The role of repeat fine needle aspiration in managing indeterminate thyroid nodules

Deep convolutional neural network model ResNeSt for discrimination of papillary thyroid carcinomas and benign nodules in thyroid nodules diagnosed as atypia of undetermined significance

Background

A deep convolutional neural network (DCNN) model was employed for the differentiation of thyroid nodules diagnosed as atypia of undetermined significance (AUS) according to the 2023 Bethesda System for Reporting Thyroid Cytopathology (TBSRTC). The aim of this study was to investigate the efficiency of ResNeSt in improving the diagnostic accuracy of fine-needle aspiration (FNA) biopsy.

Methods

Fragmented images were used to train and test DCNN models. A training dataset was built from 1,330 samples diagnosed as papillary thyroid carcinoma (PTC) or benign nodules, and a test dataset was built from 173 samples diagnosed as AUS. ResNeSt was trained and tested to provide a differentiation. With regard to AUS samples, the characteristics of the cell nuclei were compared using the Wilcoxon test.

Results

The ResNeSt model achieved an accuracy of 92.49% (160/173) on fragmented images and 84.78% (39/46) from a patient wise viewpoint in discrimination of PTC and benign nodules in AUS nodules. The sensitivity and specificity of ResNeSt model were 95.79% and 88.46%. The κ value between ResNeSt and the pathological results was 0.847 (P<0.001). With regard to the cell nuclei of AUS nodules, both area and perimeter of malignant nodules were larger than those of benign ones, which were 2,340.00 (1,769.00, 2,807.00) vs. 1,941.00 (1,567.50, 2,455.75), P<0.001 and 190.46 (167.64, 208.46) vs. 171.71 (154.95, 193.65), P<0.001, respectively. The grayscale (0 for black, 255 for white) of malignant lesions was lower than that of benign ones, which was 37.52 (31.41, 46.67) vs. 45.84 (31.88, 57.36), P <0.001, indicating nuclear staining of malignant lesions were deeper than benign ones.

Conclusions

In summary, the DCNN model ResNeSt showed great potential in discriminating thyroid nodules diagnosed as AUS. Among those nodules, malignant nodules showed larger and more deeply stained nuclei than benign nodules.

Repeat Fine-Needle Aspiration With Molecular Analysis in Management of Indeterminate Thyroid Nodules

OBJECTIVE

To analyze clinical outcomes in a series of indeterminate thyroid nodules (ITNs) with repeat fine-needle aspiration (FNA) biopsy and results of genomic classifier.

STUDY DESIGN

Historical chart review.

SETTING

Tertiary care center.

METHODS

We reviewed FNA samples from subjects with Bethesda III or IV diagnoses from January 2015 to December 2018 at a single institution and selected those with repeat FNA and ThyroSeq testing of the same nodule. Patient demographics, Bethesda classifications, ThyroSeq results, treatment detail, and surgical pathology, when available, were analyzed.

RESULTS

Ninety-six patients with cytologic diagnosis of ITN, repeat FNA, and ThyroSeq testing were identified. Following repeat FNA, 55 nodules (57%) remained ITN; 40 (42%) were reclassified as benign; and 1 (1%) was reclassified as suspicious for malignancy. In 31 patients with ThyroSeq analysis accompanying initial and repeat FNA, 26 (84%) had the same result on each, while 5 (16%) tested ThyroSeq positive following an initially negative result (κ = 0.24). Most nodules that were downgraded to Bethesda II on repeat FNA (37/40, 93%) were managed nonsurgically. Patients with ThyroSeq-positive results were treated with surgery more often (25/28, 89%) than patients with ThyroSeq-negative results (11/68, 16%; P < .0001). In excised nodules, the prevalence of malignancy and noninvasive follicular thyroid neoplasm with papillary-like nuclear features was 28% (n = 10) and 22% (n = 8), respectively, and all malignancies were low risk.

CONCLUSION

In this case series, repeat FNA helped patients with ITNs avoid diagnostic surgery through reclassification to benign cytology. The risk of high-risk malignancy in ThyroSeq-positive nodules with repeat indeterminate cytology was low.

A thyroid EIF1AX story: how clinical, cytologic, and molecular surveillance led to appropriate management

INTRODUCTION

Indeterminate thyroid cytology diagnoses are associated with intermediate risks of malignancy. Application of molecular testing (MT) to indeterminate specimens provides additional diagnostic and prognostic information. While a positive or suspicious MT result may prompt surgery, a negative MT result is associated with a low probability of cancer or noninvasive follicular thyroid neoplasm with papillary-like nuclear features and approximates that of a benign cytology diagnosis. Furthermore, ThyroSeq v3 MT has a "currently negative" result for findings with the probability of cancer or noninvasive follicular thyroid neoplasm with papillary-like nuclear feature that is slightly greater than that for the negative ThyroSeq v3 MT result but less than 10%, suggesting active surveillance. In this report, we discuss a case of a patient for whom clinical, cytologic, and molecular surveillance led to timely surgery and management.

CLINICAL DETAILS

A 53-year-old man with a thyroid isthmus nodule had a fine-needle aspiration cytology diagnosis of atypia of undetermined significance and a subsequent ThyroSeq v3 MT, which revealed an EIF1AX mutation and a "currently negative" MT result. Surveillance with additional fine-needle aspiration samples demonstrated concerning genomic alterations (fluctuating EIF1AX allelic frequency and a non-V600E BRAF mutation), culminating in the conversion to a positive MT result 3 years later. Resection revealed an encapsulated noninvasive, oncocytic solid subtype of papillary thyroid carcinoma with increased mitotic activity.

CONCLUSION

The case is notable for clinical, cytologic, and molecular surveillance demonstrating sequential pathologic alterations in an indeterminate thyroid nodule with EIF1AX mutation, leading to timely resection of the neoplasm before invasion manifested.

Risk assessment of cytologically indeterminate thyroid nodules with integrated molecular testing and repeat biopsy: a surgical decision-oriented tool

BACKGROUND

The preoperative diagnosis of cytologically indeterminate thyroid nodules (ITNs) is very challenging. In this study, we aim to provide an integrated risk assessment for thyroid nodules with indeterminate cytology to guide surgical decision-making, which includes results of blood tests, molecular tests, and repeat fine-needle aspiration biopsy (FNAB).

METHODS

The study retrospectively included 265 ITNs between June 2019 and April 2022. According to our integrated risk assessment process that starts with blood testing, followed by supplementary DNA mutation detection on the first FNAB, and finally repeat FNAB, we divided the ITNs into high-risk and low-risk groups. Performance was evaluated with sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), area under the receiver operating characteristic curve (AUC), and the consistency between the risk evaluation and histological results.

RESULTS

Of the 265 ITNs, 87 were included in the risk assessment process. The risk assessment had a sensitivity of 84.1%, specificity of 83.3%, PPV of 95.1%, NPV of 57.7%, and AUC of 0.837. The nodules with consistent results between the risk groups and histological outcomes, which included malignant cases in the high-risk group and benign cases in the low-risk group, accounted for 83.9% of all risk-assessed nodules.

CONCLUSIONS

These data suggest that the integrated risk assessment might provide proper information for surgical decision-making in patients with ITNs.

The Italian Consensus for the Classification and Reporting of Thyroid Cytology: Cytohistologic and molecular correlations on 37,371 nodules from a single institution

BACKGROUND

The Italian Consensus for the Classification and Reporting of Thyroid Cytology (ICCRTC) includes six diagnostic categories (TIR 1/1C, TIR 2, TIR 3A, TIR 3B, TIR 4, and TIR 5), each indicating a different risk of malignancy. The objective of this monocentric retrospective study was to evaluate the distribution of the ICCRTC classes at the authors' institution and assess their cytohistologic correlations.

METHODS

The authors retrospectively collected 37,371 consecutive cytologic reports of thyroid nodules and described the clinical-pathologic features of the different cytologic categories. The cytologic diagnoses also were compared with histologic outcomes in a subset of patients.

RESULTS

The cytologic classes were distributed as follows: nondiagnostic, 15.6%; benign, 66.5%; low-risk indeterminate, 10% (TIR 3A); high-risk indeterminate, 3.5% (TIR 3B); suspicious, 1.7%; and malignant, 2.6%. According to histology, the risk of malignancy was very high in the nondiagnostic category (29.8%), with young male patients more exposed to malignancy, and it was relatively high among benign (7.8%) and indeterminate nodules (32.5% in TIR 3A; 52.1% in TIR 3B), mainly because of the high prevalence of follicular architecture in malignant tumors. On histology, the malignancy rates were 92.4% and 99.3% for the suspicious and malignant categories, respectively; aggressive variants of papillary thyroid carcinoma were mostly diagnosed in these categories.

CONCLUSIONS

In this series, nondiagnostic nodules showed high prevalence and, surprisingly, high malignancy rates. Malignant tumors with follicular architecture represented a diagnostic pitfall in benign and indeterminate nodules. The suspicious and malignant categories had high specificity for malignancy. Importantly, the ICCRTC had high reliability for identifying preoperatively aggressive histotypes of thyroid carcinoma.

The use of diagnostic patterns for interventional cytopathology during rapid on-site evaluation and final classification

Pathologist-performed fine-needle aspiration, or interventional cytopathology, is a minimally invasive, highly accurate technique for sampling and diagnosing palpable lesions. Utilizing cytomorphologic patterns during rapid onsite evaluation (ROSE) and final classification is one of many strategies that an interventional cytopathologist can employ to simplify the diagnostic approach. Herein, we provide an overview of the salient cytomorphologic patterns encountered in common specimens obtained by the interventional cytopathologist, including major salivary glands, the thyroid gland, and superficial lymph nodes. The topics covered should provide a primer for those interested in utilizing a site-specific, pattern-based approach to cytopathologic evaluation. In summary, cytomorphologic patterns can be used during ROSE to establish adequacy, build a differential diagnosis, and to appropriately triage the specimen for additional investigation, such as microbiology cultures, a liquid-based preparation, a cell block preparation, flow cytometry, chemical analysis, or molecular diagnostic tests. Finally, this approach can be applied at the time of diagnosis to suggest additional ancillary studies, such as immunohistochemistry, and to inform accurate and definitive classification.

Evaluation of ACR TI-RADS cytologically indeterminate thyroid nodules and molecular profiles: a single-institutional experience

INTRODUCTION

The American College of Radiology (ACR) Thyroid Imaging Reporting and Data Systems (TI-RADS) was developed to standardize thyroid ultrasound reports and predict the likelihood of malignancy. In our study, we aimed to correlate indeterminate thyroid fine needle aspiration cytology cases with preceding ultrasound (US) ACR TI-RADS scores and concurrent molecular testing results to examine how well the use of the ACR TI-RADS in our institution predicted which patients with indeterminate cytology might harbor molecular alterations.

MATERIALS AND METHODS

We performed a retrospective review of thyroid nodules. Patients with US reports that included TI-RADS scores, fine needle aspiration specimens with indeterminate cytology (Bethesda class III-V), and molecular testing results were included.

RESULTS

A total of 46 indeterminate cytology cases had had preceding US reports with TI-RADS scores and molecular testing (Bethesda class III, n = 37; Bethesda class IV, n = 6; Bethesda class V, n = 3). Most of the indeterminate cases had had a TI-RADS score of TR4 (31 of 46; 67.39%) or TR5 (9 of 46; 19.57%). RAS mutations were the most common alteration (n = 12). Of the 46 cases, 22 (47.85%) showed no alterations. Ten cases proceeded to surgery, of which seven displayed malignancies.

CONCLUSIONS

Molecular testing in cytologically indeterminate thyroid nodules provided valuable information for TR4 and TR5 lesions; however, the TR2 and TR3 lesions often had no molecular alterations. These findings highlight the potential value of including US imaging features when assessing the significance of indeterminate cytology findings.

Performance of repeat cytology with reflex ThyroSeq genomic classifier for indeterminant thyroid cytology

BACKGROUND

The American Thyroid Association recommends either repeat fine-needle aspiration biopsy (FNAB) or molecular testing (eg, ThyroSeq) of Bethesda category III (atypia of undetermined significance/follicular lesion of undetermined significance [AUS/FLUS]) nodules to provide further risk stratification. How a testing algorithm that uses ancillary molecular tests performs as a reflex test for repeat sampling of indeterminant nodules remains unclear.

METHODS

Thyroid FNABs performed over a 24-month period that received a diagnosis of AUS/FLUS and underwent subsequent FNAB were analyzed.

RESULTS

In total, 187 patients were identified who received an FNAB diagnosis of AUS/FLUS and had repeat sampling. Of these patients, 64% received a subsequent indeterminant diagnosis on repeat biopsy: 7 (3.7%) repeat biopsies were diagnosed as nondiagnostic/unsatisfactory, 104 (55.6%) were diagnosed as AUS/FLUS, and 8 (4.3%) were diagnosed as follicular neoplasm/suspicious for follicular neoplasm. Of the repeat biopsied nodules, 63% underwent subsequent testing with ThyroSeq version 3. The diagnostic performance was calculated using only surgically confirmed nodules (sensitivity, 100%; specificity, 30%; positive predictive value, 41%; negative predictive value, 100%) and by assigning nonresected nodules with negative ThyroSeq or benign cytology results as benign (sensitivity, 100%; specificity, 88%; positive predictive value, 41%; negative predictive value, 100%).

CONCLUSIONS

In the majority of patients, repeat FNAB for AUS/FLUS did not preclude subsequent molecular ancillary testing because of the high rate of indeterminant results on repeat biopsy. The diagnostic performance of the testing algorithm reported here was very similar to other reports using either repeat biopsy or molecular testing alone. Ultimately, the algorithm of performing molecular testing on repeat indeterminant nodules increased the number of biopsies performed and lengthened the time to definitive risk stratification without a disproportionate decrease in the use of molecular testing or an appreciable improvement in diagnostic performance.

IS REPEAT FNAB NECESSARY FOR THYROID NODULES WITH ND / UNS CYTOLOGY?

CONTEXT/OBJECTIVE

The standard approach is to perform repeat FNAB (rFNAB) in thyroid nodules with non-diagnostic (ND) / insufficient (UNS) cytology. However, due to the nature of these nodules, recurrent FNABs may also be insufficient. Therefore, by comparing the clinical-radiological-pathological parameters of nodules with a definite diagnosis of excision, we questioned the possibility of patient management without rFNAB.

METHODS

Clinical-radiological parameters of 275 nodules belonging to 264 patients in the ND/UNS aspiration group with definite pathological diagnosis after surgery were determined. Under the guidance of these parameters, those with and without rFNAB were compared.

RESULTS

The incidence of malignancy was found to be significantly higher in nodules without rFNAB compared to nodules with rFNAB (p = 0.036). In addition, the incidence of malignancy in BC-1 nodules without rFNAB was significantly higher than in nodules with rFNAB result also BC-1 (p = 0.009). In all cases, nodule size smaller than 10 mm and border irregularity were found to be statistically significant for malignancy (p <0.020, p <0.002). When looking at the distribution of rFNAB results, a significant correlation was observed with female gender, solid component, hypoechogenicity, border irregularity and halo loss around the nodule in patients with BC-4,5,6 cytology results (respectively, 0.005 / 0.031 / 0.001 / 0.012 / 0.004).

CONCLUSION

rFNAB did not show the expected effect in ND / UNS nodules. We recommend direct surgical excision without rFNAB for nodules with border irregularity, solid structure, halo loss and hypoechogenicity, which should be considered more important in female patients.

2021 Korean Thyroid Imaging Reporting and Data System and Imaging-Based Management of Thyroid Nodules: Korean Society of Thyroid Radiology Consensus Statement and Recommendations

Incidental thyroid nodules are commonly detected on ultrasonography (US). This has contributed to the rapidly rising incidence of low-risk papillary thyroid carcinoma over the last 20 years. The appropriate diagnosis and management of these patients is based on the risk factors related to the patients as well as the thyroid nodules. The Korean Society of Thyroid Radiology (KSThR) published consensus recommendations for US-based management of thyroid nodules in 2011 and revised them in 2016. These guidelines have been used as the standard guidelines in Korea. However, recent advances in the diagnosis and management of thyroid nodules have necessitated the revision of the original recommendations. The task force of the KSThR has revised the Korean Thyroid Imaging Reporting and Data System and recommendations for US lexicon, biopsy criteria, US criteria of extrathyroidal extension, optimal thyroid computed tomography protocol, and US follow-up of thyroid nodules before and after biopsy. The biopsy criteria were revised to reduce unnecessary biopsies for benign nodules while maintaining an appropriate sensitivity for the detection of malignant tumors in small (1-2 cm) thyroid nodules. The goal of these recommendations is to provide the optimal scientific evidence and expert opinion consensus regarding US-based diagnosis and management of thyroid nodules.

Rate of malignancy for thyroid nodules with AUS/FLUS cytopathology in a tertiary care center - a retrospective cohort study

BACKGROUND

Thyroid nodules are stratified through fine-needle aspiration (FNA) and are often categorized using The Bethesda System for Reporting Thyroid Cytopathology, which estimates the risk of malignancy for six cytopathological categories. The atypia of undetermined significance (AUS) and follicular lesion of undetermined significance (FLUS) categories have varying malignancy rates reported in the literature which can range from 6 to 72.9%. Due to this heterogeneity, we assessed the malignancy rate and effectiveness of repeat FNA (rFNA) for AUS/FLUS thyroid cytopathology at our institution.

METHODS

Electronic health records of patients with AUS/FLUS thyroid cytopathology on FNA at our center since the implementation of the Bethesda System on May 1, 2014-December 31, 2019 were retrospectively reviewed. Patient demographics, treatment pathway, and pathology results were collected. The treatment pathway of the nodules, the rFNA results, and the malignant histopathology results were reported. Malignancy rates were calculated as an upper and lower limit estimate.

RESULTS

This study described 182 AUS/FLUS thyroid nodules from 177 patients. In total, 24 thyroid nodules were deemed malignant upon histopathology, yielding a final malignancy rate of 13.2-25.3%. All of the malignancies were variants of papillary thyroid carcinoma. The malignancy rate of the nodules which underwent resection without rFNA (21.5%) was lower than the malignancy rate of the nodules which underwent resection after rFNA (43.8%). 45.5% of the rFNA results were re-classified into more definitive categories.

CONCLUSION

The malignancy rate of AUS/FLUS thyroid cytopathology at our center is in line with the risk of malignancy stated by the 2017 Bethesda System. However, our malignancy rate is lower than some other Canadian centers and approximately half of our rFNAs were re-classified, highlighting the importance of establishing center-specific malignancy and rFNA re-classification rates to guide treatment decisions.

Longitudinal Assessment of Quality of Life Following Molecular Testing for Indeterminate Thyroid Nodules

Background

Molecular testing can refine the risk of malignancy in cytologically indeterminate thyroid nodules and can reduce the need for diagnostic thyroidectomy. However, quality of life (QOL) in patients mananged with molecular testing is not well studied.

Objective

We aimed to assess the QOL of patients undergoing surveillance after a benign molecular test result, or thyroidectomy after a suspicious molecular test result.

Methods

This prospective longitudinal follow-up of the Effectiveness of Molecular Testing Techniques for Diagnosis of Indeterminate Thyroid Nodules randomized trial utilized the Thyroid-Related Patient-Reported Outcome, 39-item version (ThyPro-39) to assess the QOL of patients with indeterminate cytology on thyroid fine needle aspiration (FNA) biopsy. All patients underwent molecular testing at the time of initial FNA. A mixed-effect model was used to determine changes in QOL over time.

Results

Of 252 eligible patients, 174 completed the assessment (69% response rate). Molecular test results included 72% (n = 124) benign and 28% (n = 50) suspicious. ThyPro-39 scores of benign molecular test patients were unchanged from baseline (following initial FNA and molecular test results) to 18 months of ultrasound surveillance. Baseline symptoms of goiter, anxiety, and depression were more severe for patients with suspicious compared with benign molecular test results. At a median of 8 months after thyroidectomy, suspicious molecular test patients reported improved symptoms of goiter, anxiety, and depression.

Conclusion

A benign molecular test provides sustained QOL throughout ultrasound surveillance, without worsening anxiety or depression relating to the risk of malignancy. Definitive surgery results in improvement of QOL in patients with suspicious molecular tests.

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.

Analysis of Clinical-Radiological-Pathological Factors in FN/SFN Bethesda Category Thyroid Nodules, Contribution of FNAB Repeat, Single Center Experience

Objectives:

Follicular neoplasm/suspected follicular neoplasm (FN/FNS) Bethesda Category (BC)-4 group cases are known as the gray zone. Nodules diagnosed in cytology are excised. However, very few of these nodules are malignant. Our aim is to investigate the usability of clinical-radiological-pathological parameters to reduce unnecessary surgery. In addition, we questioned the benefit of repeating fine-needle aspiration biopsy (rFNAB) in these nodules, which is not recommended, but performed for clinical or patient-related reasons.

Methods:

The files of all thyroid FNAB patients conducted in our institution between January 2014 and September 2020 were scanned in the database. In our study, 185 (5.1%) nodules with cytology results of which were classified as FN/FNS were identified among 3624 nodules that were applied FNAB during this period. Twenty-eight patients were excluded from the study group. 157 nodules belonging to 157 patients between the ages of 21 and 82 years who were operated and met the study criteria were identified from patients with these nodules. The files of all patients were scanned and the results of age, gender, ultrasonographic nodule characteristics, FNAB repeat, type of surgery, and postoperative pathology were recorded. All data were analyzed by comparing them with nodule features. SPSS 15.0 for Windows program was used for statistical analysis.

Results:

A significant correlation was found between the incidence of malignancy and male gender and hypervascularization (p=0.017 and p=0.002, respectively). Malignancy was less in nodules larger than 2 cm (p=0.014). There was no relationship between other clinical and radiological features and malignancy. In 29 nodules with rFNAB, a significant correlation was found between malignancy and advanced age (52.9-years-old), presence of nodules smaller than 2 cm and hypervascularization (p=0.047, p=0.047, and p=0.030, respectively).

Conclusion:

We recommend careful review of patients with hypervascular, hypoechogenic, and microcalcific BC-4 nodules (male gender and older patients at greater risk). Because of the serious risk of malignancy, patients with these features should be prepared for patient management with total thyroidectomy after examination with frozen section applied to the nodule during the operation.

Cytological Sub-Classification of Atypia of Undetermined Significance May Predict Malignancy Risk in Thyroid Nodules

BACKGROUND

Atypia/follicular lesion of undetermined significance (AUS/FLUS) carries a malignancy risk reaching up to 50%. Based on the reported malignancy rate in a given population, the clinical practice towards such a category varies. We hereby identify clinical parameters for risk stratification to aid in decision-making for either surgical referral or a clinical follow-up. Our aim is to identify clinical parameters that guided both clinicians and patients at our institutions to reach a clinical decision including atypia types.

METHODS

A retrospective review of patients with Bethesda III category thyroid nodules from tertiary centres in the Emirate of Abu Dhabi during January 2011 through December 2015 was carried out. Malignancy risk in Bethesda category III nodules and repeat FNA utility were calculated. Parameters that guided both clinicians and patients for appropriate referral to surgery were studied.

RESULTS

Two hundred and two cases were included in the study. Of these, 101 cases underwent surgery initially following the first FNA and 10 cases following FNA repeat. Histology confirmed malignancy in (41%) of cases that went initially to surgery and in (40%) of cases that underwent a repeat FNA. Repeat FNA resulted in 17 (44.74%) cases being re-classified into benign category, 10 (26.3%) being AUS/FLUS category, 6 (15.7%) being both suspicious and malignant, and 5 (13.16%) being unsatisfactory. Repeating FNA resulted in a definitive diagnostic utility in 50% of the cases. Eighty percent of malignant cases demonstrated nuclear atypia.

CONCLUSION

The relatively high malignancy rate in our institutions, the suspicious radiographic features, the atypia groups, and the repeat FNA predictive value stratified Bethesda III category nodules for proper malignancy prediction and appropriate management.

Molecular analysis of fine-needle aspiration cytology in thyroid disease: where are we?

PURPOSE OF REVIEW

The prevalence of thyroid nodules in the general population is high but only about 5% are malignant lesions. Cytology is usually appropriate to rule out malignancy in sonographically suspicious nodules but in many cases, reports are indeterminate. Molecular testing is a more recent approach to rule out malignancy and guide subsequent management.

RECENT FINDINGS

Although several different molecular testing approaches have proven useful in reducing unnecessary surgery, there are still several remaining issues, such as the possible occurrence of RAS mutations (which are difficult to interpret in clinical management) and the role of molecular analysis in specific histotypes, such as Hürthle cell carcinomas. Furthermore, conclusive evidence is lacking regarding the cost-effectiveness and appropriateness of surgical options following molecular tests.

SUMMARY

To be useful in clinical practice, molecular tests should be applied to appropriate candidates. In truly uncertain thyroid nodules in which diagnostic surgery may be considered, molecular testing may change the clinical approach and 'save' a number of thyroids.

Contemporary Thyroid Nodule Evaluation and Management

CONTEXT

Approximately 60% of adults harbor 1 or more thyroid nodules. The possibility of cancer is the overriding concern, but only about 5% prove to be malignant. The widespread use of diagnostic imaging and improved access to health care favor the discovery of small, subclinical nodules and small papillary cancers. Overdiagnosis and overtreatment is associated with potentially excessive costs and nonnegligible morbidity for patients.

EVIDENCE ACQUISITION

We conducted a PubMed search for the recent English-language articles dealing with thyroid nodule management.

EVIDENCE SYNTHESIS

The initial assessment includes an evaluation of clinical risk factors and sonographic examination of the neck. Sonographic risk-stratification systems (e.g., Thyroid Imaging Reporting and Data Systems) can be used to estimate the risk of malignancy and the need for biopsy based on nodule features and size. When cytology findings are indeterminate, molecular analysis of the aspirate may obviate the need for diagnostic surgery. Many nodules will not require biopsy. These nodules and those that are cytologically benign can be managed with long-term follow-up alone. If malignancy is suspected, options include surgery (increasingly less extensive), active surveillance or, in selected cases, minimally invasive techniques.

CONCLUSION

Thyroid nodule evaluation is no longer a 1-size-fits-all proposition. For most nodules, the likelihood of malignancy can be confidently estimated without resorting to cytology or molecular testing, and low-frequency surveillance is sufficient for most patients. When there are multiple options for diagnosis and/or treatment, they should be discussed with patients as frankly as possible to identify an approach that best meets their needs.

Quality of Life Following Molecular Marker Testing for Indeterminate Thyroid Nodules

OBJECTIVE

Thyroid cancer has a disproportionately negative effect on the quality of life (QOL) compared to malignancies with a worse prognosis. The QOL of patients with indeterminate thyroid nodules has not been previously evaluated. We aimed to assess the impact of molecular test results on the QOL of patients with indeterminate thyroid nodules.

METHODS

A short version of the Thyroid-Related Patient-Reported Outcome (ThyPro-39) was used to assess the QOL of patients who underwent thyroid fine needle aspiration (FNA) biopsy throughout UCLA Health from May, 2016, to June, 2017. All patients with indeterminate biopsy results underwent molecular testing with either Afirma Gene Expression Classifier or ThyroSeq v2 at the time of the initial biopsy. The QOL associated with symptoms of goiter, anxiety, depression, and impaired daily life were analyzed.

RESULTS

Of 825 consented patients, 366 completed the assessment (44.4% response rate). FNA results included 76% benign, 7% malignant, and 17% indeterminate. There were no differences in QOL between patients with a benign FNA and patients with an indeterminate result with benign molecular testing. In patients with an indeterminate FNA, symptoms of goiter (20.5 versus 10.4; P = .033) and depression (33.3 versus 21.0; P = .026) were worse for patients with suspicious versus benign molecular test results; however, no significant differences were observed in anxiety or impaired daily life.

CONCLUSION

A benign molecular test result may provide reassurance for patients with indeterminate thyroid nodules that the risk of malignancy is low. Long-term follow-up is necessary to determine if benign molecular test results maintain improved QOL.

TIRADS Management Guidelines in the Investigation of Thyroid Nodules; Illustrating the Concerns, Costs, and Performance

Context

Ultrasound (US) risk-stratification systems for investigation of thyroid nodules may not be as useful as anticipated.

Objective

We aimed to assess the performance and costs of the American College of Radiology Thyroid Image Reporting And Data System (ACR-TIRADS).

Design, Settings and Participants

We examined the data set upon which ACR-TIRADS was developed, and applied TR1 or TR2 as a rule-out test, TR5 as a rule-in test, or applied ACR-TIRADS across all nodule categories. We assessed a hypothetical clinical comparator where 1 in 10 nodules are randomly selected for fine needle aspiration (FNA), assuming a pretest probability of clinically important thyroid cancer of 5%.

Results

The gender bias (92% female) and cancer prevalence (10%) of the data set suggests it may not accurately reflect the intended test population. Applying ACR-TIRADS across all nodule categories did not perform well, with sensitivity and specificity between 60% and 80% and overall accuracy worse than random selection (65% vs 85%). Test performance in the TR3 and TR4 categories had an accuracy of less than 60%. Using TR5 as a rule-in test was similar to random selection (specificity 89% vs 90%). Using TR1 and TR2 as a rule-out test had excellent sensitivity (97%), but for every additional person that ACR-TIRADS correctly reassures, this requires >100 ultrasound scans, resulting in 6 unnecessary operations and significant financial cost.

Conclusions

Perhaps surprisingly, the performance ACR-TIRADS may often be no better than random selection. The management guidelines may be difficult to justify from a cost/benefit perspective. A prospective validation study that determines the true performance of TIRADS in the real-world is needed.

Rapid On-site Molecular Evaluation in thyroid cytopathology: A same-day cytological and molecular diagnosis

BACKGROUND

Thyroid fine-needle aspirates (FNAs) with undetermined morphology can be outsourced to centralized laboratories for comprehensive molecular profiling. When a local, rapid screening rules out easily detectable BRAF and NRAS mutations outsourcing is minimized, leading to cost savings. The fully automated Idylla technology, that does not require trained staff, is an emerging option. However, Idylla platform has only been validated to process formalin fixed paraffin embedded (FFPE) sections. Here we investigate whether also the FNA needle rinse could be genotyped by the same cytopathologist who performs the FNA, a procedure that can be termed rapid on site molecular evaluation (ROME).

METHODS

To validate this approach, the Idylla BRAF and NRAS Test was performed on the rinses from 25 simulated (bench-top) FNAs, in a first part of the study. Genotyping data were compared with those obtained on matched histological FFPE blocks. The second part of the study was carried out on 25 prospectively collected routine FNAs to assess the performance of the Idylla BRAF and NRAS assay against a gold standard real time polymerase chain reaction method.

RESULTS

Idylla NRAS-BRAF Mutation Test was performed on needle rinse as well as histological FFPE blocks. A sensitivity of 88.9%, a specificity of 100.0% were obtained comparing the Idylla NRAS-BRAF Mutation Test on needle rinse to the reference method.

CONCLUSIONS

The FNA needle rinse can be directly genotyped. This obviates the need of cell block preparation, making possible a rapid combined morphological and molecular evaluation. Since DNA extraction is no longer necessary, the cytopathologist can perform ROME him/herself.