Overview of Molecular Biomarkers for Enhancing the Management of Cytologically Indeterminate Thyroid Nodules and Thyroid Cancer

ObjectiveTo provide information on molecular bio markers that can help assess cytologically indeterminate thyroid nodules.MethodsPublished studies on immunohistologic, somatic mutation, gene expression classifier, microRNA, and thyrotropin receptor messenger RNA biomarkers are reviewed, and commercially available molecular test pan els are described.ResultsThyroid nodules are common, and clinical guidelines delineate an algorithmic approach including serum thyroid-stimulating hormone measurement, diagnostic ultrasound examination, and, when appropriate, fine-needle aspiration (FNA) biopsy for determination of a benign versus malignant status. In clinical practice, approximately 20% of FNA-derived cytology reports are classified as “indeterminate” or follicular nodules that do not fulfill either benign or malignant criteria. In this set ting, the actual risk for malignancy of a cytologically indeterminate nodule ranges from approximately 15% to 34%. Research describing molecular biomarkers from thyroid cancer tissue has been applied to FNA-derived thyroid nodule material. There is also a serum molecular marker that has been reported with goals similar to those for the FNA-derived molecular markers: to enhance the preoperative diagnosis of thyroid cancer and reduce the large number of patients who have a diagnostic surgical procedure for benign thyroid nodules.ConclusionProgress toward the foregoing goals has been made and continues to evolve with the recent appearance of molecular biomarker tests that can be selectively applied for further assessment of cytologically indeterminate thyroid nodules. (Endocr Pract. 2012;18:611-615)     

Utility of Afirma Gene Expression Classifier for Evaluation of Indeterminate Thyroid Nodules and Correlation with Ultrasound Risk Assessment: Single Institutional Experience

Objective: We assessed our experience with Afirma gene expression classifier (GEC) combined with sono-graphic risk assessment, using both the American Thyroid Association (ATA) and the Thyroid Imaging Reporting and Data System (TI-RADS) in evaluating indeterminate thyroid nodules.Methods: We identified 98 patients with 101 nodules who had a second fine needle aspiration biopsy (FNA) between January 1, 2014, and September 30, 2017, and sent to Veracyte for cytopathology and subsequent Afirma GEC testing. A second FNA biopsy was performed if the initial cytopathology was either Bethesda III or IV (n = 94) or nondiagnostic (n = 7). We correlated cytopathology, histopathology, and Afirma GEC results with sonographic risk assessment using both the ATA system and TI-RADS.Results: The mean age of the cohort was 57.4 ± 12.3 years; 84% women and 60% white. Repeat FNA was benign in 51 of 101 nodules, and of the remaining 50 nodules, 18 (36%) were GEC-benign and 32 (64%) GEC-suspicious. Eighteen of the 32 GEC-suspicious nodules underwent surgery with the following results: 7 benign (39%), 1 follicular thyroid carcinoma (6%), 6 follicular variant of papillary thyroid cancer (33%), and 4 noninvasive follicular tumor with papillary-like nuclear features (22%). The malignancy rate among the surgical cohort was 39% (without noninvasive follicular tumor with papillary-like nuclear features [NIFTP]) and 61% (with NIFTP) and about 50% and 20% of this group scored in the high suspicion category by ATA and TR5 by TI-RADS, respectively.Conclusion: Afirma GEC was useful in avoiding surgery in one-third of indeterminate nodules and performed similarly to ATA and TI-RADS. However, the use of echogenicity in scoring may underestimate the risk of malignancy in patients with indeterminate nodules.Abbreviations:ATA = American Thyroid Association; AUS = Atypia of Undetermined Significance; FLUS = Follicular Lesion of Undetermined Significance; FN = follicular neoplasm; FNA = fine needle aspiration; FTC = follicular thyroid cancer; FVPTC = follicular variant of papillary thyroid cancer; GEC = Gene Expression Classifier; ND = nondiagnostic; NIFTP = noninvasive follicular tumor with papillary-like nuclear features; TI-RADS = Thyroid Imaging Reporting and Data System; TR = TI-RADS     

Do all Thyroid Nodules >4 cm need to be Removed? An Evaluation of Thyroid Fine-Needle Aspiration Biopsy in Large Thyroid Nodules

Objective: Controversy exists regarding the ability of fine-needle aspiration (FNA) biopsy to rule out malignancy when thyroid nodules exceed 4 cm in diameter. The goal of this study was to provide data regarding FNA accuracy in a clinical setting for detecting/ruling out malignancy in large thyroid nodules (≥4 cm) and discuss FNA utility in guiding surgical decisions.Methods: All thyroid FNA cases performed at Marshfield Clinic from 1/1/2000 to 12/31/2010 followed by complete or partial thyroidectomy on nodules of at least 4 cm were identified. Demographics, medical history, nodule biopsy characteristics, surgical procedures, and diagnosis data were abstracted. FNA was compared to histologic evaluation of surgical specimens.Results: A total of 198 patients with large thyroid nodules were identified. Most had a single large nodule, but ~40% were multinodular, and 206 total nodules were assessed. Females outnumbered males, and the mean age was ~50 years. After surgery, cancer was histologically identified in 49/206 (23.8%) nodules, including 9/123 nodules that had been categorized as benign by FNA, corresponding to a false-negative rate of 7.3%. Sensitivity/specificity for detecting malignancy by FNA was ~80%. The positive predictive value (PPV) was just below 60%, and the negative predictive value (NPV) was 93% but rose to 96% when papillary microcarcinomas were excluded.Conclusion: While FNA sensitivity in large nodules was relatively low, NPV was high, especially if incidental papillary microcarcinomas were excluded. When cancer prevalence and NPV are known, FNA can be a reliable “rule out” test in nodules ≥4 cm. This information is critical and can help guide the surgery decision, especially in high-risk patients. The decision for surgery should not be solely based on nodule size but should consider additional factors including cancer prevalence, clinical history, ultrasound features, surgical risk, and life expectancy.Abbreviations:FNA = fine-needle aspirationNPV = negative predictive valuePPV = positive predictive value     

Community Endocrine Surgical Experience With False-Negative Afirma Gec® Results: 2011–2017

Objective: Afirma Gene Expression Classifier® (Afirma GEC) molecular analysis (Veracyte, Inc, San Francisco, CA) is a negative predictive value test developed to reduce the number of thyroidectomies in thyroid nodule patients with indeterminate cytology. GEC technology has reportedly reduced unnecessary thyroid surgery, but few studies have examined Afirma GEC false-negative rates, since usually patients with GEC benign nodules do not undergo surgery for definitive diagnosis. Occasionally, Afirma GEC benign patients require removal of their thyroid nodules for other reasons; this work describes the incidence of malignancy and noninvasive follicular thyroid neoplasms with papillary-like nuclear features (NIFTP) in this population.Methods: We reviewed our community endocrine surgical practice database for patients who had undergone thyroid surgery from January 2011 through April 2017 despite benign Afirma GEC results.Results: Afirma GEC testing was completed for 475 patients during the study period. Surgery was clinically indicated for other reasons in 42 of the 193 patients (22%) with Afirma GEC benign results. Malignancy or NIFTP in the targeted nodule was found in the final histologic evaluation of 14 of the 42 Afirma GEC benign surgical patients. The Afirma GEC false-negative percentage for our incomplete surgical group (FNP-ISG), defined as the surgically proven false negatives divided by the total Afirma GEC benign patients, was 7.3%.Conclusion: Our high surgical rate in Afirma GEC benign nodules reveals an FNP-ISG of 7.3% in our community endocrine surgical patient population; this value exceeds the 5.7% reported in the multicenter 2012 Afirma GEC validation study.Abbreviations: Afirma GEC = Afirma Gene Expression Classifier; FNA = fine-needle aspiration; FNP = false-negative percentage; FNP-ISG = false-negative percentage for an incomplete surgical group; NIFTP = noninvasive follicular thyroid neoplasms with papillary-like nuclear features     

Surgical Utility of Afirma: Effects of High Cancer Prevalence and Oncocytic Cell Types in Patients with Indeterminate Thyroid Cytology

ObjectiveThe Afirma Gene Expression Classifier (GEC) molecular marker assay was developed for the purpose of improving surgical decision-making with indeterminate fine-needle aspiration (FNA) biopsies of thyroid nodules. In this paper, we analyze the performance of the GEC over 27 months in a community hospital-based thyroid surgery practice.MethodsWe began using GEC and Thyroid Cytopathology Partners (TCP) exclusively for thyroid FNA analysis in January 2011, shortly after the Afirma GEC became commercially available. In this paper, we focus on patients with indeterminate FNA results and the outcomes of GEC analysis, with particular attention paid to the calculation of the negative predictive value (NPV) of the Afirma test.ResultsWe performed 645 FNAs in 519 patients over 27 months. Overall, 58 FNAs (9%) were read as indeterminate, with 36 of these classified as suspicious by GEC (62%), 20 characterized as GEC benign (34%), and 2 determined to be inadequate due to low mRNA content. Of the 36 suspicious GEC patients, 30 underwent thyroidectomy, and 21 of the 30 had malignant final pathology. Of the 20 benign GEC patients, 5 underwent thyroid surgery, and 2 were discovered to have malignancies. The NPV for the Afirma GEC in our practice environment was 89.6%.ConclusionIn a practice with a high incidence of thyroid cancer in patients with indeterminate FNAs (33% for our practice), the NPV of the Afirma GEC test may not be as robust as suggested in the existing literature. (Endocr Pract. 2014;20:364-369)     

Statistical Comparison of Afirma Gsc and Afirma Gec Outcomes in a Community Endocrine Surgical Practice: Early Findings

Objective: The Veracyte Afirma Gene Expression Classifier (GEC) has been the most widely used negative predictive value molecular classifier for indeterminate cytology thyroid nodules since January 2011. To improve the specificity and further reduce unnecessary thyroid surgeries, a second-generation assay (Afirma Genetic Sequence Classifier [GSC]) was released for clinical use in August 2017. We report 11 months of clinical outcomes experience with the GSC and compare them to our 6.5-year experience with the GEC.Methods: We searched our practice registry for FNAB nodules with Afirma results from January 2011through June 2018. GEC versus GSC results were compared overall, in oncocytic and nononcocytic aspirates and by pathologic outcomes.Results: GSC identified less indeterminate cytology nodules as suspicious (38.8%; 54/139) when compared to GEC (58.4%; 281/481). There was a decrease of in the percentage of oncocytic fine-needle aspiration thyroid biopsy (FNAB) subjects classified as suspicious in the GSC group, with 86 of 104 oncocytic indeterminates (82.7%) classified as suspicious by GEC and 12 of 34 (35.3%) classified as suspicious by GSC. The surgery rate in patients with oncocytic aspirates fell from 56% in the GEC group to 31% in the GSC-evaluated group (45%). Pathology analysis demonstrated a false-negative percentage for an incomplete surgical group of 9.5% for GEC and 1.2% for GSC.Conclusion: Our GSC data suggest that the GSC further reduces surgery in indeterminate thyroid nodules by improving the specificity of Afirma technology without compromising sensitivity. A primary determinant for this change is a significant improvement in the specificity of the Afirma GSC test in oncocytic FNAB aspirates.Abbreviations: FNAB = fine-needle aspiration biopsy; GEC = Gene Expression Classifier; GSC = Genetic Sequence Classifier     

The Role of Core-Needle Biopsy for Thyroid Nodules with Initially Nondiagnostic Fine-Needle Aspiration Results: A Systematic Review and Meta-Analysis

Objective: This study evaluated the prevalence of nondiagnostic results, diagnostic performance, and complications of core-needle biopsy (CNB) compared with repeat fine-needle aspiration (FNA) for thyroid nodules with previous nondiagnostic FNA findings.Methods: The Ovid-MEDLINE and EMBASE databases were thoroughly searched for studies evaluating CNB or repeat FNA for thyroid nodules with initially nondiagnostic FNA results. Pooled proportions of nondiagnostic results of CNB and repeat FNA were calculated. A meta-analysis was performed to evaluate the diagnostic accuracy of CNB and repeat FNA for a diagnosis of malignancy using a bivariate random-effects model. Complication rates were also evaluated.Results: A review of 52 articles identified 4 eligible articles, involving 1,028 patients with 1,028 thyroid nodules, which were included in the meta-analysis. CNB demonstrated significantly lower rates of nondiagnostic results (6.4%) than repeat FNA (36.5%) (P<.0001). In the 3 studies that analyzed the diagnostic accuracy of CNB in diagnosing malignancy, CNB demonstrated significantly higher summary estimates of sensitivity (89.8%) than repeat FNA (60.6%) (P = .022), but summary specificity did not differ between CNB (99.2%) and repeat FNA (99.0%) (P = .576). None of the patients who underwent CNB or repeat FNA experienced any major complications.Conclusion: CNB demonstrates lower rates of nondiagnostic results and higher diagnostic accuracy than repeat FNA. CNB, rather than repeat FNA, can be utilized to diagnose thyroid nodules previously nondiagnostic on FNA.Abbreviations:CI = confidence intervalCNB = core-needle biopsyFNA = fine-needle aspirationSROC = summary receiver operating characteristicUS = ultrasound     

No Benefit of Dedicated Thyroid Nodule Screening in Patients with Acromegaly

Objective: Acromegaly results from the excessive production of growth hormone and insulin-like growth factor-1. While there is up to a 2-fold increased prevalence of thyroid nodules in patients with acromegaly, the incidence of thyroid cancer in this population varies from 1.6 to 10.6% in several European studies. The goal of our study was to determine the prevalence of thyroid nodules and thyroid cancer among patients with acromegaly at a large urban academic medical center in the United States (U.S.).Methods: A retrospective chart review was performed of all patients with acromegaly between 2006–2015 within the University of California, Los Angeles health system. Data were collected regarding patient demographics, thyroid ultrasounds, thyroid nodule fine needle aspiration (FNA) biopsy cytology, and thyroid surgical pathology.Results: In this cohort (n = 221, 49.3% women, mean age 53.8 ± 15.2 &lsqb;SD] years, 55.2% Caucasian), 102 patients (46.2%) underwent a thyroid ultrasound, from which 71 patients (52.1% women, mean age 52.9 ± 15.2 &lsqb;SD] years, 56.3% Caucasian) were found to have a thyroid nodule. Seventeen patients underwent a thyroid nodule FNA biopsy and the results revealed 12 benign biopsies, 1 follicular neoplasm, 3 suspicious for malignancy, and 1 papillary thyroid cancer (PTC), from which 6 underwent thyroidectomy; PTC was confirmed by surgical pathology for all cases (8.5% of all nodules observed).Conclusion: In this sample, the prevalence of thyroid cancer in patients with acromegaly and coexisting thyroid nodules is similar to that reported in the general U.S. population with thyroid nodules (7 to 15%). These findings suggest that there is no benefit of dedicated thyroid nodule screening in patients newly diagnosed with acromegaly.Abbreviations: AACE = American Association of Clinical Endocrinologists; ATA = American Thyroid Association; DTC = differentiated thyroid cancer; FNA = fine needle aspiration; GH = growth hormone; IGF-1 = insulin-like growth factor-1; PTC = papillary thyroid cancer; U.S. = United States     

False-Positive FNA Due to Highly Sensitive BRAF Assay

ObjectiveFalse-positive BRAF analysis on fine-needle aspiration (FNA) has rarely been reported in the literature but may become more common with the advent of assays that can detect the BRAF V600E mutation in only 2% of otherwise wild-type thyroid cells. We present the case of an indeterminate BRAF-positive FNA that showed no evidence of cancer on final surgical pathology.MethodsCase report and literature review.ResultsAn 87-year-old female with an indeterminate 1.7-cm nodule but BRAF-positive cytology underwent thyroid lobectomy. Final pathology revealed a benign adenomatoid nodule. An area rich in tumor cells from the nodule was identified, labeled, and microdissected for molecular testing, which demonstrated only wild-type BRAF, at the analytical limit of the assay.ConclusionIncreasingly sensitive BRAF assays using dual-priming oligonucleotide-based multiplex polymerase chain reaction analysis can detect the BRAF V600E mutation when present in only 2% of a population of wild-type cells. This increases the risk of false-positive results, particularly in cases of indeterminate FNA. Clinicians must caution patients in these circumstances that BRAF molecular testing may not have a 100% positive predictive value. (Endocr Pract. 2014;20:e8-e10)     

Thyroid Cytology and Risk of Thyroid Cancer: Differences Among Indeterminate Specimens

ObjectiveTo assess the potential for stratification of indeterminate cytologic findings on fine-needle aspiration (FNA) of thyroid nodules in an effort to improve therapeutic strategies.MethodsWe attempted to determine the malignant risk associated with various indeterminate FNA cytologic patterns by correlation of specimens with the final histologic diagnosis. For this analysis, we identified 294 computerized medical records of surgically treated thyroid nodules during a 5-year period at our institution with the corresponding FNA cytology reports available.ResultsOf the 294 surgical cases, 162 with a positive or indeterminate cytologic report were selected, reviewed, and classified. Of 52 patients with positive cytologic findings on FNA, 51 (98%) had a final histologic report of a malignant thyroid nodule. Of 110 patients with indeterminate specimens, 30 (27%) had a final histologic diagnosis of thyroid carcinoma. The presence of nuclear atypia was predictive of thyroid carcinoma in 75% of patients, a Hürthle cell cytologic pattern was associated with a malignant thyroid nodule in 33%, and a hypercellular smear was suggestive of malignant involvement in 26% of cases. The lowest rate of malignant potential was associated with cytologic microfollicular and scant colloid alone subtype (6%).ConclusionThe results of this study show that indeterminate thyroid cytologic specimens can be subdivided into groups with different malignant risks. A microfollicular cytologic pattern in the absence of a hypercellular smear or nuclear atypia does not support a recommendation of surgical treatment. A malignant cytologic diagnosis has a high positive predictive value for detection of thyroid cancer. (Endocr Pract. 2004;10:330-334)     

Correlation of Findings from Iodine 123 Scan and Ultrasonography in the Recommendation for Thyroid Fine-Needle Aspiration Biopsy

ObjectiveTo assess the impact of correlating findings from iodine I 123 (¹²³I) radionuclide scans and thyroid ultrasonography on the decision to perform fine-needle aspiration (FNA) biopsy of thyroid nodules.MethodsIodine 123 scans and sonographic images of adult patients who had both examinations performed within 6 months of each other at our institution were retrospectively reviewed. The presence of 1 or more nodules satisfying imaging-specific criteria for recommending FNA biopsy was recorded. Iodine 123 scan and sonographic images were then directly compared to determine how frequently the FNA recommendation would be affected by discordant findings.ResultsThe study included 97 adult patients, with a total of 291 thyroid lobes (right thyroid lobe, left thyroid lobe, and isthmus). Recommendations for FNA biopsy were concordant in 231 of 291 lobes (79.4%), with both modalities recommending FNA biopsy in 55 lobes and not recommending FNA biopsy in 176 lobes. A discordant recommendation occurred in 60 of 291 lobes (20.6%). Using only ultrasonography findings, a recommendation for FNA biopsy was not indicated for 11 of the 291 lobes (3.8%) with functioning nodules. Using only ¹²³I findings, a recommendation for FNA biopsy was not indicated for 23 of the 291 lobes (7.9%); 13 had nodules, but none that fulfilled sonographic criteria, and 10 had no identifiable nodule on ultrasonography. Iodine 123 scan did not identify 26 lobes with nodules (8.9%) for which FNA biopsy was recommended based on ultrasonography findings.ConclusionRecommendations for FNA biopsy should not be based on the presence of hypofunctioning regions on ¹²³I scan without sonographic confirmation. (Endocr Pract. 2011;17:699-706)     

Does Unilateral Lobectomy Suffice to Manage Unilateral Nontoxic Goiter?

ObjectiveTo evaluate the effectiveness of ipsilateral lobectomy to treat unilateral, nontoxic, benign nodular goiter and to define predictive factors for recurrence.MethodsPatients undergoing thyroid lobectomy for unilateral, nontoxic, benign nodular goiter between 2002 and 2007 were included. Patients were excluded if coincidental thyroid cancer was detected at histopathologic examination and completion thyroidectomy was performed. Potential predictors of recurrence including age; sex; family history; preoperative volume of the thyroid gland; preoperative number, size, and ultrasonography characteristics of the nodules; duration of postoperative follow-up; postoperative use of thyroxine; and histopathologic diagnoses were recorded at baseline. Follow-up visits were scheduled every 3 months during the first year and every 6 months thereafter. Recurrent disease was defined as a hypoechogenic or hyperechogenic nodule larger than or equal to 3 mm detected in the remaining contralateral lobe during ultrasonography. Patients with a thyrotropin value greater than 5 mIU/L received thyroxine. Fineneedle aspiration biopsy was performed for nodules greater than 10 mm or for nodules with characteristics suggestive of malignancy. Reoperation was indicated if a nodule was greater than 3 cm in diameter, posed a risk of malignancy, or caused compression signs or symptoms.ResultsA total of 104 patients were included. Histopathologic diagnoses at initial operation were adenoma in 45 patients, colloidal nodular goiter in 45 patients, and chronic lymphocytic thyroiditis in 14 patients. Average duration of follow-up was 39.75 ± 21.75 months (range, 5-87 months). Recurrence was seen in 63 patients (60.6%). Histopathologic characteristics of the lobectomy material (P <.001), preoperative volume of the thyroid gland (P <.006), and multinodularity (P <.011) were significant predictors of recurrence.ConclusionsHigher preoperative thyroid volume, histopathologic characteristics of nodules, and multinodular disease are associated with an increased risk of recurrence in patients with unilateral nodular goiter. Unilateral lobectomy is an effective therapeutic option with low reoperation rates in unilateral benign thyroid disease. (Endocr Pract. 2010;16:36-41)     

IS MEASUREMENT OF CIRCULATING TUMOR DNA OF DIAGNOSTIC USE IN PATIENTS WITH THYROID NODULES?

Objective: Circulating tumor DNA (ctDNA), a subset of cell-free DNA (cfDNA), is a potential biomarker for thyroid cancer. We determined the performance of a ctDNA panel for detecting thyroid malignancy in patients with thyroid nodules.Methods: Sixty-six patients with thyroid nodules without a prior history of cancer enrolled in a prospective, 1-year study in which blood was drawn for ctDNA analysis prior to undergoing fine-needle aspiration biopsy (FNAB) of thyroid nodules. The ctDNA panel consisted of 96-mutations in 9 cancer driver genes. The primary outcome measures were the sensitivity, specificity, and positive and negative predictive values (PPV, NPV) of our ctDNA panel for the diagnosis of thyroid malignancy as determined by pathologic and/or molecular tissue examination.Results: Results from 10 subjects could not be determined due to inadequate volume or technical issues. The final classifications of the thyroid nodules were 13 malignant and 43 benign lesions. A KRAS G12V mutation was detected in the plasma of 1 patient with stage IVA papillary carcinoma whose tissue contained the same mutation. Two of the 43 patients with benign lesions also had ctDNA detected, giving a sensitivity of 7.7%, specificity of 95.35%, PPV of 33.33%, and NPV of 77.35%. There were no significant differences between benign or malignant lesions in cfDNA levels.Conclusion: Neither cfDNA measurements nor our panel of ctDNA mutations are sensitive or specific enough to provide valuable information over FNAB. An expanded panel and the inclusion of proteomics may improve sensitivity and specificity for thyroid cancer detection.Abbreviations: cfDNA = cell-free DNA; ctDNA = circulating tumor DNA; FNAB = fine-needle aspiration biopsy; NIFTP = noninvasive follicular thyroid neoplasm with papillary-like nuclear features     

Guideline Implementation on Fine-Needle Aspiration for Thyroid Nodules: Focusing on Micronodules

Objective: We investigated patients who were referred to our institution after fine-needle aspiration (FNA) was performed at outside clinics to evaluate how many nodules satisfied the FNA indications of the Korean Thyroid Imaging Reporting and Data System (K-TIRADS) and compare that to the number of thyroid nodules that satisfy the FNA indications of the American College of Radiology (ACR)-TIRADS and American Thyroid Association (ATA) guidelines.Methods: Between January 2018 and December 2018, 2,628 patients were included in our study. The included patients were those referred for thyroid surgery after having a suspicious thyroid nodule. We retrospectively applied the three guidelines to each thyroid nodule and determined whether each nodule satisfied the FNA indications. We compared the proportion of nodules satisfying the FNA indications of each guideline using a generalized linear model and generalized estimating equation.Results: The median size of the 2,628 thyroid nodules was 0.9 cm (range, 0.2 to 9.5 cm). We found that FNA was not indicated for 54.1%, 47.7%, and 19.1% of nodules and 87.3%, 99.0%, and 97.8% among them were micronodules (<1 cm) according to the ACR-TIRADS, ATA guideline, and K-TIRADS, respectively. The proportion of micronodules which satisfied the FNA indications was significantly higher for the K-TIRADS (65.1%) compared to the ACR TIRADS (12.1%) and ATA guideline (12.1%) (P<.001).Conclusion: Among patients referred for thyroid surgery to our institutions, about 35% of the micronodules underwent FNA despite not being appropriate for indications by the K-TIRADS. Systematic training for physicians as well as modifications to increase the sensitivity of the guideline may be needed to reduce the overdiagnosis of thyroid cancers, especially for micronodules.     

Focus: Personalized Medicine: Simultaneously Detection of 50 Mutations at 20 Sites in the BRAF and RAS Genes by Multiplexed Single-Nucleotide Primer Extension Assay Using Fine-Needle Aspirates of Thyroid Nodules

Fine-needle aspiration (FNA) is commonly used for primary evaluation of thyroid nodules. Twenty to 30 percent of thyroid nodules remain indeterminate after FNA evaluation. Studies show the BRAF p.V600E to be highly specific for papillary thyroid carcinoma (PTC), while RAS mutations carry up to 88 percent positive predictive value for malignancy. We developed a two-tube multiplexed PCR assay followed by single-nucleotide primer extension assay for simultaneous detection of 50 mutations in the BRAF (p.V600E, p.K601E/Q) and RAS genes (KRAS and NRAS codons 12, 13, 19, 61 and HRAS 61) using FNA smears of thyroid nodules. Forty-two FNAs and 27 paired formalin-fixed, paraffin-embedded (FFPE) tissues were tested. All BRAF p.V600E-positive FNA smears (five) carried a final diagnosis of PTC on resection. RAS mutations were found in benign as well as malignant lesions. Ninety-two percent concordance was observed between FNA and FFPE tissues. In conclusion, our assay is sensitive and reliable for simultaneous detection of multiple BRAF/RAS mutations in FNA smears of thyroid nodules.     

Thyroid Nodule Growth as A Predictor of Malignancy

Objective: To assess which measure of thyroid nodule growth on serial neck ultrasound, if any, is associated with malignancy.Methods: Retrospective exploratory chart review of malignant thyroid nodules assessed at Kingston Health Sciences Centre (2006–2016) and benign thyroid nodules (2016), at least 1 cm in diameter and with 2 ultrasounds completed at least 30 days apart. Groups were compared using independent samples Student's t test, chi-square test, or Mann-Whitney U test as appropriate, as well as multivariable logistic and linear regression modelling to adjust for age and baseline volume.Results: One hundred and seventy-eight nodules were included in the study. When growth was defined as >20% increase in 2 dimensions (minimum 2 mm), malignant nodules (MNs) underwent significantly more growth than benign nodules (BNs) (16.8% BN versus 29.8% MN &lsqb;P = .026]; odds ratio = 2.49; 95% confidence interval = 1.12 to 5.56). There was no significant difference between the groups when growth was defined as >2 mm/year or ≥50% volume growth. Nodules shrank >2 mm/year in each group and the difference was not statistically significant (24.2% BN versus 20.7% MN &lsqb;P = .449]). The median doubling time for the nodules that grew was 1022.1 days in the BN group and 463.2 days in the MN group (P = .036). The median doubling time for all nodules was 456.5 days in the BN group and 244.2 days in the MN group (P = .015).Conclusion: Thyroid nodule growth defined as >20% increase in 2 dimensions (minimum 2 mm) is associated with risk of malignancy. Nodule shrinkage did not distinguish between BNs and MNs.Abbreviations: BN = benign nodule; CI = confidence interval; FNA = fine needle aspiration; KHSC = Kingston Health Science Centre; MN = malignant nodule; OR = odds ratio; ROC = receiver operating characteristic     

Assay of Free Thyroxine and Free Triiodothyronine in Fine-Needle Aspiration of Thyroid Nodules: a Useful and Low-Cost Assessment

ObjectiveTo evaluate whether analysis of thyroid hormones in fine-needle aspiration (FNA) of thyroid nodules can provide information about the functional status and the nature of the nodules.MethodsWe studied 4 groups of patients: group 1, 17 patients with autonomous hyperfunctioning thyroid nodules; group 2, 52 patients with cold nonfunctioning thyroid nodules; group 3, 12 patients with malignant thyroid nodules; and group 4 (control group), 10 patients with nonthyroid nodular lesions (enlarged parathyroid glands or lymph nodes). The assay of thyroid hormones was performed in FNA after the washing of needles and, with patient consent, also in normal thyroid parenchyma.ResultsThe free thyroxine (FT₄) and free triiodothyronine (FT₃) values were remarkably high in group 1 (mean, 5.5 ± 0.53 ng/dL and 27.6 ± 3.1 pg/mL, respectively; P < 0.05 versus group 2 and group 4, the control group). The levels of FT₄ and FT₃ were very low in group 3 (< 0.2 ng/dL and < 1.0 pg/mL, respectively; P < 0.05 versus group 2). Thyroglobulin values in FNA specimens were much higher than the normal range in human serum, but no significant differences were found between the various groups. The control group had low levels of FT₄ and FT₃ (< 0.2 ng/dL and < 1.0 pg/mL, respectively) in conjunction with low levels of thyroglobulin, whereas parathyroid hormone levels were high in parathyroid nodules.ConclusionThese results show that assay of FT₄ and FT₃ in FNA can yield information about the functional status of thyroid nodules and, indirectly, about the nature of nodules. In this era of sophisticated new molecular markers in FNA cytology, this low-cost diagnostic method can be readily performed in every laboratory. (Endocr Pract. 2004;10:311-316)     

Can the American Thyroid Association,K-Tirads,and Acr-Tirads Ultrasound Classification Systems Be Used to Predict Malignancy in Bethesda Category IV Nodules?

Objective: Management of thyroid nodules with Bethesda category III and IV cytology on fine needle aspiration (FNA) is challenging as they cannot be adequately classified as benign or malignant. Ultrasound (US) patterns have demonstrated the utility in evaluating the risk of malignancy (ROM) of Bethesda category III nodules. This study aims to evaluate the value of 3 well-established US grading systems (American Thyroid Association &lsqb;ATA], Korean Thyroid Imaging Reporting and Data System &lsqb;Korean-TIRADS], and The American College of Radiology Thyroid Imaging Reporting and Data System &lsqb;ACR-TIRADS]) in determining ROM in Bethesda category IV nodules.Methods: Ninety-two patients with 92 surgically resected thyroid nodules who had Bethesda category IV cytology on FNA were identified. Nodule images were retrospectively graded using the 3 systems in a blinded manner. Associations between US risk category and malignant pathology for each system were analyzed.Results: Of the 92 nodules, 56 (61%) were benign and 36 (39%) were malignant. Forty-seven per cent of ATA high risk nodules, 53% of K-TIRADS category 5 nodules, and 50% of ACR-TIRADS category 5 nodules were malignant. The ATA high-risk category had 25% sensitivity, 82% specificity, 47% positive predictive value (PPV) for malignancy. K-TIRADS category 5 had 25% sensitivity, 85% specificity, 53% PPV for malignancy. ACR-TIRADS category 5 had 25% sensitivity, 84% specificity, 50% PPV for malignancy. None of the 3 grading systems yielded a statistically significant correlation between US risk category and the ROM (P = .30, .72, .28).Conclusion: The ATA, Korean-TIRADS, and ACR-TIRADS classification systems are not helpful in stratifying ROM in patients with Bethesda category IV nodules. Clinicians should be cautious of using ultra-sound alone when deciding between therapeutic options for patients with Bethesda category IV thyroid nodules.     

Utility of Ultrasound Versus Gene Expression Classifier in Thyroid Nodules with Atypia of Undetermined Significance

Objective: Thyroid nodules with fine-needle aspiration (FNA) cytology categorized as atypia of undetermined significance (AUS) often undergo additional diagnostic analysis with the Afirma Gene Expression Classifier (GEC), which classifies these as either high probability of being benign (GEC-B) or suspicious for malignancy (GEC-S). Our goal was to assess the clinical validity and utility of GEC in the evaluation of AUS cytology and evaluate the performance of ultrasonography (USG) for predicting malignancy in this subset.Methods: We conducted a study with a retrospective cohort of patients from January 2012 to January 2014 who had FNA of thyroid nodules >1 cm in size with AUS cytology.Results: Cleveland Clinic Florida has an overall prevalence of AUS of 5%. A total of 119 cases with nodules >1 cm in size were reported as AUS. Forty-eight (40.3%) had a GEC performed after the first FNA (AUS-1), and 27 of these were GEC-S. Of those 27, 21 went for surgery and 14 (66.6%) had thyroid cancer on histopathology. The remaining 71 with AUS-1 were sent for a second FNA: 19 nodules were benign and did not undergo further evaluation, while the remaining 52 were reported as AUS for the second consecutive time (AUS-2). AUS-2 samples were sent for GEC. Of these 52 AUS-2, 38 (73.1%) were reported as GEC-S. Thirty-five went for surgery and 32 (91.4%) had confirmed malignancy on histopathology. Positive predictive value (PPV) was 91.4% for AUS-2 and 66.6% for AUS-1. Moreover, AUS-2 nodules that were hypoechoic and solid on USG showed a PPV of 92% for malignancy.Conclusion: In our practice, the diagnostic accuracy to predict malignancy with GEC for AUS-1 nodules was poor (PPV, 66.6%). The PPV of GEC testing was markedly higher at 91.4% performed after two consecutive AUS cytologies. AUS-2 nodules that were solid and hypoechoic on USG also had a high probability to be malignant (PPV, 92%). We recommend repeat FNA on AUS-1 nodules rather than proceeding directly to GEC testing. Also, we suggest that among AUS-2 nodules, surgery can be recommended when USG shows solid and hypoechoic features with GEC testing reserved for the remainder.Abbreviations:AUS = atypia of undetermined significanceFNA = fine-needle aspirationGEC = gene expression classifierGEC-B = GEC-benignGEC-S = GEC-suspicious for malignancyNPV = negative predictive valuePPV = positive predictive valueUSG = ultrasonography     

The Value of Gross Visual Assessment of Specimen Adequacy for Liquid-Based Cytology During Ultrasound-Guided,Fine-Needle Aspiration of Thyroid Nodules

Objective: Major problems of fine-needle aspiration (FNA) of thyroid nodules arise due to nondiagnostic results caused by inadequately obtained FNA specimens. The purpose of this study was to evaluate the value of visual assessment of liquid-based cytology specimens during FNA of thyroid nodules for predicting sampling adequacy.Methods: For 3 months, visual assessment of FNA specimens was used for 534 consecutive nodules in 534 patients. The FNA specimens were visually graded immediately following aspiration for each nodule, and the visual grades were classified into 2 categories: inadequate (<6 cell groups) and adequate (>6 cell groups). The cytology results were classified as diagnostic or nondiagnostic based on the Bethesda system. We compared the ultrasound features and FNA characteristics between the diagnostic and nondiagnostic results. Multiple logistic regression analysis was used to determine factors independently predictive of nondiagnostic results. We also evaluated the interobserver agreement regarding the visual assessment.Results: Visual assessment was feasible in all patients, and the nondiagnostic rate was 11.6% (62 of 534). Nondiagnostic results were more frequent in the inadequate visual assessment group (38.1%) than in the adequate visual assessment group (10.5%) (P = .001). Independent predictive factors for nondiagnostic results were inadequate visual assessment (odds ratio, 5.18), >50% vascularity (odds ratio, 3.98), and macrocalcification (odds ratio, 3.60). Interobserver agreement for the prediction of visual assessment was good (κ value, 0.767; P<.001).Conclusion: Immediate visual assessment of a specimen during FNA of a thyroid nodule is a feasible method for predicting sampling adequacy.Abbreviations: FNA = fine-needle aspiration LBC = liquid-based cytology US = ultrasound