Ultrasonographic findings relating to lymph node metastasis in single micropapillary thyroid cancer

Risk factors for metastasis in indeterminate lymph nodes in preoperative patients with thyroid cancer

OBJECTIVES

To investigate the relevance of clinical and sonographic features as indicators of metastasis in indeterminate lymph node (LN), to determine possible indications for fine-needle aspiration (FNA).

METHODS

Consecutive patients who underwent US-guided FNA for sonographic indeterminate LNs from differentiated thyroid carcinoma between January 2014 and December 2018 were retrospectively reviewed. Indeterminate LNs were defined as LNs which had neither an echogenic hilum nor hilar vascularity in the absence of any suspicious finding in accordance with the Korean Society of Thyroid Radiology (KSThR) guidelines. Univariate and multivariate logistic regression analyses were performed to identify significant risk factors related to malignancy of indeterminate LNs.

RESULTS

Of the 236 LNs in 212 patients enrolled in this study, 67 LNs (28.3%) were metastatic. The multivariate logistic regression analysis showed that the long diameter of LNs has a negative association with metastasis in indeterminate LNs and the sonographic features of extrathyroidal extension (ETE) and nonparallel orientation of the primary tumor are associated with metastasis in indeterminate LNs. The sensitivity and positive predictive value were increased when FNA was performed for LNs with primary tumors showing ETE or nonparallel orientation than when FNA was performed for LNs larger than 5 mm (59.7% and 40.4% vs. 11.94% and 15.69%).

CONCLUSIONS

The size of LNs has a negative association with metastasis in indeterminate LNs. Performing FNA for indeterminate LNs in patients whose primary tumor shows ETE or a nonparallel orientation can improve the diagnostic performance and decrease the rate of unnecessary FNA.

KEY POINTS

• The size of lymph nodes was negatively related to the risk of metastasis in indeterminate lymph nodes. • Extrathyroidal extension and a nonparallel orientation of the primary tumor were suggested as sonographic features predicting metastasis in indeterminate lymph nodes. • The routine practice of FNA for large indeterminate lymph nodes detected during preoperative evaluation of thyroid cancer should be discouraged.

Diagnostic Strategies for Thyroid Nodules Based on Ultrasonographic Findings in Japan

Simple Summary

In recent years, the incidence of thyroid cancer has been increasing worldwide, mainly due to the widespread use of imaging examination methods, such as ultrasonography. In Japan, the risk of overdiagnosis due to the use of diagnostic imaging has been discussed since the 1990s, and measures have been taken to reduce the risk of overdiagnosis and overtreatment by establishing criteria for the implementation of fine needle aspiration cytology and non-surgical follow-up. This article outlines the diagnostic criteria and management guidelines in Japan in comparison with those published in other countries.

Abstract

In recent years, the incidence of thyroid cancer has been increasing worldwide, which is believed to be mainly due to the widespread use of imaging examinations, such as ultrasonography. In this context, ultrasonography has become increasingly important because it can evaluate not only the presence or absence of nodules, but also the detailed characteristics of the nodule, making it possible to diagnose benign or malignant nodules before cytology is performed. In Japan, the third edition of the sonographic diagnostic criteria for thyroid nodules is currently widely used, and its content is similar to that of recent meta-analyses and guidelines from medical societies in other countries. In addition, since overdiagnosis of very-low-risk thyroid cancer has recently become an issue, criteria for the implementation of fine needle aspiration cytology (FNAC) have been published by various countries. The Japan Society of Breast and Thyroid Sonology provides guidelines for FNAC implementation for solid and cystic nodules. In the United States, the ATA, NCCA, and ACR have published guidelines, whereas in Europe, the ESMO and ETA have done the same. All of these guidelines used to classify risk are based on nodule size and sonographic findings. This article outlines the diagnostic criteria and management guidelines in Japan in comparison with those published in other countries. Case studies using actual images were also performed to examine the differences in the FNAC guidelines.

Radiogenomic Analysis of Papillary Thyroid Carcinoma for Prediction of Cervical Lymph Node Metastasis: A Preliminary Study

Background

Papillary thyroid carcinoma (PTC) is characterized by frequent metastases to cervical lymph nodes (CLNs), and the presence of lymph node metastasis at diagnosis has a significant impact on the surgical approach. Therefore, we established a radiomic signature to predict the CLN status of PTC patients using preoperative thyroid ultrasound, and investigated the association between the radiomic features and underlying molecular characteristics of PTC tumors.

Methods

In total, 270 patients were enrolled in this prospective study, and radiomic features were extracted according to multiple guidelines. A radiomic signature was built with selected features in the training cohort and validated in the validation cohort. The total protein extracted from tumor samples was analyzed with LC/MS and iTRAQ technology. Gene modules acquired by clustering were chosen for their diagnostic significance. A radiogenomic map linking radiomic features to gene modules was constructed with the Spearman correlation matrix. Genes in modules related to metastasis were extracted for Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analyses, and a protein-protein interaction (PPI) network was built to identify the hub genes in the modules. Finally, the screened hub genes were validated by immunohistochemistry analysis.

Results

The radiomic signature showed good performance for predicting CLN status in training and validation cohorts, with area under curve of 0.873 and 0.831 respectively. A radiogenomic map was created with nine significant correlations between radiomic features and gene modules, and two of them had higher correlation coefficient. Among these, MEmeganta representing the upregulation of telomere maintenance via telomerase and cell-cell adhesion was correlated with ‘Rectlike’ and ‘deviation ratio of tumor tissue and normal thyroid gland’ which reflect the margin and the internal echogenicity of the tumor, respectively. MEblue capturing cell-cell adhesion and glycolysis was associated with feature ‘minimum calcification area’ which measures the punctate calcification. The hub genes of the two modules were identified by protein-protein interaction network. Immunohistochemistry validated that LAMC1 and THBS1 were differently expressed in metastatic and non-metastatic tissues (p=0.003; p=0.002). And LAMC1 was associated with feature ‘Rectlike’ and ‘deviation ratio of tumor and normal thyroid gland’ (p<0.001; p<0.001); THBS1 was correlated with ‘minimum calcification area’ (p<0.001).

Conclusions

The radiomic signature proposed here has the potential to noninvasively predict the CLN status in PTC patients. Merging imaging phenotypes with genomic data could allow noninvasive identification of the molecular properties of PTC tumors, which might support clinical decision making and personalized management.

Ultrasound Echogenicity of Papillary Thyroid Cancer Is Affected by Tumor Growth Patterns and Tumor Fibrosis

BACKGROUND/AIM

The association between preoperative ultrasound (US) echogenicity and histopathological characteristics of papillary thyroid cancer (PTC) has been rarely investigated is not well characterized. This study evaluated a relationship between the clinical characteristics of PTC, histopathological phenomena including tumor growth patterns (TGPs) and tumor fibrosis (TF), and US echogenicity.

PATIENTS AND METHODS

In total, 170 patients with PTC (<2 cm) underwent total thyroidectomy with central neck dissection. Demographics, US echogenicity, tumor size, extra-thyroidal extension (ETE), lymph node metastasis (LNM) within the central and lateral neck, TGPs, and TF percentage were reviewed.

RESULTS

Patients with TGP II (encapsulated growth with partial pericapsular extension) and III (infiltrative growth) were more frequently burdened by ETE and lateral neck LNM compared to patients with TGP I (encapsulated growth with a well-defined cystic or solid characteristic). Older age was significantly deterministic of TGP III, and male gender and higher TF percentage were independent risk factors for lateral neck LNM. TGP III and TF were independent determining factors for marked hypoechogenicity on US.

CONCLUSION

PTC with TGP II and III and higher tumor fibrosis exhibited more aggressive clinicopathologic behaviors. TGP III and TF were determinants for marked hypoechogenicity.

Risk factors for central lymph node metastasis in the cervical region in papillary thyroid carcinoma: a retrospective study

Background

To investigate the influence of different risk factors on central lymph node metastasis (CLNM) in the cervical region in patients with papillary thyroid carcinoma (PTC).

Methods

This retrospective study included 2586 PTC patients. Potential risk factors were identified by univariate analysis, and the relationships between these factors and CLNM were ascertained by multivariable analysis. A scoring system was constructed, and the optimal cut-off value was determined.

Results

On univariate analysis, sex, age, tumor diameter, multifocality, capsule invasion, vascular invasion, total number of lymph nodes in the central region, and serum thyroid peroxidase antibody (TPOAb) concentration were identified as potential risk factors for CLNM in the cervical region, whereas nerve invasion, thyroid-stimulating hormone concentration, and thyroglobulin antibody (TgAb) concentration were not. Multivariable analysis indicated that male sex, young age, large tumor diameter, multifocality, vascular invasion, a large number of central lymph nodes, and a low TPOAb concentration were significant risk factors. From these factors, a preoperative CLNM risk assessment scale was constructed for predicting CLNM in the cervical region for PTC patients.

Conclusion

Male sex, young age, large tumor diameter, multifocality, vascular invasion, a large number of central lymph nodes, and a low TPOAb concentration were positively correlated with CLNM in the cervical region in PTC patients. The preoperative CLNM risk assessment scale based on these risk factors is expected to offer accurate preoperative assessment of central lymph node status in PTC patients.

The Impact of Coexistent Hashimoto's Thyroiditis on Central Compartment Lymph Node Metastasis in Papillary Thyroid Carcinoma

BACKGROUND

Hashimoto's thyroiditis (HT) is the most prevalent inflammatory disorder of the thyroid gland. Current studies have reported the coexistence rate between HT and papillary thyroid carcinoma (PTC) is quite high. The objective of this study was to evaluate the impact of HT on the predictive factors of central compartment lymph node metastasis (CLNM) in PTC.

METHODS

A retrospective investigation was performed on PTC patients. They were subclassified into HT and non-HT groups. The results of preoperative neck ultrasound (US) examinations were reviewed. The clinical characteristics and the predictive value for CLNM were explored and compared between the two groups.

RESULTS

A total of 756 patients were included in this study. There were more female patients (86.1%) in the PTC coexistent with the HT group than non-HT group. The patients with HT group had higher preoperative serum level of TSH. There was statistically significant difference between the HT patients and non-HT patients in nodular vascularization. Univariate and multivariate analyses showed that male, age ≤45 years old, tumor diameter >1 cm, and presence of suspicious central compartment lymph node on US, irregular nodular shape, multifocal carcinoma were independent predictive factors of CLNM in PTC patients. It was showed that male, age ≤45 years old, tumor diameter >1 cm, multifocality, and presence of suspicious central lymph node on US were risk factors for CLNM in non-HT patients. Only tumor diameter >1 cm and presence of suspicious central lymph node on US were independently correlated with CLNM in HT patients. The sensitivity of the multivariate model was 63.5%, and specificity was 88.9% for prediction CLNM in HT patients. For non-HT patients, the AUC was 80.6%, the sensitivity of the multivariate model was 64.5%, and specificity was 85.2.

CONCLUSION

PTC combined with HT is more common in women, and TSH level in HT group is higher than that in patients with PTC alone. Regardless of that HT is not a related risk factor of CLNM in PTC, our result suggested that different predictive systems should be used for HT and non-HT patients respectively to have a more accurate evaluation of CLNM in clinic.

Suspicious ultrasound characteristics correlate with multiple factors that predict central lymph node metastasis of papillary thyroid carcinoma: Significant role of HBME-1

PURPOSE

Papillary thyroid carcinoma (PTC) is frequently associated with central lymph node metastasis (CLNM). In the present study, we aimed to identify possible risk factors for CLNM in PTC, including suspicious ultrasound (US) features coexisting with thyroid diseases, immunohistochemical markers, and BRAF_V600E. These were used to establish a model to predict the risk of CLNM.

METHODS

From January 2016 to March 2018, we identified a cohort of patients with classic PTC who underwent cervical US and were diagnosed by postoperative pathology. Fine-needle aspiration biopsies were analyzed for the presence ofBRAF_V600E, and immunohistochemistry was used to detect tumor markers. US imaging was performed in accordance with a standardized protocol. A model to determine the risk of CLNM was established using the outcomes of univariate and multivariate analyses.

RESULTS

Age of ≥45 years, male sex, mean tumor diameter of ≥1.0 cm, taller-than-wide tumor shape, multiple PTCs, capsule contact, and HBME-1 expression were significant independent risk predictors of CLNM. Hashimoto's thyroiditis, nodular goiter, andBRAF_V600E were not significantly associated with CLNM. The cutoff value (area under the curve = 0.760) for predicting risk was determined from receiver operating characteristic curves (sensitivity, 75.6 %; specificity, 60.7 %).

CONCLUSIONS

Male sex, age of ≥45 years, mean tumor diameter of ≥1.0 cm, taller-than-wide shape, multiple tumors, capsule contact, and HBME-1 expression were independent predictors of the risk of CLNM in patients with PTC. The risk model may be useful for evaluating patients' prognoses and selecting optimal surgical strategies.

Gender-Specific Risk of Central Compartment Lymph Node Metastasis in Papillary Thyroid Carcinoma

Our aim was to evaluate the impact of gender on the predictive factors of central compartment lymph node metastasis (CLNM) in papillary thyroid carcinoma (PTC). A retrospective study of 590 patients treated for PTC was performed. Univariate and multivariate analyses showed that gender (female; P = 0.001), age (≥45 y; P < 0.001), tumor size (>1 cm; P < 0.001), and multifocality (P = 0.004) were independent predictive factors of CLNM in PTC patients. Patients were divided into male group (n = 152) and female group (n = 438). Age (≥45 y; P = 0.001), T4 (P = 0.006) and multifocality (P = 0.024) were independent predictive risk factors of CLNM in male patients. As for female patients, age (≥45 y; P < 0.001), tumor size (>1 cm; P < 0.001), multifocality (P = 0.002), and microcalcification (P = 0.027) were independently correlated with CLNM. The sensitivity of the multivariate model for predicting CLNM in male patients was 64.9%, specificity was 82.9%, and area under the ROC curve (AUC) was 0.764. As for female patients, the sensitivity was 55.7%, specificity was 77.9%, and AUC was 0.73. This study showed that the predictive factors of CLNM indeed varied according to gender. To have a more accurate evaluation of CLNM, different predictive systems should be used for male and female patients.

Current trends of practical issues concerning micropapillary thyroid carcinoma: The Korean Society of Thyroid-Head and Neck Surgery

Although several thyroid associations have published various guidelines, controversies especially in cases of micropapillary thyroid cancer (MPTC) still exist. This survey was designed to collect information about diagnostic tests and treatments performed on patients with MPTC and help identify current trends in thyroid surgery.We developed questionnaires about the management methods for MPTC, which were used to identify factors related to indications of fine needle aspiration (FNA), type of surgery, and central lymph node dissection (CLND). Active 60 members of the Korean Society of Thyroid-Head and Neck Surgery participated in the study in September 2016.Ultrasound-guided FNA was usually initiated when the tumor was at least 5 mm (60%). All respondents preferred ultrasound-guided FNA and surgery for nodules with extrathyroidal extension (ETE). The preferred treatment option for intraglandular MPTC was lobectomy (92%) rather than active surveillance (8%). Posterolateral ETE increased the respondents' preference for total thyroidectomy (61.7%). Active surveillance was preferred for tumors <5 mm, which was decreased by the presence of ETE. The presence of ETE (73.3%) and its proximity to critical organs (46.7%) were the main determining factors for prophylactic CLND. For multiple metastatic lymph nodes at level III, selective neck dissection including levels IIb (23.3%) and V (78.3%) was preferred in addition to levels IIa, III, VI, and V.Korean head and neck surgeons favored total thyroidectomy and CLND in cases wherein ETE, central lymph node metastasis, or critical organ involvement was suspected.

Ultrasonographic Evaluation of Cervical Lymph Nodes in Thyroid Cancer

Objective To determine what ultrasonographic features can identify metastatic cervical lymph nodes, both preoperatively and in recurrences after complete thyroidectomy. Study Design Prospective. Setting Outpatient clinic, Department of Head and Neck Surgery, School of Medicine, University of São Paulo, Brazil. Subjects and Methods A total of 1976 lymph nodes were evaluated in 118 patients submitted to total thyroidectomy with or without cervical lymph node dissection. All the patients were examined by cervical ultrasonography, preoperatively and/or postoperatively. The following factors were assessed: number, size, shape, margins, presence of fatty hilum, cortex, echotexture, echogenicity, presence of microcalcification, presence of necrosis, and type of vascularity. The specificity, sensitivity, positive predictive value, and negative predictive value of each variable were calculated. Univariate and multivariate logistic regression analyses were conducted. A receiver operator characteristic (ROC) curve was plotted to determine the best cutoff value for the number of variables to discriminate malignant lymph nodes. Results Significant differences were found between metastatic and benign lymph nodes with regard to all of the variables evaluated ( P < .05). Logistic regression analysis revealed that size and echogenicity were the best combination of altered variables (odds ratio, 40.080 and 7.288, respectively) in discriminating malignancy. The ROC curve analysis showed that 4 was the best cutoff value for the number of altered variables to discriminate malignant lymph nodes, with a combined specificity of 85.7%, sensitivity of 96.4%, and efficiency of 91.0%. Conclusion Greater diagnostic accuracy was achieved by associating the ultrasonographic variables assessed rather than by considering them individually.

Is Ultrasonography More Sensitive Than Computed Tomography for Identifying Calcifications in Thyroid Nodules?

OBJECTIVES

The primary objective of this study was to evaluate the difference and agreement between ultrasonography (US) and computed tomography (CT) for identifying calcifications in thyroid nodules.

METHODS

Data from the medical records of 20,248 patients were reviewed for preoperative diagnostic investigations and postoperative pathologic diagnoses. In total, 5247 records were selected for analysis based on the presence of calcifications reported in any of the following 3 modes: US, CT, and pathologic analysis. All 5247 patients underwent US examinations, whereas 3827 underwent cervical CT examinations. All patients had a postoperative pathologic diagnosis serving as a reference. The value of US for identification of calcifications and prediction of malignancy was analyzed on the basis of the entire cohort of 5247 records, whereas that of CT was based on 3827 records. The agreement between US and CT was analyzed on the basis of the 3827 common records.

RESULTS

Of the 5247 patients who underwent US, 4855 (92.5%) were found to have calcifications, whereas of the 3827 patients who underwent CT, 2040 (53.3%) were found to have calcifications (P < .0005). Among the 404 cases with calcifications reported by pathologic analysis, the agreement rate between US and pathologic findings was significantly higher than that between CT and pathologic findings (87.9% versus 81.9%, respectively; P = .018).

CONCLUSIONS

US is more sensitive and accurate than CT for detecting calcifications in thyroid nodules. Hence, US is recommended as the preferred imaging modality for calcification detection in thyroid nodules.

Risk prediction and clinical model building for lymph node metastasis in papillary thyroid microcarcinoma

The surgical management of papillary thyroid microcarcinoma (PTMC), especially regarding the necessity of central/lateral lymph node dissection, remains controversial. This study investigated the clinicopathologic factors predictive of lymph node metastasis (LNM) in patients diagnosed with PTMC. Multivariate logistic regression analysis was used for PTMC patients identified from the Surveillance, Epidemiology, and End Results database who were treated by surgery between 2002 and 2012, to determine the association of clinicopathologic factors with LNM. According to the results, a total of 31,017 patients met the inclusion criteria of the study. Final histology confirmed 2,135 (6.9%) cases of N1a disease and 1,684 cases (5.4%) of N1b disease. Our multivariate logistic regression analysis identified variables associated with both central LNM and lateral lymph node metastasis (LLNM), including a younger age (<45 years), male sex, non-Hispanic white and other race, classical papillary histology, larger tumor size, multifocality, and extrathyroidal extension; distant metastasis was also significantly associated with LLNM. The significant predictors identified from multivariable logistic regression were integrated into a statistical model that showed that extrathyroidal extension had maximum weight in the predictive role for LNM. LLNM was validated to be a significant risk factor for cancer-specific death in Cox regression analyses, whereas central LNM failed to predict a worse cancer-specific survival according to our data. Therefore, we suggested that central lymph node dissection could be performed in certain patients with risk factors. Given the prevalence of LLNM in PTMC, a thorough inspection of the lateral compartment is recommended in PTMC patients with risk factors for precise staging; from the viewpoint of a radical treatment for tumors, prophylactic lateral lymph node dissection that aims to remove the occult lateral lymph nodes may be an option for PTMC with risk factors. Multicenter studies with long-term follow-up are recommended to better understand the risk factors and surgical management for cervical nodes in PTMC.

The relevance of preoperative ultrasound cervical mapping in patients with thyroid cancer

BACKGROUND

Cervical lymph node involvement in thyroid cancer is associated with locoregional recurrence and decreased disease-free survival. Preoperative lymph node mapping helps in planning surgery for neck dissection and improves patient outcomes. We sought to perform a qualitative and quantitative analysis of ultrasound mapping for thyroid cancer and evaluate the clinical importance of this exam in terms of identifying the group of patients who would benefit most from subsequent surgical dissection.

METHODS

We retrospectively reviewed the cases of 263 patients who underwent thyroid surgery between 2009 and 2013. We calculated the positive predictive values (PPVs) of ultrasound mapping of both the lateral and central compartments together and the lateral or central compartment individually. A quantitative analysis was performed by comparing the number of positive lymph nodes at ultrasound imaging with histopathologic evaluation.

RESULTS

A total of 136 cases of thyroid cancer in 120 patients met the inclusion criteria for ultrasound mapping analysis. The PPVs (and 95% confidence intervals) were 83.82 (0.76-0.89) for the lateral and central compartments, 85.39% (0.76-0.91) for the lateral compartment, and 80.48% (0.7-0.87) for the central compartment. When comparing the positive lymph nodes at ultrasound imaging with histopathologic evaluation, the result was χ(2) = 10.33 (p = 0.006).

CONCLUSION

This single-institution study indicated that preoperative ultrasound mapping is an accurate imaging procedure for predicting lymphatic spread in differentiated and medullary thyroid cancer. Ultrasound mapping can be used as an efficient tool for surgical planning and prognosis determination, as well as for identifying the group of patients who would benefit most from subsequent surgical intervention.

Utility of sentinel lymph node biopsy for thyroid cancer: a comprehensive review

Sentinel lymph node biopsy (SLNB) is a minimally invasive lymphatic mapping technique, used to identify lymph node micrometastases and stage multiple cancer types. Despite the performance of SLNB for thyroid cancer having been under study since 1998, its role has remained controversial. The objective of this review is to summarize current research reporting on SLNB for thyroid cancer, focusing on recent studies of its application to differentiated thyroid cancer. The technique and potential benefits of SLNB are reviewed with regards to its ability to identify lymph node metastases, aid in cancer prognostication, and direct surgical and medical treatment.