Thyroid incidentalomas: epidemiology, risk stratification with ultrasound and workup

Differential Diagnosis of Benign and Malignant Thyroid Nodules Using Deep Learning Radiomics of Thyroid Ultrasound Images

PURPOSE

We aimed to propose a highly automatic and objective model named deep learning Radiomics of thyroid (DLRT) for the differential diagnosis of benign and malignant thyroid nodules from ultrasound (US) images.

METHODS

We retrospectively enrolled and finally include US images and fine-needle aspiration biopsies from 1734 patients with 1750 thyroid nodules. A basic convolutional neural network (CNN) model, a transfer learning (TL) model, and a newly designed model named deep learning Radiomics of thyroid (DLRT) were used for the investigation. Their diagnostic accuracy was further compared with human observers (one senior and one junior US radiologist). Moreover, the robustness of DLRT over different US instruments was also validated. Analysis of receiver operating characteristic (ROC) curves were performed to calculate optimal area under it (AUC) for benign and malignant nodules. One observer helped to delineate the nodules.

RESULTS

AUCs of DLRT were 0.96 (95% confidence interval [CI]: 0.94-0.98), 0.95 (95% confidence interval [CI]: 0.93-0.97) and 0.97 (95% confidence interval [CI]: 0.95-0.99) in the training, internal and external validation cohort, respectively, which were significantly better than other deep learning models (P < 0.01) and human observers (P < 0.001). No significant difference was found when applying DLRT on thyroid US images acquired from different US instruments.

CONCLUSIONS

DLRT shows the best overall performance comparing with other deep learning models and human observers. It holds great promise for improving the differential diagnosis of benign and malignant thyroid nodules.

Online Transfer Learning for Differential Diagnosis of Benign and Malignant Thyroid Nodules With Ultrasound Images

OBJECTIVE

We aimed to propose a highly automatic and objective model named online transfer learning (OTL) for the differential diagnosis of benign and malignant thyroid nodules from ultrasound (US) images.

METHODS

The OTL mothed combined the strategy of transfer learning and online learning. Two datasets (1750 thyroid nodules with 1078 benign and 672 malignant nodules, and 3852 thyroid nodules with 3213 benign and 639 malignant nodules) were collected to develop the model. The diagnostic accuracy was also compared with VGG-16 based transfer learning model and different input images based model. Analysis of receiver operating characteristic (ROC) curves were performed to calculate optimal area under it (AUC) for benign and malignant nodules.

RESULTS

AUC, sensitivity and specificity of OTL were 0.98 (95% confidence interval [CI]: 0.97-0.99), 98.7% (95% confidence interval [CI]: 97.8%-99.6%) and 98.8% (95% confidence interval [CI]: 97.9%-99.7%) in the final online learning step, which was significantly better than other deep learning models (P < 0.01).

CONCLUSION

OTL model shows the best overall performance comparing with other deep learning models. The model holds a good potential for improving the overall diagnostic efficacy in thyroid nodule US examinations.

SIGNIFICANCE

The proposed OTL model could be seamlessly integrated into the conventional work-flow of thyroid nodule US examinations.

Advanced Ultrasound Application - Impact on Presurgical Risk Stratification of the Thyroid Nodules

AIM

Current major guidelines recommend risk stratification of the thyroid nodules, after each diagnostic evaluation, in order to focus attention on potentially risky nodules. The main aim of our study was to evaluate the performance of combined advanced ultrasound techniques in this process, compared with conventional stratification models, in order to reduce unnecessary fine-needle biopsies, respectively, surgery.

MATERIAL AND METHODS

We evaluated 261 cases (261 nodules) using conventional ultrasound (2B), real-time Doppler evaluation (4D) respectively, real-time elastography, using a linear multifrequency probe and a linear volumetric probe (Hitachi Prerius Machine, Hitachi Inc, Japan). All the nodules were classified using a risk stratification model comprising seven conventional US characteristics, two 4 D characteristics and a color map RTE aspect. The results were compared with the pathology results, considered the golden standard diagnosis.

RESULTS

The prevalence of malignant nodules was 21.83% (57 cases). Conventional risk classification generated: 106 low-risk cases, 113 intermediate-risk and 42 high-risk cases. Our proposed risk classification changes the conventional risk classification with a risk upgrade in 27 cases and with a risk downgrade in 69 cases. The diagnostic quality of the combined risk stratification model was better, considering a low-risk category predictive for benignancy and a high category predictive for malignancy: Sensitivity: 80.88% versus 49.01%, respectively, Specificity: 91.22% versus 54.38. The diagnostic power differences were observed regardless of the nodule size.

CONCLUSION

Advanced ultrasound techniques did add diagnostic value in the presurgical risk assessment of the thyroid nodules.

Interobserver agreement and efficacy of consensus reading in Kwak-, EU-, and ACR-thyroid imaging recording and data systems and ATA guidelines for the ultrasound risk stratification of thyroid nodules

PURPOSE

To investigate the interobserver agreement (IA) and the impact of consensus reading using four risk stratification systems for thyroid nodules (TN).

METHODS

Four experienced specialists independently rated US images of 80 TN according to the Kwak-TIRADS, EU-TIRADS, ACR TI-RADS, and ATA Guidelines. The cases were randomly extracted from a prospectively acquired database (n > 1500 TN). The observers were blinded to clinical data. This study was divided into two sessions (S1 and S2) with 40 image sets each. After every session, a consensus reading was carried out (C1, C2). Subsequently, the effect of C1 was tested in S2 with 40 new cases followed by C2. Fleiss' kappa (κ) was calculated for S1 and S2 to estimate the IA and learning curves. The results of C1 and C2 were used as reference for diagnostic accuracy calculations.

RESULTS

IA significantly increased (p < 0.01) after C1 with κ values of 0.375 (0.615), 0.411 (0.596), 0.321 (0.569), and 0.410 (0.583) for the Kwak-TIRADS, EU-TIRADS, ACR TI-RADS, and ATA Guidelines in S1 (S2), respectively. ROC analysis (C1 + C2) revealed similar areas under the curve (AUC) for the Kwak-TIRADS, EU-TIRADS, ACR TI-RADS, and ATA Guidelines (0.635, 0.675, 0.694, and 0.654, respectively, n.s.). AUC did not increase from C1 (0.677 ± 0.010) to C2 (0.632 ± 0.052, n.s.). ATA Guidelines were not applicable in five cases.

CONCLUSIONS

IA and diagnostic accuracy were very similar for the four investigated risk stratification systems. Consensus reading sessions significantly improved the IA but did not affect the diagnostic accuracy.

Features and outcome of differentiated thyroid carcinoma associated with Graves' disease: results of a large, retrospective, multicenter study

BACKGROUND

Whether differentiated thyroid cancer (DTC) occurring concomitantly with Graves' disease (GD) is more aggressive and bound to a less favorable outcome is controversial.

OBJECTIVE

Aim of this multicenter retrospective study was to compare baseline features and outcome of DTC patients with GD (DTC/GD+) or without GD (DTC/GD-).

PATIENTS

Enrolled in this study were 579 patients referred to five endocrine units (Cagliari, Pavia, Pisa, Siena, and Varese) between 2005 and 2014: 193 patients had DTC/GD+ , 386 DTC/GD-. Patients were matched for age, gender and tumor size. They underwent surgery because of malignancy, large goiter size, or relapse of hyperthyroidism in GD.

RESULTS

Baseline DTC features (histology, lymph node metastases, extrathyroidal extension) did not differ in the two groups, except for multifocality which was significantly more frequent in DTC/GD+ (27.5% vs. 7.5%, p < 0.0001). At the end of follow-up (median 7.5 years), 86% of DTC/GD+ and 89.6% DTC/GD- patients were free of disease. Patients with persistent or recurrent disease (PRD) had "biochemical disease" in the majority of cases. Microcarcinomas were more frequent in the DTC/GD+ group (60% vs. 37%, p < 0.0001) and had an excellent outcome, with no difference in PRD between groups. However, in carcinomas ≥ 1 cm, PRD was significantly more common in DTC/GD+ (24.4% vs. 11.5%; p = 0.005). In the whole group, univariate and multivariate analyses showed that GD+ , lymph node involvement, extrathyroidal invasion, multifocality and tall cell histotype were associated with a worse outcome. Female gender and microcarcinomas were favorable features. No association was found between baseline TSH-receptor antibody levels and outcome. Graves' orbitopathy (GO) seemed to be associated with a better outcome of DTC, possibly because patients with GO may early undergo surgery for hyperthyroidism.

CONCLUSIONS

GD may be associated with a worse outcome of coexisting DTC only if cancer is ≥ 1 cm, whereas clinical outcome of microcarcinomas is not related to the presence/absence of GD.

A Cohort Analysis of Clinical and Ultrasound Variables Predicting Cancer Risk in 20,001 Consecutive Thyroid Nodules

CONTEXT

Assessing thyroid nodules for malignancy is complex. The impact of patient and nodule factors on cancer evaluation is uncertain.

OBJECTIVES

To determine precise estimates of cancer risk associated with clinical and sonographic variables obtained during thyroid nodule assessment.

DESIGN

Analysis of consecutive adult patients evaluated with ultrasound-guided fine-needle aspiration for a thyroid nodule ≥1 cm between 1995 and 2017. Demographics, nodule sonographic appearance, and pathologic findings were collected.

MAIN OUTCOME MEASURES

Estimated risk for thyroid nodule malignancy for patient and sonographic variables using mixed-effect logistic regression.

RESULTS

In 9967 patients [84% women, median age 53 years (range 18 to 95)], thyroid cancer was confirmed in 1974 of 20,001 thyroid nodules (9.9%). Significant ORs for malignancy were demonstrated for patient age <52 years [OR: 1.82, 95% CI (1.63 to 2.05), P < 0.0001], male sex [OR: 1.68 (1.45 to 1.93), P < 0.0001], nodule size [OR: 1.30 (1.14 to 1.49) for 20 to 19 mm, OR: 1.59 (1.34 to 1.88) for 30 to 39 mm, and OR: 1.71 (1.43 to 2.04) for ≥40 mm compared with 10 to 19 mm, P < 0.0001 for all], cystic content [OR: 0.43 (0.37 to 0.50) for 25% to 75% cystic and OR: 0.21 (0.15 to 0.28) for >75% compared with predominantly solid, P < 0.0001 for both], and the presence of additional nodules ≥1 cm [OR: 0.69 (0.60 to 0.79) for two nodules, OR: 0.41 (0.34 to 0.49) for three nodules, and OR: 0.19 (0.16 to 0.22) for greater than or equal to four nodules compared with one nodule, P < 0.0001 for all]. A free online calculator was constructed to provide malignancy-risk estimates based on these variables.

CONCLUSIONS

Patient and nodule characteristics enable more precise thyroid nodule risk assessment. These variables are obtained during routine initial thyroid nodule evaluation and provide new insights into individualized thyroid nodule care.

Ultrasound characterization for thyroid nodules with indeterminate cytology: inter-observer agreement and impact of combining pattern-based and scoring-based classifications in risk stratification

BACKGROUND

The American Thyroid Association (ATA) sonographic patterns stratify the risk of malignancy of cytologically indeterminate thyroid nodules (ITNs). This study aimed to (1) assess inter-observer agreement for sonographic features and patterns; (2) identify potential sources of disagreement; and (3) evaluate whether the number of suspicious features risk-stratifies non-ATA and high-suspicion patterns.

METHODS

Three observers independently reviewed the ultrasound images of 463 ITNs with histological follow-up consecutively evaluated between October 2008 and June 2015 at an academic cancer center. Each observer evaluated individual sonographic features. ATA sonographic patterns were derived from the interpretation of sonographic features. Nodules not fitting into any of the proposed patterns were clustered into a non-ATA pattern.

RESULTS

The inter-observer agreement for ATA sonographic patterns and echogenicity was fair, moderate for margins, good for composition and echogenic foci, and very good for extrathyroidal extension and lymph node metastasis. The interpretation of each sonographic feature was significantly different between observers, and there was complete disagreement in at least one of the features in 104 (22%) nodules. A total of 169 nodules (37%) were classified into the non-ATA pattern. The number of suspicious features allowed risk stratifying nodules with non-ATA and high-suspicion sonographic patterns. Most Non-invasive Follicular Thyroid Neoplasms with Papillary-like Nuclear Features had 0-1 suspicious features and none had >2.

CONCLUSIONS

Echogenicity interpretation was the greatest source of disagreement. The number of suspicious features risk-stratifies ITNs with non-ATA or high-suspicion patterns. Future studies attempting to objectivize the interpretation of echogenicity and heterogeneity are needed.

Development and validation of a preoperative prediction model for follicular thyroid carcinoma

OBJECTIVE

The low pre- and intraoperative diagnostic rates in follicular thyroid carcinoma (FTC) often lead to inadequate surgical resection and necessitate further completion surgery. Therefore, the preoperative prediction of FTC in thyroid nodules is essential. DESIGN AND PATIENT: Patients were categorized into two data sets: the modelling data set, which included 3649 patients admitted to our centre between January 2014 and December 2016, and the validation data set, which included 1253 patients admitted between January and December 2017. Patient data from the FTC and non-FTC groups were initially included in a modelling data set to establish a preoperative prediction model. This model was subsequently employed in a validation data set for external validation of the predictive value. The positivity rate for FTC predicted by the model was compared with that of the intraoperative frozen sections.

RESULTS

The preoperative serum thyroglobulin level, nodule diameter, calcification status, solidity and blood supply were selected as predictors for the model. The regression equation was as follows: Y = 0.010 × (thyroglobulin level) + 0.556 × (nodule diameter) + 0.675 × (calcification status) + 2.355 × (nodule component) + 1.072*(blood flow) - 9.787. The model positively predicted FTC at values of Y ≥ -4.11. The accuracy, sensitivity, specificity, positive likelihood ratio and negative likelihood ratio of the prediction model were 89.2%, 90.2%, 87.7%, 39.2 and 0.11, respectively. External validation of the model demonstrated acceptable results. The positive prediction rate of the model was 90.7% (78/86), which was significantly higher than that of the intraoperative frozen sections (10.5% [9/86]; P < 0.0001).

CONCLUSIONS

We successfully established and validated a simple and reliable preoperative prediction model for FTC using the preoperative thyroglobulin level and ultrasonographic features of the thyroid nodules. This model may improve the preoperative evaluation of FTC in clinical settings and facilitate the development of a reasonable surgical programme for FTC.

The association between the ultrasonography TIRADS classification system and surgical pathology among indeterminate thyroid nodules

BACKGROUND

A high proportion of cytologically indeterminate, Afirma-suspicious thyroid nodules are benign. The Thyroid Imaging Reporting and Data System was proposed by the American College of Radiology in 2015 to determine appropriate management of thyroid nodules in a standardized fashion. Our aim was to determine the diagnostic value of the Thyroid Imaging Reporting and Data System in cytologically indeterminate and Afirma-suspicious nodules.

METHODS

We retrospectively queried cytopathology archives for retrospectively for thyroid fine-needle aspiration specimens obtained between February 2012 and September 2016 that were associated with the following: (1) indeterminate diagnosis, (2) ultrasonographic imaging at our institution, (3) an Afirma Gene Expression Classifier-suspicious result, and (4) surgery at our institution. We then calculated the diagnostic value of the Thyroid Imaging Reporting and Data System in predicting surgical pathology.

RESULTS

Our cohort consisted of 133 nodules among 131 patients who underwent thyroid surgery for cytologically indeterminate, Afirma-suspicious nodules. A total of 9 nodules (6.8%) were assigned TR2 "not suspicious," 25 (18.8%) TR3 "mildly suspicious," 81 (60.9%) TR4 "moderately suspicious," and 18 (13.5%) TR5 "highly suspicious." Among our cohort, the sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of the Thyroid Imaging Reporting and Data System was 71.4%, 38.1%, 40.2%, 69.6%, and 50.4%, respectively.

CONCLUSION

Among cytologically indeterminate and Afirma-suspicious nodules, the Thyroid Imaging and Reporting and Data System was a poor predictor of final surgical pathology. Additional prospective studies are needed to validate these findings.

Fine-needle aspiration in all thyroid incidentalomas at 18 F-FDG PET/CT: Can EU-TIRADS revise the dogma?

OBJECTIVE

Focal thyroid incidentalomas (TIs) are observed in 2% of ¹⁸ F-FDG PET/CT representing malignancy in one-third of cases. Currently, due to the lack of evidence on their optimal management, guidelines suggest fine-needle aspiration cytology (FNAC). The study aim was to evaluate the role of ultrasound evaluation according to EU-TIRADS to assess the risk of TIs and inform FNAC prescriptions.

DESIGN

We retrospectively reviewed ¹⁸ F-FDG PET/CT TIs recorded during the period 2014-2017. Enrolled were TIs with histological outcome and autonomous nodules. Cases with uncertain matching between ¹⁸ F-FDG PET/CT, ultrasound and histology were excluded.

RESULTS

According to the selection criteria, 75 TIs, being 13 (17.3%) malignant and 62 (82.7%) benign, were included. Cancers had significantly higher SUVmax and SUVmax ratio (Mann-Whitney P < 0.01) than benign, and the most accurate cut-offs were >7.1 and >3.65, respectively. At ultrasound, the cancer rate was 0% in EU-TIRADS 2, 2.9% in EU-TIRADS 3, 4.2% in EU-TIRADS 4% and 78.6% in EU-TIRADS 5 (chi-squared P < 0.001). Sensitivity, specificity, PPV, NPV and accuracy for malignancy were 92%, 64%, 35%, 98% and 69% for SUVmax; 85%, 68%, 36%, 96% and 71% for SUVmax ratio; and 85%, 95%, 79%, 97% and 93% for EU-TIRADS, respectively. The absence of all these three features reached a specificity of 97.1%.

CONCLUSIONS

EU-TIRADS, within a clinical careful approach, can discriminate with significant accuracy lesions at high risk of malignancy from those at low risk among TIs at ¹⁸ F-FDG PET/CT. Additionally, a centre-based threshold for SUV parameters should be useful for the initial assessment of these lesions during PET/CT reading and reporting.

THYROID NODULE LOCATION ON ULTRASONOGRAPHY AS A PREDICTOR OF MALIGNANCY

OBJECTIVE

The diagnostic capacity of ultrasonography (US) for differentiating between malignant and benign thyroid nodules is crucial in preventing unnecessary invasive procedures. This is the first study to evaluate whether thyroid nodule location on US has predictive value for malignancy.

METHODS

We retrospectively reviewed data from 219 patients with thyroid nodules who underwent fine-needle aspiration biopsy in 1 year. Patients' demographics as well as nodule's laterality, polarity, morphology, and multinodularity were analyzed. All malignant lesions were confirmed by surgical pathology.

RESULTS

The majority of the patients were female (86.2%). Nodules were evenly distributed between the right lobe (46.3%) and left lobe (49.5%). Eight nodules (4.2%) were located in the isthmus. Most nodules (79.3%) were located in the lower pole, while 9.6% were located in the upper pole and 6.9% in the middle pole. Seventy-five patients (39.9%) had multiple nodules. Fourteen nodules were malignant, representing a prevalence of 7.4%. A significantly higher frequency of malignancy was observed in upper pole (22.2%) compared to lower pole (4.7%) and middle pole (15.4%). A multiple logistic regression model confirmed such association after adjusting for age, body mass index, multinodularity, and laterality. The odds of malignancy in the upper pole were 4 times higher than other locations (odds ratio, 4.6; P = .03).

CONCLUSION

Our study is the first showing that thyroid nodules located in the upper pole can be considered as having higher risk for malignancy. It may enhance the predictive value of malignancy if it is included in thyroid nodule ultrasound classification guidelines.

ABBREVIATIONS

AACE = American Association of Clinical Endocrinologists; ATA = American Thyroid Association; BMI = body mass index; FNA = fine-needle aspiration; TMS = total malignancy score; TTW = taller than wide; US = ultrasonography.

Hounsfield unit value has null effect on thyroid nodules at 18F-FDG PET/CT scans

OBJECTIVES

Detection rate of thyroid nodules is increasing with the use of new imaging modalities, especially in screening for malignancies. Positron emission tomography/computed tomography (PET/ CT)-positive thyroid nodules should be differentiated for malignancy to avoid unnecessary operations and further follow-up. Most trials evaluate the role of SUVmax, but there is no definitive information about the utility of Hounsfield unit (HU) values for prediction of malignancy. This study aimed to evaluate the HU values beside SUVmax for detecting malignancy risk of PET/CT-positive thyroid nodules.

SUBJECTS AND METHODS

Results of 98 cancer patients who had fine needle aspiration biopsy (FNAB) for thyroid nodules detected on PET/CT between January 2011 and December 2015 were assessed. The FNABs and surgical pathological results were recorded.

RESULTS

FNABs revealed benign results in 32 patients (32.7%), malignant in 18 (18.4%), non-diagnostic in 20 (20.4%), and indeterminate in 28 (28.5%). Twenty-four patients underwent thyroidectomy. The mean HU values were not significantly different in benign and malignant nodules (p = 0.73). However, the mean SUVmax was significantly higher (p < 0.001) in malignant ones. Area under curve (AUC) was 0.824 for SUVmax; the cut-off value was over 5.55 (p < 0.001), with 80% sensitivity, 84.5% specificity.

CONCLUSIONS

Our current study demonstrated that HU value does not add any additional valuable information for discriminating between malignant and benign thyroid nodules. We also defined a SUV cut-off value of 5.55 for malignant potential of thyroid nodules detected on PET/CT Arch Endocrinol Metab. 2018;62(4):460-5.

Radiation and Second Primary Thyroid Cancer Following Index Head and Neck Cancer

OBJECTIVES/HYPOTHESIS

Radiation is thought to increase risk of developing second primary thyroid cancer (SPTC). This study estimated the rate of SPTC following index head and neck cancer (HNC) and determined whether radiation treatment among HNC survivors increased SPTC risk.

STUDY DESIGN

Retrospective data analysis.

METHOD

The Surveillance, Epidemiology, and End Results database (1975-2014) was queried for cases of index HNC (N = 127,563) that developed SPTC. Adjusted multivariable competing risk proportional hazards model tested risk of developing a SPTC following index HNC. Sensitivity analyses using proportional hazards models were also performed restricting data to patients who 1) received both radiation and chemotherapy and 2) radiation alone.

RESULTS

Only 0.2% of index HNC survivors (n = 229) developed SPTC, yielding a rate of 26.1 per 100,000 person-years. For every increasing year of age at diagnosis, patients were 3% less likely to develop an SPTC (adjusted hazard ratio [aHR] = 0.97, 95% CI: 0.96-0.98). Males were also less likely to develop an SPTC (aHR = 0.73, 95% CI: 0.55-0.96). Radiation (aHR = 0.92, 95% CI: 0.68-1.25), surgery (aHR = 0.79, 95% CI: 0.56-1.11), and chemotherapy (aHR = 1.13, 95% CI: 0.76-1.69) were not significantly associated with developing SPTC. The sensitivity models also did not find an association between treatment and risk of SPTC.

CONCLUSIONS

Rate of developing SPTC following index HNC was very low, and previous exposure to radiation did not significantly increase risk in our study population. More studies are needed to understand the increasing incidence of thyroid cancer across the United States.

LEVEL OF EVIDENCE

NA Laryngoscope, 129:1014-1020, 2019.

The Frequency of Focal Thyroid Incidental Findings and Risk of Malignancy Detected by 18F-Fluorodeoxyglucose Positron Emission Tomography in an Iodine Deficient Population

Incidental focal uptake of 18F-fluorodeoxyglucose (FDG) in the thyroid on positron emission tomography (PET/CT) is rare but often associated with malignancy. The epidemiology of thyroid incidentalomas has only to some extent been described in countries with iodine deficiency. Here we report data from Denmark, a country with known iodine deficiency and wide access to PET/CT. All FDG PET/CT comprising the head and neck region, during 2014, were retrospectively reviewed, and patients with focal FDG uptake in the thyroid gland were identified. A total of 2451 patients had an FDG PET/CT of which 59 (2.4%) patients presented with FDG-avid focal lesions in the thyroid gland. Among the 59 patients with FDG-avid lesions, 33 patients (56%) received work up with ultrasound, thyroid technetium scintigraphy, fine needle aspiration, and/or histology of which 20 patients had a conclusive pathology report. Ten patients with FDG-avid lesions were identified with thyroid malignancy. The risk of thyroid malignancy was 16.9% among patient with incidental FDG-avid thyroid lesions. Our findings indicated a similar frequency of FDG thyroid incidentalomas and malignancy rates in an iodine deficient population compared to summary data from prior studies, studies mostly performed in geographical areas of normal or excess iodine supplementation.

Prospective Validation of ATA and ETA Sonographic Pattern Risk of Thyroid Nodules Selected for FNAC

CONTEXT

Recently, the American Thyroid Association (ATA) and the European Thyroid Association (ETA) have proposed that thyroid ultrasound (US) should be used to stratify the risk of malignancy in thyroid nodules and to aid decision-making about whether fine-needle aspiration cytology (FNAC) is indicated.

OBJECTIVE

To validate and to compare the ATA and ETA US risk stratification systems of thyroid nodules in a prospective series of thyroid nodules submitted to FNAC.

SETTING

We prospectively evaluated 432 thyroid nodules selected for FNAC from 340 patients. Cytology reports were based on the five categories according to the criteria of the British Thyroid Association.

RESULTS

The proportion of Thy2 nodules decreased significantly, whereas the proportion of Thy4/Thy5 nodules significantly increased with increasing US risk class (P < 0.0001). The ability to identify benign and malignant nodules was similar between ATA and ETA systems. According to ATA and ETA US risk stratification systems, 23.7% and 56.0% nodules did not meet the criteria for FNAC, respectively. Considering only categories at lower risk of malignancy, the cumulative malignancy rate in these nodules was 1.2% for ATA and 1.7% for ETA US risk stratification systems.

CONCLUSIONS

ETA and ATA US risk stratification systems provide effective malignancy risk stratification for thyroid nodules. In clinical practice, using this approach, we should be able to reduce the number of unnecessary FNAC without losing clinically relevant thyroid cancer.

Thyroid Incidentalomas Detected on 18F-Fluorodeoxyglucose Positron Emission Tomography with Computed Tomography: Malignant Risk Stratification and Management Plan

OBJECTIVE

The aims of this study were to stratify the risk of malignancy in thyroid incidentalomas detected on ¹⁸F-fluorodeoxyglucose positron emission tomography with computed tomography (¹⁸F-FDG PET/CT) using ultrasound features according to guidelines for thyroid nodules and to develop a subsequent management plan.

METHODS

From a historical cohort of 96,942 consecutive patients who underwent ¹⁸F-FDG PET/CT between October 2008 and September 2015, 1342 patients with 1364 nodules underwent ultrasound evaluation for focal uptake in thyroid gland, with a final diagnosis made for 877 patients with 907 nodules, which were included in this study. Ultrasound images were retrospectively reviewed, and they were stratified according to the American Thyroid Association and Korean Thyroid Image Reporting and Data System guidelines. The calculated malignancy risks were compared with the estimated risks suggested by the guidelines.

RESULTS

The overall malignancy risk of thyroid incidentalomas detected on ¹⁸F-FDG PET/CT was 54.7%. When stratified according to the American Thyroid Association guidelines, the malignancy risks of thyroid incidentalomas with high and intermediate suspicion (93.2% and 45.2%, respectively) were higher than those indicated in the guidelines. The malignancy risks of thyroid incidentalomas with low and very low suspicion (8.1% and 0%, respectively) were within the guideline ranges. These findings were also noted when thyroid incidentalomas were stratified according to the Korean Thyroid Image Reporting and Data System, and in a subgroup of nodules >1 cm.

CONCLUSIONS

Ultrasound examinations can be used to stratify the malignancy risk of thyroid incidentalomas detected on ¹⁸F-FDG PET/CT. The risk of malignancy did not increase in thyroid incidentalomas with low and very low suspicion, indicating that only selective biopsies may be needed in these categories of thyroid incidentalomas.

Ultrasound requested by general practitioners or for symptoms unrelated to the thyroid gland may explain higher prevalence of thyroid nodules in females

BACKGROUND

A higher prevalence of thyroid nodules/carcinoma in females is well-known from the literature. The reasons for this difference are not fully explained. We intended to assess gender variation in the referral for ultrasound-guided fine needle aspiration (FNA) of thyroid nodules, to study reasons for gender referral differences, and to assess differences in nodules characteristics between genders.

METHODS

Included were 272 consecutive patients, with 290 nodules submitted to FNA. Patients were questioned on the reason why ultrasound (US) examination was required. Electronic medical records were reviewed. Nodules' ultrasound/cytological characteristics were assessed. Variables studied: referral cause; referral pattern (hospital-specialist versus general-practitioner); number of nodules; age, thyroid function; nodule size, TIRADS classification, resistive index, Doppler pattern, Bethesda categorisation. Variables were compared between males and females referred for FNA. Significant variables were assessed with logistic regression.

RESULTS

Of the 272 patients, 215(79%) were women with a female:male referral ratio for FNA of 3.8:1. Non-parametric statistically significant differences (p < 0.05) were found between genders in: thyroid function, nodule size, referral pattern and referral cause. Nodule size and thyroid function tests became non-significant in logistic regression. Cause and referral pattern remained significantly associated with gender. Referral by a general-practitioner was associated with a 2.6-fold increase in odds of referring a female. Causes unrelated to the thyroid were associated with a 3.2-fold increase in odds of female reference.

CONCLUSIONS

A referral bias might be responsible for the higher rate of thyroid nodules in female patients, both due to referral by general practitioners and due to causes indirectly related to the thyroid gland.

Ultrasound criteria for risk stratification of thyroid nodules in the previously iodine deficient area of Austria - a single centre, retrospective analysis

Background

We aimed to study the validity of six published ultrasound criteria for risk stratification of thyroid nodules in the former severely iodine deficient population of Austria.

Methods

Retrospective, single centre, observer blinded study design. All patients with a history of thyroidectomy due to nodules seen in the centre between 2004 and 2014 with preoperative in-house sonography and documented postoperative histology were analyzed (n = 195). A board of five experienced thyroidologists evaluated the images of 45 papillary carcinomas, 8 follicular carcinomas, and 142 benign nodules regarding the following criteria: mild hypoechogenicity, marked hypoechogenicity, microlobulated or irregular margins, microcalcifications, taller than wide shape, missing thin halo.

Results

All criteria but mild hypoechogenicity were significantly more frequent in thyroid cancer than in benign nodules. The number of positive criteria was significantly higher in cancer (2.79 ± 1.35) than in benign nodules (1.73 ± 1.18; p < 0.001). Thus, with a cut-off of two or more positive criteria, a sensitivity of 85% and a specificity of 45% were reached to predict malignancy in this sample of thyroid nodules. As expected, the findings were even more pronounced in papillary cancer only (2.98 ± 1.32 vs. 1.73 ± 1.18, p < 0.001). The six ultrasound criteria could not identify follicular cancer.

Conclusion

Our findings support the recently published EU-TIRADS score. Apart from mild hypoechogenicity, the analyzed ultrasound criteria can be applied for risk stratification of thyroid nodules in the previously severely iodine deficient population of Austria.

Use of the thyroid imaging, reporting, and data system (TI-RADS) scoring system for the evaluation of subcentimeter thyroid nodules

BACKGROUND

The American Thyroid Association (ATA) recommends fine-needle aspiration (FNA) biopsy of nodules measuring >1.5 cm with low-suspicion sonographic patterns or >1.0 cm with high/intermediate-suspicion features. Routine biopsy of nodules <1 cm is not recommended. However, despite these recommendations, subcentimeter nodules are often referred for FNA biopsy.

METHODS

This was a retrospective chart review of consecutive thyroid FNAs during an 18-month period (1157 patients, 1491 nodules, 2016-2017) to evaluate age, sex, medical history, diagnoses, and follow-up. Radiographic information was used to identify 61 subcentimeter nodules (4%) from 57 patients. Ultrasound studies were re-evaluated using criteria according to the American College of Radiology Thyroid Imaging, Reporting, and Data System (TI-RADS).

RESULTS

Reported reasons for biopsy included a larger companion nodule (44%), a personal or family history of cancer (26%), or a suspicious sonogram, including calcification and/or irregular contours (16%). FNA diagnoses included: 69% benign (42 of 61 nodules), 10% papillary thyroid carcinoma (PTC) (6 of 61 nodules), and 15% atypia of undetermined significance/follicular lesion of undetermined significance (AUS/FLUS) (9 of 61 nodules). Seven percent of nodules were unsatisfactory/nondiagnostic (4 of 61 nodules) compared with a 3% nondiagnostic rate for all sized nodules. Fifty-one nodules had an ultrasound available for re-review using the TI-RADS scoring system. A high TI-RADS score (4-5) was indicative of PTC in 29.4% of nodules. A low TI-RADS score (1-2) was indicative of PTC in 0% of nodules (P < .01). High and intermediate TI-RADS scores (3 and 4-5, respectively) were indicative of PTC/AUS/FLUS in 32% of nodules compared with 0% in those with low TI-RADS scores (P < .01).

CONCLUSIONS

The current results demonstrate successful use of the TI-RADS scoring system in evaluation of the risk of malignancy in subcentimeter nodules. Larger studies will be necessary to determine whether biopsy is warranted for TI-RADS high-subcentimeter nodules. Cancer Cytopathol 2018. © 2018 American Cancer Society.

The prevalence of thyroid nodules in northwest China and its correlation with metabolic parameters and uric acid

This study aimed to estimate the prevalence of thyroid nodules (TN) and investigate its correlation with metabolic parameters, especially uric acid (UA) in northwest Chinese population. We conducted a large cross-sectional survey with 67,781 residents (33,020 men, 34,761 women), aged from 18 to 86 years in Shanxi, China, from January 2012 to December 2014. A thyroid ultrasound examination was performed with number and size of nodules being recorded. Metabolic parameters including body mass index (BMI), blood pressure (BP), triglycerides (TG), total cholesterol (TC), low-density lipoprotein cholesterol (LDL-c), high-density lipoprotein cholesterol (HDL-c), fasting glucose (FG), and uric acid (UA) were also examined. Our study revealed that approximately 30.7% of men and 39.9% of women in Northwest China had TN, about half of which were multi-nodularity and a quarter of their TN larger than 1 cm. The prevalence of TN increased with aging and increasing BMI, and metabolic disorders, which also related to the increased incident of multi-nodularity and larger TN. Serum UA appeared to be a protective factor for TN in men older than 30 years, but a risk factor in both men younger than 30 years and women older than 30 years. This phenomenon needs to be further investigated.

Preoperative diagnostics in differentiated thyroid carcinoma

AIM

The preoperative diagnosis of differentiated thyroid carcinomas (DTC) is particularly challenging in view of the high prevalence of thyroid nodules in the general population. Incidental diagnosis of DTC, on the other hand, can lead to reoperations and increased risk of morbidity. This study aimed to assess the prediction value of preoperative DTC dignity assessment and it's impact on surgical approaches.

METHODS

We retrospectively reviewed 107 cases of DTC and subdivided them in three groups based on the preoperative dignity assessment: suspected malignancy (SM), unclear dignity (UD), and incidental findings (IF). The group differences were investigated in terms of diagnostic methods, findings, and impact on the subsequent surgical approach.

RESULTS

The patient groups consisted of n = 51 (SM), n = 32 (UD), and n = 24 (IF). The tumor size, T staging, and ultrasound (US) assessment had the largest impact on the dignity classification (each p < 0.001). Scintigraphy was performed in 80 % of the patients, fine-needle aspiration cytology (FNAC) in 28 %. Hypofunction at scintigraphy (p < 0.001) and cytology results (p < 0.01) were identified as significant predictors for group assignment. Other significant factors were the frequency of the US documentation of nodule characteristics (p < 0.001) and malignancy criteria (p < 0.01) as well as reduced thyroid-stimulating hormone (TSH) levels (p < 0.01). Frozen section (p < 0.001) and total thyroidectomy (p < 0.01) at initial surgery were performed significantly more often in the MV group. Reoperations were significantly more frequent in the IF group (p < 0.001).

CONCLUSIONS

A relevant number of DTC cases was diagnosed incidentally, leading to significantly more frequent reoperations. A more systematic diagnostic approach with complete documentation of the findings according to current guidelines should be pursued.

Factors affecting operative time in robotic thyroidectomy

BACKGROUND

The purpose of this study was to evaluate factors related to operative time in robotic thyroidectomy.

METHODS

We retrospectively analyzed 240 patients who underwent robotic thyroidectomy. The total thyroidectomy cases and lobectomy cases were both categorized into those with long operative times (LOTs; upper 25% of cases) and those with short operative times (SOTs; lower 25%).

RESULTS

Among the total thyroidectomy cases, body mass index (BMI) ≥23 kg/m² (hazard ratio [HR] 5.34; P = .008) and bilateral central neck dissection (CND; HR 14.92; P = .028) were more frequent in the LOT group in multivariate analysis. Among the lobectomy cases, BMI ≥23 kg/m² (HR 12.92; P = .003) and unilateral CND (HR 21.38; P = .017) were the only independent risk factors for prolonged operative time.

CONCLUSION

Body habitus and clinical nodal status in the central compartment should be considered in deciding the indications for robotic thyroidectomy.

Thyroid Nodule Diagnostic Markers in the Face of the New NIFTP Category: Time for a Reset?

BACKGROUND

Current thyroid molecular tests are specifically designed for the differential diagnosis of nodules with indeterminate or suspicious fine-needle aspiration (FNA) cytology.

SUMMARY

However, their clinical validity faces challenges from both variation among institutions in cancer prevalence and, most recently, the new category of non-invasive follicular thyroid neoplasm with papillary-like nuclear features (NIFTP). The latter diagnosis was previously classified as malignant. Relevant to this, all molecular panels on the market today were originally tested and validated within the context of these entities being considered malignant.

CONCLUSION

This review examines possible effects of the NIFTP reclassification as a precancerous lesion on the original validation studies and, investigates the effect of the significant reported variability in thyroid cancer prevalence on the performance of these tests.

Risk Factors for Thyroid Cancer in Systemic Lupus Erythematosus

We studied 3 patients with systemic lupus erythematosus (SLE) who developed thyroid cancer (TC). Potential risk factors for TC development was explored. Fifty-three patients with a clinical diagnosis of rheumatic diseases including SLE at our hospital between July 2014 and December 2014 were enrolled. Demographic, clinical, and laboratory findings were retrospectively compared between TC-positive and TC-negative patients. Among rheumatic diseases, lymphadenopathy/splenomegaly at treatment commencement, and lymphadenopathy/splenomegaly, painless ulcer (oral, nasal, or mucosal), and weight loss during the entire study period were precipitating factors. Lower current values of hemoglobin and methylprednisolone pulse therapy favored TC development. In 29 SLE patients, lymphadenopathy/splenomegaly at treatment commencement, lymphadenopathy/splenomegaly and weight loss during the entire study period, urinary granular casts at treatment commencement, and a lower current value of hemoglobin predisposed patients to TC. Several risk factors of TC are present in pediatric SLE. Patients with SLE should be investigated vigorously for TC with ultrasound.

European Thyroid Association Guidelines for Ultrasound Malignancy Risk Stratification of Thyroid Nodules in Adults: The EU-TIRADS

Thyroid ultrasound (US) is a key examination for the management of thyroid nodules. Thyroid US is easily accessible, noninvasive, and cost-effective, and is a mandatory step in the workup of thyroid nodules. The main disadvantage of the method is that it is operator dependent. Thyroid US assessment of the risk of malignancy is crucial in patients with nodules, in order to select those who should have a fine needle aspiration (FNA) biopsy performed. Due to the pivotal role of thyroid US in the management of patients with nodules, the European Thyroid Association convened a panel of international experts to set up European guidelines on US risk stratification of thyroid nodules. Based on a review of the literature and on the American Association of Clinical Endocrinologists, American Thyroid Association, and Korean guidelines, the panel created the novel European Thyroid Imaging and Reporting Data System, called EU-TIRADS. This comprises a thyroid US lexicon; a standardized report; definitions of benign and low-, intermediate-, and high-risk nodules, with the estimated risks of malignancy in each category; and indications for FNA. Illustrated by numerous US images, the EU-TIRADS aims to serve physicians in their clinical practice, to enhance the interobserver reproducibility of descriptions, and to simplify communication of the results.

US-Guided Percutaneous Radiofrequency versus Microwave Ablation for Benign Thyroid Nodules: A Prospective Multicenter Study

Compared with microwave ablation (MWA), percutaneous radiofrequency ablation (RFA) and laser ablation (LA) have been recommended as minimally invasive treatments for patients with symptomatic benign thyroid nodules (BTNs) because of the large number of clinical applications. This prospective multicenter study sought to evaluate the clinical outcomes of RFA and MWA for BTNs. In eight participating institutions, the total number of 1252 patients treated by RFA and MWA were 649 ones with 687 BTNs and 603 ones with 664 BTNs, respectively. The clinical outcomes including the nodular maximal diameter reduction ratio (MDRR), the nodular volume reduction ratio (VRR), and the incidence of complications were compared to evaluate the efficacy and safety of the two techniques. The results for the nodular MDRR and VRR in the RFA group were significantly better than those in the MWA group at 6 months and later follow-up, and the major complication rates of 4.78% and 6.63% in RFA and MWA groups showed no statistically significant differences. In conclusion, both RFA and MWA are safe and effective techniques for selected patients with symptomatic BTNs. The achieved MDRR and VRR in the RFA group were greater than those in the MWA group at 6 months and later follow-up.

Selection of Atypia/Follicular Lesion of Unknown Significance Patients for Surgery Versus Active Surveillance, Without Using Genetic Testing: A Single Institute Experience, Prospective Analysis, and Recommendations

BACKGROUND

Atypia/follicular lesion of unknown significance (AUS/FLUS) has variable rates of malignancy. The recommended management includes active surveillance (AS), repeated fine-needle aspiration (RFNA), diagnostic surgery, or genetic testing for malignancy. The objective of this study was to assess the management of AUS/FLUS patients in a dedicated thyroid clinic without implementing genetic testing.

METHODS

This was a single institute cohort study of all patients aged ≥18 years who underwent ultrasound-guided FNA thyroid biopsies between January 2009 and January 2013 and were followed until January 2016. The median follow-up time was 4.6 years (range 3.2-6.8 years). Forty-eight (57%) patients were referred to AS, and 36 (43%) patients were referred for diagnostic surgery. Thirty-six (75%) patients from the AS group underwent RFNA. An additional eight patients from the AS group subsequently underwent diagnostic surgery.

RESULTS

Malignancies were found in 15/44 (34%) diagnostic surgical samples, and benign cytologies were found in 61.1% of the RFNAs. Analysis of adherence to follow-up in the 36 AS patients showed an adherence rate of only 53%, with males tending to comply better than females did (31.6% vs. 5.8%, respectively; p = 0.052), especially males in their sixth decade of life.

CONCLUSIONS

Genetic tests for AUS/FLUS patients are accepted today as complementary evaluations in many well-developed health systems. Yet, when these tests are not feasible due to financial or availability issues, careful management of AUS/FLUS patients may still offer good results in the selection of patients for surgery or AS. The present results also indicate that compliance to follow-up schedules is a major consideration when selecting patients for AS.

Fine-Needle Aspiration Versus Frozen Section in the Evaluation of Malignant Thyroid Nodules in Patients With the Diagnosis of Suspicious for Malignancy or Malignancy by Fine-Needle Aspiration

Context.—

The Bethesda System for Reporting Thyroid Cytopathology recommends against the use of intraoperative frozen section (FS) during lobectomy of a thyroid nodule with a fine-needle aspiration (FNA) diagnosis of malignant. Bethesda recommendations for FS in the FNA category of suspicious for malignancy (SFM) is less well-defined. In some institutions in China, FS examination is performed during lobectomy even for FNA-proven malignant cases.

Objective.—

—To compare the efficacy of FNA versus FS in the evaluation of malignant thyroid lesions.

Design.—

A 3-year retrospective analysis from a single institution was performed on cases with an FNA diagnosis of SFM or malignant with subsequent FS examination during thyroidectomy. The results of FNA and FS findings were compared to the final thyroidectomy pathology.

Results.—

—A total of 5832 thyroidectomy procedures were performed: 1265 cases had FNA and FS results available. Fine-needle aspiration gave a diagnosis of SFM to 306 cases and a diagnosis of malignant to 821 cases. Of the SFM cases, 10.5% (32 of 306) had benign/indeterminate, 4.6% (14 of 306) suspicious, and 84.9% (260 of 306) malignant FS results. Final pathology showed 56.3% (18 of 32), 64.3% (9 of 14), and 100% (260 of 260) malignancy rates, respectively. For the malignant FNA group, 10.0% (82 of 821) had benign/indeterminate, 4.4% (36 of 821) suspicious, and 85.6% (703 of 821) malignant FS results. The final pathology showed 96.4% (79 of 82), 97.2% (35 of 36), and 99.9% (702 of 703) malignancy rates, respectively.

Conclusions.—

Frozen section should not be performed for the malignant FNA category because FS evaluation may result in 10% falsely negative findings. Performing FS for SFM may be better justified; however, more than half of FS cases read as benign in this category had malignant final pathology. Therefore, caution should be taken for FS results even in the SFM group.

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

OBJECTIVE

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

What is the care pathway of patients who undergo thyroid surgery in France and its potential pitfalls? A national cohort

CONTEXT

The rate of thyroid cancer is increasing in France, as well as concerns about overdiagnosis and treatment.

OBJECTIVES

To examine the care pathway of patients who undergo thyroid surgery in France and detect potential pitfalls.

DESIGN

A large observational study based on medical reimbursements, 2009-2011.

SETTING

Data from the Sniiram (National Health Insurance Information System).

PATIENTS

Patients with thyroid surgery in 2010, classified into 4 groups: thyroid cancer, benign nodule, goitre or multiple nodules, other (hyperthyroidism, head-neck cancer).

MAIN OUTCOME MEASURES

Medical investigations during, prior and after thyroidectomy.

RESULTS

A total of 35 367 patients underwent surgery (mean age 51 years, 80% women): 17% had a reported diagnosis of thyroid cancer, 20% benign nodule, 38% goitre or multiple nodules and 25% another diagnosis. The ratio of thyroidectomies with cancer over thyroidectomies with benign nodule was 0.8 and varied across regions. In the year preceding surgery, 82% of patients had an investigation by thyroid ultrasonography, 21% thyroid scintigraphy, 34% fine-needle aspiration cytology, 40% serum calcitonin assay and 54% serum calcium assay. In the following year, all patients with total thyroidectomy and 44% of patients with partial thyroidectomy and a diagnosis of benign nodule were taking thyroid hormone therapy. 100 patients had been reoperated for a compressive haematoma and 63 died during the first month, half of whom had been operated for cancer. Mean rates of recurrent laryngeal nerve injury and hypocalcaemia (requiring blood tests plus treatments within 4-12 months) were estimated at 1.5% and 3.4%, respectively, and were higher in the cancer group (2.3% and 5.7%).

CONCLUSIONS

This almost nationwide study demonstrates the suboptimal management of patients prior to thyroidectomy in France. It suggests overdiagnosis and potential harms to patients, and calls for a review of the relevance of thyroidectomy, particularly with regard to microcancers.

A 2016 Italian Survey about Guidelines and Clinical Management of Thyroid Nodules

BACKGROUND

While thyroid nodules are frequent in endocrine clinical practice, patients are often asymptomatic and euthyroid, and death is rare in cases of malignancy.

OBJECTIVES

To evaluate the perception of current international guidelines regarding thyroid nodule management among Italian endocrinologists, and to compare daily clinical practice with suggested recommendations.

METHODS

Italian Association of Clinical Endocrinologists (AME) members were invited to participate in a Web-based survey.

RESULTS

A total of 566 physicians responded. About 50% had read the full text of the guidelines. Over half appreciated the suggested ultrasound (US) risk categories. Fine-needle aspiration (FNA) was obtained more frequently than recommended. Follow-up of a cytologically benign nodule was largely performed according to the guidelines. Molecular testing would be most commonly requested when cytology reports showed atypia of undetermined significance/follicular lesion of undetermined significance (AUS/FLUS) (TIR3A for Italian System). Iodine and/or levothyroxine were largely prescribed for cytologically benign asymptomatic nodules. Laser/radiofrequency ablation and percutaneous ethanol injection were commonly considered as alternatives to surgery (46.2 and 71.4%, respectively).

CONCLUSIONS

Efforts are needed to make the guidelines more user-friendly and to encourage the use of codified risk categories in thyroid US reports. FNA indications remain a matter of debate as FNA is obtained in clinical practice more often than is recommended. Current US follow-up modalities for a benign nodule are correct, but probably could be performed less frequently without any harm. Molecular testing, if accessible, would be helpful in guiding clinicians' strategies in cases of AUS/FLUS-TIR3A cytologic results. Nonsurgical procedures are favorably embraced.

Ultrasonographic prevalence and characteristics of non-palpable thyroid incidentalomas in a hospital-based population in a sub-Saharan country

Background

Thyroid incidentalomas (TI) are highly prevalent asymptomatic thyroid nodules with ultrasound as the best imaging modality for their detection and characterization. Although they are mostly benign, potential for malignancy is up to 10–15%.

In sub-Saharan Africa little data exists on the prevalence and risk categorization of TI. The aim of this study was to determine the prevalence and ultrasound characteristics of non-palpable thyroid incidentalomas among adults in sub-Saharan setting.

Methods

A cross sectional study was carried out between March and August 2015, at two university teaching hospitals. Sampling was consecutive and included all adults aged ≥ 16 years, presenting for any ultrasound other than for the thyroid, with no history or clinical signs of thyroid disease, and no palpable thyroid lesion. Ultrasound was done using 4 to 11 MHz linear probes. Subjects with diffuse thyroid abnormalities were excluded. Variables studied were age, gender, thyroid volume, ultrasound characteristics of thyroid nodules, TIRADS scores. Differences were considered statistically significant for p-value < 0.05.

Results

The prevalence of TI was 28.3% (126 persons with TI /446 examined). This prevalence was 46.2% in population ≥ 61-year-old; 6.3% in population ≤ 20-year-old; 33.3% for females and 18.4% for males (p < 0.001). Of the 241 TI found, 49.4% were cysts, 33.6% solid, 17.0% mixed; 37.8% <5 mm and 22% >10 mm. Solid TI were mainly hyperechoic (42.0%), 3/81 were markedly hypoechoic. Sixty-nine out of 126 persons with TI (54.8%) had at least two nodules. Solitary nodules were predominant in the age group ≤20 years. Of 241 TI, 129 (53.5%) were classified TIRADS 2, 81 (33.6%) TIRADS 3, 25 (10.4%) TIRADS 4A, 6 (2.5%) TIRADS 4B, and none TIRADS 5. Characteristics associated with increased risk of malignancy where mostly founded on solid nodules (p < 0.000) and nodules larger than 15 mm (p < 0.001).

Conclusion

Thyroid incidentalomas were very frequent with a prevalence of 28.3% and potential risk of malignancy in 12.9%. Prevalence had a tendency to increase with age and in female. Cystic nodules were the most prevalent. Potential for malignancy would be increased for larger and solid nodules.

Evaluation of Diagnostic Performance of Screening Thyroid Ultrasonography and Imaging Findings of Screening-Detected Thyroid Cancer

Purpose

The purpose of this study was to evaluate the diagnostic performance and cost of screening thyroid ultrasonography (US) in an asymptomatic population and determine the US features of screening-detected thyroid cancer.

Materials and Methods

This study included 1,845 asymptomatic participants who underwent screening thyroid US between March and August 2012 at the screening center in our hospital. We evaluated the diagnostic performance of screening thyroid US for thyroid cancer and the average cost of diagnosis for each patient. We also determined the characteristic US features of screening-detected thyroid cancer.

Results

Of the 1,845 subjects, 661 showed no abnormalities, 1,155 exhibited benign thyroid nodules, and 29 exhibited thyroid cancer. Imaging features such as solid composition, hypoechogenicity, taller-than-wide axis, and ill-defined or spiculated margins of nodules were suggestive of malignancy. The rate of detection of cancer was 1.6% (29/1,845), and the sensitivity, specificity, and positive and negative predictive values were 100% (18/18), 98.7% (1,051/1,065), 56.3% (18/32), and 100% (1,051/1,051), respectively. Of 18 patients who underwent thyroidectomy, three (16.7%) had a pathological tumor staging of T3, and four (22.2%) had a pathological nodal staging of N1a. The average cost of diagnosis for each patient with cancer was $7,319.

Conclusion

Screening thyroid US exhibited a good diagnostic performance, with a feasible social cost of use. This modality demonstrated significant differences in sonographic features between screening-detected cancer and benign nodules.

Diagnostic Value of RAS Mutations in Indeterminate Thyroid Nodules

Objectives To determine the diagnostic value of HRAS, KRAS, and NRAS mutations in fine-needle aspiration biopsies of thyroid nodules that are nondiagnostic on cytology. Data Sources PubMed, Scopus, Embase, CINAHL. Review Methods Two authors independently searched the data sources. To be included, studies reported the RAS mutational status and postoperative histopathologic diagnosis of nodules that exhibited indeterminate cytology after fine-needle aspiration biopsy. Data were extracted to calculate sensitivity, specificity, and positive/negative predictive values of any HRAS, KRAS, or NRAS mutation. A meta-analysis was performed to generate pooled values for each parameter. Results A total of 7 studies with a combined 1025 patients met inclusion criteria. The pooled sensitivity of a RAS mutation for detecting cancer was 0.343 (95% confidence interval [95% CI], 0.198-0.506), while the pooled specificity was 0.935 (95% CI, 0.882-0.973). The weighted averages for positive predictive value and negative predictive value were 78.0% and 64.0%, respectively, with 68.0% accuracy. The positive likelihood ratio was 4.235 (95% CI, 1.506-11.910), and the negative likelihood ratio was 0.775 (95% CI, 0.630-0.953). Conclusion Our data suggest that testing for any RAS mutation is unlikely to change the clinical management of thyroid nodules that have indeterminate cytology. While a RAS mutation may rule in malignancy, the sensitivity of testing is low enough to merit further mutational analysis, repeat fine-needle aspiration, or surgical excision, even in the presence of a negative test.

Contrast-enhanced ultrasound and real-time elastography in the differential diagnosis of malignant and benign thyroid nodules

The diagnostic value of contrast-enhanced ultrasound (CEUS) or real-time elastography (RTE) alone, as well as a combination of CEUS and RTE, in distinguishing benign from malignant thyroid nodules was investigated. Between August 2012 and June 2014, a total of 97 consecutive patients (50 male and 47 female patients; mean age, 48.6±12.4; age range, 27-70 years) with thyroid nodules referred for surgical treatment were examined by CEUS and RTE. The final diagnosis was obtained based on histological findings. Image analysis of the CEUS and RTE scans was performed. Considering the postoperative pathological results as the golden standard, a receiver operating characteristic (ROC) curve was constructed. Subsequently, the sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV) and accuracy of CEUS alone, RTE alone and CEUS + RTE combination were calculated. Pathological examination showed 66 papillary carcinomas and 43 benign lesions, including 21 adenomas and 22 nodular goiters. The sensitivity, specificity, PPV, NPV and accuracy of CEUS were 81.82, 90.70, 93.10, 90.70 and 85.32%, respectively. In the case of RTE, the sensitivity, specificity, PPV, NPV and accuracy were 80.30, 88.37, 91.38, 88.37 and 83.49%, respectively. Furthermore, the combination of CEUS + RTE had a sensitivity of 95.45%, specificity of 95.35%, PPV of 96.92%, NPV of 95.35% and accuracy of 95.41%. Therefore, the CEUS + RTE combination showed a significantly higher sensitivity and specificity compared with CEUS or RTE alone (all P<0.05). Based on ROC analysis, the area under the curve (AUC) for CEUS, RTE and CEUS + RTE combination was 0.883, 0.863 and 0.959, respectively. The AUC of RTE alone was significantly lower compared with that of the CEUS + RTE combination. In conclusion, our results demonstrate that CEUS + RTE combination significantly increases the diagnostic performance for differential diagnosis of malignant and benign thyroid nodules compared with CEUS or RTE alone.

Differentiation between malignant and benign thyroid nodules and stratification of papillary thyroid cancer with aggressive histological features: Whole-lesion diffusion-weighted imaging histogram analysis

PURPOSE

To explore the usefulness of whole-lesion histogram analysis of apparent diffusion coefficient (ADC) derived from reduced field-of-view (r-FOV) diffusion-weighted imaging (DWI) in differentiating malignant and benign thyroid nodules and stratifying papillary thyroid cancer (PTC) with aggressive histological features.

MATERIALS AND METHODS

This Institutional Review Board-approved, retrospective study included 93 patients with 101 pathologically proven thyroid nodules. All patients underwent preoperative r-FOV DWI at 3T. The whole-lesion ADC assessments were performed for each patient. Histogram-derived ADC parameters between different subgroups (pathologic type, extrathyroidal extension, lymph node metastasis) were compared. Receiver operating characteristic curve analysis was used to determine optimal histogram parameters in differentiating benign and malignant nodules and predicting aggressiveness of PTC.

RESULTS

Mean ADC, median ADC, 5^th percentile ADC, 25^th percentile ADC, 75^th percentile ADC, 95^th percentile ADC (all P < 0.001), and kurtosis (P = 0.001) were significantly lower in malignant thyroid nodules, and mean ADC achieved the highest AUC (0.919) with a cutoff value of 1842.78 × 10^-6 mm² /s in differentiating malignant and benign nodules. Compared to the PTCs without extrathyroidal extension, PTCs with extrathyroidal extension showed significantly lower median ADC, 5^th percentile ADC, and 25^th percentile ADC. The 5^th percentile ADC achieved the highest AUC (0.757) with cutoff value of 911.5 × 10^-6 mm² /s for differentiating between PTCs with and without extrathyroidal extension.

CONCLUSION

Whole-lesion ADC histogram analysis might help to differentiate malignant nodules from benign ones and show the PTCs with extrathyroidal extension. J. Magn. Reson. Imaging 2016;44:1546-1555.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSION

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

Value of additional von Kossa staining in thyroid nodules with echogenic spots on ultrasound

PURPOSE

To evaluate the clinical value of additional von Kossa staining on cytology in thyroid nodules with echogenic spots on ultrasound (US).

MATERIALS AND METHODS

342 thyroid nodules were analyzed for cytology and von Kossa staining was performed to detect microcalcifications. We compared diagnostic performances and accuracies of FNA and FNA with von Kossa staining to detect malignancy. We evaluated associations of aggressive pathologic features and von Kossa positivity in the surgically confirmed papillary thyroid carcinoma (PTC) group.

RESULTS

Two hundred and thirty two (67.8%) nodules were malignant and 110 (32.2%) were benign on cytopathology. Compared to cytology alone, additional von Kossa staining slightly improved sensitivity from 89.7% to 90.9% (P=0.081). In 207 cases of surgically confirmed PTC, von Kossa positivity was an independent predictor of central lymph node metastasis in PTCs by multivariate analysis (odds ratio, 2.218; P=0.021).

CONCLUSIONS

Adding von Kossa staining to cytology improved the sensitivity of thyroid nodules with echogenic spots on US. Positive von Kossa stains in PTCs may also be useful in predicting central lymph node metastasis.

Thyroid Doppler US: Tips and tricks

Incidental diagnosis of thyroid nodules is very common on adult neck ultrasonography (US) examination. They are primarily assessed on size and greyscale ultrasound criteria such as hypoechogenicity, taller than wide, spiculated margins and calcifications. In difficult situations Doppler US features may improve tumour characterisation and staging.

Risk Stratification of Thyroid Incidentalomas Found on PET/CT: The Value of Iodine Content on Noncontrast Computed Tomography

BACKGROUND

The Hounsfield unit (HU) ratio of thyroid nodules was assessed compared to the contralateral thyroid lobe on noncontrast computed tomography (CT) to stratify further the risk of malignancy in thyroid incidentalomas found on 18F-fluorodeoxyglucose ((18)F-FDG) positron emission tomography/CT (PET/CT).

METHODS

This retrospective analysis included 82 patients who had thyroid incidentalomas on PET/CT in 2011. On PET/CT, the maximal standardized uptake value ratios of the thyroid nodule compared to liver (T/BSUV) and the HU ratios of the thyroid nodule compared to contralateral thyroid lobe (T/BHU) were calculated. Diagnostic performances of the T/BSUV and T/BHU were compared.

RESULTS

The area under the curve of T/BHU was higher than that of T/BSUV (0.941 vs. 0.689, p < 0.0001). The sensitivity, specificity, and accuracy of T/BHU were significantly higher than those of T/BSUV (100% vs. 77.8%, p = 0.0313; 80.0% vs. 60.0%, p = 0.0433; 86.6% vs. 65.9%, p = 0.0041, respectively). The risk of malignancy was much higher (71.1%) in nodules with a T/BHU cutoff value ≤0.68, whereas it was 0% in nodules with a T/BHU of >0.68. In this study, there were 18 nodules with nondiagnostic (n = 7) or atypia of undetermined significance or follicular lesion of undetermined significance cytologies (n = 11) after fine-needle aspiration biopsy (FNAB). When the T/BHU cutoff value was applied, three (60%) of the five nodules with a T/BHU of ≤0.68 were found to be papillary carcinomas. The remaining 13 nodules with a T/BHU of >0.68 were all benign with a risk of malignancy of 0%.

CONCLUSIONS

T/BHU is a simple and effective parameter to stratify the risk of malignancy in thyroid incidentalomas found on PET/CT. This may be of clinical relevance in those nodules with nondiagnostic or undetermined significance cytologies upon FNAB in the scheme of current clinical practice.

The utility of molecular markers in pre-operative assessment of thyroid nodules

The pre-operative diagnosis of thyroid tumors is determined by gold standard fine needle aspiration (FNA) biopsy. This has been widely accepted and offers the most cost-effective approach for evaluation of thyroid nodules. However, its diagnostic accuracy can pose a challenging scenario to surgeons. These diagnostic difficulties may subject patients to unnecessary thyroidectomies for benign thyroid nodules. Thus, additional molecular tests are needed to improve the sensitivity and specificity of FNA. The role of molecular markers is being proposed to predict the type and risk of malignancy to abate the need for diagnostic thyroidectomies. This review discusses their utility and validity in pre-operative diagnosis of thyroid nodules and how these markers can enhance the accuracy of FNA cytology.