Molecular Testing for Thyroid Nodules Including Its Interpretation and Use in Clinical Practice

Serum microRNA-146a-5p and microRNA-221-3p as potential clinical biomarkers for papillary thyroid carcinoma

PURPOSE

Papillary thyroid carcinoma (PTC) is the most common malignant thyroid neoplasm, accounting for approximately 85% of all follicular cell-derived thyroid nodules. This study aimed to assess the diagnostic potential of circulating microRNA-146a-5p and microRNA-221-3p as biomarkers for PTC and their usefulness in monitoring disease progression during patient follow-up.

METHODS

An observational study was conducted on two cohorts of PTC patients and healthy controls (HCs) using digital PCR. We collected patients' clinical, biochemical, and imaging data during the post-surgery surveillance. We analyzed the levels of circulating miRNAs in serum samples of patients before surgery and during the follow-up, including those with indeterminate/biochemical incomplete response (IndR/BIR) and residual thyroid tissues (Thy Residue).

RESULTS

Both miR-146a-5p and miR-221-3p were confirmed as effective biomarkers for PTC diagnosis. They enabled differentiation between pre-surgery PTC patients and HCs with an area under the curve (AUC) of 92% and 87.3%, respectively, using a threshold level of 768,545 copies/uL for miR-146a-5p and 389,331 copies/uL for miR-221-3p. It was found that miRNA fold change levels, rather than absolute levels, can be useful during patient follow-up. In particular, we found that a fold change of 2 for miR-146a-5p and 2.2 for miR-221-3p can identify a progressive disease, regardless of the presence of TgAbs or remnant thyroid.

CONCLUSION

MiRNA-146a-5p and miRNA-221-3p, particularly the former, could be valuable diagnostic biomarkers for PTCs. They also seem to be effective in monitoring disease progression during patient follow-up by evaluating their fold change, even when thyroglobulin is uninformative.

ThyroSeq overview on indeterminate thyroid nodules: An institutional experience

BACKGROUND

Molecular triage of indeterminate thyroid aspirates offers the opportunity to stratify the risk of malignancy (ROM) more accurately. Here we examine our experience with ThyroSeq v3 testing.

METHODS

We analyzed 276 of 658 (42%) fine needle aspiration samples classified as indeterminate thyroid nodules using ThyroSeq v3 (Sept 2017-Dec 2019). The test provides a ROM and detects specific mutations. Surgical diagnoses were reviewed.

RESULTS

Of 276 ThyroSeq-tested cases, 42% (n = 116) harbored genetic alterations, whereas 64% (n = 74) had surgical follow-up. Notably, 79% cases within intermediate to higher risk mutations were highly associated with surgical intervention, resulting in a 77.5% ROM when including both cancer and noninvasive follicular thyroid neoplasia with papillary-like features (cancer+NIFTP) and 68% malignant diagnosis when excluding NIFTP. RAS-like alterations were most common (66%), exhibiting a 73.4% ROM and a 59% malignant diagnosis. Interestingly, this group included 24 encapsulated follicular variant papillary thyroid carcinomas (EFVPTCs), 1 infiltrative FVPTC, 9 follicular carcinomas, and 7 NIFTP. Additionally, three high-risk mutations and eight BRAF/V600E mutations had a 100% ROM, all diagnosed as classic-type papillary thyroid carcinoma (cPTC). Combined analysis of thyroid nodules from Bethesda III and IV categories revealed a 78.2% positive predictive value (PPV) and a 75.9% negative predictive value (NPV).

CONCLUSION

ThyroSeq v3 effectively stratifies the ROM in indeterminate thyroid nodules based on specific genetic alterations, guiding appropriate surgical management. Notably, the BRAFV600E/high-risk group and RAS-like groups exhibited ROM of 100% and 77.5%, respectively, with promising predictive accuracy (PPV of 78.2% and NPV of 75.9%).

Serum cholesterol levels are inversely associated with the risk of malignancy in subjects with Bethesda category IV thyroid nodules

INTRODUCTION

Some epidemiological data suggest that there may be an inverse relationship between cholesterol levels and the risk of thyroid cancer in the overall population. The present study was aimed to evaluate the lipid profile specifically in subjects with Bethesda category IV thyroid nodules, and compare whether there were any differences between those with benign and malignant nodules.

METHODS

Single-centre, retrospective study on 204 subjects treated by partial or total thyroidectomy for excision of a Bethesda category IV thyroid nodule, who had undergone a blood lipid profile test in the 12 months prior to surgery. In addition to lipid measures, other demographic, clinical, biochemical and ultrasound data were collected.

RESULTS

Seventy-five subjects (36.8%) were diagnosed with thyroid carcinoma in the definitive histopathological examination. Patients with thyroid cancer had lower levels of total cholesterol, LDL-cholesterol and non-HDL-cholesterol than subjects with benign thyroid diseases. There were no differences in HDL-cholesterol, triglycerides or total cholesterol/HDL-cholesterol ratio. There were no differences either between groups in other clinical, biochemical and ultrasound variables, including the use of lipid-lowering drugs. In multivariate analysis, only LDL-cholesterol was independently associated with malignancy. Subjects with follicular carcinoma showed the lowest cholesterol levels, while those with papillary carcinoma had intermediate values between the group with follicular carcinoma and the group with benign thyroid diseases.

CONCLUSIONS

In subjects with cytologically indeterminate Bethesda category IV thyroid nodules, levels of total cholesterol, non-HDL-cholesterol and, particularly, LDL-cholesterol are lower among those with malignant nodules.

An update on the management of thyroid nodules: rationalising the guidelines

BACKGROUND

Guidance for the management of thyroid nodules has evolved over time, from initial evaluation based predominantly on clinical grounds to now including the established role of ultrasound and fine needle aspiration cytology in their assessment. There is, however, significant variation in the management of thyroid nodules depending on which national guidelines are followed. In addition, there are certain clinical situations such as pregnancy and paediatric thyroid nodules that have differing evaluation priorities.

OBJECTIVES

This review aimed to provide an overview of currently accepted practices for the initial investigation and subsequent management of patients with thyroid nodules for the non-specialist. The review also addresses areas of variance between the systems in common clinical use, as well as newer, evolving technologies, including molecular testing in the evaluation of malignancy in thyroid nodules.

Comparing Diagnostic Efficacy of C-TIRADS Positive Features on Different Sizes of Thyroid Nodules

Purpose

To explore the diagnostic value of positive features in the Chinese Thyroid Imaging Reporting and Data System (C-TIRADS) for thyroid nodules of different sizes.

Patients and Methods

A total of 1864 patients with 2347 thyroid nodules were selected from January 2021 to December 2022 and assessed according to C-TIRADS. According to the maximum diameter, nodules were divided into the A1 group (≤10 mm), A2 group (>10 mm,<20 mm), and A3 group (≥20 mm). With surgical pathology as the golden standard, the receiver operating characteristic curves (ROC) were constructed, and each group's area under the curve (AUC) was calculated. The diagnostic value of positive features in C-TIRADS for different sizes of thyroid nodules was analyzed.

Results

In all groups, malignant thyroid nodules had a higher incidence of positive features than benign nodules (P < 0.05). In A1 group, the diagnostic efficiency of C-TIRADS positive features for thyroid nodules was vertical orientation> ill-defined/irregular margin or extrathyroidal extension> solid composition> markedly hypoechoic> microcalcifications. The AUCs were 0.718, 0.675, 0.609, 0.558, and 0.581, respectively. In A2 group, the diagnostic efficacy of each positive features for thyroid nodules was ill-defined/irregular margins or extra-thyroid invasion> solid composition> microcalcifications> markedly hypoechoic> vertical orientation. The AUCs were 0.854, 0.730, 0.719, 0.670, and 0.609, respectively. In A3 group, the diagnostic efficacy of each positive features for thyroid nodules was ill-defined/irregular margin or extrathyroidal extension> microcalcifications> solid composition> vertical orientation> markedly hypoechoic. The AUCs were 0.847, 0.778, 0.767, 0.584, and 0.560, respectively.

Conclusion

C-TIRADS positive features exhibited different diagnostic efficacy for thyroid nodules of various sizes, especially for thyroid nodules ≤10 mm, for which all positive features had low diagnostic efficacy.

Thyroid cancer pathologic upstaging: Frequency and related factors

INTRODUCTION

Histopathologic assessment of thyroid tumors can lead to stage migration. We assessed frequency of pathologic upstaging, and associations with patient and tumor factors.

METHODS

Primary thyroid cancers treated between 2013 and 2015 were included from our institutional cancer registry. For tumor, nodal, and summary stage, upstaging was present when final pathologic stage was greater than clinical staging. Multivariate logistic regression and Chi-squared tests were performed.

RESULTS

5,351 resected thyroid tumors were identified. Upstaging rates for tumor, nodal, and summary stage were 17.5% (n = 553/3156), 18.0% (n = 488/2705), and 10.9% (n = 285/2607), respectively. Age, Asian race, days to surgery, lymphovascular invasion, and follicular histology were significantly associated. Upstaging was significantly more common after total vs partial thyroidectomy, for tumor (19.4% vs 6.2%, p < 0.001), nodal (19.3% vs 6.4%, p < 0.001), and summary stages (12.3% vs 0.7%, p < 0.001).

CONCLUSIONS

Pathologic upstaging occurs in a considerable proportion of thyroid tumors, most commonly after total thyroidectomy. These findings can inform patient counseling.

Prognostic Value of Preoperative Molecular Testing and Implications for Initial Surgical Management in Thyroid Nodules Harboring Suspected (Bethesda V) or Known (Bethesda VI) Papillary Thyroid Cancer

Importance

Molecular testing is commonly used in the diagnosis of thyroid nodules with indeterminate cytology. The role of molecular testing in prognosticating oncologic outcomes in thyroid nodules with suspicious or malignant cytology is unclear.

Objective

To determine whether molecular profiling of Bethesda V (suspicious for thyroid cancer) and VI (thyroid cancer) nodules is associated with improved prognostication and whether it may inform initial treatment.

Design, Setting, and Participants

This retrospective cohort study included consecutive patients with Bethesda V or VI nodules who underwent surgery, with histopathology showing differentiated thyroid cancer, between May 1, 2016, and July 31, 2019 in the University of California, Los Angeles health system. Data were analyzed between April 2, 2021, and January 18, 2023.

Exposures

Masked ThyroSeq, version 3 molecular analysis after completion of initial treatment and acquisition of follow-up data.

Main Outcomes and Measures

Structural disease persistence or recurrence, distant metastasis, and recurrence-free survival were assessed using ThyroSeq Cancer Risk Classifier (CRC) molecular risk groups (low, RAS-like; intermediate, BRAF-like; high, combination of BRAF/RAS plus TERT or other high-risk alterations) using Cox proportional hazards regression models.

Results

In 105 patients with papillary thyroid cancer (median [IQR] follow-up, 3.8 [3.0-4.7] years), ThyroSeq identified genomic alterations in 100 (95%) samples (6 [6%] low risk, 88 [88%] intermediate risk, and 6 [6%] high risk; median [IQR] age, 44 [34-56] years; 68 [68%] female and 32 [32%] male). No patients with low-risk or negative results experienced recurrence. Of the 88 patients with intermediate risk, 6 (7%) experienced local recurrence, with 1 of them also developing distant metastasis. The 6 patients with high risk (all with BRAF V600E plus TERT mutation) underwent total thyroidectomy followed by radioactive iodine (RAI) ablation. Four patients with high risk (67%) experienced local recurrence, with 3 of them also developing distant metastasis. Thus, patients with high-risk alterations were more likely to experience persistence or recurrence and distant metastasis than patients with intermediate risk. In a multivariable analysis incorporating patient age, sex, cancer size, ThyroSeq molecular risk group, extrathyroidal extension, lymph node positivity, American Thyroid Association risk, and RAI ablation, only cancer size (hazard ratio, 1.36; 95% CI, 1.02-1.80) and ThyroSeq CRC molecular risk group (high vs intermediate and low: hazard ratio, 6.22; 95% CI, 1.04-37.36) were associated with structural recurrence.

Conclusions and Relevance

Among the 6% of patients with high-risk ThyroSeq CRC alterations in this cohort study, the majority experienced recurrence or distant metastasis despite initial treatment with total thyroidectomy and RAI ablation. In contrast, patients with low- and intermediate-risk alterations had a low recurrence rate. Preoperative knowledge of molecular alteration status at diagnosis may allow for deescalation of initial surgery and refining of the intensity of postoperative surveillance in patients presenting with Bethesda V and VI thyroid nodules.

A Review of Evidence for the Involvement of the Circadian Clock Genes into Malignant Transformation of Thyroid Tissue

(1) Background: In 2013, the results of a pioneer study on abnormalities in the levels and circadian rhythmicity of expression of circadian clock genes in cancerous thyroid nodules was published. In the following years, new findings suggesting the involvement of circadian clockwork dysfunction into malignant transformation of thyroid tissue were gradually accumulating. This systematic review provides an update on existing evidence regarding the association of these genes with thyroid tumorigenesis. (2) Methods: Two bibliographic databases (Scopus and PubMed) were searched for articles from inception to 20 March 2023. The reference lists of previously published (nonsystematic) reviews were also hand-searched for additional relevant studies. (3) Results: Nine studies published between 2013 and 2022 were selected. In total, 9 of 12 tested genes were found to be either up- or downregulated. The list of such genes includes all families of core circadian clock genes that are the key components of three transcriptional-translational feedback loops of the circadian clock mechanism (BMAL1, CLOCK, NPAS2, RORα, REV-ERBα, PERs, CRYs, and DECs). (4) Conclusions: Examination of abnormalities in the levels and circadian rhythmicity of expression of circadian clock genes in thyroid tissue can help to reduce the rate of inadequate differential preoperative diagnosis for thyroid carcinoma.

Prospects of Testing Diurnal Profiles of Expressions of TSH-R and Circadian Clock Genes in Thyrocytes for Identification of Preoperative Biomarkers for Thyroid Carcinoma

Thyroid Nodules (TN) are frequent but mostly benign, and postoperative rate of benign TN attains the values from 70% to 90%. Therefore, there is an urgent need for identification of reliable preoperative diagnosis markers for patients with indeterminate thyroid cytology. In this study, an earlier unexplored design of research on preoperative biomarkers for thyroid malignancies was proposed. Evaluation of reported results of studies addressing the links of thyroid cancer to the circadian clockwork dysfunctions and abnormal activities of Thyroid-Stimulating Hormone (TSH) and its receptor (TSH-R) suggested diagnostic significance of such links. However, there is still a gap in studies of interrelationships between diurnal profiles of expression of circadian clock genes and TSH-R in indeterminate thyroid tissue exposed to different concentrations of TSH. These interrelationships might be investigated in future in vitro experiments on benign and malignant thyrocytes cultivated under normal and challenged TSH levels. Their design requires simultaneous measurement of diurnal profiles of expression of both circadian clock genes and TSH-R. Experimental results might help to bridge previous studies of preoperative biomarkers for thyroid carcinoma exploring diagnostic value of diurnal profiles of serum TSH levels, expression of TSH-R, and expression of circadian clock genes.

Management of thyroid nodules

In the past 30 years, there has been a substantial rise in the detection of thyroid nodules. Largely asymptomatic, thyroid nodules are most often incidental findings that typically pose minimal risk. Data supporting these findings show a rapid rise in the incidental detection of thyroid nodules and cancer, but minimal effect on mortality rates, despite treatment. These data imply that historical approaches to thyroid nodule and cancer care might at times include unnecessary or excessive care. To address this issue, the past decade has witnessed an increasingly conservative approach to nodule management, seeking to individualise care and provide the most focused intervention that leads to favourable outcomes. Benign nodules can be safely monitored with minimal, or long-interval follow-up imaging. Molecular testing should be considered for cytologically indeterminate nodules because of its ability to improve preoperative cancer risk determination and reduce unnecessary surgery. The treatment of biopsy-proven malignant nodules has become increasingly nuanced, since recommendations for near-total thyroidectomy are no longer routine. Hemithyroidectomy is now commonly considered when operative intervention is favoured. Some patients with small volume, isolated cancerous nodules are safely managed non-operatively with active monitoring. In summary, modern management strategies for thyroid nodular disease seek to incorporate the growing amount of available diagnostic and prognostic data, inclusive of demographic, radiological, pathological and molecular findings. Once obtained, an individualised management plan can be effectively formulated.

MicroRNA profiling predicts positive nodal status in papillary thyroid carcinoma in the preoperative setting

BACKGROUND

The molecular characterization of thyroid nodules in cytological samples has so far been focused on discriminating between benign and malignant forms in a purely diagnostic setting. The evidence on the impact of molecular biomarkers to determine the risk of aggressiveness in cytologically "neoplastic" lesions is limited to genomic alterations (such as BRAF and TERT mutations). The aim of our study was to assess the preoperative role of microRNAs (miRNAs) in predicting the nodal status of patients with papillary thyroid cancer.

METHODS

A pilot series of histological samples of papillary thyroid carcinoma with (6 cases) or without (6 cases) lymph node metastases, matched for other major clinical and pathological features, was analyzed for global miRNA expression in a screening phase. A set of miRNAs was then validated in a series of 63 consecutive cytological samples of papillary carcinomas: 48 pN-negative and 15 pN-positive at histology.

RESULTS

Unsupervised cluster analysis segregated surgical pN-negative and pN-positive samples, except for 1 case. The 45 differentially expressed miRNAs in pN-positive versus pN-negative cases were predicted to regulate a wide range of cellular pathways, enriched for Wnt, gonadotropin-releasing hormone receptor, and cerulein/cholecystokinin receptor signaling. In agreement with their profiles in surgical samples, 4 miRNAs of the 10 selected for validation (miR-154-3p, miR-299-5p, miR-376a-3p, and miR-302E) had a significant differential expression in cytological samples of papillary carcinoma with lymph node metastases and predicted the positive nodal status with a relatively good performance.

CONCLUSIONS

MiRNA profiling is a potential promising strategy to define papillary carcinoma aggressiveness in the preoperative setting.

Efficacy and safety of ultrasound-guided radiofrequency ablation for papillary thyroid microcarcinoma: a systematic review and meta-analysis

BACKGROUND

We comprehensively evaluate the efficacy and safety of US-guided radiofrequency ablation (RFA) in the treatment of papillary thyroid microcarcinoma (PTMC) via a systematic review and meta-analysis.

METHODS

We searched the PubMed, Embase and Cochrane Library databases for studies published during the time between the establishment of the database through October 2021. We included a 10 non-randomized controlled trial (non-RCT) that reported the application of US-guided RFA in PTMC. The sample size of patients totaled 1279. We evaluated the ablation efficacy by analyzing the volume reduction rate (VRR), complete disappearance rate (CDR) and recurrence rate of PTMC treated by RFA. We analyzed all data using STATA version 15.1 (Stata Corporation, College Station, TX).

RESULTS

Our pooled results proved RFA treatment significantly reduces the volume of tumors (Weighted Mean Difference [WMD] = -103.20, 95% CI: -111.93 - -94.48, p = 0.000). We also found the VRR at 12 months after RFA was 93.27% (95% CI: 84.68-101.86), and the CDR at 12 months after RFA was 64% (95% CI: 39-89%). Additionally, pooled results showed the incidence of mPTC residue in ablation area, newly discovered mPTC and lymph node metastases after RFA treatment were respectively 0.3% (95% CI: -0.1-0.7%), 2.5% (95% CI: 1.1-3.9%) and 1.0% (95% CI: 0.2-1.9%), and the incidence of complications after RFA treatment was 1.8% (95% CI: 0.7-3.2%).

CONCLUSIONS

US-guided RFA is effective and safe for treating PTMC. It could be an excellent alternative to the existing treatment options.