Impact of clinicopathologic factors on subclinical central lymph node metastasis in papillary thyroid microcarcinoma

Risk factors for tumor enlargement in low-risk papillary thyroid microcarcinoma patients: a systematic review and meta-analysis

PURPOSE

The current management guidelines for low-risk papillary thyroid microcarcinoma (PTMC) do not specify how to screen for growing tumors. We sought to explore the possible risk factors for tumor enlargement in patients with low-risk PTMC under active surveillance (AS).

METHODS

We searched the PubMed and Embase databases for high quality studies up to January 10th, 2024. The Newcastle-Ottawa Scale (NOS) was used to assess the quality of the included studies, and Review Manager 5.4 was used to analyze possible risk factors and calculate pooled risk ratios (RRs) via the inverse-variance calculation method.

RESULTS

Eleven studies were included in our meta-analysis. Among the 8880 participants, 464 experienced tumor growth, and the incidence of tumor growth varied from 3.4% to 19.4%. The results of the meta-analysis showed that tumor enlargement was associated with younger age (pooled RR = 2.32, 95% CI = 1.85-2.90, p < 0.00001; 8 studies), and higher serum thyroid-stimulating hormone (TSH) levels (pooled RR = 2.28, 95% CI = 1.19-4.37, p = 0.01; 6 studies), and could be related to pregnancy (pooled RR = 2.54, 95% CI = 1.17-5.52, p = 0.02; 2 studies). However, these following factors showed no significant association with tumor growth: sex (pooled RR = 1.07, 95% CI = 0.63-1.84, p = 0.79; 7 studies), tumor size at diagnosis (pooled RR = 1.08, 95% CI = 0.63-1.85, p = 0.77; 5 studies), and Hashimoto's thyroiditis (HT) (pooled RR = 1.56, 95% CI = 0.93-2.60, p = 0.09; 2 studies).

CONCLUSION

Our analysis identified that younger age and higher serum TSH levels were higher risk factors for tumor enlargement in low-risk PTMC patients. Pregnancy is a suspected risk factor.

Predictive factors of lymph node metastasis in papillary thyroid cancer

This study aimed to evaluate factors that predict lymph node metastasis (LNM) in papillary thyroid cancer (PTC). This retrospective cross-sectional study compared the demographic, clinical, and ultrasonographic findings of patients with PTC with and without LNM. Subgroup analysis was conducted for micro-PTCs (<1 cm). Among total (n = 512; mean age, 47.3 ± 12.7 years) and micro-PTC patients (n = 312), 35.7% and 19.6% had LNM, respectively. Younger age, male sex, tumor size, bilaterality, and suspicious ultrasound features of the tumor were associated with LNM. In multiple logistic regression analysis, among all patients, age, tumor size, and extrathyroidal extension were independent risk factors for LNM (all p<0.05). In the micro-PTC subgroup, age, extrathyroidal extension, bilaterality of tumor, and presence of autoimmune thyroid disease were independent risk and protective factors for LNM (all p<0.05). In the receiver operating characteristic analysis, the accuracy of the multivariable logistic regression model for predicting LNM among all patients and micro-PTC was acceptable (area under the curve = 0.729 and 0.733, respectively). Age, sex, tumor size, and extrathyroidal extension can assist in predicting LNM in PTC patients. Additionally, the bilaterality of tumors and presence of autoimmune thyroid disease can assist in predicting LNM in micro-PTCs.

Evaluation of Etiology, Clinical Manifestations, Diagnosis, Follow-up, Histopathology and Prognosis Factors in Papillary Thyroid Microcarcinoma: A Systematic Review and Meta-analysis

Background & Objective

The most frequent type of cancer found in the endocrine system is thyroid carcinoma. Among well-differentiated thyroid malignancies, the most commonly occurring type is identified as papillary thyroid carcinoma (PTC), which makes up 70-90% of the cases. A subtype of PTC is papillary thyroid microcarcinoma (PTMC), which includes tumors smaller than 10 mm in diameter. Due to the advancements in diagnostic techniques, the incidence of this type of cancer is on the rise. In this study, we aimed to analyze the factors worsening the PTMC prognosis.

Methods

In the first step, we searched various databases for the factors affecting this tumor. The relevant articles were collected and different outcomes of this tumor and its associated factors which were studied in more than one article, were classified. Finally, we conducted a meta-analysis of these outcomes and their related factors.

Results

In the meta-analysis, a significantly association was found between the following factors: recurrence with gender (P<0.001) lymph node metastasis (LNM) (P= 0.003), and extrathyroidal invasion (P<0.001); lymph node metastasis with extrathyroidal invasion (P<0.001), and multifocality (P<0.001); central lymph node metastasis (CLNM) with gender (P=0.001), tumor size (P<0.001), extracapsular invasion (P<0.001), lateral cervical lymph node metastasis (P<0.001), and extrathyroidal invasion (P<0.001); lymph node metastasis resulted in poor outcomes (P<0.001); and finally tumor size with BRAFV600E mutation (P<0.001).

Conclusion

In conclusion, it is essential to note that greater awareness and understanding of this tumor characteristics and special and separate attention to PTMC can significantly improve the society overall health.

The risk of central nodal metastasis based on prognostic factors of the differentiated thyroid carcinoma: a systematic review and meta-analysis study

BACKGROUND AND AIM

Despite improving the 10-year disease-free-survival, prophylactic central neck dissection (pCND) in differentiated thyroid carcinoma (DTC) should only be considered in patients with high risk factors for lymph node (LN) metastasis due to the increases in the risk of postoperative complications. Our aim was to identify the risk factors for central lymph node metastasis (CLNM) in DTC.

METHOD

We searched PubMed, Scopus, Web of science, Cochrane library for eligible studies from inception to November 1, 2021 and a systematic review and meta-analysis were carried out to identify the risk factors for CLNM in DTC.

RESULTS

We included 41 studies with total of 27,741 patients in this study. The pooled results in this meta-analysis showed that these risk factors were significantly associated with CLNM: age < 45 years (odds ratio (OR) 1.64, 95% confidence interval (CI) 1.34-1.99, p < 0.00001), male sex (OR 1.73, 95% CI 1.54-1.93, p < 0.00001), multifocality (OR 1.87, 95% CI 1.59-2.19, p < 0.00001), bilateral disease (OR 1.43, 95% CI 1.15-1.78, p < 0.001), capsular invasion (OR 1.67, 95% CI 1.10-2.54, p < 0.02), lymphovascular invasion (OR 4.89, 95% CI 2.76-8.66, p < 0.00001) and extra-thyroidal extension (OR 2.43, 95% CI 1.97-3.00, p < 0.00001). In addition, young age (< 45 years), male sex, multifocality, and extra-thyroidal extension were significantly associated with large-volume CLNM in clinically N0 DTC patients. However, the presence of Hashimoto's thyroiditis was not a predictors of large-volume CLNM.

CONCLUSION

Young age (< 45 years), male sex, bilateral disease, multifocality, capsular invasion, lymphovascular invasion and extra-thyroidal extension are significantly associated with CLNM and pCND would be expected to have a higher yield in patients with these risk factors.

Risk and Prognostic Factors for BRAFV600E Mutations in Papillary Thyroid Carcinoma

Background

Over the past ten years, the incidence rate of papillary thyroid carcinoma (PTC) worldwide has been increasing rapidly year by year, with the incidence rate increasing 6% annually. PTC has become the malignant tumor with the highest growth rate in the world that fourteen PTC-related mutant genes have been identified. Whether the BRAF^V600E mutation related to more aggressive clinicopathologic features and worse outcome in PTC remains variable and controversial. We aim to investigate the risk factors that may predict the BRAF^V600E mutation potential of these lesions and new prevention strategies in PTC patients.

Methods

A total of 9,908 papillary thyroid carcinoma patients with average 74.6% BRAF^V600E mutations were analyzed (RevMan 5.3 software) in this study. The PubMed, Embase, and ISI Web of Science databases were systematically searched for works published through December 15, 2021.

Results

The following variables were associated with an increased risk of BRAF^V600E mutation in PTC patients: age ≥ 45 years (OR = 1.39, 95%CI = 1.21–1.60, p < 0.00001), male gender (OR = 1.13, 95%CI = 0.99–1.28, p = 0.06), multifocality (OR = 1.22, 95%CI = 1.07–1.40, p = 0.004), lymph node metastasis (OR = 1.33, 95%CI = 0.79–2.23, p = 0.28), extrathyroidal extension + (OR = 1.61, 95%CI = 1.06–2.44, p = 0.03), vascular invasion + (OR = 2.04, 95%CI = 1.32–3.15, p = 0.001), and tumor node metastasis stage (OR = 1.61, 95%CI = 1.38–1.88, p < 0.00001). In addition, tumor size (>1 cm) (OR = 0.51, 95%CI = 0.32–0.81, p = 0.005) and distant metastasis (OR = 0.69, 95%CI = 0.22–2.21, p = 0.54) had no association or risk with BRAF^V600E mutation in PTC patients.

Conclusion

Our systematic review identified the following significant risk factors of BRAF^V600E mutation in PTC patients: age (≥45 years), gender (male), multifocality, lymph node metastasis, vascular invasion, extrathyroidal extension, and advanced tumor node metastasis stage (stages III and IV). Tumor size (>1 cm) and distant metastasis do not appear to be correlated with BRAF^V600E mutation in PTC patients.

Clinicopathologic predictors of central lymph node metastases in clinical node-negative papillary thyroid microcarcinoma: a systematic review and meta-analysis

Background

The presence of central lymph node metastases (CLNM) has been suggested as a risk factor for poorer prognosis and recurrence in papillary thyroid microcarcinoma (PTMC). However, the clinicopathologic factors for CLNM in clinical node-negative (CN0) PTMC were not well defined. This study aimed to perform a systematic review and meta-analysis to investigate the significant clinicopathologic predictors of CLNM in CN0 PTMC.

Methods

A systematic literature search was performed in PubMed, Embase, Cochrane Library, and Web of Science. Case-control studies on the association of clinicopathologic risk factors with CLNM in CN0 PTMC were included.

Results

Thirteen eligible studies involving 6068 patients with CN0 PTMC were included. From the pooled analyses, male (odds ratio [OR]: 2.07, 95% CI: 1.49–2.87, P < 0.001), multifocality (OR: 1.88, 95% CI: 1.54–2.29, P < 0.001), tumor size > 5 mm (OR: 1.84, 95% CI: 1.55–2.18, P < 0.001), and extrathyroidal extension (OR: 1.96, 95% CI: 1.30–2.95, P = 0.001) are significantly associated with increased risk of CLNM in CN0 PTMC. A sample size with a cutoff point of 200 was identified as the source of heterogeneity for sex according to meta-regression (t = 3.18, P = 0.033). Then, the subgroup analysis of male was performed, which illustrated that male increased the risk of CLNM in the small sample group (SG) and the large sample group (LG) by 6.11-folds and 2.01-folds, respectively (SG: OR, 6.11, 95% CI, 3.16–11.81, P < 0.001; LG: OR, 2.01, 95% CI, 1.65–2.46, P < 0.001).

Conclusions

Male, multifocality, tumor size > 5 mm, and extrathyroidal extension may be reliable clinical predictors of CLNM in CN0 PTMC. Moreover, prophylactic central lymph node dissection should be considered in surgical decision-making for CN0 PTMC patients, who are male, multifocal, with tumor size > 5 mm, and with extrathyroidal extension.

Trial registration

CRD42021242211 (PROSPERO)

Supplementary Information

The online version contains supplementary material available at 10.1186/s12957-022-02573-7.

Prediction of central compartment nodal metastases in papillary thyroid cancer using TI-RADS score, blood flow, and multifocality

BACKGROUND

The relationship between the American College of Radiology (ACR) Thyroid Imaging Reporting and Data System (TI-RADS) and the risk of lymph node metastases in papillary thyroid cancer (PTC) could improve the detection rate of lymph node metastases in thyroid cancer and provide a scientific basis for clinical diagnosis.

PURPOSE

To evaluate the risk of lymph node metastases of PTC associated with the score from ACR TI-RADS adjusted for other correlative factors.

MATERIAL AND METHODS

A total of 560 patients with pathologically confirmed PTC were included in the study and classified into a metastases group and a non-metastases group. Clinical and pathological manifestations of the patients were collected.

RESULTS

The median TI-RADS score was 13 (p₂₅-p₇₅ = 11-14) among the patients with lymph node metastases, higher than those without metastases 9 (8-10) (P < 0.001). Multiple logistic regression indicated that TI-RADS score (odds ratio [OR] = 2.204), male sex (OR = 2.376), multifocality (OR = 4.170), and rich blood flow (OR = 3.656) were risk factors for lymph node metastases in patients with thyroid carcinoma. Some related factors such as TI-RADS score, age(<45years old), male, multifocality and rich blood flow were related to lymph node metastases in the central area of the neck which could provide therapeutic strategy for further treatment.

CONCLUSION

it is not just the TI-RADS score but also multifocality, blood flow, and sex that influence the prediction of the risk of PTC central lymph node metastases.

Preoperative prediction of lymph node metastasis in patients with papillary thyroid carcinoma by an artificial intelligence algorithm

BACKGROUND

It is necessary to identify patients at risk of developing lymph node metastasis prior to papillary thyroid carcinoma (PTC) surgery. This can be challenging due to limiting factors, and an artificial intelligence algorithm may be a viable option.

OBJECTIVE

In this study, we aimed to evaluate whether combining an artificial intelligence algorithm (support vector machine and probabilistic neural network) and clinico-pathologic data can preoperatively predict lymph node metastasis of papillary thyroid carcinoma (PTC).

METHODS

We retrospectively examined 251 PTCs with lymph node metastasis and 194 PTCs without lymph node metastasis. The artificial intelligence algorithm included the support vector machine (SVM) and the probabilistic neural network (PNN).

RESULTS

The ACR TI-RADS (Thyroid Imaging, Reporting and Data System), number of tumours, no well-defined margin, lymph node status and rim calcification on ultrasonography (US), age, sex, tumour size, and presence of Hashimoto's thyroiditis were significantly more frequent among PTCs with central lymph node metastasis than those without metastasis (P<0.05). The PNN classifier revealed an F1 score of 0.88 on the central lymph node metastasis test set. The SVM classifier revealed an F1 score of 0.93 on the lateral lymph node metastasis test set. Our study demonstrates that combining artificial intelligence algorithms and clinico-pathologic data can effectively predict the lymph node metastasis of papillary thyroid carcinoma prior to surgery.

Peripheral Versus Intraparenchymal Papillary Thyroid Microcarcinoma: Different Morphologies and PD-L1 Expression

Peripheral localisation of papillary thyroid microcarcinoma (PTMC), in comparison with intraparenchymal PTMC (i-PTMC) is related to some clinicopathological features related with biological aggressiveness, including lymph node metastasis (LNM). The expression of PD-L1 in tumour cell has been associated with increased tumour survival, progression, and potentially an aggressive clinical course. This study evaluates the relation between clinicopathological features of PTMC, including tumour localisation, with PD-L1 immunoexpression. The study included 99 patients with the histological diagnosis of PTMC (≥ 5 mm). PD-L1 protein expression was assessed by immunohistochemistry. PTMCs were divided into the four following groups: G1- peripherally localised PTMC (p-PTMC) with PD-L1 expression; G2-p-PTMC without PD-L1 expression; G3-i-PTMC with PD-L1 expression and G4-i-PTMC without PD-L1 expression. G1 was the most frequent (n = 46; 46.5%), followed by G4 (n = 25; 25.3%) and similar distribution of G3 (n = 15; 15.2%) and G2 (n = 13; 13.1%). In comparison with other groups, G1 was significantly associated with classical morphology, invasive growth, lymphatic invasion (LI), vascular invasion (VI), psammoma bodies, intratumoral fibrosis, PD-L1 positive tumour-infiltrating lymphocytes, and multinuclear giant cells (MGCs). G4 more commonly exhibited follicular morphology, expansive/circumscribed growth, and absence of the following: intratumoural fibrosis, LI, VI, psammoma bodies, PD-L1 positive tumour-infiltrating lymphocytes, and MGCs. LNMs were significantly more frequent in G1 in comparison with the other groups (p = 0.000). In conclusion, morphology and tumour microenvironment of p-PTMC with PD-L1 expression is different from i-PTMC without PD-L1 expression. The differences between these two groups of PTMC include clinicopathological features related with biological aggressiveness such as the occurrence of LNM.

The impact of thyroid tumor features on lymph node metastasis in papillary thyroid carcinoma patients in head and neck department at KAMC: A retrospective cross-sectional study

Papillary thyroid carcinoma (PTC) is the most prevalent type of thyroid cancer. It is one of the most common types of malignancy of the thyroid that spreads to cervical lymph nodes. Lymph node metastasis (LNM) is an important factor when determining recurrence risk, and determining the extent of lymph node involvement can guide treatment. Our main objective is to evaluate the association between the size of the tumor and the number of lymph node metastases in patients with PTC. Methods: We conducted an electronic retrospective chart review of 125 patients with PTC followed in the Head and Neck Department at KAMC from 2009 to 2020. Twenty-two patients included in our study were pathologically and clinically diagnosed and confirmed to have LNM of PTC. Results: The study included 22 PTC patients who had undergone lymph node dissections. Patients had a median age of 38.8 years (IQR = 32.2–54.5), and the median tumor size was 20.5 mm. The most commonly affected level of the neck was IV (76.2%). Distant metastasis M1 was seen in only two patients (9.1%). Tumors sizes >30mm (75%) had ≥5 LNM. Most cases were the classic subtype PTC. For the site of the tumor, the site had a significant impact on the number of LNM (p = 0.004). Multifocality had a high impact on LNM (p = 0.019). Conclusions: This study showed no association between the size of PTC and the number of LNMs. The bilaterality of PTC was significantly associated with a high number of LNMs.

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Lymph nodes in level IV were the most common metastasis site for PTC.

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Bilateral and multifocal PTC were significantly associated with a higher number of lymph nodes metastasis.

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The size of the tumor was not significantly related to the number of lymph node metastasis.

Risk Factors for Lymph Node Metastasis in Papillary Thyroid Carcinoma: A Systematic Review and Meta-Analysis

Purpose: To explore the risk factors that may predict the lymph node metastasis potential of these lesions and new prevention strategies in papillary thyroid carcinoma patients. Materials and Methods: In total, 9,369 papillary thyroid carcinoma patients with 37.17% lymph node metastasis were analyzed (Revman 5.3 software) in this study. The PubMed and Embase databases were used for searching works systematically that were published through to January 22, 2020. Results: Several factors were related to the increased risk of lymph node metastasis in patients with papillary thyroid carcinoma: age <45 years (pooled OR = 1.52, 95% CI = 1.14-2.01, p <0.00001); gender = male (pooled OR = 1.68, 95% CI = 1.51-1.87, p <0.00001); multifocality (pooled OR = 2.05, 95% CI = 1.45-2.89, p <0.0001); tumor size ≥1.0 cm (pooled OR = 3.53, 95% CI = 2.62-4.76, p <0.00001); tumor location at the upper pole 1/3 (pooled OR =1.46, 95% CI = 1.04-2.04, p = 0.03); capsular invasion + (pooled OR = 3.48, 95% CI = 1.69-7.54, p = 0.002); and extrathyroidal extension + (pooled OR = 2.03, 95% CI= 1.78-2.31, p <0.00001). However, tumor bilaterality (pooled OR = 0.85, 95% CI = 0.54-1.34, p = 0.49) and Hashimoto's thyroditis (pooled OR = 1.08, 95% CI = 0.79-1.49, p = 0.62) showed no correlation with lymph node metastasis in papillary thyroid carcinoma patients. Conclusion: The systematic review and meta-analysis defined several significant risk factors of lymph node metastasis in papillary thyroid cancer patients: age (<45 years), gender (male), multifocality, tumor size (>1 cm), tumor location (1/3 upper), capsular invasion, and extra thyroidal extension. Bilateral tumors and Hashimoto's thyroiditis were unrelated to lymph node metastasis in patients with papillary thyroid cancer.

Analysis of risk factors for cervical lymph node metastasis of papillary thyroid microcarcinoma: a study of 268 patients

BACKGROUND

To investigate the risk factors of cervical lymph node (LN) metastasis in papillary thyroid microcarcinoma (PTMC) patients.

METHODS

We retrospectively analyzed the clinicopathologic data of all patients who received standard lobectomy for PTMC at our institution between October 2017 and January 2019. Central LNs were dissected in all patients. Lateral LNs were dissected if metastasis to the lateral LNs was suggested based on pre-op fine-needle aspiration biopsy. The relationship between variables available prior to surgery and cervical LN metastasis was examined using multivariate regression.

RESULTS

Post-op pathologic examination revealed cervical LN metastasis in 79 (29.5%) patients. Seventy subjects had metastasis only to central LNs, and 4 (1.5%) patients had metastasis only to lateral LNs. Five patients had metastasis to both central and lateral LNs. In comparison to patients without cervical LN metastasis, those with LN metastasis were significantly younger (40.63 ± 13.07 vs. 44.52 ± 12.23 years; P = 0.021) and had significantly larger tumor diameter on pathology (6.7 ± 2.2 vs. 5.9 ± 2.4 mm; P = 0.010). Multivariate regression analysis identified the following independent risks for cervical LN metastasis: male sex (OR 2.362, 95%CI 1.261~4.425; P = 0.007), age (OR 0.977, 95%CI 0.956~0.999; P = 0.042) and ultrasound tumor diameter at > 5 mm (OR 3.172, 95%CI 1.389~7.240; P = 0.006).

CONCLUSION

Cervical LN metastasis occurs in a non-insignificant proportion of PTMC patients. Independent risks included male sex, younger age and larger tumor diameter on ultrasound.

Predictive factors for non-small-volume central lymph node metastases (more than 5 or ≥ 2 mm) in clinically node-negative papillary thyroid carcinoma

The benefits of prophylactic central neck dissection (pCND) for treating patients with clinical node-negative (cN0) papillary thyroid carcinoma (PTC) remain controversial. Lymph node metastases have been strongly associated with local recurrence and low survival, especially in PTC patients with 5 or more or ≥2 mm metastatic lymph nodes. The following study investigates the incidence and risk factors of more than 5 or ≥2 mm metastatic lymph nodes in the central compartment.A total of 611 patients with cN0 PTC were retrospectively analyzed. Cervical lymph nodes were harvested, and the size of metastatic lymph nodes was consequently analyzed.Non-small-volume central lymph node metastases (NSVCLNM), defined as more than 5 or ≥2 mm metastatic lymph nodes) were detected in 67 (11.0%) patients. Male gender, age ≤36 years, multifocal lesions, extrathyroidal extension, and tumor size > 0.85 cm were independent risk factors for NSVCLNM in cN0 PTC. The sensitivity and specificity of having ≥3 risk factors for predicting NSVCLNM was 46.3% and 86.8%, respectively.These findings suggest that pCND is a suitable treatment strategy for cN0 PTC patients with 3 or more risk factors for NSVCLNM.

The anteroposterior diameter of nodules in the risk assessment of papillary thyroid microcarcinoma

This study investigates the application of ultrasound, especially the anteroposterior diameter of nodules in the malignancy and metastasis risk assessment of papillary thyroid microcarcinoma through a retrospective analysis of 500 cases of thyroid nodule ultrasonography.We selected 500 patients with thyroid nodules (maximum nodule diameter ≤2.0 cm) that had been diagnosed clinically and graded TI-RADS 4c by ultrasonography and surgically treated. Among these, there were 258 cases of pathologically diagnosed papillary thyroid microcarcinoma, 72 cases of nodular goiter or adenoma, 137 cases of papillary thyroid carcinoma, 28 cases of acinar cell carcinoma, and 5 cases of undifferentiated carcinoma. In all cases, color Doppler ultrasonography had been performed preoperatively to determine the size and number of nodules, surrounding lymph node metastasis, and TI-RADS grading. Cases of papillary thyroid microcarcinoma diagnosed by pathology were selected as the study group, and cases of nodular goiter or adenoma as the control group. Each group was further subdivided based on the anteroposterior, vertical, and transverse nodule diameters. Intergroup statistical analysis was also performed. Receiver operating characteristic (ROC) curve analysis was conducted on the study and control groups based on the anteroposterior nodule diameters, and the optimal critical value for malignancy risk was determined. Thyroid nodules in the study group were divided into groups based on the presence or absence of lymph node metastasis. Based on the anteroposterior nodule diameter, ROC curve analysis was performed, and the optimal critical value for metastasis risk was determined.There were 500 cases of malignant nodules diagnosed by ultrasound. Among these, there were 428 cases of malignant nodules diagnosed by pathology. The coincidence rate of the ultrasound diagnosis with pathological diagnosis was 85.60%. While, interestingly, There was a significant statistical difference between the study and control groups based on the anteroposterior nodule diameter. When the anteroposterior nodule diameter was 0.7 cm, sensitivity of malignant diagnosis was 76.70% and specificity of that was 66.70%, and the Youden index was the highest. The lymph node metastasis rate for papillary thyroid microcarcinoma was 13.95%. Within this group, the lymph node metastasis rate for nodules ≥0.9 cm (anteroposterior diameter) was 38.46%. When the anteroposterior nodule diameter was equal to 0.9 cm, sensitivity of diagnosis was 83.30%, and specificity of that was 77.80%, and the Youden index was the highest.The anteroposterior diameter of thyroid nodules is more suitable for assessing their malignancy with 0.7 cm, which can be used as the critical value. Nodules ≥ 0.7 cm require surgical treatment, and those <0.7 cm can be observed. An anteroposterior diameter of 0.9 cm can be used as the critical value for assessing the metastasis risk of malignant thyroid nodules. During surgery, the dissection of central cervical lymph nodes is required for nodules ≥0.9 cm.

The synergic effect of BRAFV600E mutation and multifocality on central lymph node metastasis in unilateral papillary thyroid carcinoma

The purpose of this study is to evaluate the potential synergic effect of BRAF^V600E mutation and multifocality on central lymph nodes metastasis (CLNM) in the patients with unilateral papillary thyroid carcinoma (PTC). We enrolled 413 patients with unilateral PTCs who accepted prophylactic unilateral or bilateral central lymph node dissection (LND). Univariate and multivariate analyses were made to determine the association between related factors and CLNM. Then, all patients were divided into 4 groups based on their status of BRAF^V600E mutation and multifocality. Relative excess risk of interaction (RERI), attributable proportion (AP) of interaction and synergy index (SI) were applied to evaluate the interactive effect of these two factors on CLNM. Results showed that BRAF^V600E mutation and multifocality were independent risk factors for CLNM. A further study revealed that unilateral PTCs accompanying multifocality with BRAF^V600E mutation had the highest incidence of CLNM compared with other subgroups. Besides, RERI was 4.323 (95% CI = 1.276-7.369), AP was 0.523 (95% CI = 0.364-0.682) and SI was 2.469 (95% CI = 1.607 to 3.794), indicating a significant additive interaction of BRAF^V600E mutation and multifocality on CLNM. The present study has confirmed that BRAF^V600E mutation and multifocality are risk factors for CLNM in unilateral PTC. Additionally, unilateral PTC patients accompanying multifocality with BRAF^V600E mutation may have an increased risk of CLNM in clinically negative CLNM.

Relationships between clinicopathological prognostic factors in papillary thyroid microcarcinoma: a refined analysis based on 428 cases

A clear definition of the prognostic factors for papillary thyroid microcarcinoma (PTMC) is still debatable, as the tumor characteristics which indicate a high risk of metastasis are little known. We investigated the clinicopathological profile of a large group of PTMC, aiming to ascertain possible relationships between a set of clinicopathological characteristics and four parameters expressing tumor extension and aggressiveness (namely lympho-vascular invasion, thyroid capsule invasion, extrathyroidal extension and lymph node metastasis). For 428 patients, the following data were retrospectively documented: sex, age, tumor size, histological variant, associated thyroid pathology, location (subcapsular, intraparenchymal), unilateral or bilateral involvement, number of foci, lympho-vascular invasion, thyroid capsule invasion, extrathyroidal extension and lymph node metastasis. Data were analyzed using univariate and multivariate logistic regression analysis. Multivariate analysis confirmed that the tumor size is a negative prognostic factor for lympho-vascular invasion, thyroid capsule invasion, extrathyroidal extension and lymph node metastasis. We also demonstrated a strong relationship between the subcapsular location and lympho-vascular and capsule invasion, and extrathyroidal extension. The multifocality was correlated only with thyroid capsule invasion and extrathyroidal extension. Regarding the histological variants, the only validated correlation was between the oncocytic variant and extrathyroidal extension. Our work contributes to the validation of PTMC prognostic factors, useful in stratification of PTMC in high or low risk classes, and able to explain the behavioral differences in the tumor development.

Risk factors for lymph node metastasis (LNM) in patients with papillary thyroid microcarcinoma (PTMC): role of preoperative ultrasound

Objective This study aimed to investigate the risk factors and clinical value of lymph node metastasis (LNM) and missed central lymph node metastasis (CLNM) using preoperative ultrasound (US) in patients with papillary thyroid microcarcinoma (PTMC). Methods This retrospective study included 521 patients who underwent thyroidectomy for confirmed PTMC based on a final histological examination between January 2014 and June 2015. Based on the presence of LNM, 521 cases were divided into two groups: metastasis (218) and non-metastasis (303). Univariate and multivariate logistic regression analyses were used to analyse the US and clinical characteristics of the primary tumour. Results We defined LNM based on the tumour diameter with an optimal critical value of 0.55 cm using ROC analysis with a sensitivity of 65.6% and specificity of 59.6%. We defined US-missed CLNM based on the optimal critical value of 0.65 cm using diagnostic ROC analysis with a sensitivity of 66.0% and specificity of 73.0%. The odds ratios of significant factors with LNM by US were 10.3 (95% confidence interval [95% CI], 6.2-17.0), 5.3 (95% CI, 3.3-8.7), 2.7 (95% CI, 1.1-6.5), 4.3 (95% CI, 1.7-10.5), 2.5 (95% CI, 1.5-4.1), and 2.7 (95% CI, 1.7-4.4) for extrathyroidal invasion, blood flow, multifocality, tumour diameter greater than 0.55 cm, male sex, and age younger than 47 years, respectively. Conclusions US characteristics, such as extrathyroidal invasion, blood flow, tumour diameter, sex, and age, may improve the efficacy of predicting LNM and facilitating diagnosis of PTMC. Furthermore, tumour invasion to the extracapsular thyroid and a diameter greater than 0.65 cm indicate CLNM.

Bidirectional Approach of Video-Assisted Neck Surgery (BAVANS): Endoscopic complete central node dissection with craniocaudal view for treatment of thyroid cancer

INTRODUCTION

Endoscopic thyroidectomy is a well-established surgical technique that is mainly performed for benign thyroid disease. We considered that endoscopic surgery could also be widely indicated for the treatment of thyroid cancer. We herein describe our new bidirectional approach of video-assisted neck surgery (BAVANS) for complete central node dissection in endoscopic thyroid cancer surgery.

METHODS

BAVANS involves two different directional pathways to the cervical lesion. Before lymph node dissection, we perform endoscopic thyroidectomy via a conventional gasless precordial or axillary approach. After thyroidectomy, the surgeon repositions by the head of the patient and inserts three ports in front of the upper neck lesion in the submandibular area to approach the paratracheal lesion from an overhead-to-caudal direction.

RESULTS

BAVANS allows for an excellent craniocaudal view and easy access to the peritracheal lymph nodes. Sixteen patients with papillary thyroid cancer underwent BAVANS and progressed satisfactorily after surgery. Of those patients, eight underwent total or near total thyroidectomy, and five patients underwent bilateral central node dissection. The average number of retrieved lymph nodes with unilateral central node dissection was nine, which was higher than that achieved with conventional open surgery. All patients began oral intake within 5 h after surgery. Postoperative Horner syndrome occurred in one patient. No other complications were noted.

CONCLUSIONS

BAVANS is a very effective surgical procedure that many endoscopic surgeons can perform safely and easily. It has both a cosmetic advantage and excellent curability in endoscopic thyroid cancer surgery.

The incidence and risk factors for central lymph node metastasis in cN0 papillary thyroid microcarcinoma: a meta-analysis

Although there have been many studies identifying clinical and pathologic factors that may predict central lymph node metastases (CLNM) in papillary thyroid microcarcinoma (PTMC) patients without clinically cervical lymph node metastasis (cN0), the results were inconsistent. And whether prophylactic central lymph node dissection (pCLND) should be performed in cN0 PTMC remains controversial. The EMBASE, PubMed, MEDLINE and the Cochrane Library were searched until Oct 2015 to identify relevant studies. Primary outcomes were clinical and pathologic factors for CLNM. Secondary outcomes included CLNM rate, surgical complications of hypocalcaemia and recurrent laryngeal nerve(RLN) injury and neck recurrences. Statistical analysis was performed using Stata 12.0. Fourteen eligible studies enrolling 4573 patients were included in this meta-analysis. The overall incidence of CLNM was 33 % (95 % CI 29-37). An elevated risk of CLNM was significantly associated with male gender (OR 2.33, 95 % CI 1.71-3.17), age <45 years (OR 1.27, 95 % CI 1.08-1.48), tumor size >5 mm (OR 2.16, 95 % CI 1.87-2.50), multifocality (OR 1.73, 95 % CI 1.45-2.05), extrathyroidal extension (OR 1.99, 95 % CI 1.66-2.37) and lymphovascular invasion (OR 3.87, 95 % CI 1.64-9.10), but not with thyroid bilaterality (OR 1.41, 95 % CI 0.89-2.22) and chronic lymphocytic thyroiditis (OR 0.98, 95 % CI 0.66-1.47). The pooled frequency of permanent hypocalcaemia, permanent RLN injury and neck recurrences was 1.1, 0.5 and 2.8 %, respectively. cN0 PTMC patients have a considerable CLNM rate and have a low pooled incident of surgical complications and neck recurrences with pCLND. Six unfavorable clinical and pathologic factors, which were significantly associated with CLNM, were identified. These findings may help guide the application of pCLND or subsequent treatment in cN0 PTMC.

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.

Risk Factors for Central Compartment Lymph Node Metastasis in Papillary Thyroid Microcarcinoma: A Meta-Analysis

BACKGROUND

The surgical management of papillary thyroid microcarcinoma (PTMC), especially regarding the necessity of central lymph node dissection (CLND), remains controversial. This meta-analysis was conducted to investigate the clinicopathologic factors predictive of central compartment lymph node metastasis (CLNM) in patients diagnosed with PTMC.

METHODS

PubMed, EMBASE, Ovid, Web of Science, and the Cochrane Library were searched from their inception to September 2013. Published studies that explored the association between clinicopathologic factors and CLNM in PTMC patients were included. From the identified studies, we extracted the number of individuals with or without each risk factor to calculate the CLNM-positive proportions and used fixed/random-effects models for the meta-analyses of overall relative risk (RR). The pooling analysis on the association between CLNM or the different CLNDs and prognosis was also conducted.

RESULTS

A total of 19 eligible studies that included 8345 patients were identified. Three studies did therapeutic CLND, while the other 16 studies performed prophylactic CLND in PTMC patients. Meta-analyses revealed that CLNM was associated with male gender (RR = 1.36; 95 % CI 1.22-1.52, p = 0.001), younger age (<45 years; RR = 1.15; 95 % CI 1.04-1.27, p = 0.006), larger tumor size (>5 mm; RR = 1.51 95 % CI 1.32-1.65, p = 0.001), multifocality (RR = 1.40; 95 % CI 1.27-1.54, p = 0.001), and extrathyroidal extension (RR = 1.81; 95 % CI 1.34-2.43, p = 0.001). Meta-regression analysis indicated that a disparity in the proportion of PTMC patients with CLNM in each study was the main factor resulting in heterogeneity among the 19 studies. In addition, the pooling analyses suggested that CLNM did not significantly predict neck recurrences [hazard ratio (HR) = 0.95, 95 % CI 0.67-1.22, p = 0.054], and the prophylactic CLND group did not improve local control significantly compared to the therapeutic group (RR = 0.96, 95 % CI 0.46-2.01, p = 0.544).

CONCLUSION

Prophylactic CLND may be performed in PTMC patients with clinically uninvolved central lymph nodes but with high risk factors; multicenter studies with long-term follow-up are recommended to better understand the risk factors and surgical management for central nodes in PTMC.

Predictive Factors for Lymph Node Metastasis in Papillary Thyroid Microcarcinoma

BACKGROUND

Because lymph node (LN) metastasis has been proven to be a predictor for locoregional recurrence (LRR) in papillary thyroid microcarcinoma (PTMC), better knowledge about the predictors for LN metastasis in PTMC is required.

METHODS

We retrospectively reviewed 5656 PTMC patients who underwent total thyroidectomy and central neck dissection and/or lateral neck dissection between January 1997 and June 2015.

RESULTS

Male gender (adjusted odds ratio [OR] 2.332), conventional variant (adjusted OR 4.266), tumor size >0.5 cm (adjusted OR 1.753), multiplicity (adjusted OR 1.168), bilaterality (adjusted OR 1.177), and extrathyroidal extension (ETE) (adjusted OR 1.448) were independent predictors for high prevalence of central LN metastasis (CLNM), whereas per 10-year age increment (adjusted OR 0.760) and chronic lymphocytic thyroiditis (adjusted OR 0.791) were independent predictors for low prevalence of CLNM. In addition, male gender (adjusted OR 1.489), tumor size >0.5 cm (adjusted OR 1.295), multiplicity (adjusted OR 1.801), ETE (adjusted OR 1.659), and CLNM (adjusted OR 4.359) were independent predictors for high prevalence of lateral LN metastasis (LLNM), whereas per 10-year age increment (adjusted OR 0.838) was an independent predictor for low prevalence of LLNM. There was a statistically significant difference in LRR with regard to nodal stage (p < 0.001).

CONCLUSIONS

Meticulous perioperative evaluation of LN metastasis is required for PTMC patients with the above predictors.

Pathologic features of metastatic lymph nodes identified from prophylactic central neck dissection in patients with papillary thyroid carcinoma

The importance of pathologic features of metastatic lymph nodes (LNs), such as size, number, and extranodal extension, has been recently emphasized in patients with papillary thyroid carcinoma (PTC). We evaluated the characteristics of metastatic LNs identified after prophylactic central neck dissection (CND) in patients with PTC. We performed a retrospective review of 1,046 patients who underwent unilateral or bilateral thyroidectomy with ipsilateral prophylactic CND. We reviewed the characteristics of the metastatic LNs and analyzed their correlation to the clinicopathologic characteristics of the primary tumor. Cervical LN metastasis after prophylactic CND was identified in 280 out of 1046 patients (26.8 %). The size of metastatic foci (≥2 mm) was independently correlated with primary tumor size (≥1 cm) (p = 0.016, OR = 1.88). Primary tumor size (≥1 cm) was also correlated to the number of metastatic LNs (≥5) (p = 0.004, OR = 3.14) and extranodal extension (p = 0.021, OR = 2.41) in univariate analysis. The size of the primary tumor affects pathologic features of subclinical LN metastasis in patients with PTC. Patients with primary tumors ≥1 cm have an increased risk of larger LN metastases (≥2 mm), an increased number of LN metastases (≥5), and a higher incidence of ENE, which should be considered in decision for prophylactic CND.

Thyroid Papillary Microcarcinoma: Etiology, Clinical Manifestations,Diagnosis, Follow-up, Histopathology and Prognosis

BACKGROUND

Thyroid carcinoma is the most common malignancy of the endocrine system. Papillary thyroid carcinoma (PTC) is the most common type of thyroid cancer, accounting for 70-90% of well-differentiated thyroid malignancies. Thyroid papillary microcarcinoma is a subtype of papillary carcinoma that included tumors with less than 10mm diameter. As a result of diagnostic methods improvement, prevalence of this tumor is increasing. In this study we reviewed different characteristics of tumor.

METHODS

We searched various factors about this tumor in different databases (PubMed, Ovid, Google scholar, Iran medex and SID databases, from July 2012 until August 2013), after that, the articles were classified. Data of each article were extracted and sorted in tables. Data of each factor in different articles were summarized.

RESULTS

Etiology, clinical presentation, prognosis, histopathology, follow-up, diagnosis and also age, gender, tumor size and treatment were factors about this tumor described in details here.

CONCLUSION

Awareness and better understanding of the characteristics of this tumor and manage it as an individual and valuable tumor can take an effective step in promoting public health practice.

Risk Factors for Central Lymph Node Metastasis in CN0 Papillary Thyroid Carcinoma: A Systematic Review and Meta-Analysis

Background

Central lymph node metastasis (CLNM) is common in papillary thyroid carcinoma (PTC). Prophylactic central lymph node dissection (PCLND) for patients with clinically negative central compartment lymph nodes (CN0) remains controversial. The phrase “clinically negative” is used to indicate that patients exhibited no clinical evidence of CLNM by ultrasonography (US) or computerized tomography (CT) preoperatively. In this study, we analyze the risk factors for CLNM in CN0 patients.

Methods

The PUBMED and SCIE databases were systematically searched for works published through January 31, 2015. All of the patients included in this study underwent thyroidectomy+PCLND. Revman 5.3 software was used to analyze the data.

Results

Twenty studies and 9084 patients were included in this meta-analysis. The following variables were associated with an increased risk of CLNM in CN0 patients: age < 45 years (OR = 1.59, 95% CI = 1.42–1.78, p<0.00001), male sex (OR = 1.95, 95% CI = 1.63–2.32, p<0.00001), multifocality (OR = 1.43, 95% CI = 1.22–1.67, p<0.00001), tumor size > 2 cm for PTC patients (OR = 2.98, 95% CI 2.08–4.28, p<0.00001) or tumor size > 0.5 cm for papillary thyroid microcarcinoma (PTMC) patients (OR = 2.30, 95% CI = 1.71–3.09, p<0.00001), location of the primary tumor in the central area and low pole (OR = 1.86, 95% CI = 1.48–2.33, p<0.00001), lymphovascular invasion (OR = 4.35, 95% CI = 2.24–8.46, p<0.0001), extrathyroidal extension (OR = 2.27, 95% CI = 1.76–2.94, p<0.00001), and capsular invasion (OR = 1.72, 95% CI = 1.39–2.41, p<0.00001). PTC (tumor size>1cm) exhibited a higher risk factor associated with CLNM than PTMC (tumor size<1cm) (OR = 2.83, 95% CI = 2.15–3.72, p<0.00001). Bilateral tumors (OR = 1.21, 95% CI = 0.92–1.58, p = 0.17) and lymphocytic thyroiditis (OR = 0.88, 95% CI = 0.71–1.09, p = 0.25) had no association with CLNM in CN0 patients.

Conclusions

Our systematic review identified several clinical features associated with CLNM in CN0 patients, including age, sex, multifocality, size, location, lymphovascular invasion, capsular invasion, and extrathyroidal extension. These factors should guide the application of PCLND in CN0 patients.

Prediction of central lymph node metastasis in 392 patients with cervical lymph node-negative papillary thyroid carcinoma in Eastern China

Central lymph node metastasis (CLNM) is common in papillary thyroid microcarcinoma (PTMC). The aim of the present study was to investigate the risk factors associated with CLNM in clinical lateral cervical lymph node-negative (cN0) PTMC in Eastern China. A total of 392 patients with confirmed PTMC by histological examination who underwent thyroidectomy and central neck lymph node dissection (CND) between May 2011 and October 2012 at the First Affiliated Hospital of Wenzhou Medical University (Wenzhou, China) were enrolled. The clinicopathological and ultrasonographic data from the patients were analyzed retrospectively. A scoring system was developed on the basis of independent predictive factors for CLNM. Male gender, age <45 years, maximum tumor diameter >5 mm, lower lobe location, multifocal carcinoma with total tumor diameter >10 mm and extracapsular spread were independent predictive factors for CLNM according to logistic regression analysis. The clinicopathological score was statistically significant, with an index point ≥2 indicating CLNM with 86.2% sensitivity and 70.4% specificity. The findings of the present study indicate that CND may be recommended to be routinely performed when the clinicopathological index point ≥2.

Clinical risk factors for central lymph node metastasis in papillary thyroid carcinoma: a systematic review and meta-analysis

BACKGROUND

Prophylactic central lymph node dissection (CLND) in clinically node-negative patients remains controversial, and predictive factors for central lymph node metastasis (CLNM) in patients with papillary thyroid carcinoma (PTC) are not well defined. Herein, we conducted a systematic review to quantify the clinicopathologic factors predictive for CLNM in patients with PTC.

METHODS

A systematic search of electronic databases (PubMed, Embase, Cochrane CENTRAL, Scopus and Wanfang Database) for studies published until July 2014 was performed. Cohort, case-control studies and randomized controlled trials that examined clinical risk factors of CLNM were included.

RESULTS

Twenty-five studies (4 prospective and 21 retrospective studies) involving 7,719 patients met final inclusion criteria. From the pooled analyses, male gender (OR 1.93, 95% CI 1.40 to 2.64), tumour multifocality (OR 1.93, 95% CI 1.62 to 2.30), tumour size >0.5 cm (OR 3.48, 95% CI 2.24 to 5.41), capsular invasion (OR 1.91, 95% CI 1.36 to 2.67), extrathyroidal extension (OR 2.42, 95% CI 1.58 to 3.71), lymphovascular invasion (OR 13.29, 95% CI 5.61 to 31.48) and lateral lymph node metastasis (OR 14.33, 95% CI 5.34 to 38.50) were significantly associated with increased risk of CLNM, while age >45 years (OR 0.65, 95% CI 0.51 to 0.83) and lymphocytic thyroiditis (OR 0.70, 95% CI 0.53 to 0.92) resulted in decreased risk of CLNM. Bilaterality and tumour location were not significantly associated with CLNM development (all P > 0.05).

CONCLUSIONS

Our analysis identified several clinicopathologic factors associated with CLNM. These findings may guide the necessity and extent of prophylactic CLND and ultimately improve the outcomes of patients with PTC.

Real-Time PCR Cycle Threshold Values for the BRAFV600E Mutation in Papillary Thyroid Microcarcinoma May Be Associated With Central Lymph Node Metastasis: A Retrospective Study

Papillary thyroid microcarcinoma (PTMC) usually has excellent prognosis, but a small subset shows aggressive behavior. Although the B-Raf proto-oncogene, serine/threonine kinase (BRAF)V600E mutation is the most common oncogenic alteration in PTMCs, it is frequently heterogeneously distributed within tumors. The aim of this study was to investigate the association of the BRAFV600E mutation found in fine needle aspirates from PTMCs with known clinicopathologic prognostic factors, based on both its presence and a quantitative approach that uses cycle threshold (Ct) values obtained by a real-time PCR technique. The 460 PTMC patients were included, with 367 patients having the BRAFV600E mutation. Clinicopathologic variables were compared between patients with and without the BRAFV600E mutation. BRAFV600E Ct values were compared according to clinicopathologic prognostic factors. Multivariate analyses were performed to evaluate factors predicting extrathyroidal extension and central and lateral lymph node metastasis (LNM). Each analysis used either the BRAFV600E mutation status or the Ct value as an independent variable for all the study patients and the 367 BRAFV600E-positive patients. Receiver-operating characteristic (ROC) curve analysis was performed to evaluate the diagnostic performance of BRAFV600E Ct values in predicting central and lateral LNM. The BRAFV600E mutation status was not associated with clinicopathologic prognostic factors among the 460 PTMC patients. Of the 367 BRAFV600E-positive patients, Ct values were significantly lower in patients with central and lateral LNM (P < 0.001, P = 0.007). The Ct value was the only independent factor to predict central LNM (OR 0.918, P = 0.025). The area under the ROC curve (AUC) for diagnosing central LNM was 0.623 (sensitivity, 50.0%; specificity, 71.9%) and for diagnosing lateral LNM, it was 0.796 (sensitivity, 71.4%; specificity, 94.7%). In conclusion, real-time PCR Ct values for the BRAFV600E mutation obtained from fine needle aspirates can be associated with central LNM in PTMC patients. Although BRAFV600E Ct values did not reach statistical significance for predicting lateral LNM in our study, further validation through larger studies can be used to overcome any possible type-II errors. With further studies, Ct values for the BRAFV600E mutation obtained from fine needle aspirates may have important implications for predicting both central and lateral LNM in patients with PTMCs.

Impact of tumor size on subclinical central lymph node metastasis in papillary thyroid microcarcinoma depends on age

BACKGROUND

The aim of this study is to evaluate whether the associations between clinicopathologic factors of papillary thyroid microcarcinoma (PTMC), especially tumor size, and subclinical central lymph node metastasis (LNM) are dependent on patient age.

METHODS

The medical records of 428 patients who underwent thyroid surgery for PTC measuring ≤1 cm were reviewed. All patients were clinically lymph node negative and underwent thyroidectomy with unilateral or bilateral central lymph node dissection. Univariate and multivariate analyses were performed to identify clinicopathologic factors associated with central LNM.

RESULTS

Central LNM was identified in 96 of 428 (22.4%) patients. Mean tumor size was significantly greater in patients with than without central LNM (0.74 ± 0.22 cm vs. 0.64 ± 0.23 cm, P = 0.001). Tumor size > 0.5 cm was significantly predictive of central LNM. Subgroup analysis according to age groups showed that tumor size was an independent predictor of subclinical central LNM only in patients aged ≥45 years.

CONCLUSIONS

Factors predictive of central LNM in patients with PTMC differed by age. PTMC size was an independent predictor of subclinical central LNM only in patients aged ≥45 years.

Conventional US, elastography, and contrast enhanced US features of papillary thyroid microcarcinoma predict central compartment lymph node metastases

Lymph node metastases at the time of diagnosis have a major impact on both therapeutic strategy and tumor recurrence for patients with papillary thyroid microcarcinoma (PTMC). Our objective was to evaluate the usefulness of PTMC characteristics on ultrasonography for predicting central compartment lymph node metastases (CCLNM) of PTMC. One hundred twenty seven patients who underwent surgery for PTMC were enrolled in this study. The relationship between the CCLNM and the characteristics on conventional US, elastographic, and contrast enhanced ultrasound (CEUS) were investigated. Univariate analysis indicated that PTMCs with CCLNM were more often nodule irregular shape, microcalcifications, hyperenhancing or isoenhancing parametric maps, and peak index ≥1 at preoperative US and CEUS than those without CCLNM (P< 0.01, 0.05, 0.01 and 0.05 respectively). Multivariate analysis showed that microcalcification (OR:2.378, 95% CI: 1.096–5.158) and hyperenhancement or isoenhancement (OR:2.8, 95% CI: 1.287–6.094) were predictive for the presence of CCLNM. Elastography score was not significantly different between the groups. Our study indicated that preoperative thyroid nodule characteristics on conventional US and CEUS may serve as a useful tool to predict central compartment lymph node metastases in PTMC.

Gray-scale ultrasonography combined with elastography imaging for the evaluation of papillary thyroid microcarcinoma: as a prognostic clinicopathology factor

Ultrasonography (US) is the preferred imaging modality for papillary thyroid microcarcinoma (PTMC). The aim of this study was to evaluate the importance of gray-scale ultrasound combined with elastography to predict extrathyroidal extension and cervical lymph node (LN) metastasis in patients with PTMC. We retrospectively evaluated gray-scale ultrasonic and elastographic results from 119 consecutive cases of PTMC with 138 nodules and correlated the histopathological findings. The results indicated that pathological extrathyroidal extension was significantly associated with T staging on US, extrathyroidal extension on US, bilaterality on US, boundary, strain ratio and hard malignancy as measured with the Rago score. Central LN metastasis on pathology was significantly associated with central LN metastasis on US, lateral LN metastasis on US, multifocality on US and bilaterality on US. Lateral LN metastasis on US was significantly associated with lateral LN metastasis on pathology. On multivariate analysis, T staging on US, extrathyroidal extension on US and hard malignancy as measured with the Rago score were significantly associated with pathological extrathyroidal extension. Lateral LN metastasis on US and bilaterality on US were independent factors in predicting central LN metastasis on pathology. Lateral LN metastasis on US was the predictive factor for lateral LN metastasis on pathology. US should be helpful in the diagnosis of PTMC and in the evaluation of possible PTMC recurrence on US in routine clinical practice.

Risk factors of central lymph node metastasis in cN0 papillary thyroid carcinoma: a study of 529 patients

Background

Lymph node metastasis in papillary thyroid carcinoma (PTC) is common; however, the need for prophylactic central lymph node dissection (CLND) in PTC is still controversial. The objective of this study was to investigate the risk factors of central lymph node metastasis (CLNM) in clinically lymph node-negative (cN0) PTC patients.

Material/Methods

A total of 529 cN0 PTC patients who underwent lobectomy plus isthmusectomy or total thyroidectomy with unilateral or bilateral CLND between 2010 and 2012 were enrolled in this study. Clinicopathologic risk factors for CLNM were studied using univariate and multivariate analysis.

Results

CLNM was found in 238 (45.0%) cases. In univariate analysis, male sex, age <45 years, tumor size >2 cm, tumor located in the middle/lower third of lobe, and multifocality were significantly associated with CLNM (P<0.05); extrathyroid extension, Hashimoto’s thyroiditis, and TSH value were not associated with CLNM. In multivariate analysis, tumor size >2 cm, age <45 years, multifocality, and tumor located in the middle/lower third of the lobe were independent predictors for CLNM.

Conclusions

Prophylactic CLND should be considered in cN0 PTC patients with the following risk factors: tumor size >2 cm, age <45 years, multifocality, or tumor located in the middle/lower third of the lobe. However, further long-term follow-up studies and multicenter research are needed to better understand these risk factors and the significance of prophylactic CLND.

E-cadherin expression and cell proliferation in the primary tumor and metastatic lymph nodes of papillary thyroid microcarcinoma

Although papillary thyroid microcarcinoma (PTMC) has an excellent prognosis, certain cases exhibit aggressive clinical manifestations. In this study, we assessed the expression of E-cadherin and Ki-67 in primary PTMC tumors and metastatic lymph nodes, in order to investigate the mechanism underlying the mainly indolent but potentially malignant nature of PTMC. A total of 93 PTMC patients treated in our institute were included in this study. All primary tumors and 57 metastatic lymph nodes were immunohistochemically stained and a total of 73 tumors (78.5%) were positive for E-cadherin. E-cadherin expression was significantly less common at the invasive front (58.1%, P<0.01) compared to that at the center of the tumor. Tumors that had lost E-cadherin expression at the invasive front frequently presented with lymph node metastasis (70.6%). Small tumors (≤5 mm diameter) expressed E-cadherin significantly more frequently compared with larger tumors (P=0.04); however, no other particular characteristic was found to correlate with the status of E-cadherin expression in the primary tumors. E-cadherin expression was detected in 49 (86.0%) of the 57 metastatic foci and correlated significantly with the expression status at the invasive front of the tumor (P=0.02). The Ki-67 index was universally low and was not correlated with the clinicopathological characteristics or the E-cadherin expression of the tumors. These results suggested that cancer cells in the metastatic lymph nodes exhibit indolent characteristics, similar to those of the primary PTMC. However, the metastatic cancer cells may have already completed the process of epithelial-to-mesenchymal transition (EMT) and mesenchymal-to-epithelial transition (MET), suggesting an innate malignant potential.

Optimal indication of thyroglobulin measurement in fine-needle aspiration for detecting lateral metastatic lymph nodes in patients with papillary thyroid carcinoma

BACKGROUND

The purpose of this study was to evaluate optimal indication of thyroglobulin (Tg) measurement in fine-needle aspiration (FNA) for detecting lateral metastatic lymph nodes in patients with papillary thyroid carcinoma (PTC).

METHODS

We performed a retrospective study of 241 lymph nodes of 220 patients who underwent ultrasound-guided FNA with Tg in FNA (FNA-Tg) washout fluid measurements for suspicious lymph nodes.

RESULTS

On multivariate analysis, hyperechogenicity, cystic change, presence of calcifications, and peripheral vascularity were independent factors predictive of lymph node metastasis. After adding FNA-Tg, sensitivity and accuracy were significantly increased when the lymph node had 1 or 2 suspicious ultrasound features. However, sensitivity and accuracy were not significantly increased when the lymph node had multiple suspicious ultrasound features.

CONCLUSION

Additional FNA-Tg can help diagnose a metastatic lymph node with 1 or 2 suspicious ultrasound features. However, additional FNA-Tg is not beneficial in lymph nodes with highly suspicious ultrasound features, in which FNA alone is sufficient for diagnosis of predictive of lymph node.

Clinical characteristics of papillary thyroid microcarcinoma less than or equal to 5 mm on ultrasonography

Management of papillary thyroid microcarcinoma sized ≤5 mm identified on ultrasonography is controversial. In this study, we evaluated the clinical characteristics of papillary thyroid microcarcinoma sized ≤5 mm on ultrasonography in comparison to those >5 mm and sought to present rationales for optimal management in papillary thyroid microcarcinoma ≤5 mm. The medical records of 396 patients who underwent surgery for papillary thyroid carcinoma between 2009 and 2011 were retrospectively analyzed. The patients were grouped into A (≤5 mm, n = 132) or B (>5 mm, n = 264) and the clinicopathologic characteristics of the patients were reviewed and compared between the two groups. Tumor capsular invasion (45.5 vs. 59.8 %, p = 0.007) and cervical lymph node metastasis (18.2 vs. 29.2 %, p = 0.018) were more frequent in group B. Nonetheless, group A presented lymph node metastasis in 42.3 % of multifocal cases showing no difference to that of group B (41.5 %, p = 0.946) and also included five cases (3.8 %) of lateral neck metastasis. Multifocality was the only predictive factor for lymph node metastasis in group A (p < 0.001). Over half (55.3 %) of the patients of group A were diagnosed with papillary carcinoma in private clinics; however, only 5.5 % of these patients underwent assessment of lateral neck lymph nodes initially. In conclusion, higher risk of cervical lymph node metastasis should be considered in evaluation and surgical decision of papillary thyroid microcarcinoma ≤5 mm identified on ultrasonography with multifocality. Evaluation of the cervical lymph nodes including the lateral neck should not be overlooked when suspicious thyroid nodule suggesting malignancy sized ≤5 mm shows multifocal lesions.