Is thyroid nodule location associated with malignancy risk?

Prediction model construction of cervical central lymph node metastasis in papillary thyroid carcinoma combined with Hashimoto's thyroiditis utilizing conventional ultrasound and elastography

Background

When papillary thyroid carcinoma (PTC) is accompanied by Hashimoto's thyroiditis (HT), it is often challenging for preoperative ultrasound to distinguish between central lymph node enlargement caused by PTC metastasis and inflammatory reaction due to HT. However, central lymph node metastasis (CLNM) is closely associated with the risk of PTC recurrence after surgery. In this study, we developed a model to predict in patients with PTC combined with HT, based on conventional ultrasound characteristics and shear wave elastography (SWE) quantitative parameters of the primary lesion. We aimed to evaluate its predictive value to provide a useful reference for clinical decisions regarding central lymph node dissection.

Methods

This retrospective study included ultrasound data for 181 PTC patients with concurrent HT (totaling 215 nodules), confirmed by surgical pathology at our hospital and routinely undergoing central neck lymph node dissection. All enrolled PTC patients were randomly divided into training and test groups at a 7:3 ratio. Then, patients in each group were further segregated into two distinct cohorts: the CLNM group and the non-CLNM group as per the gold standard of pathology assessment. Subsequent statistical analysis of conventional ultrasound characteristics pertaining to primary foci alongside quantitative parameters derived from SWE, facilitated the identification of independent risk factors associated with CLNM. Then, a nomogram model was constructed, and its predictive value was evaluated. The test group was used for internal validation.

Results

Univariate analysis results in the training group indicated that nodule size, multiplicity, location, capsular invasion, and Emax were significantly associated with CLNM (all P<0.05). Multivariate analysis further identified nodule size, multiplicity, location, capsular invasion, and Emax as independent risk factors for CLNM (all P<0.05). Based on the multivariate analysis results, a nomogram model was developed to predict the occurrence of CLNM in PTC patients with HT. Receiver operating characteristic (ROC) curve analysis showed high predictive accuracy for CLNM, with an area under the ROC curve (AUC) of 0.837 in the training group and 0.882 in the test group. Calibration curves demonstrated good fit, closely aligning with the diagonal, indicating strong consistency in predicting CLNM.

Conclusions

The nomogram model, based on primary lesion ultrasound characteristics and SWE quantitative parameters in PTC patients with HT, may aid clinicians in preoperatively predicting the likelihood of CLNM in PTC patients.

Cancer Risk in Thyroid Nodules: An Analysis of Over 1000 Consecutive FNA Biopsies Performed in a Single Canadian Institution

Objective: To determine the cancer risk in thyroid nodules using ACR TI-RADS. Methods: A retrospective analysis of all thyroid biopsies was performed over a 3-year period (2021 to 2023). Variables including gender, age, history of thyroid cancer or neck irradiation, nodule size and location, TR level, and sonographic features such as punctate echogenic foci (PEF), a very hypoechoic appearance, taller-than-wide shape, and suspected extrathyroidal extension were analyzed. Results: A total of 1140 nodules were assessed in 993 patients, including 740 females (74.5%) and 253 males (25.5%). The mean patient age was 57.1 ± 15.4 years. Variables significantly associated with nodule malignancy included (1) younger age, (2) a prior history of thyroid cancer or neck irradiation, (3) a higher TR level, (4) a taller-than-wide shape in nodules <1 cm, (5) PEF, (6) a very hypoechoic appearance, and (5) suspected extrathyroidal extension (p < 0.05). Gender, nodule location and size were not associated with a higher cancer risk (p > 0.05). Malignancy was found in 40.7% of TR5, 4.8% of TR4, 0.3% of TR3, and 0% of TR1 and 2 nodules. The odds ratios (ORs) for cancer were as follows: TR4 or 5, OR = 19; PEF, OR = 11; a very hypoechoic appearance, OR = 13.3; and suspected extrathyroidal extension, OR = 27.2 (p < 0.01). Conclusions: Higher TR levels, PEF, a very hypoechoic appearance, and suspected extrathyroidal extension are important features for predicting cancer risk. These findings affirm the effectiveness of ACR TI-RADS in nodule risk stratification.

Thyroid nodules: diagnosis and management

Thyroid nodules, with a prevalence of almost 25% in the general population, are a common occurrence. Their prevalence varies considerably depending on demographics such as age and sex as well as the presence of risk factors. This article provides a comprehensive overview of the prevalence, risk stratification and current management strategies for thyroid nodules, with a particular focus on changes in diagnostic and therapeutic protocols that have occurred over the past 10 years. Several sonography-based stratification systems (such as Thyroid Imaging Reporting and Data Systems (TIRADS)) might help to predict the malignancy risk of nodules, potentially eliminating the need for biopsy in many instances. However, large or suspicious nodules necessitate cytological evaluation following fine-needle aspiration biopsy for accurate classification. In the case of cytology yielding indeterminate results, additional tools, such as molecular testing, can assist in guiding the management plan. Surgery is no longer the only treatment for symptomatic or malignant nodules: active surveillance or local ablative treatments might be beneficial for appropriately selected patients. To enhance clinician-patient interactions and discussions about diagnostic options, shared decision-making tools have been developed. A personalized, risk-based protocol promotes high-quality care while minimizing costs and unnecessary testing.

Evaluation of the Malignancy Risk in Nodules Expanding the Thyroid Gland Capsule

There has been an increase in the diagnosis of thyroid nodules in recent years. In addition to the well-known criteria, features that are likely to increase the risk of malignancy are in the research process. In this study, we aimed to evaluate the malignant potential of nodules that expand the thyroid capsule ultrasonographically. A total of 109 patients with thyroid capsule-expanding nodules and 288 patients with non-expanding nodules were included in the study. Demographical data, ultrasonography features, and cytology results were noted, and histopathological findings were determined in operated patients. While malignant cytology was detected in 5.5% of capsule-expanding nodules in FNAB results, this rate was 0.7% in the non-capsule expanding group (p<0.001). According to the histopathological results, the incidence of malignancy was 15.6% in the capsule-expanding nodule group, while it was 3.1% in the other group (p=0.001). As a result of logistic regression analysis, it was determined that the risk of malignancy increased by 4.44-fold (95% CI 1.4-13.8, p=0.01) in patients with capsule-expanding nodules. Other features that increased the risk of malignancy were hypoechogenicity, microcalcification, and irregular margin presence. In this study, we found that the risk of malignancy increased in nodules expanding the thyroid capsule. Based on the increasing study data on this subject, monitoring thyroid capsule expansion in nodules may take its place among the criteria for malignancy in future evaluations.

Should there be a paradigm shift for the evaluation of isthmic thyroid nodules?

PURPOSE

Although the thyroid isthmus seems like a rudimentary structure that connects bilateral lobes, it is an undiscovered area that needs to be explored. Currently, the data is evolving that the increase in the risk of malignancy is higher in the isthmic nodules, and extrathyroidal extensions and lymph node metastases are more common in isthmic-derived malignant thyroid nodules. Therefore, we aimed to compare the malignancy rate of isthmic and lobar nodules, the ultrasonographic features of isthmic and lobar nodules, and presence of lymph node metastases, distant metastases, and extrathyroidal invasions in malignant isthmic nodules.

METHODS

In this retrospective study, we enrolled patients between the ages of 18-80 years, who had thyroid nodule/nodules cytology and/or pathology results from January 2009 to November 2022. 9504 nodules were selected for the analysis of US findings, cytopathology results, and malignancy rates.

RESULTS

A mean ± SD age of 55.3 ± 13.0 years with a female to male ratio of [7618 (80.2%)/1886(19.8%)] were included in the study. 962 of the nodules were at isthmic localization; whereas 8542 nodules were at lobar localization. 1188 nodules were resulted as malignant from histopathological evaluation. Of the 1188 malignant nodules, 986 nodules were (83.0%) PTC, 114 nodules (9.6%) were FTC, 55 nodules were (4.6%) MTC, 16 nodules 1.3% were Hurtle cell carcinoma, 8 nodules (0.7%) were anaplastic thyroid carcinoma, and 9 nodules (0.8%) were thyroid tumors of uncertain malignant potential (TT-UMP). 156 of the malignant nodules (13.1%) were located in the isthmus, whereas the majority of the malignant nodules (n = 1032, 86.9%) were located at the lobar parts (right or left) of the thyroid. When the metastasis patterns of isthmic and lobar thyroid cancers were examined, no significant relationship was found between isthmic and lobar cancers in terms of capsule invasion (p = 0.435), muscle invasion (p = 0.294), and lymph node metastasis (p = 0.633). A significant relation was found between nodule localization (isthmus-upper-middle and lower lobes) and malignancy (p < 0.001). In our logistic regression analysis, isthmic and upper pole nodule localizations, age and TI-RADS were evaluated as independent risk factors for malignancy (p < 0.001 for all factors).

CONCLUSION

We recommend nodule localization has to be considered an additional risk factor when performing a Fine Needle Aspiration Biopsy for the increased malignancy risk in this localization.

Is the nodule location a predictive risk factor for cancer in AUS/FLUS thyroid nodules? A retrospective cohort study

BACKGROUND

Atypia of undetermined significance/follicular lesion of undetermined significance (AUS/FLUS) is a heterogeneous category of thyroid nodules with uncertain cytology and controversial management. This study aimed to assess the association between nodule location and malignancy risk and whether the location can be used as a predictive risk factor for cancer in AUS/FLUS nodules.

METHODS

A cohort of 102 patients (79 [77.5%] women, 23 [22.5%] men) was retrospectively analyzed. Only patients with a final histopathology of benign or well-differentiated thyroid cancer and an available nodule location were included. Sociodemographic, histopathological, and sonographic data were statistically evaluated and correlated.

RESULTS

Based on pathology findings, 54 (52.9%) and 48 (47.1%) nodules were benign and malignant, respectively. Most nodules were right-sided (54.9%). Considering the nodule location, 41.2% of nodules occupied the whole lobe, 20.6% only the lower pole, 15.7% only the upper pole, and 2.9% the isthmus. Cases with nodules occupying only the upper, middle, or lower pole showed significant associations with cancer risk (odds ratio, [95% confidence interval]: 2.6, [1.1-5.7]; 2.0, [1.0-4.7]; and 1.9, [1.0-3.9], respectively). Male sex and the presence of a peripheral halo were significantly associated with malignancy risk (3.3, [1.2-9.1], P = 0.014; and 2.7, [1.0-9.5], P = 0.049, respectively). Isthmic nodules had the highest malignancy level (66.7%).

CONCLUSIONS

Nodule location is a promising predictor of malignancy in AUS/FLUS nodules. Furthermore, isthmic nodules had the highest malignancy level, emphasizing the significance of careful evaluation of these nodules. Further large prospective studies are required to confirm these findings.

Cancer rates and characteristics of thyroid nodules with macrocalcification

AIMS

The aim of this study was to determine the malignant potential of thyroid nodules with macrocalcifications and to evaluate the role of other sonographic findings in the diagnosis of malignancy in thyroid nodules besides macrocalcifications.

METHODS

The findings of 8250 patients who applied to our outpatient clinic and underwent thyroid ultrasonography(US) between 2008 and 2021 were retrospectively reviewed. We included a total of 296 patients with 296 macrocalcified nodules (macrocalcification group) and an age- and sex matched group of 300 patients (control group) with the cytopathologic and/or histopathologic data of fine-needle aspiration biopsy (FNAB) of thyroid nodules without calcification. Demographic characteristics of these patients, US characteristics of the nodules, and thyroid function tests were recorded. Cytopathological data of FNAB were classified according to BETHESDA.

RESULTS

The malignancy rate was 14.2% (42/296) in the macrocalcification group and 5.3% (16/300) in the control group (p < 0.001). There was no significant relationship between interrupted peripheral calcification and malignancy. Hypoechoic or markedly hypoechoic appearance, irregular border, solid structure, presence of accompanying pathological lymphadenopathy on sonographic examination and upper and middle zone localization were other sonographic features that increased the risk of malignancy of a nodule. The presence of autoimmunity was not found to be associated with the risk of malignancy. TSH and calcitonin levels of malignant nodules were higher than benign nodules. There was no significant difference between gender and malignancy. In the univariate analysis, it was found that the presence of macrocalcification increased the risk of malignancy 2.935 times. (OR:2.935, p < 0.001.95% CI for OR 1.611-5.349) In addition, being younger, being in the high TIRADS category, and being in the upper and middle zones were factors that increased the risk of malignancy. Gender, TSH level, nodule volume and structure were not associated with malignancy. However, after multivariate analysis, factors that significantly increased the risk of malignancy were younger age, higher TIRADS category, and nodule localization.

CONCLUSION

In our study, the malignancy rate was higher in the macrocalcification group than in the control group. However, no correlation was found after multivariate analysis. In the multivariate analysis, younger age, higher TIRADS category, and nodules located in the upper and middle zone were other factors associated with malignancy. There was no association between peripheral interrupted calcification and malignancy risk.

Comparison of the diagnostic effectiveness of ultrasound imaging coupled with three mathematical models for discriminating thyroid nodules

BACKGROUND

The overlapping nature of thyroid lesions visualized on ultrasound (US) images could result in misdiagnosis and missed diagnoses in clinical practice.

PURPOSE

To compare the diagnostic effectiveness of US coupled with three mathematical models, namely logistic regression (Logistics), partial least-squares discriminant analysis (PLS-DA), and support vector machine (SVM), in discriminating between malignant and benign thyroid nodules.

MATERIAL AND METHODS

A total of 588 thyroid nodules (287 benign and 301 malignant) were collected, among which 80% were utilized for constructing the mathematical models and the remaining 20% were used for internal validation. In addition, an external validation cohort comprising 160 nodules (80 benign and 80 malignant) was employed to validate the accuracy of these mathematical models.

RESULTS

Our study demonstrated that all three models exhibited effective predictive capabilities for distinguishing between benign and malignant nodules, whose diagnostic effectiveness surpassed that of the TI-RADS classification, particularly in terms of true negative diagnoses. SVM achieved a higher diagnostic rate for malignant thyroid nodules (93.8%) compared to Logistics (91.5%) and PLS-DA (91.6%). PLS-DA exhibited higher diagnostic rates for benign thyroid nodules (91.9%) compared to Logistics (86.7%) and SVM (88.7%). Both the area under the receiver operating characteristic curve (AUC) values of PLS-DA (0.917) and SVM (0.913) were higher than that of Logistics (0.891).

CONCLUSION

Our findings indicate that SVM had significantly higher rates of true positive diagnoses and PLS-DA exhibited significantly higher rates of true negative diagnoses. All three models outperformed the TI-RADS classification in discriminating between malignant and benign thyroid nodules.

Global scientific trends on thyroid disease in early 21st century: a bibliometric and visualized analysis

Background

Bibliometrics has been used to analyze the literature in the field of thyroid disease studies in the early 21st century, indicating the changes in current international study trends.

Methods

In this study, a bibliometric analysis of data retrieved from the Web of Science (WoS) database was conducted, and the publication trends and thematic evolution in the field of thyroid disease research from January 1, 2000, to November 16, 2022, were analyzed. A total of 69283 articles related to thyroid diseases were evaluated for their characteristics, including annual publication volume, countries, journals, institutions, authors, keywords, and references. VOSviewer was utilized to perform the analysis of co-authorship, co-citation, co-occurrence and descriptive.

Results

The annual publication volume of thyroid disease research literature showed a fluctuating upward trend from 2000 to 2021, exceeding 5,000 articles for the first time in 2021. The United States (16120 counts, 678255 cities) ranks first in terms of publication volume and citation. Thyroid (n=3201) and Journal of Clinical Endocrinology&Metabolism (n=140399) are the most prolific and cited journals, respectively. The organization with the highest publication volume and citation frequency is Harvard University (1011 counts, 59429 cities), Miyauchi Akira (n=422), Schlumberger, and Martin (n=24839) possess the highest publication volume and citation frequency, respectively. Co-occurrence analysis of 307 keywords with frequencies of more than 20 resulted in 6 clusters (1): Thyroid dysfunction and diseases (2); mechanism of occurrence and development of thyroid cancer (3); autoimmune thyroiditis (4); scope and postoperative management of thyroid surgery (5); fine needle aspiration of thyroid nodules (6); radioactive iodine therapy for thyroid cancer. Active monitoring, thermal ablation, Lenvatinib, and long noncoding RNA refer to the latest keywords. Discussing the six clusters helps scholars to determine the scope and direction of studies.

Conclusion

Over the past two decades, the literature related to thyroid diseases has increased year by year, with closer collaboration between countries, institutions, and authors. In this study, the global trends, research hotspots, emerging subjects, and basic knowledge of literature related to thyroid diseases were respectively elucidated, which will facilitate researchers in this field to seek better development.

Radiofrequency ablation for papillary thyroid cancer located in isthmus: comparison with that originated in thyroid lobe

PURPOSE

To analyze the outcomes of radiofrequency ablation (RFA) for isthmus papillary thyroid cancer (PTC) versus PTC originating from the lobes.

METHODS

Patients with solitary low-risk PTC treated with RFA between July 2014 and December 2019 were retrospectively reviewed. This study was approved by our institutional review board. Of the 562 patients, 104 and 458 had PTCs located in the thyroid isthmus and thyroid lobes, respectively. Local tumor progression (LTP), LTP-free survival (LTPFS), changes in tumor volume, and complications were compared between the two groups using propensity-score matching (PSM).

RESULTS

The isthmic and lobar groups showed no significant differences in LTP (2.9% vs. 3.8%), new PTC (2.9% vs. 2.9%), persistent lesions (0.0% vs. 0.2%), or LTPFS after PSM. Before PSM, the two groups showed significant differences in the volume reduction ratio (VRR) of the ablated tumors at 1, 3, 24, 30, and 48 months after RFA, but no differences between the two groups were observed in tumor volume, VRR, or disappearance rate after PSM (p > .05). One patient in the isthmic group presented with coughing, while another complained of hoarseness. Complications did not differ significantly between the two groups (p > .05).

CONCLUSIONS

The outcomes of RFA for patients with low-risk PTC in the thyroid isthmus and thyroid lobes were similar. Therefore, RFA may serve as an alternative treatment option for patients with low-risk isthmic PTC.

Comparative study of fine needle aspiration cytology and histopathology in thyroid nodules at a tertiary care hospital: First report from Somalia

BACKGROUND

FNAC is a minimally invasive procedure and cost-effective, especially in developing countries where patients are mostly poor and surgery is not affordable. The present is the first study that examines the correlation between FNAC and histopathology in diagnosing thyroid cancers at a tertiary hospital in Somalia.

METHOD

This study included 231 patients with thyroid lesions who underwent pre-operative FNACs and histopathologic examination over five years. Investigated clinical parameters include sociodemographic and clinical features and cyto-histopathological findings.

RESULTS

The mean patient age was 39.3 ± 15.5 years, and there was a significant female predominance (n = 194; 84%), with a female to male ratio of 5.2:1. The overall sensitivity, specificity, and accuracy rate of cyto-histopathology correlation was 91.1%, 96.6%, and 94.9%, respectively. According to the Bethesda classification system of thyroid FNACs, (n = 141, 61%) of cases were Bethesda II (Benign), of which 95.7% of patients had a benign final histological diagnosis, while 4.3% had malignancy (6 false-negative results). Twenty-two patients (9.5%) were Bethesda III, (n = 3,1.3%) were Bethesda IV (suspicious for neoplasm), and all cases had a follicular adenoma on their final histological diagnosis. Forty-four of the patients were Bethesda V, found in 88.6% of its final histological diagnosis, while 11.4% were benign. Bethesda IV accounted for 9.1%, and all patients in this group were papillary thyroid carcinoma on its final histological confirmation.

CONCLUSION

Our study findings revealed that FNAC of thyroid lesions has a high accuracy rate, sensitivity, and specificity, allowing appropriate initial diagnostic management. It should be applied as the first investigative tool for thyroid lesions.

[Sociodemographic, clinical and ultrasound characterization of thyroid nodule pathology and its association with malignancy in a Colombian high-complexity center]

BACKGROUND AND OBJECTIVE

Thyroid nodules are among the most frequent conditions, with a 10% risk of malignancy. The objective is to describe the frequency of demographic, clinical, and ultrasonographic characteristics of thyroid nodule pathology in adults and to explore the relationship with tumor malignancy.

METHODS

An analytical, retrospective cross-sectional study in adults with thyroid nodules and nodular fine-needle aspiration performed in adult patients from a Colombian reference center between 2009-2019. Data were obtained from the clinical history, descriptive measures of the patient's demographic, clinical, and ultrasound variables were estimated, and their relationship with the malignancy of the tumor was explored.

RESULTS

A total of 445 patients and 515 nodules were included. The median age was 55 years (IQR 44-64), 86.8% of women, and 54.8% had a single lesion. Percentages of 80.2 and 19.8 were benign and malignant nodules, with a median of 15.7mm (IQR 11-25) and 12.7mm (IQR 8.5-18.3), respectively (p<0.001). Hypothyroidism and levothyroxine consumption were higher in those with malignant nodules (p<0.001). The echographic characteristics were statistically different between the nodules. In the malignant ones, there was a higher frequency of solid composition, hypoechogenicity, and irregular margins. In contrast, in the benign ones, the absence of echogenic focus stood out (p<0.001).

CONCLUSION

The ultrasound characteristics are essential to define the risk of malignancy of a thyroid nodule. Therefore, considering the most frequent ones can help in the most appropriate approach to primary care.

A Reappraisal of Suspicious Sonographic Features of Thyroid Nodules: Shape Is Not an Independent Predictor of Malignancy

CONTEXT

For the correct clinical application of the sonographic risk-stratification systems, the definition of independent risk features that are foundational to each system is crucial.

OBJECTIVE

The aim of this study was to identify the gray-scale sonographic features independently associated with malignancy, and to compare different definitions.

METHODS

This prospective, diagnostic accuracy study took place in a single thyroid nodule referral center. All patients consecutively referred to our center for fine-needle aspiration cytology of a thyroid nodule between November 1, 2015 and March 30, 2020, were enrolled before cytology. Each nodule was examined by 2 experienced clinicians to record the sonographic features on a rating form. Histologic (when available) or cytologic diagnosis was used as the reference standard. For each single sonographic feature and definition, the sensitivity, specificity, positive and negative predictive values, and diagnostic odds ratios (DOR) were calculated. The significant predictors were then included in a multivariable regression model.

RESULTS

The final study cohort consisted of 903 nodules in 852 patients. A total of 76 nodules (8.4%) were malignant. Six features were independent predictors of malignancy: suspicious lymph node (DOR 16.23), extrathyroidal extension (DOR 6.60), irregular or infiltrative margins (DOR 7.13), marked hypoechogenicity (DOR 3.16), solid composition (DOR 3.61), and punctate hyperechoic foci (including microcalcifications and indeterminate foci; DOI 2.69). Taller-than-wide shape was not confirmed as an independent predictor.

CONCLUSION

We identified the key suspicious features of thyroid nodules and provided a simplified definition of some debated ones. Malignancy rate increases with number of features.

Thyroid malignancy in children: where does it locate?

OBJECTIVE

As far as we know, in English literature, a limited number of studies has examined the relationship between the location of the nodule and malignancy risk. The studies were performed with adults and their results were mainly inconsistent. We aim to evaluate the potential association between the location of the thyroid nodules and risk for malignancy in the pediatric population.

MATERIALS AND METHODS

Patients younger than 18 years old with a pathological diagnosis were included. Nodules were divided into 5 categories according to the Thyroid Imaging Reporting and Data System (TI-RADS) algorithm. The location of the nodules was recorded: Right lobe, left lobe, isthmus, upper pole, lower pole, and middle. Thyroid glands were divided into 3 equal longitudinal areas to define upper, lower, and middle portions.

RESULTS

Ninety-seven nodules of 103 children were included. The mean age of the population was 14.9 ± 2.51 years (7-18 years). Eighty-one participants were female (83.5%) and 16 male (16.5%). Fifty nodules were benign (51.5%) and 47 nodules were malignant (48.5%). We did not detect a significant correlation between the risk of malignancy and location of the nodule as right or left lobes or isthmus (P = 0.38). Rate of malignant nodules were significantly higher in middle lobe (23%, P = 0.002). Being located at middle part of thyroid gland increases the possibility of malignancy 11.3 times (OR = 11.3, P = 0.006).

CONCLUSION

Nodule location can be used as a predictor for thyroid malignancy in pediatric patients, similar to adults. Middle lobe location increases the risk of malignancy. Using nodule location along with TI-RADS categorization can increase the efficacy of malignancy prediction.

Solitary and multiple thyroid nodules as predictors of malignancy: a systematic review and meta-analysis

BACKGROUND

The debate on whether or not there is a difference in the incidence of thyroid cancer between the patients with Solitary thyroid Nodule (STN) and Multinodular Goiter (MNG) has been constantly present for the last few decades. With newer studies yielding mixed results, it was imperative to systematically compile all available literature on the topic.

METHODS

PubMed/MEDLINE, Cochrane Central, ScienceDirect, GoogleScholar, International Clinical Trials registry, and reference lists of the included articles were systematically searched for article retrieval. No filter was applied in terms of time, study design, language or country of publication. Rigorous screening as per PRISMA guidelines was undertaken by 2 independent reviewers in order to identify the articles that were most relevant to the topic.

RESULTS

Twenty-two studies spanning from 1992 to 2018 were included in this analysis and encompassed 50,321 patients, 44.2% of which belonged to the STN subgroup and 55.37% to the MNG subgroup. MNG was found to be associated with a significantly lower risk of thyroid cancer (OR = 0.76; 95% CI 0.61-0.96) when compared with STN. Papillary carcinoma was the most frequently occurring carcinoma across both groups, followed by follicular and medullary carcinomas. A subgroup analysis was performed to assess the efficacy of the two most commonly employed diagnostic tools i.e. surgery and fine needle aspiration cytology (FNAC), however it yielded nonsignificant results, indicating a comparable usefulness of the two. Another subgroup analysis run on the basis of the presumed iodine status of the participants also yielded nonsignificant results.

CONCLUSION

There is a higher incidence of thyroid cancer among patients of STN, however, given the low quality of existing evidence on the topic, it is crucial to conduct larger studies that can establish association with a greater precision.

Investigating the possible association between thyroid nodule location and the malignancy risk of the nodules in FNA samples

INTRODUCTION

In this study we aimed to investigate the association between thyroid nodule location and the malignancy risk of the nodules in FNA samples.

METHODS

In this cross sectional study, 400 patients with thyroid nodule size >1.5 cm, thyroid nodule size >1 cm with micro-calcification, and thyroid nodule size <1 cm with sonographic or clinical signs of malignancy who referred to a training hospital, were involved. Morphologic characteristics of nodules, including nodule size, laterality and polarity were recorded. In patients with multinodular goiter, the anatomical location was recorded and analyzed.

RESULTS

In our study, 345 female patients (86.3 %) and 55 male patients (13.8 %) with thyroid nodule were involved. The majority of thyroid nodules were identified in the right lobe (n = 182, 45.5 %) and left lobe (n = 177, 44.3 %), respectively. A total of 323 nodules were benign and the remaining (n = 77) were malignant. The frequency of malignancy in the upper pole of the thyroid (31.6 %) was higher compared to that in the middle pole (10.7 %), lower pole (19.1 %), and isthmus region (26.8 %), leading to a significant difference (p.value = 0.001). The mean size of thyroid nodules was 15.68 mm in benign nodules and 20.08 mm in malignant nodules.

CONCLUSION

Our results showed that thyroid nodules found in the upper lobe carried the greatest risk for malignancy. Accordingly, it seems that the location of thyroid nodules can be an independent risk factor in determining the malignancy risk of thyroid nodules and can be used to enhance clinical decision making in thyroid FNA samples.

Introducing a Pole Concept for Nodule Growth in the Thyroid Gland: Taller-than-Wide Shape, Frequency, Location and Risk of Malignancy of Thyroid Nodules in an Area with Iodine Deficiency

Purpose: (i) To examine the criterion taller-than-wide (TTW) for the sonographic assessment of thyroid nodules in areas of iodine deficiency in terms of frequency, anatomical distribution within the thyroid gland and risk of malignancy. (ii) To develop a model for nodule growth in the thyroid gland. Methods: German multicenter study consisting of two parts. In the prospective part, thyroid nodules were sonographically measured in all three dimensions, location within the thyroid gland and contact to a protrusion-like formation (horn) in the dorsal position of thyroid gland was noted. In addition, further sonographic features such as the composition, echogenity, margins and calcifications were investigated. All nodules from the prospective part were assessed for malignancy as part of clinical routine at the decision of the treating physician adhering to institutionally based algorithms. In the retrospective part, only nodules with fine needle aspiration and/or histology were included. The risk of malignancy in TTW nodules was determined by correlating them with cyotological and histological results. Results: Prospective part: out of 441 consecutively evaluated thyroid nodules, 6 were found to be malignant (1.4%, 95% CI 0.6–2.7%). Among the 74 TTW nodules (17%), 1 was malignant (1%, 95% CI 0–4%). TTW nodules were more often located in the dorsal half of the thyroid than non-TTW nodules (factor 2.3, p = 0.01, 95% CI 2.1–2.5) and more often located in close proximity to a horn than non-TTW nodules (factor 3.0, p = 0.01, 95% CI 2.4–3.8). Retrospective part: out of 1315 histologically and/or cytologically confirmed thyroid nodules, 163 TTW nodules were retrieved and retrospectively analyzed. A TTW nodule was 1.7 times more often benign when it was dorsal (95% CI 1.1–2.5) and 2.5 times more often benign when it was associated with a horn (95% CI 1.2–5.3). The overall probability of malignancy for TTW nodules was 38% (95% CI 30–46%) in this highly preselected patient group. Conclusion: TTW nodules are common in iodine deficient areas. They are often located in the dorsal half of the thyroid gland and are frequently associated with a dorsal protrusion-like formation (horn) of the thyroid. Obviously, the shape of benign nodules follows distinct anatomical preconditions within the thyroid gland. The frequency of TTW nodules and their predominant benignity can be explained by a pole concept of goiter growth. The difference between the low malignancy risk of TTW nodules found on a prospective basis and the high risk found retrospectively may be the result of a positive preselection in the latter.

Related factor analysis for predicting large-volume central cervical lymph node metastasis in papillary thyroid carcinoma

The aim of this study was to investigate the factors related to large-volume central cervical lymph node metastasis (LNM) in papillary thyroid carcinoma. A retrospective study of 340 patients with 642 papillary thyroid carcinoma nodules who underwent thyroidectomy in Peking Union Medical College Hospital between 2011 and 2015 was conducted. These nodules were divided into two groups by the number of central cervical lymph node metastases: large-volume central cervical LNM (>5 metastatic lymph nodes, n = 129) and no central cervical LNM (n = 211). We evaluated the correlations between gender, age, chronic lymphocytic thyroiditis, thyroid ultrasonographic features, and large-volume central cervical LNM. We found that younger age (≤40 years) (OR = 3.796, 95% CI = 2.842, 5.070), male gender (OR = 4.005, 95% CI = 2.858, 5.61), and ultrasonographic features such as tumor macroaxis size (OR = 2.985, 95% CI = 1.581, 5.633), tumor located in the isthmus (OR = 7.578, 95% CI = 4.863, 11.810), ill-defined margin (OR = 3.008, 95% CI = 1.986, 4.556), microcalcification (OR = 2.155, 95% CI = 1.585, 2.929), and abnormal cervical lymph nodes (OR = 13.753, 95% CI = 9.278, 20.385) were independent risk factors for large-volume central cervical LNM in papillary thyroid carcinoma, while chronic lymphocytic thyroiditis (OR = 0.248, 95% CI = 0.172, 0.358) was a protective factor. Younger age (≤40 years), male sex, and ultrasonographic features such as tumor macroaxis size, tumor located in the isthmus, ill-defined margin, microcalcification, and abnormal cervical lymph nodes were independent risk factors for large-volume central cervical LNM in papillary thyroid carcinoma, while chronic lymphocytic thyroiditis can be considered a protective factor. Our results provide a reference for adjusting clinical treatment approaches.

Diagnostic performance of US-based FNAB criteria of the 2020 Chinese guideline for malignant thyroid nodules: comparison with the 2017 American College of Radiology guideline, the 2015 American Thyroid Association guideline, and the 2016 Korean Thyroid Association guideline

Background

To investigate the diagnostic performance of the ultrasonography-based fine-needle aspiration biopsy criteria of the Chinese Thyroid Imaging Reporting and Data System (C-TIRADS) for malignant nodules compared to 3 other guidelines.

Methods

This study included 2,309 thyroid nodules in 1,697 patients with histopathological and cytopathological diagnoses of benign and malignant nodules from January 2018 to August 2020. The clinical and ultrasonographic features of the nodules were retrospectively reviewed and classified according to the Chinese guideline (C-TIRADS), the American College of Radiology guideline (ACR-TIRADS), the American Thyroid Association guideline (ATA guideline), and the Korean Thyroid Association guideline (K-TIRADS). The diagnostic performance of the guidelines and their unnecessary fine-needle aspiration biopsy rates were calculated using randomized, blinded trials.

Results

Of the 2,309 nodules, 1,418 (61.4%) were benign and 891 (38.6%) were malignant, with 884 (99.21%) papillary carcinomas. The accuracy of C-TIRADS was 84.71%, followed by the guidelines of ACR-TIRADS (82.11%), K-TIRADS (81.64%), and the ATA guideline (78.56%). Furthermore, the area under the receiver operating characteristic curve (AUC) was the highest for the C-TIRADS (0.905). Similar results were revealed for both the diagnostic performance and AUC of nodules smaller and larger than 10 mm. The ACR-TIRADS showed the lowest unnecessary biopsy rate (17.54%), followed by the C-TIRADS (22.61%), ATA guideline (27.90%), and the K-TIRADS (28.67%).

Conclusions

The C-TIRADS demonstrated high diagnostic performance and a relatively low unnecessary biopsy rate in detecting thyroid cancer compared to the 3 other guidelines. However, further understanding of the ultrasonography-based fine-needle aspiration biopsy criteria of the C-TIRADS should be gained in the future.

Are clinicopathological features of the isthmic thyroid nodule different from nodules in thyroid lobes? A single center experience

Objective

Thyroid nodules located in isthmus were found less prevalent, although papillary thyroid cancer in this location was reported to be more aggressive behaviour in some studies. Our aim was to evaluate hormonal, ultrasonographic, and cytopathologic features of nodules located in isthmus (isthmic nodules).

Methods

Patients who underwent thyroidectomy between 2006-2014 reviewed retrospectively. Hormonal, ultrasonographic, and cytopathologic features compared between patients with isthmic (Group-1) and with lober (non-isthmic, Group-2) nodules.

Results

Group-1 and Group-2 consisted of 251 and 2076 patients, respectively. 260 isthmic (5.5%) and 4433 non-isthmic (94.5%) nodules were compared. However, most ultrasonographical features such as presence of microcalcification and halo, diameters, echogenicity, texture, margin, and vascularity were similar between groups, macrocalcification rate was lower in isthmic nodules (18.8%, 25.9%; p = 0.012). Cytologic results were also similar. Although malignancy rate was lower in isthmic nodules (6.2%, 12.5%; p = 0.002), type of thyroid cancer was similar in isthmic and non-isthmic nodules. When malignant isthmic (n = 16,2.8%) and malignant non-isthmic nodules (n = 553, 97.2%) were compared, diameter and type of tumor, lymphovascular and capsular invasions, extrathyroidal extension and multifocality rates were not statistically significant. Malignant isthmic nodules (n = 16, 6.2%) had smaller size [10.1 (7.5-34.5) mm, 19.95 (8.4-74.1) mm; p = 0.002], and higher hypoechogenicity rate (31.3%, 5.7%, p = 0.003) compared to benign isthmic nodules (n = 244, 93.8%). Negative predictive value was higher and positive predictive value was lower in isthmic nodules compared to non-isthmic nodules (p = 0.033, p = 0.047, respectively).

Conclusion

Isthmic nodules appear to be indolent because of having lower malignancy rate. FNAB might be required in isthmic nodules even if it has relatively small size. The surgery with limited extent or follow-up might seem to be reliable in the management of patients having isthmic nodules especially with indeterminate cytology.

Thyroid imaging reporting and data system (TIRADS) for ultrasound features of nodules: multicentric retrospective study in China

PURPOSE

To establish a practical and simplified Chinese thyroid imaging reporting and data system (C-TIRADS) based on the Chinese patient database.

METHODS

A total of 2141 thyroid nodules that were neither cystic nor spongy were used in the current study. These specimens were derived from 2141 patients in 131 alliance hospitals of the Chinese Artificial Intelligence Alliance for Thyroid and Breast Ultrasound. The ultrasound features, including location, orientation, margin, halo, composition, echogenicity, echotexture, echogenic foci and posterior features were assessed. Univariate and multivariate analyses were performed to investigate the association between ultrasound features and malignancy. The regression equation, the weighting, and the counting methods were used to determine the malignant risk of the thyroid nodules. The areas under the receiver operating characteristic curve (Az values) were calculated.

RESULTS

Of the 2141 thyroid nodules, 1572 were benign, 565 were malignant, and 4 were borderline. Vertical orientation, ill-defined, or irregular margin (including extrathyroidal extension), microcalcifications, solid, and markedly hypoechoic were positively associated with malignancy, while comet-tail artifacts were negatively associated with malignancy. The logistic regression equation yielded the highest Az value of 0.913, which was significantly higher than that obtained using the weighting method (0.893) and the counting method (0.890); however, no significant difference was found between the latter two. The C-TIRADS, based on the counting method, was designed following the principle of balancing the diagnostic performance and sensitivity of the risk stratification with the ease of use.

CONCLUSIONS

A relatively simple C-TIRADS was established using the counting value of positive and negative ultrasound features.

Inclusion of Thyroid Nodule Location in American College of Radiology TI-RADS Scoring: Impact on System Performance

Emerging data suggest that the location of thyroid nodules influences malignancy risk. The purpose of this study was to explore the impact of including location in American College of Radiology Thyroid Imaging Reporting and Data System (ACR TI-RADS) scoring. Four of five revised scoring algorithms that added 1 or 2 points to higher-risk locations were associated with lowered accuracy due to lower specificity. However, an algorithm that added 1 point to isthmic nodules did not differ significantly from ACR TI-RADS in accuracy; one additional isthmic cancer was diagnosed for each 10.3 additional benign nodules recommended for biopsy.

Transverse and Longitudinal Ultrasound Location of Thyroid Nodules and Risk of Thyroid Cancer

BACKGROUND

The high prevalence of thyroid nodules demands accurate assessment tools to avoid unnecessary biopsies. Prior studies demonstrated a correlation between the longitudinal location of thyroid nodules and the likelihood of malignancy. No study has evaluated the predictive value of transverse location on ultrasonography with malignancy.

METHODS

We retrospectively reviewed the records of thyroid nodules that underwent fine-needle aspiration over 13 years, including demographics, risk factors, nodule sonographic features, location, and surgical pathology. Univariate and multivariable logistic regression models were used to evaluate the risk of malignancy.

RESULTS

Of the 668 thyroid nodules, 604 were analyzed with a definitive diagnosis. Thirty-seven nodules were malignant, representing a prevalence of 6.1%. In the longitudinal plane, the upper pole nodules carried the highest incidence of malignancy (14.9%). In the transverse plane, the highest incidence of malignancy occurred in nodules located laterally (12.5%) and anterior-laterally (11.8%). Compared with the upper pole, the odds of malignancy were significantly lower for lower pole (odds ratio [OR] = 0.26, 95% confidence interval [CI]: 0.09-0.70) and midlobe nodules (OR = 0.31, 95% CI: 0.12-0.83). In the transverse plane, posteriorly situated nodules carried a significantly lower risk of malignancy (OR = 0.07, 95% CI: 0.01-0.69). Multiple logistic regression confirmed these associations after adjusting for age, sex, family history, radiation exposure, nodule size, and sonographic characteristics.

CONCLUSION

Both the transverse and longitudinal planes were independent predictors of cancer in thyroid nodules. Lateral, anterior-lateral, and upper pole nodules carried the highest risk and posterior nodules had the lowest risk of malignancy.

Lateral Lymph Node Metastases in T1a Papillary Thyroid Carcinoma: Stratification by Tumor Location and Size

OBJECTIVE

To analyze the incidence and risk factors for lateral lymph node metastases (LNMs) in T1a papillary thyroid carcinoma (PTC) with a focus on tumor location and size.

MATERIALS AND METHODS

The incidence of lateral LNM in 345 cases of T1a PTC was retrospectively analyzed. Univariate and multivariate analyses were performed to assess the relationships between lateral LNM and clinicopathological characteristics.

RESULTS

The incidence of skip metastasis to lateral LNM in T1a PTC located in the upper lobe was 12.1% (8/66). Logistic regression analysis indicated tumor size >5 mm (OR = 5.04, 95% CI = 1.79 to 14.18, P = 0.002), upper lobe location (OR = 7.68, 95% CI = 3.05-19.34, P < 0.001) and the number of central neck LNM (<2: OR = 24.79, 95% CI = 8.23-74.60, P < 0.001; ≥2: OR = 4.99, 95% CI = 1.95-12.73, P < 0.001) were independently associated with lateral LNM. Comparing the lateral and central LNM stratification based on tumor location revealed that both the incidences of lateral (33.3%) and central (30.3%) LNM of T1a PTC located in the upper lobe were higher than those of T1a PTC located in the middle and lower lobes. Of T1a PTC located in the upper lobe, the incidence of lateral LNM was 33.3% (22/66), which was higher than that [30.3% (20/66)] of central LNM. This finding is reversed in all T1a PTC cases and T1a PTC cases with tumor located in the middle and lower lobes.

CONCLUSION

A particularly high likelihood of lateral LNM was observed in T1a PTC patients with tumor located in the upper lobe of the thyroid gland, especially the tumor >5 mm in size, which could be considered a risk factor for lateral LNM in the clinical management of T1a PTC.

Thyroid Nodules Located in the Lower Pole Have a Higher Risk of Malignancy than Located in the Isthmus: A Single-Center Experience

PURPOSE

The aim of our study is to investigate whether thyroid nodules (TNs) localization has value as a predictor of malignancy. Ultrasonography provides very valuable information in the evaluation of TNs, but it does not correlate perfectly with histopathologic findings. Therefore, studies that will include new diagnostic methods that can improve these unknowns can be welcomed gratefully.

METHODS

This study was carried out retrospectively in a tertiary care center from September 2016 to January 2020. The study included 862 adult patients who have one or more nodules. Ultrasonography of characteristics of nodules such as echogenicity, content, margins, calcifications, size, and localization was recorded. Fine-needle aspiration biopsy (FNAB) was performed on dominant and suspicious 1142 nodules.

RESULTS

The patients were composed of 692 (80.3%) females and 170 (19.7%) males. Compared to nodules located in the isthmus; the malignancy risk increased 8.39 (OR: 8.39 (2.34-30.12), p = 0.001) times in the lower pole, 4.27 (OR: 4.27 (1.16-15.72), p = 0.029), times in the middle pole, 8.09 (OR: 8.09 (2.11-30.94), p = 0.002) times in the upper pole, and 7.63 (OR: 7.63 (1.95-29.81), p = 0.003) times in the nodules covering the whole of the lobe. Although the most nodular location was in the middle pole, the risk of malignancy was less than that in the lower and upper poles.

CONCLUSIONS

Unlike the other localization studies, we found a higher risk of malignancy in the lower and similarly upper thyroid poles. Besides well-defined malignancy indicators in the literature and guidelines, localization information is promising for this purpose in the future.

2020 Chinese guidelines for ultrasound malignancy risk stratification of thyroid nodules: the C-TIRADS

Thyroid nodules are very common all over the world, and China is no exception. Ultrasound plays an important role in determining the risk stratification of thyroid nodules, which is critical for clinical management of thyroid nodules. For the past few years, many versions of TIRADS (Thyroid Imaging Reporting and Data System) have been put forward by several institutions with the aim to identify whether nodules require fine-needle biopsy or ultrasound follow-up. However, no version of TIRADS has been widely adopted worldwide till date. In China, as many as ten versions of TIRADS have been used in different hospitals nationwide, causing a lot of confusion. With the support of the Superficial Organ and Vascular Ultrasound Group of the Society of Ultrasound in Medicine of the Chinese Medical Association, the Chinese-TIRADS that is in line with China's national conditions and medical status was established based on literature review, expert consensus, and multicenter data provided by the Chinese Artificial Intelligence Alliance for Thyroid and Breast Ultrasound.

Bethesda System Categories of Fine Needle Aspiration Cytology Are Not Associated with Thyroid Nodule Location: A Single Institution Experience

INTRODUCTION

Thyroid isthmus is defined as the thin band connecting thyroid tissue between both lateral thyroid lobes. Recently, a possible association between thyroid nodules located in the isthmus and malignancy was proposed. The aim of this study was to compare the frequency of The Bethesda System for Reporting Thyroid Cytopathology (TBSRTC) categories between nodules from the isthmus and nodules from both thyroid lobes.

METHODS

All fine needle aspiration cytology procedures performed between January 2016 and December 2019 at the Pathology Institute of Araçatuba, São Paulo, Brazil, were analyzed. For each nodule, at least 2 conventional slides were produced (1 stained by Giemsa and the other by hematoxylin and eosin). All cases were reported according to the TBSRTC. Clinical information (gender, age, and localization) and ultrasound data (size of nodules) were collected from medical requisition forms. To assess the association between the frequency of TBSRTC categories and nodule location, univariate analysis was performed using the χ2 test or Fisher's exact test, as appropriate. A p value <0.05 was considered statistically significant. Nodules located in transition between the isthmus and a right or left lobe were included in the isthmus group.

RESULTS

Considering the p value between the TBSRTC categories and thyroid nodule location, statistic association was not observed: nondiagnostic or unsatisfactory (p = 0.1442), atypia of undetermined significance or follicular lesion of undetermined significance (p = 0.3296), follicular neoplasm or suspicious for a follicular neoplasm (p = 0.0817), suspicious for malignancy (p = 0.8464), and malignant (p = 0.1082).

CONCLUSION

In the studied population, nodules located in the isthmus were not related to any Bethesda System category.

Contemporary Thyroid Nodule Evaluation and Management

CONTEXT

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

EVIDENCE ACQUISITION

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

EVIDENCE SYNTHESIS

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

CONCLUSION

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

Sonographic Risk Stratification Systems for Thyroid Nodules as Rule-Out Tests in Older Adults

Ultrasonographic risk-stratification systems (RSS), including various Thyroid Imaging Reporting and Data Systems (TIRADS), were proposed to improve reporting and reduce the number of fine-needle aspiration biopsies. However, age might be a confounder since some suspicious ultrasonographic features lack specificity in elderly patients. We aimed to investigate whether the diagnostic performance of the RSS varied between age groups. All patients consecutively referred for thyroid biopsy between November 1, 2015, and March 10, 2020, were included. The malignancy risk of each nodule was estimated according to five RSS: the American Association of Clinical Endocrinologists/American College of Endocrinology/Associazione Medici Endocrinologi guidelines, the American College of Radiology (ACR) TIRADS, the American Thyroid Association guidelines, the European TIRADS, and the Korean TIRADS. Overall, 818 nodules (57 malignant) were evaluated. The malignancy rate was higher in patients ≤ 65 years (8.1%) than in patients > 65 years (3.8%; p = 0.02). All RSS confirmed a significant discriminative performance in both age groups, with a negative predictive value of 100% in patients > 65 years, although specificity was lower in older patients. The ACR TIRADS was the best performing in both age groups. RSS could avoid a sizable number of biopsies when applied as rule-out tests in elderly patients.

Isthmic Papillary Thyroid Carcinoma Presents a Unique Pattern of Central Lymph Node Metastasis

Purpose

Treatment protocols for occult central lymph node metastasis (LNM) associated with papillary thyroid cancer (PTC) located in the isthmus are debatable. We aimed to analyze the pattern of occult central LNM in isthmic PTC, including risk factors for bilateral paratracheal LNM.

Patients and Methods

Consecutive patients with PTC were recruited to this study. All patients underwent total thyroidectomy and prophylactic bilateral central neck dissection. The clinicopathologic features and distribution of central LNM were compared between the two groups, and risk factors for bilateral paratracheal LNM were analyzed.

Results

A total of 174 patients with PTC were enrolled in this study, of whom 87 patients had isthmic PTC (study group) and 87 patients had lobe-originating PTC (control group). The two groups had comparable demographics and tumor features. There were higher frequencies of pretracheal LNM (P =0.001) and bilateral paratracheal LNM (P = 0.002) in the isthmic PTC group. Bilateral paratracheal LNM was significantly associated with age <55 years (P = 0.037), capsular invasion (P = 0.034), tumor location (isthmus) (P < 0.001), BRAF gene mutation (P = 0.013), and pretracheal LNM (P < 0.001). Isthmus location (odds ratio [OR]: 4.116, 95% confidence interval [CI]: 1.264–13.433, P = 0.019) and pretracheal LNM (OR: 3.422, 95% CI: 1.214–9.642, P = 0.020) were independent risk factors for bilateral paratracheal LNM.

Conclusion

Because of its unique anatomic location, isthmic PTC differs from PTC in the lobe with respect to pretracheal and bilateral paratracheal LNM, even in patients of comparable age, sex, tumor size, extrathyroidal extension, BRAF mutation, and pathologic TNM staging. The isthmus location was found to be an independent risk factor for bilateral paratracheal LNM. This information may contribute to the development of an appropriate surgical protocol for isthmic PTC.

Whirling technique for thyroid fine needle aspiration biopsy: a preliminary study of effectiveness and safety

PURPOSE

This study was aimed to compare thyroid fine needle aspiration biopsy (FNAB) techniques (conventional vs. whirling) in terms of cell harvesting ability ex vivo, the unsatisfactory rate and complication rate in vivo, and multi-operator performance in a phantom study.

METHODS

In the ex vivo study, cell counts per background at ×100 magnification were compared between both techniques. In the in vivo study, 70 patients who underwent whirling FNAB from July 2019 to November 2019 were retrospectively compared to 140 matched patients who underwent conventional FNAB from January 2018 to November 2019 regarding the unsatisfactory rate and complication rate. As a subgroup analysis, thyroid nodules in difficult biopsy situations (nodule diameter <10 mm and location within 3 mm from major anatomical structures) were compared. In the phantom study, eight operators with varying experience recorded levels of dexterity and needle tip visualization, and their preferences for both techniques.

RESULTS

In the ex vivo study, cell counts were comparable between both techniques in all thyroid nodule mimickers (80.0% vs. 87.5%, P=0.178). In the in vivo study, the unsatisfactory rate was comparable between the two groups (15.7% vs. 12.9%, P=0.859). In the subgroup analysis, the whirling technique demonstrated a lower unsatisfactory rate (5.9% vs. 24.2%, P=0.045) and a lower complication rate (0% vs. 6.1%, P=0.553). In the phantom study, the whirling technique demonstrated better dexterity and needle tip visualization and was preferred by all operators.

CONCLUSION

This newly proposed whirling technique for thyroid FNAB may be effective and safe, especially in difficult biopsy situations.

Investigating the Effect of Thyroid Nodule Location on the Risk of Thyroid Cancer

Background: Thyroid nodules are routinely evaluated with ultrasound. Our aim was to determine if thyroid nodule location was a useful feature to predict thyroid cancer. Materials and Methods: Retrospective review of patients with thyroid nodules from six referral centers from 2006 to 2010. A total of 3313 adult patients with thyroid nodules and confirmed benign or malignant thyroid diagnoses were included. Results: Mean patient age was 54.2 (18-97) years, and the majority were women (n = 2635, 79.8%). A total of 3241 nodules were analyzed, 335 (10.3%) of which were malignant. Thyroid nodule location was an independent risk factor in predicting thyroid cancer (p = 0.005). Thyroid cancer odds were highest in the isthmus (odds ratio [OR] = 2.4, 95% confidence interval [CI] 1.6-3.6, p < 0.0001). In a multivariate regression model adjusting for age, sex, family history of thyroid cancer, radiation exposure, nodule size, and American College of Radiology (ACR) TI-RADS (Thyroid Imaging Reporting and Data System) score, the isthmus nodules had the highest risk of malignancy (OR = 2.4 [CI 1.5-3.9], p = 0.0007), followed by upper thyroid nodules (OR = 1.8 [CI 1.2-2.7], p = 0.005) and then middle thyroid nodules (OR = 1.5 [CI 1.1-2.0], p = 0.01) compared with lower thyroid nodules. Isthmus nodules were significantly smaller in size compared with middle (p < 0.0001) and lower (p = 0.0004), but not upper nodules (p = 0.25), with a mean size of 15.5 mm (±10.7). Conclusions: Thyroid nodule location is an independent risk factor in predicting the risk of thyroid cancer. Isthmic nodules carry the highest risk of cancer diagnosis and lower lobe nodules carry the lowest risk.

Taller-Than-Wide Shape: A New Definition Improves the Specificity of TIRADS Systems

INTRODUCTION

A taller-than-wide (TTW) shape is a suspicious feature of thyroid nodules commonly defined as an anteroposterior/transverse diameter (AP/T) ratio >1. An intraobserver variability of up to 18% in AP diameter evaluations has been described, which may lead to overreporting of this feature. To potentially improve the reliability of the TTW definition, we propose an arbitrary ratio of ≥1.2.

OBJECTIVE

The aim of this study was to estimate the impact of this definition on diagnostic performance.

METHODS

We prospectively analyzed 553 thyroid nodules referred for cytology evaluation at an academic center. Before fine-needle aspiration, two examiners jointly defined all sonographic features considered in risk stratification systems developed by the American Thyroid Association (ATA), the American Association of Clinical Endocrinologists (AACE), the American College of Radiology (ACR TIRADS), the European Thyroid Association (EU-TIRADS), and the Korean Society of Thyroid Radiology (K-TIRADS). TTW was defined according to the current definition (AP/T diameter ratio >1) and an arbitrary alternative definition (AP/T ratio >1.2).

RESULTS

The alternative definition classified fewer nodules as TTW (28, 5.1% vs. 94, 17%). The current and proposed definitions have a sensitivity of 26.2 and 11.9% (p = 0.03) and a specificity of 83.8 and 95.5% (p < 0.001). Thus, as a single feature, the arbitrary definition has a lower sensitivity and a higher specificity. When applied to sonographic risk stratification systems, however, the proposed definition would increase the number of avoided biopsies (up to 58.2% for ACR TIRADS) and the specificity of all systems, without negative impact on sensitivity or diagnostic odds ratio.

CONCLUSIONS

Re-defining TTW nodules as those with an AP/T ratio ≥1.2 improves this marker's specificity for malignancy. Using this definition in risk stratification systems will increase their specificity, reducing the number of suggested biopsies without significantly diminishing their overall diagnostic performance.