in diameter should be considered at higher risk of cancer.