Utility and cost-effectiveness of molecular testing in thyroid nodules with indeterminate cytology

The role of the ThyGeNEXT oncogene panel used in combination with the expanded miRNA panel ThyraMIRv2 in Indeterminate thyroid nodules: A large, blinded, real-world, observational study

BACKGROUND

Molecular analysis of fine-needle aspiration biopsies (FNAB) improves the diagnostic accuracy of cytologically indeterminate thyroid nodules (ITNs). Recently, the use of MPTXv2 has been shown to further improve the accuracy of risk stratification of ITNs.

METHODS

A total of 338 patient samples with atypia of undetermined significance (n = 260) or follicular neoplasm (n = 78) cytology diagnosis and corresponding surgical outcomes or clinical follow-up, collected between 2016 and 2020 were included. All samples underwent multiplatform testing (MPTXv1), which includes an oncogene panel (ThyGeNEXT®) plus a microRNA risk classifier (ThyraMIR®). A blinded, secondary analysis was performed to assess the added utility of MPTXv2 (ThyraMIR®v2). The average length of follow-up for the surveillance group (n = 248) was 30 months.

RESULTS

Sensitivity at moderate threshold was 96% and specificity at positive threshold was 99% for MPTXv2. At 14% disease prevalence, the negative predictive value at the moderate threshold was 99% and the positive predictive value at the positive threshold was 89% for MPTXv2. MPTXv2 had fewer patients classified into the moderate-risk group than MPTXv1, which was statistically significant (p < .001). Using surgical resection, the gold standard for outcomes, MPTXv2 showed a statistically greater area under the curve (p = .028) than MPTXv1, demonstrating greater accuracy for MPTXv2.

CONCLUSION

Both test versions demonstrated robust performance with low false-positive molecular results. Data suggest that incorporation of MPTXv1, and more recently MPTXv2, into clinical practice within our healthcare network resulted in improved accuracy of ITN risk stratification.

Does the Adoption of Molecular Testing Cause Decreased Thyroidectomy Rates in a National Cohort? A Quasiexperimental Study of High- Versus Low-Adoption States

Background: Over the last decade, the utilization of molecular testing (MT) for the evaluation of thyroid nodules has increased. Rates and patterns of adoption of MT and its effect on thyroidectomy rates nationally are unknown. Varying rates of MT adoption at the state level provide an opportunity to study the effects of MT on thyroidectomy rates using a quasiexperimental study design. Methods: We performed a retrospective analysis of American adult patients in the Merative™ MarketScan® Research Databases who underwent thyroid fine-needle aspiration (FNA) from 2011 to 2021. MT included commercially available DNA and RNA platforms and traditional targeted mutational analysis. Interrupted time series analysis was used to evaluate the inflection of MT adoption and thyroidectomy rates after 2015. Difference-in-differences (DID) analysis was used to causally analyze the effect of MT adoption on thyroidectomy rates in high-adoption (at least a 10% increase in MT utilization) versus low-adoption states (no more than 5% increase in MT utilization) from 2015 to 2021. Results: We identified 471,364 patients who underwent thyroid FNA. The utilization of MT increased over the study period from 0.01% [confidence interval, CI: 0.00% to 0.02%] to 10.1% [CI: 9.7% to 10.5%], in 2021, with an immediate (β2 = 1.61, p = 0.002) and deeper (β3 = 0.6, p < 0.001) increase in MT adoption after 2015. Utilization of MT was lower in black patients, the elderly, rural areas, and patients with Medicaid (p < 0.05). Thyroidectomy rates were inversely correlated with MT utilization (r = -0.98, p < 0.0001). From 2015 to 2021, the average MT utilization rate increased from 2.4% to 15.3% in high-adoption states and 1.6% to 5.6% in low-adoption states. In low-adoption states, thyroidectomy rates decreased more but to similar levels (18.5-13.2%) compared with high-adoption states (15.9-13.4%) with an adjusted DID rate of -3.3% [CI -5.6% to -0.8%]. Conclusions: The acceleration in adoption of MT after 2015 likely coincides with the publication of American Thyroid Association guidelines. Black, elderly, and rural patients are less likely to receive MT. Although thyroidectomy rates were inversely correlated with MT utilization, our study suggests that this correlation is not causal. The effect of MT on thyroidectomy rates may be overshadowed by decreasing aggressiveness of thyroid nodule evaluation.

Ultrasonographic predictors of thyroid cancer in Bethesda III and IV thyroid nodules

Background

Bethesda III and IV thyroid nodules continue to be difficult to manage. Although molecular testing may assist in decision-making, it is expensive, not widely available, and not without pitfalls. The objective of this study is to assess whether certain thyroid ultrasonographic features may predict the risk of thyroid cancer in patients with Bethesda III and IV thyroid nodules and be used as additional decision-making tools to complement cytopathological results in deciding on diagnostic thyroidectomy.

Methods

We retrospectively evaluated the ultrasonographic features of Bethesda categories III and IV thyroid nodules in patients who underwent subsequent thyroidectomy. We used the final histopathological examination of the surgical specimens as the gold-standard test and analyzed individual preoperative ultrasonographic features as predictors of malignancy.

Results

Of the 278 patients who were diagnosed with Bethesda III and IV thyroid nodules on fine needle aspiration cytology (FNAC), 111 (39.9%) had thyroid cancer, and 167 (59.9%) exhibited benign nodules. The malignancy rate was higher in patients with Bethesda IV nodules (28/50, 56%) than those with Bethesda III nodules (83/228, 36.4%; p=0.016). In univariate analysis, hypoechogenicity (55.6% in malignant vs. 35.3% in benign, p=0.006) and calcifications (54.5 in malignant vs. 35.4% in benign, p=0.008) were significantly different between the benign and malignant pathology groups, whereas the size of the dominant nodule, number of nodules, irregular borders, taller-than-wide shape, and the presence of lymph nodes were comparable between the two groups. These two ultrasonographic features (hypoechogenicity and calcifications) remained significantly associated with the risk of malignancy in multivariate logistic regression analysis (for hypoechogenicity, p=0.014, odds ratio: 2.1, 95% CI:1.0-3.7 and for calcifications, p=0.019, odds ratio: 1.98, 95% CI:1.12-3.50). The sensitivity, specificity, positive and negative predictive values, and accuracy were 31.5%, 83%, 55.6%,64.7%, and 62.6%, for hypoechogenicity, respectively and 32.4%, 82%, 54.5%, 67.8%, and 62%, for calcification, respectively.

Conclusions

Hypoechogenicity and calcifications in Bethesda III and IV thyroid nodules are strong predictors of thyroid cancer and associated with a two-fold increased risk of malignancy.

Applications of machine and deep learning to thyroid cytology and histopathology: a review

This review synthesises past research into how machine and deep learning can improve the cyto- and histopathology processing pipelines for thyroid cancer diagnosis. The current gold-standard preoperative technique of fine-needle aspiration cytology has high interobserver variability, often returns indeterminate samples and cannot reliably identify some pathologies; histopathology analysis addresses these issues to an extent, but it requires surgical resection of the suspicious lesions so cannot influence preoperative decisions. Motivated by these issues, as well as by the chronic shortage of trained pathologists, much research has been conducted into how artificial intelligence could improve current pipelines and reduce the pressure on clinicians. Many past studies have indicated the significant potential of automated image analysis in classifying thyroid lesions, particularly for those of papillary thyroid carcinoma, but these have generally been retrospective, so questions remain about both the practical efficacy of these automated tools and the realities of integrating them into clinical workflows. Furthermore, the nature of thyroid lesion classification is significantly more nuanced in practice than many current studies have addressed, and this, along with the heterogeneous nature of processing pipelines in different laboratories, means that no solution has proven itself robust enough for clinical adoption. There are, therefore, multiple avenues for future research: examine the practical implementation of these algorithms as pathologist decision-support systems; improve interpretability, which is necessary for developing trust with clinicians and regulators; and investigate multiclassification on diverse multicentre datasets, aiming for methods that demonstrate high performance in a process- and equipment-agnostic manner.

Use of molecular testing results to analyze the overuse of atypia of undetermined significance in thyroid cytology

INTRODUCTION

The suggested atypia of undetermined significance (AUS) rate for thyroid fine-needle aspiration biopsies is 10% or less. Prompted by a high institutional AUS rate, we examined using molecular testing results (MTR) as a potential quality metric tool to reduce the AUS rate. We correlated MTR with AUS cytologic findings, surgical pathology follow-up, and individual pathologist AUS rates.

MATERIALS AND METHODS

Demographic data, cytologic diagnoses, MTR, and surgical pathology diagnoses were retrospectively obtained. MTR were classified as either positive or negative. AUS rates and MTR proportions were compared among pathologists. The cytomorphologic features of 143 AUS cases were assessed and correlated with MTR.

RESULTS

Between 2017 and 2022, 710 of 3247 thyroid fine-needle aspirations were classified as AUS, with a yearly average rate of 22% (range = 19%-26%). AUS cases included: 331 (47%) with architectural atypia; 204 (29%) with oncocytic (Hürthle cell) atypia; 99 (14%) with combined architectural and cytologic atypia; and 76 (10%) with isolated cytologic atypia. Most AUS cases with molecular testing had negative MTR (360/492, 73%). AUS with cytologic atypia had higher positive MTR risk (logarithm of odds ratio = 1.27, 95% credible interval [0.5-2.04], P = 0.001). The average positive MTR rate by pathologist was 21.5% (range 0%-35%); higher positive MTR rates had better correlation with subsequent neoplastic/malignant histologic diagnoses. The MTR sensitivity for malignant disease was 89% and the negative predictive value was 91%.

CONCLUSIONS

MTR analysis reveals the importance of cytologic atypia as a determinant of malignancy risk in AUS cases. Periodic analysis of MTR data alongside individual pathologist AUS rates can help refine diagnostic criteria and potentially reduce AUS overuse.

Molecular testing in fine-needle aspiration of thyroid nodules

BACKGROUND

Thyroid nodules are commonly faced by clinicians as palpable nodules or incidentally identified on imaging. Nodules that are found to be suspicious by imaging can be biopsied by fine needle aspiration, which can yield material for molecular testing to refine the diagnosis.

METHODS

The current literature concerning molecular testing in thyroid nodules including available commercial assays was reviewed and summarized.

RESULTS/CONCLUSIONS

Commonly encountered alterations include mutations in RAS, BRAF, TERT promoter, PTEN, and DICER1 as well as fusions of RET, ALK, PAX8-PPARγ, and NTRK. This article provides a summary of these molecular alterations, commercially available molecular assays, and general considerations for thyroid epithelial malignancies and benign thyroid nodules.

Cost-effectiveness analysis of molecular testing for cytologically indeterminate thyroid nodules

BACKGROUND

Thyroid nodules affect up to 65% of the population. Although fine needle aspirate (FNA) cytology is the gold standard for diagnosis, 15-30% of results are indeterminate. Molecular testing may aid in the diagnosis of nodules and potentially reduce unnecessary surgery. However, these tests are associated with significant costs. The objective of this study was to evaluate the cost-effectiveness of Afirma, a commercially available molecular test, in cytologically indeterminate thyroid nodules.

METHODS

The base case was a solitary thyroid nodule with no additional high-risk features and an indeterminate FNA. Decision tree analysis was performed from the single payer perspective with a 1-year time horizon. Costing data were collected through micro-costing methodology. A probabilistic sensitivity analysis was performed. The primary outcome was the incremental cost effectiveness ratio (ICER) of cost per thyroid surgery avoided.

RESULTS

Over 1 year, mean cost estimates were $8176.28 with 0.58 effectiveness for the molecular testing strategy and $6016.83 with 0.07 effectiveness for current standard management. The ICER was $4234.22 per surgery avoided. At a willingness-to-pay (WTP) threshold of $5000 per surgery avoided, molecular testing is cost-effective with 63% certainty.

CONCLUSION

This cost-effectiveness analysis suggests utilizing Afirma for indeterminate solitary thyroid nodules is a cost-effective strategy for avoiding unnecessary thyroid surgery. With a $5000 WTP threshold, molecular testing has a 63% chance of being the more cost-effective strategy. The cost effectiveness varies based on the cost of the molecular test and the value of Afirma for patients with indeterminate thyroid nodules depends on the WTP threshold to avoid unnecessary thyroid surgery.

The Significance of RAS-Like Mutations and MicroRNA Profiling in Predicting Malignancy in Thyroid Biopsy Specimens

In cytologically indeterminate thyroid nodules undergoing molecular testing, estimated risk of malignancy is variable. Identification of a non-cancer-specific mutation (RAS-like) confirms a neoplastic process but does not differentiate between benign, malignant, and low-risk neoplasms. This study aims to retrospectively evaluate institutional experience of Interpace (ThyGeNEXT^® and ThyraMIR^®; Pittsburgh, PA) testing and to determine the rate of malignancy in resected nodules, stratified by mutational analysis and microRNA profile. Of 1917 fine need aspirations, 140 (7.3%) underwent Interpace testing: 47 (33.6%) were molecular-not-benign (harbored mutation, fusion, and/or positive miRNA) and 93 (66.4%) were molecular-benign (no mutations or fusions and negative microRNA). Surgery was spared in 79.6% of molecular-benign and 61.4% of all tested patients. Fifty-four (38.6%) underwent resection. Seventeen (89.5%) of the resected molecular-benign were benign and 2 were malignant. Thirteen (37.1%) of the resected molecular-not-benign were benign, 7 (20%) were noninvasive follicular thyroid neoplasm with papillary-like nuclear features (NIFTP), and 15 (42.9%) were malignant (p < 0.05, negative predictive value (NPV) 89.4-95.6%, positive predictive value (PPV) 22.3-42.8%). Most molecular-not-benign (72.3%) had RAS-like mutation. Twenty-three were resected: 3 were malignant and 7 were NIFTP. Nodules with non-RAS-like mutations (BRAF V600E-like, others) were more likely to be malignant than RAS-like (H/N/KRAS, BRAF K601E) (p < 0.05, NPV 86.9-96.5%, PPV 100%). Most nodules had RAS-like mutations and most were benign or low-risk neoplasms (NIFTP). This study supports the role of histologic examination in the distinction of malignancy in RAS-like thyroid neoplasms and underscores the role of molecular testing in risk stratification, patient counseling, and operative management.

The Effect Modification of Ultrasound Risk Classification on Molecular Testing in Predicting the Risk of Malignancy in Cytologically Indeterminate Thyroid Nodules

Background: Thyroid nodules with indeterminate cytology are increasingly subjected to molecular testing. We evaluated the diagnostic performances of Afirma Genomic Sequencing Classifier (GSC) and ThyroSeq v3 in thyroid nodules with high versus low/intermediate suspicion ultrasound classification. Methods: In this prospective cohort study, we analyzed all Bethesda III and IV thyroid nodules that underwent fine-needle aspiration biopsies in the University of California Los Angeles Health System from July 2017 to April 2020. All patients underwent molecular testing with Afirma GSC or ThyroSeq v3 as part of an institutional randomized trial (NCT02681328). Nodules were categorized according to the American Thyroid Association (ATA) ultrasound risk classification. The benign call rate and the positive predictive value of molecular testing were compared between ATA high suspicion versus all other categories. Results: A total of 343 patients with 375 indeterminate thyroid nodules were included. The malignancy rate in ATA high suspicion nodules was not significantly increased by a suspicious Afirma GSC result (77.8% for all ATA high suspicion nodules vs. 87.5% for nodules with ATA high suspicion and suspicious Afirma GSC results, positive likelihood ratio [LR] = 2.0, 95% confidence interval [CI 0.5-8.0], p = 1.0) or by a positive ThyroSeq v3 result (80.0% vs. 80.0%, positive LR = 1.0 [CI 1.0-1.0], p = 1.0). The rate of malignancy in ATA low/intermediate suspicion nodules increased from 21.0% to 56.3% with a suspicious Afirma GSC result (positive LR = 4.8 [CI 3.4-6.9], p < 0.0001) and decreased to 3.8% with a benign Afirma GSC result (negative LR = 0.1 [CI 0.07-0.3], p < 0.0001). Similarly, the rate of malignancy in ATA low/intermediate suspicion nodules increased from 24.3% to 66.7% with a positive ThyroSeq v3 result (positive LR = 6.2 [CI 4.0-9.7], p < 0.0001) and decreased to 2.1% with a negative ThyroSeq v3 result (negative LR = 0.07 [CI 0.02-0.3], p < 0.0001). Conclusions: Afirma GSC and ThyroSeq v3 performed well in ruling out malignancy in sonographically low/intermediate suspicion thyroid nodules but has limited diagnostic value in sonographically high suspicion nodules. Molecular testing can prognosticate more aggressive thyroid cancers, which can inform treatment decisions.

FDG-PET/CT in indeterminate thyroid nodules: cost-utility analysis alongside a randomised controlled trial

PURPOSE

To evaluate cost-effectiveness of an [¹⁸F]FDG-PET/CT-driven diagnostic workup as compared to diagnostic surgery, for thyroid nodules with Bethesda III/IV cytology. [¹⁸F]FDG-PET/CT avoids 40% of futile diagnostic surgeries for benign Bethesda III/IV nodules.

METHODS

Lifelong societal costs and quality-adjusted life years (QALYs) were assessed for 132 patients participating in a randomised controlled multicentre trial comparing [¹⁸F]FDG-PET/CT to diagnostic surgery. The observed 1-year trial results were extrapolated using a Markov model. The probability of cost-effectiveness was estimated using cost-effectiveness acceptability curves, taking uncertainty about sampling, imputation, and parameters into account.

RESULTS

The observed 1-year cost difference of [¹⁸F]FDG-PET/CT as compared to diagnostic surgery was - €1000 (95% CI: - €2100 to €0) for thyroid nodule-related care (p = 0.06). From the broader societal perspective, the 1-year difference in total societal costs was - €4500 (- €9200 to €150) (p = 0.06). Over the modelled lifelong period, the cost difference was - €9900 (- €23,100 to €3200) (p = 0.14). The difference in QALYs was 0.019 (- 0.045 to 0.083) at 1 year (p = 0.57) and 0.402 (- 0.581 to 1.385) over the lifelong period (p = 0.42). For a willingness to pay of €50,000 per QALY, an [¹⁸F]FDG-PET/CT-driven work-up was the cost-effective strategy with 84% certainty.

CONCLUSION

Following the observed reduction in diagnostic surgery, an [¹⁸F]FDG-PET/CT-driven diagnostic workup reduced the 1-year thyroid nodule-related and societal costs while sustaining quality of life. It is very likely cost-effective as compared to diagnostic surgery for Bethesda III/IV nodules.

TRIAL REGISTRATION NUMBER

This trial is registered with ClinicalTrials.gov: NCT02208544 (5 August 2014), https://clinicaltrials.gov/ct2/show/NCT02208544 .

Molecular Characterization of Thyroid Follicular Lesions in the Era of "Next-Generation" Techniques

It is unequivocally recognized that thyroid nodules are frequently detected in the adult population and mostly characterized by benign lesions (up to 70% of them), with only 5%-15% malignant lesions. The evaluation of thyroid lesions with fine-needle aspiration cytology (FNAC) represents one of the first and most useful diagnostic tools in the definition of their nature. Despite the fact that the majority of thyroid lesions are correctly diagnosed as either benign (70%-75%) or malignant (5%-10%) entities, the remaining nodules (20%-25%) represent the "gray zone" of follicular lesions, which belong to indeterminate categories, according to the different classification systems. This indeterminate group of lesions includes both benign and malignant entities, which cannot be easily discriminate with morphology alone. In these last decades, the increasing role of molecular testings, feasibly performed on cytological material combined with the discoveries of specific genetic alterations in the field of thyroid pathology, has opened the pace to their more accurate and specific contribution on cytology. In fact, in 2015, in the revised management guidelines for patients with thyroid nodules and well-differentiated thyroid cancers (WDTCs), the American Thyroid Association (ATA) confirmed the performance of molecular testing in thyroid indeterminate cytology, and the same performance was addressed in recent update of the management of thyroid nodules in the second edition of the Bethesda system for reporting thyroid cytopathology (TBSRTC). In the current review, we discuss the role of molecular tests for the different thyroid diagnostic categories of the Bethesda system for reporting thyroid cytopathology, mostly focusing our attention on the follicular and indeterminate lesions.

Thyroid nodules >4 cm with atypia of undetermined significance cytology independently associate with malignant pathology

BACKGROUND

The risk of malignancy from nodules with atypia of undetermined significance cytology is estimated between 5% and 15%, though more recent studies suggest rates upwards of 48%. This study sought to characterize preoperative predictors of malignancy to aid in clinical decision-making.

METHODS

We performed a single institution retrospective review of all adult patients with unilateral thyroid nodules demonstrating atypia of undetermined significance cytology between March 1, 2013 and June 1, 2019 who underwent surgical resection (n = 266). Univariate and multivariate logistical analysis was performed using clinical and demographic variables to identify potential preoperative characteristics associated with malignant disease.

RESULTS

Malignancy was identified on final pathology in 24.7% of patients with atypia of undetermined significance cytology. Age, sex, exposure to ionizing radiation, family history of thyroid cancer, Hashimoto's disease, Afirma suspicious results, and smoking were not associated with malignancy on both univariate and multivariate analysis. Nodule size >4 cm was independently associated with malignancy risk on both univariate (odds ratio 2.44, 1.09-5.43, P < .03) and multivariate (odds ratio 2.96, 1.27-6.87, P < .02) analysis.

CONCLUSION

The results of this study demonstrate that nodules with atypia of undetermined significance cytology >4 cm are strongly associated with malignancy. We recommend strong consideration of surgery for all patients with thyroid nodules >4 cm and atypia of undetermined significance cytology.

Cost analysis of reflexive versus selective molecular testing for indeterminate thyroid nodules

BACKGROUND

Molecular testing is now commonly used to refine the diagnosis of indeterminate thyroid nodules. The purpose of this study is to compare the costs of a reflexive molecular testing strategy to a selective testing strategy for indeterminate thyroid nodules.

METHODS

A Markov model was constructed to estimate the annual cost of diagnosis and treatment of a real-world cohort of patients with cytologically indeterminate thyroid nodules, comparing a reflexive testing strategy to a selective testing strategy. Model variables were abstracted from institutional clinical trial data, literature review, and the Medicare physician fee schedule.

RESULTS

The average cost per patient in the reflexive testing strategy was $8,045, compared with $6,090 in the selective testing strategy. In 10,000 Monte Carlo simulations, diagnostic thyroid lobectomy for benign nodules was performed in 2,440 patients in the reflexive testing arm, compared with 3,389 patients in the selective testing arm, and unintentional observation for malignant nodules occurred in 479 patients in the reflexive testing arm, compared with 772 patients in the selective testing arm. The cost of molecular testing had the greatest impact on overall costs, with $1,050 representing the cost below which the reflexive testing strategy was cost saving compared with the selective testing strategy.

CONCLUSION

In this cost-modeling study, reflexive molecular testing for indeterminate thyroid nodules enabled patients to avoid unnecessary thyroid lobectomy at an estimated cost of $20,600 per surgery avoided.

Practice of thyroid nodule management in the Gulf Cooperation Council countries

OBJECTIVES

To assessed the current practices for the management of thyroid nodules in the Gulf Cooperation Council (GCC) countries. Methods: We conducted a descriptive web-based survey to physicians and surgeons involved in the management of thyroid nodules. The survey included questions on referral, ultrasound (US) reporting, fine needle aspiration (FNA), management of thyroid nodules including the approach for indeterminate FNA results, and usage of molecular testing. Results: A total of 311 responders, 155 (49.8%) were endocrinologists. Results showed that referrals and US report lack a number of valuable information including family history (84.9%) and high-risk US features (92.9%). Approximately 263 (84.6%) preferred to include a scoring system or protocol to assess the nodule risk in US report. Approximately 193 (62.1%) sent the patient to interventional radiologists for FNA. Almost half (n=147, 47.3%) repeat the FNA in 2-3 months if the FNA result was a follicular lesion or atypia of undetermined significance and 142 (45.7%) opted for lobectomy for follicular neoplasm or suspicious of follicular neoplasm result. Only 44 (14.1%) performed molecular testing; however, 174 (55.9%) preferred it available. Significant variations in the approach were seen between endocrinologists versus non-endocrinologists. Conclusion: Practices variation in the management of thyroid nodules mandate a common practical guideline. Molecular testing is a preferable test for indeterminate FNA results by most of the responders though it is not widely available.

Differentiated Thyroid Cancer: A Health Economic Review

Simple Summary

This review reflects on health economic considerations associated with the increasing diagnosis and treatment of differentiated thyroid cancer. Analysis of different relevant health economic topics, such as overdiagnosis, overtreatment, surgical costs, and costs of follow-up are being addressed. Several unanswered research questions such as optimising molecular markers for diagnosis, active surveillance of primary tumours, and improved risk stratification and survivorship care all influence future healthcare expenditures.

Abstract

The incidence of differentiated thyroid cancer (DTC) is rising, mainly because of an increased detection of asymptomatic thyroid nodularity revealed by the liberal use of thyroid ultrasound. This review aims to reflect on the health economic considerations associated with the increasing diagnosis and treatment of DTC. Overdiagnosis and the resulting overtreatment have led to more surgical procedures, increasing health care and patients’ costs, and a large pool of community-dwelling thyroid cancer follow-up patients. Additionally, the cost of thyroid surgery seems to increase year on year even when inflation is taken into account. The increased healthcare costs and spending have placed significant pressure to identify potential factors associated with these increased costs. Some truly ground-breaking work in health economics has been undertaken, but more cost-effectiveness studies and micro-cost analyses are required to evaluate expenses and guide future solutions.

Economic evaluations of big data analytics for clinical decision-making: a scoping review

OBJECTIVE

Much has been invested in big data analytics to improve health and reduce costs. However, it is unknown whether these investments have achieved the desired goals. We performed a scoping review to determine the health and economic impact of big data analytics for clinical decision-making.

MATERIALS AND METHODS

We searched Medline, Embase, Web of Science and the National Health Services Economic Evaluations Database for relevant articles. We included peer-reviewed papers that report the health economic impact of analytics that assist clinical decision-making. We extracted the economic methods and estimated impact and also assessed the quality of the methods used. In addition, we estimated how many studies assessed "big data analytics" based on a broad definition of this term.

RESULTS

The search yielded 12 133 papers but only 71 studies fulfilled all eligibility criteria. Only a few papers were full economic evaluations; many were performed during development. Papers frequently reported savings for healthcare payers but only 20% also included costs of analytics. Twenty studies examined "big data analytics" and only 7 reported both cost-savings and better outcomes.

DISCUSSION

The promised potential of big data is not yet reflected in the literature, partly since only a few full and properly performed economic evaluations have been published. This and the lack of a clear definition of "big data" limit policy makers and healthcare professionals from determining which big data initiatives are worth implementing.

Thyroid and Molecular Testing. Advances in Thyroid Molecular Cytopathology

Thyroid nodules are a common finding in the adult population including the fact that more than 50% of individuals, over the age of 60, have thyroid nodules. The majority have been mostly detected with ultrasonography and 10% by palpation. The majority of these nodules are benign, whereas 5–15% of them are malignant. The pre-operative diagnosis of cancer is a critical challenge in order to ensure that each patient can be treated with the best tailored management with a reduction of unnecessary surgery for benign lesions. Fine needle aspiration cytology (FNAC) represents the first and most important diagnostic tool for the evaluation of thyroid lesions. According to the literature, FNAC is able to render a conclusive diagnosis in up to 70–80% of all cases. For the remaining 20–30% of nodules, cytological diagnoses fall into the category of indeterminate lesions mostly due to the lack of specific morphological features. According to the Bethesda system for reporting thyroid cytopathology (TBSRTC), indeterminate lesions can be sub-stratified into three different subcategories including “atypia of undetermined significance/follicular lesion of undetermined significance-AUS/FLUS”; “follicular or Hürthle cell neoplasm/suspicious for follicular or Hürthle cell neoplasm-FN/SFN”; and “suspicious for malignancy-SFM”. Many of these indeterminate lesions undergo repetition or diagnostic lobectomy. Nonetheless, the majority of these cases will have a benign diagnosis due to the fact that the rate of cancer ranges between 6 and 30%. It stands to reason that the application of ancillary technique, mostly molecular testing, emerged as a critical additional tool for those thyroid indeterminate lesions. Since the early 1990s, material collected from cytological samples yields sufficient and adequate cells for the detection of point mutation or gene fusions. Nonetheless, the further availability of new sequencing technologies such as next-generation sequencing (NGS) has led to more comprehensive molecular applications adopted now in clinical use. The current review investigates the multiple advances in the field of molecular testing applied in thyroid cytology.

Selective use of Molecular Testing Based on Sonographic Features of Cytologically Indeterminate Thyroid Nodules: A Decision Analysis

BACKGROUND

Molecular diagnostics can allow some patients with indeterminate thyroid nodule cytopathology to avoid diagnostic hemithyroidectomy; however, the testing is costly. We hypothesized that molecular testing with the intention of preventing unnecessary diagnostic hemithyroidectomy would be cost-effective if this test was applied selectively based on sonographic risk of malignancy.

METHODS

A Markov model was constructed depicting a 40-year-old patient with a cytologically indeterminate thyroid nodule. Molecular testing of fine needle aspiration material was compared to a strategy of immediate diagnostic hemithyroidectomy. Data from a single tertiary-referral health system were reviewed to estimate the outcomes of molecular testing of indeterminate nodules stratified by the American Thyroid Association sonographic classification system. Other outcome probabilities and their utilities were derived from literature review. Costs were estimated with Medicare reimbursement data. A $100,000/QALY threshold for cost-effectiveness was applied. Sensitivity analysis was employed to examine uncertainty in the model's assumptions.

RESULTS

Of 123 patients who underwent molecular testing for indeterminate cytology, 12 (9.8%) were classified as high sonographic suspicion, 49 (40%) were intermediate suspicion, and 62 (50%) were low or very low suspicion. Molecular testing was only cost-effective when the pretest probability of a negative test was greater than 31%. The model was most sensitive to the cost of molecular testing and the quality adjustment factor for hypothyroidism.

CONCLUSIONS

In hypothetical modeling, molecular testing is only cost-effective for cytologically indeterminate thyroid nodules with sonographic features that are intermediate or low suspicion for malignancy. In nodules with high sonographic suspicion, molecular testing is rarely negative and appears to add minimal value.

ThyroSeq v2 Testing: Impact on Cytologic Diagnosis, Management, and Cost of Care in Patients with Thyroid Nodule

Background: Novel molecular tests (MTs), such as ThyroSeq, may improve the management of thyroid nodules with indeterminate cytologic diagnoses; however, the impact of these tests on cost and outcome of management is unknown. Here, we evaluated the impact of ThyroSeq testing on the cytopathologic diagnosis, management, and cost of care in patients with thyroid nodules. Methods: In a retrospective study, using actual patient cohorts, the outcome and cost of management of patients with thyroid nodules seen before the introduction of ThyroSeq v2 at our institution (standard of care [StC] cohort) were compared with those seen after the introduction of this test (MT cohort). Results: A total of 773 consecutive patients entered the study (393 StC, 380 MT). The incidence of cytologically benign nodules decreased from 71.0% (StC) to 53.2% (MT) and those of atypia of undetermined significance/follicular lesion of undetermined significance (AUS/FLUS) and follicular neoplasm/suspicious for follicular neoplasm (FN/SFN) increased from 8.9% (StC) to 21.3% (MT) and from 3.1% (StC) to 6.3% (MT), respectively. The overall rate of surgery did not change significantly (23.4% in StC vs. 23.2% in MT). Among patients who underwent surgery, the rate of overtreatment (surgeries performed on histologic benign nodules without clinical indication: compressive symptoms, hyperthyroidism resistant to medication, and nodule size >4 cm) slightly decreased from 18.8% (StC) to 16.7% (MT). The rate of malignancy decreased from 45.5% (StC) to 37.9% (MT) in AUS/FLUS and increased from 40.0% to 53.8% in FN/SFN. However, the overall rate of malignancy remained equal (47.8% in StC vs. 47.7% in MT). The average cost of care per patient in the AUS/FLUS and FN/SFN categories increased from $6,566 (StC) to $8,444 (MT) and from $9,313 (StC) to $10,253 (MT), respectively. Similarly, the overall average cost of care of a patient who underwent thyroid fine-needle aspiration increased from $3,088 (StC) to $4,282 (MT). Finally, the average cost per thyroid cancer detected increased from $26,312 (StC) to $38,746 (MT). Conclusions: Introduction of ThyroSeq v2 resulted in a shift toward indeterminate cytology results. The institutional rate of surgery, overtreatment, and malignancy did not change significantly. Lack of decrease in the rate of surgery along with the additional cost of ThyroSeq v2 increased the overall cost of care of patients including those with indeterminate cytology results.

Molecular testing in diagnosis of indeterminate thyroid cytology: Trends and drivers

Fine needle aspiration (FNA), the cornerstone of diagnosis in thyroid swellings, fails to render a definitive diagnosis in about 20% to 30% of cases that are reported as indeterminate on cytology. Since the clinical management in thyroid rests on the risk of malignancy (ROM) in a given nodule, this distinction between "benign" and "possibly malignant" assumes paramount clinical importance. Over the last two decades, tremendous progress has been achieved in our understanding of the molecular basis of thyroid pathologies leading to identification of several genetic alterations that could potentially be exploited for diagnostic, prognostic and therapeutic purposes. An array of molecular tests has hit the markets aiming to predict the ROM in thyroid nodules. A deeper understanding of the strengths and limitations of these tests is imperative to be able to judiciously choose the right molecular test in a given case for maximum clinical benefit. This narrative review provides an overview of current status of molecular testing in the evaluation of thyroid nodules encompassing the current status and applications of these tests in diagnostic, prognostic and therapeutic areas along with a brief insight into the future developments in this field.

miRNA expression can classify pediatric thyroid lesions and increases the diagnostic yield of mutation testing

BACKGROUND

Genetic alterations in multiple cell signaling pathways are involved in the molecular pathogenesis of thyroid cancer. Oncogene mutation testing and gene-expression profiling are routinely used for the preoperative risk management of adult thyroid nodules. In this study, we evaluated the potential value of miRNA biomarkers for the classification of pediatric thyroid lesions.

PROCEDURE

Double-blind case-control study with 113 resected pediatric lesions: 66 malignant and 47 benign. Quantitative and qualitative molecular data generated with a 10-miRNA expression panel (ThyraMIR) and a next-generation sequencing oncogene panel (ThyGeNEXT) were compared with clinicopathological parameters.

RESULTS

miRNAs were differentially expressed in benign versus malignant tumors with distinct expression patterns in different histopathology categories. The 10-miRNA classifier identified 39 (59%) malignant lesions with 100% specificity. A positive classifier score was associated with lymph node metastasis, extrathyroidal extension and intrathyroidal spread. Genetic alterations associated with increased risk for malignancy were detected in 35 (53%) malignant cases, 20 positive for point mutations in BRAF, HRAS, KRAS, NRAS, PIK3CA, or TERT and 15 positive for gene rearrangements involving ALK, NTRK3, PPARG, or RET. The 10-miRNA classifier correctly identified 11 mutation-negative malignant cases. The performance of the combined molecular test was 70% sensitivity and 96% specificity with an area under the curve of 0.924.

CONCLUSIONS

These data suggest that the regulatory miRNA pathways underlying thyroid tumorigenesis are similar in adults and children. miRNA expression can identify malignant lesions with high specificity, augment the diagnostic yield of mutation testing, and improve the molecular classification of pediatric thyroid nodules.

Comparison of 18F-FDG-PET and 18F-FDG-PET/CT for the diagnostic performance in thyroid nodules with indeterminate cytology: A meta-analysis

BACKGROUNDS

We performed a meta-analysis to compare F-FDG-PET and F-FDG-PET/CT for the diagnostic performance in thyroid nodules with indeterminate cytology by Bethesda classification.

METHODS

PubMed and Embase databases were searched for eligible studies from the earliest available date of indexing through September 2019. Only studies with clearly stated histopathology confirmation were included. Publication bias was assessed by Deeks funnel plot. The pooled sensitivity, specificity, positive likelihood ratio, negative likelihood ratio, positive predictive value, negative predictive value, and diagnostic odds ratio was determined by random-effect analysis, respectively. All diagnostic estimate indexes were determined separately for PET alone and PET/CT and were compared pair-wisely using Z-test.

RESULTS

We included 214 patients from five PET alone studies and 420 patients from 8 PET/CT studies in this meta-analysis. The range of the prevalence of malignancy was 11% to 27% for PET alone studies (Median, 20%) and 4% to 50% for PET/CT studies (Median, 24%). The sensitivity (0.95 vs 0.73, P < .01), negative likelihood ratio (0.20 vs 0.53, P = .04) and negative predictive value (0.99 vs 0.91, P < .01) of PET alone are significantly better than those of PET/CT. For PET/CT, Fagan nomogram indicated that when the pre-test probability was set at 24%, the negative post-test probability could decrease to 12%.

CONCLUSION

This meta-analysis reveals that in evaluating thyroid nodules with indeterminate cytology by Bethesda classification, the rule-out performance of F-FDG-PET is significantly better than F-FDG-PET/CT, although the latter represents a more objective and accurate technique. We hypothesize that the lack of precise localization of suspicious FDG uptake in the neck region may have contributed to this overvaluation for PET alone studies, and advocate that future studies be performed with PET/CT rather than PET alone to avoid misinterpretation and overvaluation in this scenario.

Thyroid Nodule Molecular Testing: Is It Ready for Prime Time?

Cytologically indeterminate thyroid nodules remain a diagnostic and clinical challenge, and molecular testing has been advocated and advanced as a diagnostic modality to help guide treatment. While studies have expounded on the improved diagnostic certainty with these tests, data demonstrating meaningful clinical impact and supporting their routine use is still limited at best. In this review, we discuss the limitations regarding diagnostic accuracy, impact on surgical decision-making and outcomes, and cost-effectiveness of molecular testing. By highlighting the limitations of these tests, we aim to promote more thoughtful utilization of these tools in the management of thyroid nodules going forward.

Quantifying the differences in surgical management of patients with definitive and indeterminate thyroid nodule cytology

INTRODUCTION

Thyroid nodules are increasingly common. Despite being an essential pre-operative diagnostic tool, up to 30% of fine needle aspirate cytology (FNAC) yields a non-definitive diagnosis. This study aimed to quantify differences in surgical management of patients with definitive and indeterminate thyroid nodule cytology, and determine if clinical factors can improve cytological diagnosis.

MATERIALS AND METHODS

Patients who underwent thyroidectomy for nodules from 2001 to 2015 were recruited. Those with benign and malignant preoperative cytology were included in the "definitive diagnosis" (DC) group; patients with all other preoperative cytology results were included in the "indeterminate diagnosis" (IC) group. We compared demographics and procedures between these groups. Clinical factors and demographics were also compared between patients with benign and malignant histology in the IC group.

RESULTS

A total of 3821 cases were included. A significantly larger proportion of the IC patients had a hemithyroidectomy (IC 69% vs. DC 39%, p < 0.001) initially, and also had a significantly higher rate of two-stage surgery compared to the DC group (IC 17% vs. DC 11%, p < 0.001). Patients in the DC group were twice as likely to undergo concurrent central lymph node dissection for papillary and medullary cancers than the IC group (p < 0.001). Overall, up to 60% of IC patients had been over- or under-treated at initial surgery. The clinical factors examined were not significantly associated with higher risk of malignancy in IC patients.

CONCLUSION

This study highlights the potential for improved preoperative diagnosis to streamline decision making for surgical management of patients with thyroid nodules.

Molecular Testing Versus Diagnostic Lobectomy in Bethesda III/IV Thyroid Nodules: A Cost-Effectiveness Analysis

Background: Molecular tests (MT) using gene expression and/or mutational analysis have been developed to reduce the need for diagnostic surgery for indeterminate (Bethesda III/IV) thyroid nodules. Prior cost-effectiveness studies have shown mixed results but none has included the recent and more comprehensive versions of the two commonly utilized MT. The aim of this study is to compare the cost-effectiveness of diagnostic lobectomy (DL), the Afirma Gene Sequencing Classifier (GSC), and ThyroSeq version 3 (TSv3). Methods: A decision tree from the payer perspective was created using a base case of a 40-year-old euthyroid woman with a solitary 2 cm Bethesda III or IV thyroid nodule. In this model, all patients in the DL arm had lobectomy, which was also performed for patients with positive MT, while those with negative MT underwent 20 years of surveillance. The outcome was a correct diagnosis, defined as malignant histology after DL or 20 years of nodule stability after negative MT. Costs were obtained from the Centers for Medicare & Medicaid Services (CMS) data and existing literature, and probabilities were obtained from the literature. Sensitivity analysis was performed for costs, pretest probability of malignancy, and performance parameters. Results: The cost per correct diagnosis was $14,277 for TSv3, $17,873 for GSC, and $38,408 for DL. TSv3 was preferred over both GSC and DL. One-way sensitivity analysis between TSv3 and GSC demonstrated that the results were robust to variations in cost, cancer prevalence, and length of surveillance. In the two-way sensitivity analysis, TSv3 was preferred over GSC at all considered test costs, and in probabilistic sensitivity analysis, TSv3 was the preferred management strategy in 68.5% of cases. Conclusions: In hypothetical modeling to determine whether surgery versus MT is optimal for indeterminate (Bethesda III/IV) nodules, either of the major MT was considerably more cost-effective than DL, although TSv3 was more likely to be cost-effective than GSC. Use of either MT adjunct should be strongly considered in the absence of other indications for thyroidectomy.

Clinical impact of testing for mutations and microRNAs in thyroid nodules

Background

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

Methods

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

Results

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

Conclusion

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

INITIAL ADOPTION OF RECOMBINANT HUMAN THYROID-STIMULATING HORMONE FOLLOWING THYROIDECTOMY IN THE MEDICARE THYROID CANCER PATIENT POPULATION

OBJECTIVE

Recombinant human thyroid-stimulating hormone (rhTSH) has been approved for diagnostic (1998) and therapeutic (2008) indications in conjunction with radioactive iodine (RAI) administration post-thyroidectomy. Potential benefits of rhTSH, including avoidance of hypothyroidism side effects and shorter, less costly hospital stays, have not been assessed at the population level within the United States. In this study we quantify utilization, outcomes, and associated costs of rhTSH within the nationally representative Surveillance, Epidemiology, and End Results (SEER)-Medicare patient population.

METHODS

We conducted a retrospective analysis of beneficiaries aged >65 years diagnosed within the SEER-Medicare data with differentiated thyroid cancer. Endpoints examined included ( 1) rhTSH utilization in the 2 years post-thyroidectomy (patients diagnosed 1996-2011 [utilization cohort]) and ( 2) comparison of resource utilization and costs as a function of rhTSH receipt in the 30 days prior to and 1 year following therapeutic RAI administration (patients diagnosed 2008-2011 [resource use cohort]). All costs were adjusted to reflect 2013 dollars.

RESULTS

A total of 6,482 patients met inclusion criteria, of which, 1,363 (21.0%) received rhTSH. Receipt varied by region and was higher in the South (18%), Northeast (28%), and West (44%) compared to the Midwest (10%), and lower in census tracts in the bottom quartile of high school education rates (odds ratio 0.68, 95% confidence interval [CI] 0.55-0.83). rhTSH receipt was not associated with patient sex, age, comorbidities, or stage. Post-therapeutic RAI, 1,444 patients were assessed for resource utilization (2008-2011). The average cost of rhTSH was $905 per patient, with $2,483 being spent on average among patients who received rhTSH in association with therapeutic RAI. rhTSH receipt was not significantly associated with total inpatient days or number of outpatient and emergency department visits. Multivariable analyses showed similar overall costs among patients who did versus did not receive rhTSH (cost ratio [CR] 0.96, 95% CI 0.86-1.09), partially due to increased mean outpatient costs ($5,213 vs. $4,190) being offset by lower inpatient costs ($3,493 vs. $6,143). Overall costs were significantly higher in multivariable analyses among patients with distant metastatic disease (CR 1.92, 95% CI 1.58-2.32) and multiple comorbidities (CR 2.15, 95% CI 1.83-2.53).

CONCLUSION

rhTSH recipients had higher outpatient, lower inpatient, and similar total Medicare payments as those not receiving rhTSH in conjunction with RAI, lending support to the use of rhTSH as a cost-neutral treatment option from the payer perspective.

ABBREVIATIONS

CI = confidence interval; CMS = Centers for Medicare & Medicaid Services; CR = cost ratio; HCPCS = Healthcare Common Procedure Coding System; IQR = interquartile range; mCi = millicurie; OR = odds ratio; PET = positron emission tomography; RAI = radioactive iodine; rhTSH = recombinant human thyroid-stimulating hormone; RR = risk ratio; SEER = Surveillance, Epidemiology, and End Results.

ThyroSeq®V2.0 Molecular Testing: A Cost-Effective Approach for the Evaluation of Indeterminate Thyroid Nodules

OBJECTIVE

Approximately 15 to 30% of thyroid nodules have indeterminate cytology. Many of these nodules are treated surgically, but only 5 to 30% are malignant. Molecular testing can further narrow the risk of malignancy of these nodules. Our objective was to assess the cost effectiveness of ThyroSeq^®V2.0 compared to diagnostic thyroidectomy for the evaluation of indeterminate nodules.

METHODS

Cytology and histopathology slides of Bethesda category III and IV (suspicious for follicular neoplasia [SFN]) nodules obtained between January 1, 2014 and November 30, 2016 were re-reviewed by 2 endocrine cytopathologists. Costs for a diagnostic approach using ThyroSeq^® were calculated and compared to those of diagnostic thyroidectomy.

RESULTS

We included 8 Bethesda category III nodules that underwent ThyroSeq^® and 8 that underwent diagnostic surgery. Of those submitted for ThyroSeq^®, 4 were positive for mutations and underwent thyroid surgery. The average cost per nodule evaluated was $14,669 using ThyroSeq^®, compared to $23,338 for diagnostic thyroid surgery. The cost per thyroid cancer case detected was $58,674 using ThyroSeq^® compared to $62,233 for diagnostic thyroid surgery. We included 13 nodules Bethesda category IV that underwent ThyroSeq^® and 11 that underwent diagnostic surgery. Of those submitted for ThyroSeq^®, 6 were positive for mutation and underwent thyroid surgery. The average costs per nodule evaluated were $14,641 using ThyroSeq^® and $24,345 using diagnostic thyroidectomy. The cost per thyroid cancer case detected was $31,721 when using ThyroSeq^® compared to $53,560 for diagnostic thyroidectomy.

CONCLUSION

The use of ThyroSeq® in our institution is cost effective compared to diagnostic thyroid surgery for the evaluation of Bethesda categories III and IV (SFN) nodules.

ABBREVIATIONS

FNA = fine-needle aspiration; GEC = gene expression classifier; NIFTP = noninvasive follicular thyroid neoplasm with papillary-like nuclear features; PTC = papillary thyroid cancer; SFN = suspicious for follicular neoplasia.

Outcomes of Bethesda categories III and IV thyroid nodules over 5 years and performance of the Afirma gene expression classifier: A single-institution study

OBJECTIVE

The second edition Bethesda System for Reporting Thyroid Cytology estimates 6%-18% malignancy rate of category III (B3) and 10%-40% for category IV (B4) nodules; however, reported malignancy rates have considerable variability among institutions. Use of molecular classifiers (including Afirma Gene Expression Classifier, GEC) can be utilized in management of thyroid nodules. Our objective was to analyse malignancy rates of B3 and B4 nodules and determine clinical outcomes of GEC Benign nodules.

METHODS

A retrospective analysis of 2019 thyroid FNAs was performed at the University of Colorado from 2011 to 2015, including molecular, surgical and clinical follow-up.

RESULTS

Of 2019 FNAs analysed, 231 (11.4%) were diagnosed as B3 and 80 (4.0%) as B4. GEC was obtained in 54.1% of B3 cases, with nearly half (48.8%) having a Benign result. Surgery was performed in 40.7% B3 cases with a 24.5% malignancy rate, ranging 8%-38% by year. In the B4 group, 52.5% underwent molecular testing with 28.6% as GEC Benign. About 68.8% of B4 cases underwent surgery with a 20% malignancy rate, ranging 0%-42% by year. Seventy-three GEC Benign cases were reviewed: 5 (6.8%) underwent surgery, with none demonstrating malignancy in the target nodule. Size remained stable for most GEC Benign nodules: 75.9% (B3) and 71.4% (B4) with no malignancy on repeat FNA.

CONCLUSIONS

Our 5-year review demonstrated that malignancy rates of B3 and B4 nodules showed year-to-year variability. We suggest that clinicians use a multi-year average of their institution's malignancy rates to optimally manage patients. Follow-up for GEC Benign cases thus far supports their indolent nature.

Non-invasive follicular thyroid neoplasm with papillary-like nuclear features (NIFTP): impact on the reclassification of thyroid nodules

The 2017 edition of the WHO book on Classification of Tumours of Endocrine Organs includes a new section entitled 'Other encapsulated follicular-patterned thyroid tumours', in which the newly created NIFTP (non-invasive follicular thyroid neoplasm with papillary-like nuclear features) is identified and described in detail. Despite deleting the word 'carcinoma' from its name, NIFTP is not a benign tumor either and is best regarded as a neoplasm with 'very low malignant potential'. The main goal of the introduction of NIFTP category is to prevent overdiagnosis and overtreatment. Sampling constraints, especially when dealing with heterogeneous and/or large nodules, and difficulties in the invasiveness evaluation, are the major weaknesses of the histological characterization of NIFTP. At the cytological level, NIFTP can be separated from classic papillary carcinoma (cPTC) but not from encapsulated, invasive follicular variant PTC. The impact of NIFTP individualization for cytopathology is the drop of rates of malignancy for each Bethesda category in general and for indeterminate categories in particular. The biggest impact will be seen in institutions with a high frequency of FVPTC. The introduction of NIFTP has changed the utility of predictive values of molecular tests because RAS mutations and PAX8-PPARg rearrangements are frequently detected in NIFTP. This turns less promising the application of mutation detection panels as indicators of malignancy and will probably contribute to switch to a rule-out approach of molecular testing. Selection for surgery will go on being determined by a combined detection of clinical, cytological and ultrasound suspicious features.

Diagnostic Utility of Molecular and Imaging Biomarkers in Cytological Indeterminate Thyroid Nodules

Indeterminate thyroid cytology (Bethesda III and IV) corresponds to follicular-patterned benign and malignant lesions, which are particularly difficult to differentiate on cytology alone. As ~25% of these nodules harbor malignancy, diagnostic hemithyroidectomy is still custom. However, advanced preoperative diagnostics are rapidly evolving.This review provides an overview of additional molecular and imaging diagnostics for indeterminate thyroid nodules in a preoperative clinical setting, including considerations regarding cost-effectiveness, availability, and feasibility of combining techniques. Addressed diagnostics include gene mutation analysis, microRNA, immunocytochemistry, ultrasonography, elastosonography, computed tomography, sestamibi scintigraphy, [18F]-2-fluoro-2-deoxy-d-glucose positron emission tomography (FDG-PET), and diffusion-weighted magnetic resonance imaging.The best rule-out tests for malignancy were the Afirma® gene expression classifier and FDG-PET. The most accurate rule-in test was sole BRAF mutation analysis. No diagnostic had both near-perfect sensitivity and specificity, and estimated cost-effectiveness. Molecular techniques are rapidly advancing. However, given the currently available techniques, a multimodality stepwise approach likely offers the most accurate diagnosis, sequentially applying one sensitive rule-out test and one specific rule-in test. Geographical variations in cytology (e.g., Hürthle cell neoplasms) and tumor genetics strongly influence local test performance and clinical utility. Multidisciplinary collaboration and implementation studies can aid the local decision for one or more eligible diagnostics.

Preoperative Molecular Markers in Thyroid Nodules

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

Thyroid hormone regulates hematopoiesis via the TR-KLF9 axis

Congenital hypothyroidism (CH) is one of the most prevalent endocrine diseases, for which the underlying mechanisms remain unknown; it is often accompanied by anemia and immunodeficiency in patients. Here, we created a severe CH model together with anemia and T lymphopenia to mimic the clinical features of hypothyroid patients by ethylnitrosourea (ENU) mutagenesis in Bama miniature pigs. A novel recessive c.1226A>G transition of the dual oxidase 2 (DUOX2) gene was identified as the causative mutation. This mutation hindered the production of hydrogen peroxide (H₂O₂) and thus contributed to thyroid hormone (TH) synthesis failure. Transcriptome sequencing analysis of the thymuses showed that Krüppel-like factor 9 (KLF9) was predominantly downregulated in hypothyroid mutants. KLF9 was verified to be directly regulated by TH in a TH receptor (TR)-dependent manner both in vivo and in vitro. Furthermore, knockdown of klf9 in zebrafish embryos impaired hematopoietic development including erythroid maturation and T lymphopoiesis. Our findings suggest that the TR-KLF9 axis is responsible for the hematopoietic dysfunction and might be exploited for the development of novel therapeutic interventions for thyroid diseases.

Cost-effectiveness of Gene Expression Classifier Testing of Indeterminate Thyroid Nodules Utilizing a Real Cohort Comparator

Objective

To predict the cost-effectiveness of implementing routine gene expression classifier testing for thyroid nodules with indeterminate fine-needle aspiration cytology, by utilizing a real cohort of patients as a comparator.

Study Design

Cost-effectiveness analysis of a retrospective cohort compared with a simulated cohort.

Setting

Tertiary academic medical center.

Subjects and Methods

We reviewed the records of all patients who underwent ultrasound-guided fine-needle aspiration from 2010 to 2014 at a tertiary academic medical center. All patients with Bethesda class III or IV cytopathology had the details of their management catalogued over the subsequent 2 years of care. These patients were assigned to the standard-of-care arm of the study. We compared the third-party payer costs of care and the proportion of patients who underwent surgery with a simulated cohort who underwent gene expression classifier testing after an initial indeterminate fine-needle aspiration (molecular test arm).

Results

The cost of managing 1 nodule over 2 years was $2399 higher (range, $397-$4399) for the molecular test group than the standard of care group. The molecular test group had a 13.1% decrease (base parameters; range, 0.73%-45.09%) in the number of patients undergoing surgery.

Conclusion

When applied to a real cohort of patients, routine gene expression classifier is predicted to reduce the number of patients undergoing surgery but will increase cost of care. Cost-effectiveness is heavily dependent on prevalence of malignancy and gene expression classifier specificity.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Molecular profiling of thyroid nodule fine-needle aspiration cytology

The differential diagnosis and malignancy risk stratification of thyroid nodules requires multidisciplinary expertise and knowledge of both local ultrasonography practices and the local malignancy rates for a given fine-needle aspiration (FNA) result. Even in such a multidisciplinary setting, FNA cytology has the inherent limitation that indeterminate cytology results cannot distinguish between follicular adenomas, follicular thyroid carcinomas or follicular variant papillary thyroid carcinomas. Accumulating evidence suggests that this limitation can be overcome by using molecular diagnostic approaches. In this Review, we present the advantages and disadvantages of the different molecular diagnostic methodologies, which can be divided into two approaches: those that 'rule out' malignancy (to reduce the overtreatment of benign nodules) and those that 'rule in' malignancy (to optimize surgical planning). We identify microRNA classifiers as potential additional markers for use in a two-step diagnostic approach, consider the potential implications of the reclassification of noninvasive encapsulated follicular variant papillary thyroid carcinomas to noninvasive follicular thyroid neoplasms with papillary-like nuclear features and discuss the cost-effectiveness of molecular testing. Molecular FNA diagnostics is an important complementary addition to FNA cytology that could substantially reduce unnecessary surgery and better define the need for appropriate surgery in patients who have thyroid nodules with indeterminate FNA cytology.

Cost-Effectiveness of a Bronchial Genomic Classifier for the Diagnostic Evaluation of Lung Cancer

INTRODUCTION

The use of a bronchial genomic classifier has been shown to improve the diagnostic accuracy of bronchoscopy for suspected lung cancer by identifying patients who may be more suitable for radiographic surveillance as opposed to invasive procedures. Our objective was to assess the cost-effectiveness of bronchoscopy plus a genomic classifier versus bronchoscopy alone in the diagnostic work-up of patients at intermediate risk for lung cancer.

METHODS

A decision-analytic Markov model was developed to project the costs and effects of two competing strategies by using test performance from the Airway Epithelial Gene Expression in the Diagnosis of Lung Cancer-1 and Airway Epithelial Gene Expression in the Diagnosis of Lung Cancer-2 studies. The diagnostic accuracy of noninvasive and invasive follow-up, as well as associated adverse event rates, were derived from published literature. Procedure costs were based on claims data and 2016 inpatient and outpatient reimbursement amounts. The model projected the number of invasive follow-up procedures, 2-year costs and quality-adjusted life-years (QALYs) by strategy, and resulting incremental cost-effectiveness ratio discounted at 3% per annum.

RESULTS

Use of the genomic classifier reduced invasive procedures by 28% at 1 month and 18% at 2 years, respectively. Total costs and QALY gain were similar with classifier use ($27,221 versus $27,183 and 1.512 versus 1.509, respectively), resulting in an incremental cost-effectiveness ratio of $15,052 per QALY.

CONCLUSIONS

Our analysis suggests that the use of a genomic classifier is associated with meaningful reductions in invasive procedures at about equal costs and is therefore a high-value strategy in the diagnostic work-up of patients at intermediate risk of lung cancer.

Clinical impact of molecular techniques for the presurgical diagnosis of differentiated thyroid cancer diagnosis

The gold standard for the presurgical diagnosis of thyroid cancer is fine needle aspiration cytology. In about 30% of cases a final diagnosis is not obtained and surgical treatment is required for diagnostic/therapeutic purposes. To avoid unnecessary thyroidectomies, methods based on molecular markers analysis have been explored over the last 10 years. Areas covered: The present review introduces the limits of the cytological diagnosis of thyroid nodules and describes the molecular techniques for the presurgical diagnosis of these nodules focusing on the use of the Thyroseq-V2 (Rule in) and Afirma (Rule out) tests. Expert commentary: These two types of tests have been clinically applied and validated; however they are still confined to specialized laboratories, either academic or private, and not yet routinely used. The evidence of a positive cost-benefit analysis should encourage to set up molecular pathology laboratories to apply new molecular testing(s). In the meantime, clinical judgment, which must take into consideration several parameters including the age of the patient, the size and number of the nodule(s), the ultrasound pattern and the risk level for malignancy, should guide the decision to operate or to follow up the evolution of the nodule.