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

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.

Diagnostic models for predicting malignancy in thyroid nodules classified as Bethesda Category III in an endemic region

BACKGROUND

This study aims to develop a diagnostic model to help physicians determine whether thyroid nodules categorized as atypia of undetermined significance (AUS) in category III of the Bethesda system are benign or malignant preoperatively. To create a diagnostic model for predicting thyroid nodules' benign or malignant with AUS cytology based on clinical, ultrasonographic, and cytopathological findings.

METHODS

This is a retrospective cohort study involving patients (>19) at risk of thyroid cancer who had thyroidectomy after an AUS cytology. The dataset consists of 53 variables 204 nodules from 183 patients. Binary logistic regression and factor analysis methods were used to identify risk factors for malignancy. Finally, four prediction models were developed using different approaches, based on clinical, pathological clinical + pathological, and the factors.

RESULTS

A total of 88 (48.1%) of 183 patients diagnosed with AUS were benign and 95 (51.9%) the malignant. After determining risk factors, four prediction models were developed based on different approaches to assist physicians in deciding to detect AUS nodules early. It was seen that bilaterality was found to be a risk factor for malignancy in the clinical model (pbilaterality  = .03) and it was also seen that the pathological variables pale chromatin and irregular contours in the oncocyte variables were risk factors for malignancy (ppalechromatin  = .02, pirregularcontoursintheoncocyte  = .04). The best model obtained sensitivity and specificity values are 73% and 87% based on clinical and pathological variables.

CONCLUSION

This comprehensive study may provide a more in-depth understanding of AUS and make a notable contribution to healthcare professionals before surgery.

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.

The use of thyroid isthmusectomy for management of well differentiated thyroid carcinoma - A systematic review and meta-analysis

OBJECTIVE

With the growing global incidence of thyroid carcinomas, there is an increasing need for distinct guidelines for isthmus-confined carcinomas. Here, we performed the first systematic review on the topic to date, aiming to provide understanding to isthmusectomy as surgical management for well-differentiated thyroid carcinoma of the isthmus.

METHODS

We conducted a systematic review following the PRISMA guidelines, analyzing English-language studies from the past decade that report on thyroid isthmusectomy. Exclusion criteria included isthmusectomy performed alongside full thyroidectomy or partial thyroid lobectomy, lack of data on tumor characteristics or survival outcomes, and non-English publications where a translation was unavailable. Our review identified a total of 227 patients from seven studies.

RESULTS

The average 5-year overall survival and disease-free survival rates for patients with isthmus-confined PTC who underwent isthmusectomy were 100 % and 93.1 %, respectively. Similar to that of total thyroidectomy. 3.1 % of patients required completion thyroidectomy. Furthermore, isthmusectomy resulted in fewer surgical complications than total thyroidectomy.

CONCLUSIONS

The scarcity of studies providing detailed tumor characteristics and patient outcomes limits our ability to fully evaluate the safety and efficacy of isthmusectomy for isthmus-confined PTC. Additionally, the variable sample sizes and restricted geographic distribution of the included studies calls into questions the generalizability of their findings. Despite these limitations, the data suggest that isthmusectomy may be a viable surgical option for select patients with small, isthmus-confined PTC. In the absence of a randomized controlled trial on the noninferiority of isthmusectomy, significantly more publications are needed before strong conclusions can be drawn.

Molecular characteristics of isthmus papillary thyroid cancers: Supporting evidence for unfavorable clinical behavior

BACKGROUND

Previous studies demonstrate isthmus thyroid nodules are more likely to be malignant than lobar nodules. Additional data suggest that isthmus papillary thyroid cancers (PTCs) are more aggressive than lobar PTCs. We hypothesize that isthmus PTCs have a more unfavorable molecular profile.

METHODS

The Cancer Genome Atlas (TCGA) database was queried to analyze clinical, mutation and gene expression data of isthmus PTCs compared to non-isthmus PTCs.

RESULTS

We analyzed characteristics of 472 ​PTCs, including 19 isthmus PTCs. There were no significant differences between isthmus and non-isthmus PTC demographic and clinical variables or the frequency of RAS family, fusion driver, TERT, and tumor suppressor gene mutations. There was a trend towards increased BRAF mutations (68% vs 55%, p ​= ​0.28). A more aggressive gene expression profile was observed in isthmus PTC compared to lobar/multifocal PTC with differences in ERK score (19.4 vs 7.71, p ​< ​0.05) and TDS score (-0.58 vs 0.02, p ​< ​0.05).

CONCLUSIONS

These results provide a possible molecular explanation for the more aggressive behavior reported in isthmus PTCs.

Risk factors for hypothyroidism following hemithyroidectomy

OBJECTIVE

Hypothyroidism is the most common complication of hemithyroidectomy for thyroid nodules. This retrospective cohort study investigated the prognostic factors for hypothyroidism following hemithyroidectomy.

METHODS

We included patients who underwent hemithyroidectomy between 2016 and 2017, excluding those with history of preoperative hypothyroidism or malignancy on histopathological examination. The primary endpoint was development of hypothyroidism during follow-up (TSH≥2 above normal).

RESULTS

Twenty-six of the 128 included patients (20%) developed postoperative hypothyroidism. The following independent prognostic factors were found: preoperative TSH level>1.5 mIU/L (OR 2.11; P=0.013), and remaining thyroid volume adjusted for body surface area<4.0mL/m2 (OR 1.77; P=0.015). Twenty-one patients (81%) had first TSH values above the upper limit of normal. Postoperatively, first TSH level correlated significantly with the preoperative value (R=0.5779, P<0.001). Levothyroxine was prescribed to 16% of patients, with a mean dose of 0.92μg/kg/day.

CONCLUSION

Patients with TSH>1.5 mIU/or remaining thyroid volume adjusted for body surface area<4.0mL/m2 should have intensified clinical and biological follow-up in the first year after surgery.

Prediction of cytology-histology discrepancy when Bethesda cytology reports benign results for thyroid nodules in women: with special emphasis on pregnancy

Objectives: Benign category of Bethesda classification is generally well known to carry a false-negative rate of 0-3%. The current study was designed to investigate the rate of false-negative cytology in patients who underwent thyroidectomy for presumably benign thyroid diseases. Predictive risk factors for false results and malignancy were evaluated along with cytology-histology discrepant cases.Materials and methods: Females who underwent thyroidectomy between May 2014 and December 2022 were included. Demographics, ultrasound (US) features, fine-needle aspiration (FNA) diagnosis, surgical indications and outcomes, final histology reports, risk factors, and malignancy rate were recorded. Cytology-histology discrepant cases were further evaluated for interpretation errors and risk factors. Statistical analyses were performed using Fisher's exact and Mann-Whitney U tests.Results: Of 581 women with a benign thyroid disease who underwent thyroidectomy, 91 was diagnosed as incidental carcinoma (15.6%) and most was T1a (4.9 ± 2.7 mm, 95.6%). Final histology reports revealed mostly papillary carcinoma (93.4%). Predictors of malignancy such as age, family history, previous radiation exposure, and iodine-deficient diet did not help in risk stratification (p > 0.05, for each). However, FNA taken during pregnancy was determined as a risk factor (n = 7, 7.6%, p < 0.05) since it may cause a delay in diagnosis. Cytology-histology discrepant cases were seen to be mostly due to sampling errors (45%, p < 0.05), followed by misinterpretations (37.3%, p < 0.05). There was no reason for discrepancy in 17.5%, and this was linked to inherent nature of thyroid nodule with overlapping cytologic features. Best identifiable risk factor for misinterpretation was pregnancy as well (n = 5, 14.7%, p < 0.05).Conclusions: Risk of malignancy in a presumably benign thyroid disease should not be ignored. Radiology-cytology correlation by an experienced dedicated team may help in decreasing sampling errors. Physiologic changes caused by pregnancy may shade malignant transformation in thyrocytes, and it would be appropriate to be cautious about benign FNA taken during this period.

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.

Differentiating benign and malignant thyroid nodules: A cross-sectional study on the comparison of diagnostic value of ultrasound elastography and fine needle aspiration biopsy

Background and Aim

This study examines the comparison of ultrasound elastography and fine needle aspiration (FNA) in diagnosing thyroid cancers and investigates the use of elastography as the initial diagnostic test of thyroid cancers to avoid the need for invasive diagnostic tests.

Methods

In this study, 28 patients with 48 thyroid nodules (TNs) who were candidates for FNA or surgery were examined within a period of 18 months. Cut-off and subsequently sensitivity and specificity for elastography results, compared to pathology results as the gold standard, were calculated using the receiver operating characteristic curve (ROC).

Results

Based on ROC, the cut-off point differentiating the tissue stiffness between benign and malignant TNs was 25.400 kilopascal (kPa) (sensitivity of 90.9% and specificity of 78.4%). It was observed that age affects the tissue stiffness; therefore, the cut-off was defined as 65.625 kpa for age groups under 50 years old (sensitivity of 100% and specificity of 100%) and 25.400 kpa for the age group above 50 years old (sensitivity of 88.9% and specificity of 70.4%).

Conclusion

Based on the high sensitivity and specificity of shear wave elastography in the differentiation of benign and malignant TNs, it can be employed as a stand-alone or in combination with other diagnostic techniques to reduce the need for inessential surgical operations. However, future studies or developments are needed on this promising diagnostic technique.

Management of Thyroid Nodules

Thyroid nodules are common and the prevalence varies between 4 and 7% by palpation and 19-68% by high-resolution USG. Most thyroid nodules are benign, and the malignancy rate varies between 7 and 15% of patients. Thyroid nodules are detected incidentally during clinical examination or, more often, during imaging studies performed for another reason. All detected thyroid nodules should be evaluated clinically. The main test in evaluating thyroid function is thyroid stimulating hormone (TSH). If the serum TSH level is below the normal reference range, a radionuclide thyroid scan should be performed to determine whether the nodule is hyperfunctioning. If the serum TSH level is normal or high, ultrasonography (US) should be performed to evaluate the nodule. US is the most sensitive imaging method in the evaluation of thyroid nodules. Computed tomography (CT) and magnetic resonance imaging are not routinely used in the initial evaluation of thyroid nodules. There are many risk classification systems according to the USG characteristics of thyroid nodules, and the most widely used in clinical practice are the American Thyroid Association guideline and the American College of Radiology Thyroid Imaging Reporting and Data System. Fine needle aspiration biopsy (FNAB) is the gold standard method in the evaluation of nodules with indication according to USG risk class. In the cytological evaluation of FNAB, the Bethesda System for Reporting Thyroid Cytopathology (TBSRTC) is the most frequently applied cytological classification. TBSRTC is a simplified, 6-category reporting system and was updated in 2023. The application of molecular tests to FNAB specimens, especially those diagnosed with Bethesda III and IV, is increasing to reduce the need for diagnostic surgery. Especially in Bethesda III and IV nodules, different methods are applied in the treatment of nodules according to the malignancy risk of each category, these are follow-up, surgical treatment, radioactive iodine treatment, and non-surgical ablation methods.

[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.

Predictors and a prediction model for positive fine needle aspiration biopsy in C-TIRADS 4 thyroid nodules

Objectives

To screen out the predictors and establish a prediction model of positive fine needle aspiration biopsy (FNAB) in the Chinese Guidelines for Malignant Risk Stratification of Thyroid Nodule Ultrasound (C-TIRADS) 4 thyroid nodules, and this nomogram can help clinicians evaluate the risk of positive FNAB and determine if FNAB is necessary.

Methods

We retrospectively analyzed data from 547 patients who had C-TIRADS 4 thyroid nodules and underwent fine-needle aspiration biopsy (FNAB) at the Second Affiliated Hospital of Chongqing Medical University between November 30, 2021 and September 5, 2022. Patients who met our inclusion criteria were divided into two groups based on positive or negative FNAB results. We compared their ultrasound (US) features, BRAF V600E status, thyroid function, and other general characteristics using univariate and multivariate logistic regression analyses to identify independent predictors. These predictors were then used to construct a nomogram. The calibration plot, area under the curve (AUC), and decision curve analysis were employed to evaluate the calibration, discrimination, and clinical utility of the prediction model.

Results

Out of 547 patients, 39.3% (215/547) had a positive result on fine-needle aspiration biopsy (FNAB), while 60.7% (332/547) had a negative result. Univariate logistic regression analysis revealed no significant differences in TPOAb, TgAb, TSH, Tg, nodule location, sex, or solid status between the two groups (P>0.05). However, age, nodule size, internal or surrounding blood flow signal, microcalcifications, aspect ratio, morphology, and low echo showed significant differences (P<0.05). Multivariate logistic regression analysis was conducted to explore the correlation between potential independent predictors. The results showed that only age (OR=0.444, 95% Cl=0.296~0.666, P<0.001), low echo (OR=3.549, 95% Cl=2.319~5.432, P<0.001), microcalcifications (OR=2.531, 95% Cl=1.661~3.856, P<0.001), aspect ratio (OR=3.032, 95% Cl=1.819~5.052, P<0.001), and morphology (OR=2.437, 95% Cl=1.586~3.745, P<0.001) were independent predictors for a positive FNAB. These variables were used to construct a prediction nomogram. An ROC curve analysis was performed to assess the accuracy of the nomogram, and AUC=0.793, which indicated good discrimination and decision curve analysis demonstrated clinical significance within a threshold range of 14% to 91%.

Conclusion

In conclusion, 5 independent predictors of positive FNAB, including age (≤45 years old), low echo (yes), microcalcifications (yes), aspect ratio (>1) and morphology (irregular), were identified. A nomogram was established based on the above 5 predictors, and the nomogram can be used as a complementary basis to help clinicians make decisions on FNAB of C-TI-RADS 4 thyroid nodules.

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.

Does three-dimensional intraglandular location predict malignancy in parotid tumors?

Tumors arising within the parotid encompass a heterogeneous mix of benign and malignant neoplasms and other tissue growths. The purpose of this study was to determine the association between the location of intraparotid masses and the risk of malignancy. A retrospective cohort study was performed of patients diagnosed with parotid tumors following open tumor excision. The primary predictor variable was the location of the epicenter of the tumor in three-dimensional space, as determined from preoperative imaging. Other variables were patient demographics and clinical parameters. The primary outcome variable was the final histopathologic diagnosis of a benign or malignant process. A χ² analysis was performed to test for any significant associations between demographic, clinical, and radiographic factors in relation to the outcome, and backwards stepwise logistic regression analysis was used to control for variables. Both increasing age (P = 0.002) and the presence of local pain (P = 0.020) were associated with malignancy. Tumors located anterior to the posterior border of the retromandibular vein had 2.18 times higher odds of malignancy (95% confidence interval 1.13-4.21; P = 0.020). Multivariate regression analysis suggested that patient age, the presence of pain, and tumor location anterosuperiorly and superoinferiorly could all assist in determining the odds of malignancy.

Nomogram to differentiate benign and malignant thyroid nodules in the American College of Radiology Thyroid Imaging Reporting and Data System level 5

OBJECTIVES

To develop and validate a nomogram for differentiating benign and malignant thyroid nodules of American College of Radiology (ACR) Thyroid Imaging Reporting and Data System (TI-RADS) level 5 (TR5) and improving the performance of the guideline.

METHODS

From May 2018 to December 2019, 640 patients with TR5 nodules were retrospectively included in the primary cohort. Univariate and multivariable analyses were performed to determine the risk factors for thyroid cancer. A nomogram was established on the basis of multivariable analyses; the performance of the nomogram was evaluated with respect to discrimination, calibration, and clinical usefulness. The nomogram model was also compared to the ACR score model. External validation was performed and the independent validation cohort contained 201 patients from April 2021 to January 2022.

RESULTS

Multivariable analyses showed that age, tumour location, multifocality, concomitant Hashimoto's disease, neck lymph node status reported by ultrasound (US) and ACR score were the independent risk factors for thyroid cancer (all p < .05). The nomogram showed good discrimination, with an area under the curve (AUC) of 0.786 (95% confidence interval [CI]: 0.742-0.830) and 0.712 (95% CI: 0.615-0.809) in the primary cohort and external validation cohort, respectively. Decision curve analysis demonstrated the clinical usefulness of the model. Compared to the ACR score model, the nomogram showed higher AUC (0.786 vs. 0.626, p < .001) and specificity (0.783 vs. 0.391).

CONCLUSIONS

The presented nomogram model, based on age, tumour features and ACR score, can differentiate benign and malignant thyroid nodules in TR5 and had a high specificity.

Virtual touch tissue imaging for differential diagnosis in ACR TI-RADS category 3-4 thyroid nodules: Conservative and aggressive methods

PURPOSE

Many Thyroid Imaging Reporting and Data System (TI-RADS) category 3-4 nodules are benign. Our study aimed to add virtual touch tissue imaging (VTI) to TI-RADS using two methods, namely conservative and aggressive, and to explore which method had better diagnostic performance and which method avoided more unnecessary biopsies.

METHODS

From January 2016 to December 2021, we included 121 thyroid nodules classified as TI-RADS category 3-4 in 115 consecutive patients in this retrospective study. This study used the reference standard for pathological diagnosis by surgical resection or biopsy. The diagnostic performance of the different methods was evaluated and compared by receiver operating characteristic (ROC) and area under the ROC curve (AUC).

RESULTS

In this study, the aggressive approach had the best diagnostic performance among TI-RADS alone, the conservative approach, and the aggressive approach (AUC: 0.863 versus 0.598, P = 0.0007; 0.863 versus 0.755, P = 0.0067). When we used an aggressive approach, 75.44% (43/57) of the 57 false-positive nodes diagnosed by TI-RADS were appropriately downgraded from TI-RADS category 4 to category 3, avoiding unnecessary biopsies.

CONCLUSION

VTI improves the diagnostic performance of TI-RADS. The aggressive approach of combining the TI-RADS with VTI would help reduce unnecessary biopsies.

Contrast-Enhanced Ultrasound Improves the Accuracy of the ACR TI-RADS in the Diagnosis of Thyroid Nodules Located in the Isthmus

OBJECTIVES

 To evaluate the diagnostic performance of the American College of Radiology (ACR) Thyroid Image Reporting and Data System (TI-RADS), contrast-enhanced ultrasound (CEUS), and a modified TI-RADS in differentiating benign and malignant nodules located in the isthmus.

METHODS

 This retrospective study was approved by the institutional review board. Informed consent was obtained. Grayscale ultrasound (US) and CEUS images were obtained for 203 isthmic thyroid nodules (46 benign and 157 malignant) in 198 consecutive patients (156 women, mean age: 44.7 years ± 11.3 [standard deviation]; 47 men, mean age: 40.9 years ± 11.0). The area under the receiver operating characteristic curve (AUC) of the diagnostic performance of the ACR TI-RADS, CEUS, and the modified TI-RADS were evaluated.

RESULTS

 Lobulated or irregular margins (P = 0.001; odds ratio [OR] = 9.250) and punctate echogenic foci (P = 0.007; OR = 4.718) on US and hypoenhancement (P < 0.001; OR = 20.888) on CEUS displayed a significant association with malignancy located in the isthmus. The most valuable method to distinguish benign nodules from malignant nodules was the modified TI-RADS (AUC: 0.863 with modified TR5), which was significantly better than the ACR TI-RADS (AUC: 0.738 with ACR TR5) (P < 0.001) but showed no significant difference with respect to CEUS (AUC: 0.835 with hypoenhancement) (P = 0.205). The diagnostic value was significantly different between CEUS and the ACR TI-RADS (P = 0.028).

CONCLUSION

 The modified TI-RADS could significantly improve the accuracy of the diagnosis of thyroid nodules located in the isthmus.

Comparison between cutting versus retraction of anterior cervical musculature during endoscopic thyroidectomy

To compare the different techniques of managing the anterior cervical muscle group during endoscopic thyroidectomy via the trans-thoraco-areolar approach. A total of 90 patients with thyroid tumors less than 3 cm were evaluated. The time for each intraoperative step, total surgery duration, intraoperative blood loss volume, pathology results, number of lymph nodes dissected and patient satisfaction with esthetics were assessed. Intraoperative blood loss volume, drainage volume on the first postoperative day, number of lymph nodes dissected in the central region, postoperative hospitalization duration, number of transient laryngeal nerve palsy cases, and number of transient hypocalcemia cases were similar between the muscle transection (MT) and muscle retraction (MR) groups. The MT group had significantly higher postoperative pain scores after 12 hours, but pain scores at 48 hours postoperatively were not significantly different between the 2 groups. In the unilateral thyroidectomy subgroup, the durations of isthmus resection, freeing the lateral thyroid, exposing the laryngeal recurrent nerve, and management of the inferior pole were similar for both muscle management methods. The muscle dissection and suture time was significantly longer for the MT group than that for the MR group; in contrast, the upper pole management time of the muscle resection group was significantly shorter. In the bilateral resection subgroup, both muscle management methods required similar durations for managing the contralateral upper pole after ipsilateral thyroidectomy. However, intraoperative blood loss was significantly higher for MR than for MT, while postoperative pain was relatively mild. In the malignant tumor subgroup, duration of inferior thyroid pole management was significantly less for MT than for MR. There are significant differences between the 2 muscle management methods in handling and suturing muscles. Both methods have satisfactory postoperative outcomes for resection of thyroid nodules with diameters ≤3 cm. For tumors located in the upper pole, transection of the anterior cervical muscles confers higher feasibility of the thyroidectomy technique; however, suturing becomes difficult in such scenarios.

The Importance of the Thyroid Nodule Location in Determining the Risk of Malignancy: A Retrospective Study

Introduction

Thyroid nodules are very common. However, the majority of thyroid nodules are benign. Ultrasound is the first-line imaging investigation of choice for thyroid nodules. Certain sonographic features are associated with an increased risk of malignancy. Recent studies suggested that the location of the nodule may be associated with the malignancy risk. Hence, this study aims to investigate this association.

Methods

After obtaining approval from the ethics committee, we conducted a retrospective study that involved all patients who attended our hospital, and who underwent fine-needle aspiration cytology for the evaluation of suspicious thyroid nodules (TR3-5). Electronic medical records were used to obtain data about the ultrasound and cytology reports. A multivariable binary logistic regression analysis model was conducted to identify the independent factors significantly associated with malignant thyroid nodules.

Results

The study included 366 patients who underwent fine-needle aspiration cytology for suspicious nodules on thyroid ultrasound. In total, 52 (14.2%) nodules were found to be malignant on cytology. By far, the most common thyroid malignancy was papillary carcinoma. The multivariable analysis model revealed that women were 24% less likely to have malignant thyroid nodules compared with men. After adjusting for the age, gender, and Thyroid Imaging Reporting and Data System (TI-RADS) group, the nodules located within the isthmus were four times more likely to be malignant compared to those located in the right or left lobes.

Conclusions

The study demonstrates that the isthmus location of thyroid nodules is associated with a higher risk of malignancy. Physicians should have a lower threshold to biopsy such nodules. Further studies are needed to confirm this interesting finding.

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.

A Size-Cuttable, Skin-Interactive Wearable Sensor for Digital Deciphering of Epidermis Wavy Deformation

Body shape and curvature are vital criteria for judging health. However, few studies exist on the curvature of the body. We present a skin-interactive electronic sticker that digitally decodes the epidermis deformation in a hybrid cartridge format (disposable bandages and non-disposable kits). The device consists of two functional modes: (1) as a thin electronic sticker of 76 μm thickness and a node pitch of 7.45 mm for the measurement of body curvature in static mode, and (2) as a wrist bandage for the deciphering of skin wave fluctuations into a colored core-line map in dynamic mode. This method has high detection sensitivity in the static mode and high accuracy of 0.986 in the dynamic mode, resulting in an F₁ score of 0.966 in testing by feedforward deep learning. The results show that the device can decipher 32 delicate finger folding gestures by measuring skin depths and positions via image segmentation, leading to an optimal core line in a color map. This approach can help provide a better understanding of skin wave deflection and fluctuations for potential wearable applications, such as in delicate skin-related gesture control in the metaverse, rehabilitation programs for the brain-degenerate, and as a detector of biophysical state relating to body shape and curvature in the field of digital medicine.

Improving the diagnosis of thyroid cancer by machine learning and clinical data

Thyroid cancer is a common endocrine carcinoma that occurs in the thyroid gland. Much effort has been invested in improving its diagnosis, and thyroidectomy remains the primary treatment method. A successful operation without unnecessary side injuries relies on an accurate preoperative diagnosis. Current human assessment of thyroid nodule malignancy is prone to errors and may not guarantee an accurate preoperative diagnosis. This study proposed a machine learning framework to predict thyroid nodule malignancy based on our collected novel clinical dataset. The ten-fold cross-validation, bootstrap analysis, and permutation predictor importance were applied to estimate and interpret the model performance under uncertainty. The comparison between model prediction and expert assessment shows the advantage of our framework over human judgment in predicting thyroid nodule malignancy. Our method is accurate, interpretable, and thus useable as additional evidence in the preoperative diagnosis of thyroid cancer.

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.

Construction of the Classification Model Using Key Genes Identified Between Benign and Malignant Thyroid Nodules From Comprehensive Transcriptomic Data

Thyroid nodules are present in upto 50% of the population worldwide, and thyroid malignancy occurs in only 5–15% of nodules. Until now, fine-needle biopsy with cytologic evaluation remains the diagnostic choice to determine the risk of malignancy, yet it fails to discriminate as benign or malignant in one-third of cases. In order to improve the diagnostic accuracy and reliability, molecular testing based on transcriptomic data has developed rapidly. However, gene signatures of thyroid nodules identified in a plenty of transcriptomic studies are highly inconsistent and extremely difficult to be applied in clinical application. Therefore, it is highly necessary to identify consistent signatures to discriminate benign or malignant thyroid nodules. In this study, five independent transcriptomic studies were combined to discover the gene signature between benign and malignant thyroid nodules. This combined dataset comprises 150 malignant and 93 benign thyroid samples. Then, there were 279 differentially expressed genes (DEGs) discovered by the feature selection method (Student’s t test and fold change). And the weighted gene co-expression network analysis (WGCNA) was performed to identify the modules of highly co-expressed genes, and 454 genes in the gray module were discovered as the hub genes. The intersection between DEGs by the feature selection method and hub genes in the WGCNA model was identified as the key genes for thyroid nodules. Finally, four key genes (ST3GAL5, NRCAM, MT1F, and PROS1) participated in the pathogenesis of malignant thyroid nodules were validated using an independent dataset. Moreover, a high-performance classification model for discriminating thyroid nodules was constructed using these key genes. All in all, this study might provide a new insight into the key differentiation of benign and malignant thyroid nodules.

Point of Care Measurement of Body Mass Index and Thyroid Nodule Malignancy Risk Assessment

BACKGROUND

Large scale epidemiology studies have suggested obesity may increase the risk of thyroid cancer, though no prospective analyses using real-world measurement of BMI at a time proximate to initial thyroid nodule evaluation have been performed.

METHODS

We performed a prospective, cohort analysis over 3 years of consecutive patients presenting for thyroid nodule evaluation. We measured BMI proximate to the time of initial evaluation and correlated this with the final diagnosis of benign or malignant disease. We further correlated patient BMI with aggressivity of thyroid cancer, if detected.

RESULTS

Among 1,259 consecutive patients with clinically relevant nodules, 199(15%) were malignant. BMI averaged 28.6 kg/m² (SD: 6.35, range:16.46-59.26). There was no correlation between the measurement of BMI and risk of thyroid cancer (p=0.58) as mean BMI was 28.9 kg/m² and 28.6 kg/m² in cancerous and benign cohorts, respectively. Similarly, BMI did not predict aggressive thyroid cancer (p=0.15). While overall nodule size was associated with increased BMI (p<0.01), these data require further validation as obesity may hinder nodule detection until large.

CONCLUSION

In contrast to findings published from large scale association studies drawn from national databases, these prospective data of consecutive patients presenting for nodule evaluation detect no association of obesity (as measured by BMI) with thyroid cancer. Real time measurement of BMI at the time of thyroid nodule evaluation does not contribute to cancer risk assessment.

Lack of Association Between Helicobacter pylori Infection and the Risk of Thyroid Nodule Types: A Multicenter Case-Control Studyin China

The prevalence of Helicobacter pylori infection is high worldwide, while numerous research has focused on unraveling the relationship between H. pylori infection and extragastric diseases. Although H. pylori infection has been associated with thyroid diseases, including thyroid nodule (TN), the relationship has mainly focused on potential physiological mechanisms and has not been validated by large population epidemiological investigations. Therefore, we thus designed a case-control study comprising participants who received regular health examination between 2017 and 2019. The cases and controls were diagnosed via ultrasound, while TN types were classified according to the guidelines of the American College of Radiology Thyroid Imaging Reporting and Data System (ACR TI-RADS). Moreover, H. pylori infection was determined by C14 urea breath test, while its relationship with TN type risk and severity was analyzed using binary and ordinal logistic regression analyses. A total of 43,411 participants, including 13,036 TN patients and 30,375 controls, were finally recruited in the study. The crude odds ratio (OR) was 1.07 in Model 1 (95% CI = 1.03-1.14) without adjustment compared to the H. pylori non-infection group. However, it was negative in Model 2 (OR = 1.02, 95% CI = 0.97-1.06) after being adjusted for gender, age, body mass index (BMI), and blood pressure and in Model 3 (OR = 1.01, 95% CI = 0.97-1.06) after being adjusted for total cholesterol, triglyceride, low-density lipoprotein, and high-density lipoprotein on the basis of Model 2. Control variables, including gender, age, BMI, and diastolic pressure, were significantly correlated with the risk of TN types. Additionally, ordinal logistic regression results revealed that H. pylori infection was positively correlated with malignant differentiation of TN (Model 1: OR = 1.06, 95% CI = 1.02-1.11), while Model 2 and Model 3 showed negative results (Model 2: OR = 1.01, 95% CI = 0.96-1.06; Model 3: OR = 1.01, 95% CI = 0.96-1.05). In conclusion, H. pylori infection was not significantly associated with both TN type risk and severity of its malignant differentiation. These findings provide relevant insights for correcting possible misconceptions regarding TN type pathogenesis and will help guide optimization of therapeutic strategies for thyroid diseases.

Ultrasound Guided Thyroid Biopsy

Thyroid nodules are extremely prevalent among older adults, and pose a challenge due to the frequency in which they are incidentally encountered. Approximately 5% of all nodules are malignant. Ultrasound is the first line tool to evaluate thyroid nodules, and can help identify nodules that are high-risk for malignancy. Fine needle aspiration (FNA) is an excellent low-risk procedure used to evaluate suspicious thyroid nodules and identify thyroid malignancy. It is performed with a 22-27-gauge needle under ultrasound guidance. Core needle biopsy (CNB) is usually not required; however, it can be helpful if FNA is non-diagnostic or inconclusive. On-site pathologist evaluation can help determine which patients need additional sampling. CNB is usually performed with a trocar technique using an 18-gauge biopsy device under ultrasound guidance. Complications from thyroid biopsy are rare, and the most common complications are discomfort, small to moderate hematoma, and insufficient sampling. Although rare, a rapidly expanding large hematoma can cause airway compression requiring intubation and surgery to preserve the airway and achieve hemostasis. Following biopsy, approximately 10.8% of thyroid nodules will require surgical excision.

Diagnostic value of thyroid micronodules with high b-value diffusion weighted imaging: Comparative study with high-resolution ultrasound

PURPOSE

This study aims to compare the diagnostic performance of two imaging methods for thyroid nodules ≤1.0 cm and reduce unnecessary overdiagnosis.

METHODS

A retrospective study was conducted on 80 patients with pathologically confirmed solitary thyroid micronodules underwent both high-resolution ultrasound (HRUS) and High b-value (2000 s/mm²) diffusion weighted imaging (DWI). Intra- and interobserver agreement (Intraclass correlation coefficient) was followed by Kruskal-Wallis test to detect whether the quantitative apparent diffusion coefficient (ADC) and thyroid nodule subgroups were related. Cohen's kappa analysis was applied to assess the interobserver consistency of DWI and HRUS characteristics. The receiver operating characteristic curves were adopted for evaluating the diagnostic performance of thyroid malignancy. The sensitivity, specificity, and accuracy of the two imaging methods were compared using the McNemar's test and Kappa test.

RESULTS

A total of 80 patients were included, consisting of 43 malignant and 37 benign micronodules. The sensitivity, specificity and accuracy of DWI combined with rADC (ADCmin to ADCn ratio) for the diagnosis of thyroid micronodules were 83.7%, 89.2% and 86.3%, respectively. The area under the curve (AUC) was 0.91 (95% confidence interval [CI]: 0.84-0.97). The sensitivity, specificity and accuracy of HRUS diagnosis were 100%, 62.16% and 82.5%, respectively.

CONCLUSION

High b-value DWI is superior to HRUS for evaluating the diagnostic performance of solid thyroid micronodules. DWI and its ADC quantitative analysis could be added to the evaluation of thyroid micronodules to improve the specificity of diagnosis, reduce overdiagnosis and avoid unnecessary biopsies or surgeries.

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.

Effect of trachea stiffness on tumor distribution in papillary thyroid microcarcinoma

Biomechanical factors play an important role in tumor distribution, epithelial-mesenchymal transition (EMT), invasion and other important processes. Despite fewer reports investigating biomechanical function in papillary thyroid carcinoma (PTC), a large number of PTC cases are located close to the trachea and the majority of advanced cases of PTC have been associated with invasion of the trachea. However, the effect of trachea stiffness on PTC distribution and growth remains unknown. To clarify this issue, two types of PTC cells (TPC-1 and KTC-1) were seeded on a substrate with different stiffness to observe cell proliferation and movement. To identify the effect of trachea stiffness on the thyroid, two thyroid lobes (left and right) were evenly divided into interior (close to the trachea) and lateral (away from the trachea) parts, based on the vertical line between the trachea and thyroid lateral margin with different von Mises stress values. As PTC originates from papillary thyroid microcarcinoma (PTMC) with a maximum diameter of <1 cm, the present study selected PTMC as the study subject to reflect initial PTC distribution in the thyroid. The association between the percentage of PTMC distribution in different parts of the thyroid and von Mises stress values was analyzed. Both PTC cells exhibited stronger proliferation and mobility on the stiff substrate compared with that on the soft substrate. Furthermore, the results of finite element analysis revealed that the von Mises stress values of the interior parts of the trachea were notably higher compared with that in the lateral parts. PTMC distribution in the interior trachea was notably greater compared with that in the lateral section. There was also an observed association between von Mises stress values and PTMC distribution. In addition, the results of RNA-sequencing and reverse transcription-quantitative PCR demonstrated that three biomechanical genes were overexpressed in PTMC located in the interior section compared with that in adjacent normal tissue, and the related signaling pathways were also activated in these tissues. On the whole, these results indicated that trachea stiffness may supply a suitable biomechanical environment for PTMC growth, and the related biomechanical genes may serve as novel targets for PTMC diagnosis and prognostic estimation.

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.

Update on ACR TI-RADS: Successes, Challenges, and Future Directions, From the AJR Special Series on Radiology Reporting and Data Systems

The American College of Radiology (ACR) Thyroid Imaging Reporting and Data System (TI-RADS) is an ultrasound-based risk stratification system (RSS) for thyroid nodules that was released in 2017. Since publication, research has shown that ACR TI-RADS has a higher specificity than other RSSs and reduces the number of unnecessary biopsies of benign nodules compared with other systems by 19.9-46.5%. The risk of missing significant cancers using ACR TI-RADS is mitigated by the follow-up recommendations for nodules that do not meet criteria for biopsy. In practice, after a nodule's ultrasound features have been enumerated, the ACR TI-RADS points-based approach leads to clear management recommendations. Practices seeking to implement ACR TI-RADS must engage their radiologists in understanding how the system addresses the problems of thyroid cancer overdiagnosis and unnecessary surgeries by reducing unnecessary biopsies. This review compares ACR TI-RADS to other RSSs and explores key clinical questions faced by practices considering its implementation. We also address the challenge of reducing interobserver variability in assigning ultrasound features. Finally, we highlight emerging imaging techniques and recognize the ongoing international effort to develop a system that harmonizes multiple RSSs, including ACR TI-RADS.

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.

PTC located in the upper pole is more prone to lateral lymph node metastasis and skip metastasis

Background

Lateral lymph node metastasis (LLNM) is very common in papillary thyroid carcinoma (PTC). The influence of tumour location on LLNM remains controversial. The purpose of this study was to reveal the association between PTC tumours located in the upper pole and LLNM.

Methods

We reviewed a total of 1773 PTC patients who underwent total thyroidectomy with central and lateral lymph node dissection between 2013 and 2018. Patients were divided into two groups according to tumour location. Univariate and multivariate analyses were performed to identify risk factors associated with LLNM and “skip metastasis”.

Results

In the upper pole group, LLNM and skip metastasis were significantly likely to occur. Multivariate analysis showed that tumours located in the upper pole, male sex, extrathyroidal extension (ETE), central lymph node metastasis (CLNM) and tumour size were independent risk factors for LLNM, with odds ratios ([ORs], 95% confidence intervals [CIs]) of 2.136 (1.707–2.672), 1.486 (1.184–1.867), 1.332 (1.031–1.72), 4.172 (3.279–5.308) and 2.496 (1.844–3.380), respectively. Skip metastasis was significantly associated with the primary tumour location in the upper pole and age > 55 years, with ORs of 4.295 (2.885–6.395) and 2.354 (1.522–3.640), respectively.

Conclusions

In our opinion, papillary thyroid tumours located in the upper pole may have an exclusive drainage pathway to the lateral lymph nodes. When the tumour is located in the upper pole, lateral neck dissection should be evaluated meticulously.