Predicting the factors of lateral lymph node metastasis in papillary microcarcinoma of the thyroid in eastern China

Risk factors associated with preferential lateral lymph node metastasis in papillary thyroid carcinoma

BACKGROUND

Lateral lymph node metastasis (LLNM) is common in patients with papillary thyroid cancer (PTC), usually occurring after central lymph node metastasis (CLNM). However, some patients experience LLNM without first developing CLNM. This study aimed to identify the risk factors for developing LLNM without CLNM.

METHODS

We retrospectively reviewed 421 patients diagnosed with PTC who underwent lobectomy or total thyroidectomy with central and ipsilateral lateral lymph node dissection. We collected clinicopathological data and used univariate and multivariate logistic regression analyses to determine the risk factors associated with LLNM without CLNM.

RESULTS

The LLNM without CLNM frequency was 18.3% (77/421). Univariate analyses demonstrated that age over 55 years, primary tumor in the upper portion of the thyroid, the number of central lymph node (CLN) and LLNM, primary tumor size, and the summed size of multi-foci tumors smaller than 1 cm were significantly associated with LLNM without CLNM (p < 0.05). Multivariate analysis revealed that LLNM without CLNM was more likely to occur in patients aged ≥55 years (odds ratio [OR], 2.309; 95% confidence interval [CI], 1.133-4.704; p = 0.021), and primary tumor in the upper portion of the thyroid (OR, 0.524; 95% CI, 0.295-0.934; p = 0.028).

CONCLUSION

The lymph node metastasis pattern in patients with PTC is not constant. Therefore, surgeons should evaluate the lateral lymph nodes, especially in patients older than 55 years or when the primary tumor is in the upper portion of the thyroid.

Comprehensive analysis of clinicopathologic and sonographic features in thyroid cancer with skip lymph node metastasis: establish and assessment of a prediction nomogram

Lateral Lymph Node Metastasis (LLNM) is common in Papillary Thyroid Carcinoma (PTC) and is associated with a poor prognosis. LLNM without central lymph node metastasis as skip metastasis is not common. We aimed to investigate clinicopathologic and sonographic risk factors for skip metastasis in PTC patients, and to establish a nomogram for predicting the possibility of skip metastasis in order to determine the therapeutic strategy. We retrospectively reviewed the data of 1037 PTC patients who underwent surgery from 2016 to 2020 at a single institution. Univariate and multivariate analyses were used to identify the clinicopathologic and preoperative sonographic risk factors of skip metastasis. A nomogram including the risk factors for predicting skip metastasis was further developed and validated. The incidence of skip metastasis was 10.7%. The univariate and multivariate analyses suggested that gender (p= 0.001), tumor location (p= 0.000), extrathyroidal extension (p= 0.000), and calcification (p= 0.000) were independent risk factors. For papillary thyroid microcarcinoma, tumor location (p= 0.000) and calcification (p= 0.001) were independent risk factors. A nomogram according to the clinicopathologic and sonographic predictors was developed. The receiver operating characteristic curve indicated that AUC was 0.824 and had an excellent consistency. The calibration plot analysis showed a good performance and clinical utility of the model. Decision curve analysis revealed it was clinically useful. A nomogram for predicting the probability of skip metastasis was developed, which exhibited a favorable predictive value and consistency. For the female PTC patient, tumor located at the upper pole is more likely to have skip metastasis. Surgeons and sonographers should pay close attention to the patients who have the risk factors. Evidence level: This article's evidence level is 3. Level 3 evidence is derived from non-randomized, controlled clinical trials. In this study, patients who receive an intervention are compared to a control group. Authors may detect a statistically significant and clinically relevant outcome.

Nomogram for preoperative prediction of high-volume lymph node metastasis in the classical variant of papillary thyroid carcinoma

Introduction

The objective of our study was to construct a preoperative prediction nomogram for the classical variant of papillary thyroid carcinoma (CVPTC) patients with a solitary lesion based on demographic and ultrasonographic parameters that can quantify the individual probability of high-volume (>5) lymph node metastasis (HVLNM).

Materials and methods

In this study, a total of 626 patients with CVPTC from December 2017 to November 2022 were reviewed. Their demographic and ultrasonographic features at baseline were collected and analyzed using univariate and multivariate analyses. Significant factors after the multivariate analysis were incorporated into a nomogram for predicting HVLNM. A validation set from the last 6 months of the study period was conducted to evaluate the model performance.

Results

Male sex, tumor size >10 mm, extrathyroidal extension (ETE), and capsular contact >50% were independent risk factors for HVLNM, whereas middle and old age were significant protective factors. The area under the curve (AUC) was 0.842 in the training and 0.875 in the validation set.

Conclusions

The preoperative nomogram can help tailor the management strategy to the individual patient. Additionally, more vigilant and aggressive measures may benefit patients at risk of HVLNM.

Risk factors for skip metastasis in patients with papillary thyroid microcarcinoma

BACKGROUND

Lymph node metastasis (LNM) is prevalent in papillary thyroid microcarcinoma (PTMC) and is essential when determining tumor stage and prognosis. Positive lateral LNM with negative central LNM is defined as skip metastasis. Thyroid carcinoma's risk factors for skip metastasis remain controversial, especially in PTMC. This study aimed to determine the clinical features as well as the risk factors of skip metastasis among patients with PTMC.

METHODS

We conducted retrospective research among patients with PTMC who were subjected to treatment at our Hospital between January 2018 and December 2019 by reviewing their medical records. A database containing demographic characteristics, ultrasonography features, blood test outcomes, operation information, pathology details, and follow-up information was constructed. The link between skip metastasis and clinicopathological features of PTMC was evaluated using univariate as well as multivariate analyses.

RESULTS

Overall, 293 patients diagnosed with PTMC and lateral LNM were included. There were 91 men (31.1%) and 202 women (68.9%). The median age was 38 (31-47) years. Fifty patients were diagnosed with skip metastases. Levels III and II + III were the most prevalent in single-level and two-level metastasis, correspondingly. Univariate and multivariate analyses detected two independent factors linked to skip metastasis in PTMC: female sex (odds ratio = 2.609, 95% confidence interval (CI): 1.135-6.000; p = 0.024) and location of the tumor (upper portion) (odds ratio = 2.959, 95% CI: 1.552-5.639; p = 0.001).

CONCLUSIONS

Skip metastasis is prevalent in thyroid carcinoma. Female sex and tumor location (upper portion) are independently linked to skip metastasis in PTMC. Patients who have these two risk factors should undergo a meticulous preoperative and intraoperative evaluation of lymph node status.

Indications of Superselective Neck Dissection in Patients With Lateral Node Metastasis of Papillary Thyroid Carcinoma

OBJECTIVE

The extent of neck dissection in papillary thyroid carcinoma (PTC) patients with lateral neck metastasis is controversial. This work aims to screen the patients suitable for superselective neck dissections including only levels III-IV.

STUDY DESIGN

Prospective observational cohort study.

SETTING

The study was conducted in a high-volume tertiary care setting.

METHODS

A total of 134 consecutive previously untreated PTC patients with lateral neck metastases and subjected to 154 therapeutic lateral neck dissections (including levels II, III, IV, and VB) between June 2018 and March 2021 were enrolled. Fine-needle aspiration was performed preoperatively at each suspicious neck level. Clinical predictors were analyzed for occult lymph node metastases at levels II and VB.

RESULTS

As a result, 44.8% and 5.8% of neck specimens exhibited metastatic lymph nodes at levels II and VB. In addition, univariate and multivariate analyses showed that the primary tumor in the ipsilateral thyroid upper lobe (P = .016, odds ratio = 3.528) and clinically multiple metastatic lymph nodes in level III-IV (P = .005, odds ratio = 6.414) were independent predictive factors for occult level II metastases. All 3 (1.9%) occult metastases at level VB were found in necks with preoperative multiple lymph node metastases.

CONCLUSIONS

A superselective lateral neck dissection including levels III to IV may be considered in patients with PTC when the preoperative evaluation identifies a single lymph node metastasis located at levels III to IV and the primary tumor is not in the upper lobe of the ipsilateral thyroid.

Web-Based Ultrasonic Nomogram Predicts Preoperative Central Lymph Node Metastasis of cN0 Papillary Thyroid Microcarcinoma

BACKGROUND

Many clinicians are facing the dilemma about whether they should apply the active surveillance (AS) strategy for managing Clinically Node-negative (cN0) PTMC patients in daily clinical practice. This research plans to construct a dynamic nomogram based on network, connected with ultrasound characteristics and clinical data, to predict the risk of central lymph node metastasis (CLNM) in cN0 PTMC patients before surgery.

METHODS

A retrospective analysis of 659 patients with cN0 PTMC who had underwent thyroid surgery and central compartment neck dissection. Patients were randomly (2:1) divided into the development cohort (439 patients) and validation cohort (220 patients). The group least absolute shrinkage and selection operator (Group Lasso) regression method was used to select the ultrasonic features for CLNM prediction in the development cohort. These features and clinical data were screened by the multivariable regression analysis, and the CLNM prediction model and web-based calculator were established. Receiver operating characteristic, calibration curve, Clinical impact curve and decision curve analysis (DCA) were used to weigh the performance of the prediction model in the validation set.

RESULTS

Multivariable regression analysis showed that age, tumor size, multifocality, the number of contact surface, and real-time elastography were risk factors that could predict CLNM. The area under the curve of the prediction model in the development and validation sets were 0.78 and 0.77, respectively, with good discrimination and calibration. A web-based dynamic calculator was built. DCA proved that the prediction model had excellent net benefits and clinical practicability.

CONCLUSIONS

The web-based dynamic nomogram incorporating US and clinical features was able to forecast the risk of preoperative CLNM in cN0 PTMC patients, and has good predictive performance. As a new observational indicator, NCS can provide additional predictive information.

Predictive factors for central lymph node metastases in papillary thyroid microcarcinoma

Papillary thyroid microcarcinoma (PTMC) measures 1 cm or less in its longest dimension. The incidence of PTMC is increasing worldwide. Surgery is the primary treatment; however, prophylactic central lymph node dissection is controversial, and discrepancies between different guidelines have been noted. Routine prophylactic central lymph node dissection may result in hypoparathyroidism and recurrent laryngeal nerve injury in some patients without lymph node metastasis, while simple thyroidectomy may leave metastatic lymph nodes in high-risk patients. To selectively perform prophylactic lymph node dissections in high-risk patients, it is important to identify predictive factors for lymph node metastases in patients with PTMC. Several studies have reported on this, but their conclusions are not entirely consistent. Several clinicopathologic characteristics have been identified as risk factors for central lymph node metastases, and the most commonly reported factors include age, gender, tumor size and location, multifocality, bilaterality, extrathyroidal extension, and abnormal lymph node found using ultrasound. Here, we provide an overview of previous studies along with a favorable opinion on or against these factors, with the aim of increasing the understanding of this topic among the medical community. In addition, current opinions about prophylactic central lymph node dissection are reviewed and discussed.

Clinical and Ultrasonic Risk Factors for Lateral Lymph Node Metastasis in Papillary Thyroid Microcarcinoma: A Systematic Review and Meta-Analysis

Background: Clinical and ultrasonic risk factors for lateral lymph node metastasis (LLNM) in papillary thyroid microcarcinoma (PTMC) are not well-defined. Herein, a systematic review and meta-analysis was conducted to investigate clinicopathologic and ultrasonic risk features for LLNM in PTMC.

Methods: A systematic search of electronic databases (PubMed, Embase, Cochrane Library, and Web of Science) for studies published until April 2019 was performed. Case–control studies and randomized controlled trials that studied clinical and ultrasonic risk factors of LLNM in PTMC were included.

Results: Fourteen studies (all retrospective studies) involving 43,750 patients met final inclusion criteria. From the pooled analyses, younger age<45 (OR, 1.55; 95% CI, 1.16–2.07; P = 0.003), male patients (OR, 1.94; 95% CI, 1.55–2.42; P < 0.00), extrathyroidal extension (OR, 3.63; 95% CI, 2.28–5.77; P <0.00), tumor multifocality (OR, 2.24; 95% CI, 1.53–3.28; P <0.00), tumor > 0.5 cm (OR, 2.24; 95% CI, 1.53–3.28; P < 0.00), central lymph node metastasis (OR, 5.61; 95% CI, 4.64–6.79; P < 0.00), >25% tumor contact with thyroid capsule (OR, 6.66; 95% CI, 1.96–22.65; P = 0.002), tumor calcification (OR, 2.90; 95% CI, 1.71–4.93; P < 0.00), upper tumor (OR, 3.18; 95% CI, 2.23–4.55; P < 0.00) were significantly associated with increased risk of LLNM in PTMC, while Hashimoto's thyroiditis and other ultrasonic features (solid tumor, hypoechoic tumor, smooth margin, and taller than wide tumor) were not significantly associated with LLNM in PTMC.

Conclusions: Our analysis identified several clinicopathologic and ultrasonic factors associated with LLNM in PTMC. This finding highlights the need for a cautious and frequent postoperative surveillance of the lateral neck in high-risk PTMC patients. Moreover, high-risk ultrasonic features also need to be considered during selection of PTMC for active surveillance.

Low-risk papillary thyroid microcarcinoma: Optimal management toward a more conservative approach

The incidence of papillary thyroid microcarcinoma (microPTC) has dramatically increased in the last decades. Most of these tumors remain small and clinically "silent", only small number progress. Although thyroid surgery used to be the only therapeutic approach, recent guidelines now consider active surveillance for low-risk microPTC. For this reason, more accurate risk stratification of microPTC is needed. The optimal management of low-risk microPTC through accurate risk stratification represents a major clinical issue.

Predictive Factors for Lateral Lymph Node Metastasis and Skip Metastasis in Papillary Thyroid Carcinoma

In papillary thyroid cancer (PTC) patients, cervical lymph node metastases are common, which disseminate sequentially from the central neck to the lateral neck. However, there is also a chaotic pattern of lymph node metastasis occasionally. In this study, we summarized 653 PTC patients who underwent thyroidectomy and central lymph node dissection with or without lateral lymph node dissection from two hospitals to investigate the pattern and risk factors of lateral lymph node metastasis (LLNM) and skip metastasis. LLNM was significantly associated tumor size > 1 cm, presence of extrathyroidal extension, tumors in the upper-lateral pole, and the number of metastatic lymph nodes in the central compartment. The frequency of skip metastasis was 22.5% (20 of 89 patients). Multivariate analyses showed tumor size ≤ 1 cm, and tumors in the upper-lateral pole were separately and independently associated with the risk of skip metastasis. Presence of LLNM affected the recurrence-free survival (RFS). RFS did not show the significantly difference between patients with LLNM and skip metastasis. Despite the low incidence of skip metastasis, attention should be paid to the possibility of LLNM even in the absence of central lymph node metastases. Besides, for patients with risk factors of LLNM or skip metastasis, detailed preoperative examination for the lateral compartment, especially the level III, is essential.

Risk Factors of Metastatic Lymph Nodes in Papillary Thyroid Microcarcinoma

INTRODUCTION

Papillary thyroid microcarcinoma (PTMC) usually has an indolent course, but some have worse prognostic factors, such as the presence of central (6.9%-51.5%) and lateral (3%-49.6%) lymph node metastases. The aim of this study is to analyze the factors associated with PTMC with metastatic lymph nodes and its long-term prognosis.

METHODS

Retrospective study whose study population consists of patients with PTMC (size ≤1cm). Patients with previous thyroid surgery, other synchronous malignancies and ectopic location of the PTMC were excluded. Two groups were compared: PTMC without metastatic lymph nodes (group 1) and PTMC with metastatic lymph nodes (group 2). A multivariate analysis using a logistic regression model and a Kaplan-Meier survival analysis with log-rank test were performed.

RESULTS

Out of the 161 selected patients, 9.3% (n=15) had metastatic lymph nodes. Multifocality (OR 5.284, 95%CI 1.056-26.443; P=.043) and extrathyroidal extension (OR 7.687, 95%CI 1.405-42.050; P=.019) were associated with the presence of metastatic lymph nodes. In PTMC with metastatic lymph nodes, more aggressive treatments were performed: lymphadenectomy (4.8% vs. 100%; P<.001) and radioactive iodine (24.7% vs. 100%; P<.001). During a mean follow-up of 119.8±65 months, one recurrence was detected in group 2 (0% vs. 6.7%; P=.093). No patients died due to the disease.

CONCLUSIONS

Multifocality and extrathyroidal extension of PTMC were associated with the presence of metastatic lymph nodes. Metastatic PTMC, with more aggressive treatments, presents an excellent long-term prognosis.

Predicting the factors associated with central lymph node metastasis in clinical node-negative (cN0) papillary thyroid microcarcinoma

PURPOSE

The aim of the present study was to investigate the risk factors associated with central lymph node metastasis (CLNM) in papillary thyroid microcarcinoma (PTMC).

METHODS

A total of 553 patients with PTMC confirmed by histological examination, who underwent thyroidectomy and central neck dissection (CND), were enrolled. The clinicopathological and ultrasonographic features from the patients were analyzed retrospectively.

RESULTS

PTMC patient age, Hashimoto thyroiditis (HT), tumor location, extrathyroidal extension (ETE), microcalcification and higher E values were correlated with the incidence of CLNM. Multivariate logistic regression analysis showed that age, HT, tumor location, ETE and E_max were related to the extent of CLNM. Chi-squared automatic interaction detection (CHAID) classification tree model showed that patients with tumor in upper/lower third combined ETE had a high risk of CLNM. Furthermore, cN0 PTMC patients with age ≤ 45 years and ETE had more extensive CLNM.

CONCLUSION

Our observations could be helpful for the assessment of prognostic factors of PTMC patients with CLNM.

Predicting factors of lateral neck lymph node metastases in patients with papillary thyroid microcarcinoma

The incidence of papillary thyroid microcarcinoma (PTMC) has increased dramatically in recent years. Compared with central lymph node metastases, lateral neck lymph node (LNLN) metastases in patients with PTMC were less studied. The aim of the present study is to analyze the predicting factors associated with LNLN metastases in patients with PTMC.A total of 3514 patients underwent thyroid surgery at our hospital from January 2017 to December 2017, and 936 patients with PTMC were selected and assessed retrospectively. They were further divided into 2 groups based on whether LNLN metastases existed or not. The relationship between LNLN metastases and clinicopathologic features of PTMC was analyzed.LNLN metastases were confirmed in 126 patients. Univariate and multivariate analyses found 5 independent factors associated with LNLN metastases. They were tumor size (≥0.7 cm) [odds ratio (OR) = 1.960, 95% confidence interval (95% CI) 1.227-3.131; P = .005], multifocality (OR = 2.254, 95% CI 1.398-3.634; P = .001), tumor location (upper portion) (OR = 6.312, 95% CI 3.853-10.340; P < .001), thyroid cancer family history (OR = 7.727, 95% CI 2.227-26.818; P = .001), and central lymph node metastases (OR = 11.810, 95% CI 6.547-21.302; P < .001).The findings of our study indicated that LNLN metastases were not rare in patients with PTMC, and tumor size (≥0.7 cm), multifocality, tumor location (upper portion), thyroid cancer family history, and central lymph node metastases were independent factors for LNLN metastases. In order to perform individualized management, LNLN should be meticulously evaluated when these features are detected.

Is thyroid nodule location associated with malignancy risk?

Purpose

Nodules located in the upper pole of the thyroid may carry a greater risk for malignancy than those in the lower pole. We conducted a study to analyze the risk of malignancy of nodules depending on location.

Methods

The records of patients undergoing thyroid-nodule fine-needle aspiration cytology (FNAC) at an academic thyroid cancer unit were prospectively collected. The nodules were considered benign in cases of a benign histology or cytology report, and malignant in cases of malignant histology. Pathological findings were analyzed based on the anatomical location of the nodules, which were also scored according to five ultrasonographic classification systems.

Results

Between November 1, 2015 and May 30, 2018, 832 nodules underwent FNAC, of which 557 had a definitive diagnosis. The prevalence of malignancy was not significantly different in the isthmus, right, or left lobe. Among the 227 nodules that had a precise longitudinal location noted (from 219 patients [155 females], aged 56.2±14.0 years), malignancy was more frequent in the middle lobe (13.2%; odds ratio [OR], 9.74; 95% confidence interval [CI], 1.95 to 48.59). This figure was confirmed in multivariate analyses that took into account nodule composition and the Thyroid Imaging, Reporting, and Data System (TIRADS) classification. Using the American College of Radiologists TIRADS, the upper pole location also demonstrated a slightly significant association with malignancy (OR, 6.92; 95% CI, 1.02 to 46.90; P=0.047).

Conclusion

The risk of thyroid malignancy was found to be significantly higher for mid-lobar nodules. This observation was confirmed when suspicious ultrasonographic features were included in a multivariate model, suggesting that the longitudinal location in the lobe may be a risk factor independently of ultrasonographic appearance.

Predictive Factors of Lateral Lymph Node Metastasis in Papillary Thyroid Microcarcinoma

This study was designed to determine the incidence and predictive factors for lateral lymph node metastasis (LNM) in patients with papillary thyroid microcarcinoma (PTMC). From January 2014 to July 2015, a retrospective review was conducted of 215 patients with PTMC who underwent total thyroidectomy and central lymph node dissection (LND) with lateral LND. Correlations of lateral LNM with clinicopathological features were examined using univariate analyses. Risk factors for lateral LNM were identified by multivariate analysis. Lateral LNM was observed in 163(75.8%) cases of 215 patients and often involved in level III (82.2%) and level IV (65.6%), with most found in two-levels (41.1%) and single-level (33.7%) models. Multivariate analyses showed that central LNM (odds ratio [OR]: 8.28, 95% confidence interval [CI]: 3.43-19.98, p < 0.001) and upper portion location (OR: 2.87 [CI: 1.34-6.09]; p = 0.007) were independent predictive factors for lateral LNM. The incidence of skip metastasis-Lateral LNM with central Lymph nodes negative-was 8.6% (14/163). Age ≥ 45 years old (OR: 4.37 [CI: 1.14-16.66]; p = 0.031) and upper portion location (OR: 4.34 [CI: 1.27-14.78]; p = 0.019) were independent risk factors for skip metastasis by multivariate analyses. Taken together, patients with PTMC with central LNM and tumor in the upper pole were more likely to present with lateral LNM. Even if there was no central LNM, patients with an age ≥ 45 years old and tumors in the upper portion of the thyroid should be evaluated carefully for possible lateral LNM.

Pattern of and clinicopathologic risk factors for lateral lymph node metastases in papillary thyroid carcinoma patients with lateral cervical lymphadenopathy

The surgical extension of lateral neck dissection (LND) in papillary thyroid carcinoma (PTC) with clinical lateral lymph node metastases (LLNM) remains controversial. The aim of this study was to explore the pattern of and clinicopathologic risk factors for LLNM in PTC with clinical unilateral LND to determine the rational extent of therapeutic LND.This retrospective study reviewed the records of 246 consecutive patients with PTC who simultaneously underwent total thyroidectomy, bilateral central lymph node dissection, and unilateral therapeutic LND. The frequency and pattern of LLNM were analyzed.Grossly, LLNM were present in 80.9% of patients, and level II to V lymph node metastases (LNM) were present in 45.9%, 62.6%, 56.1%, and 11.8% patients, respectively. Superior tumor location, extrathyroidal extension, and ipsilateral, contralateral, and bilateral central LNM (CLNM) were independent risk factors for gross LLNM. Age ≥45 years, superior lobe tumors, extrathyroidal extension, and ipsilateral and contralateral CLNM were independent risk factors for level II LNM. Age ≥45 years, superior and middle lobe tumors, extrathyroidal extension, and ipsilateral CLNM were independent risk factors for level III LNM. Superior lobe tumors and ipsilateral, contralateral, and bilateral CLNM were independent risk factors for level IV LNM. Only contralateral CLNM was an independent risk factor for level V LNM.In PTC patients with clinical LLNM, the predominant sites of LLNM were levels II to IV and not level V. Therapeutic elective LND should include the lateral nodal levels associated with independent risk factors, especially superior tumors location and CLNM.

Ultrasound texture analysis: Association with lymph node metastasis of papillary thyroid microcarcinoma

This retrospective study aimed to evaluate whether ultrasound texture analysis is useful to predict lymph node metastasis in patients with papillary thyroid microcarcinoma (PTMC). This study was approved by the Institutional Review Board, and the need to obtain informed consent was waived. Between May and July 2013, 361 patients (mean age, 43.8 ± 11.3 years; range, 16-72 years) who underwent staging ultrasound (US) and subsequent thyroidectomy for conventional PTMC ≤ 10 mm between May and July 2013 were included. Each PTMC was manually segmented and its histogram parameters (Mean, Standard deviation, Skewness, Kurtosis, and Entropy) were extracted with Matlab software. The mean values of histogram parameters and clinical and US features were compared according to lymph node metastasis using the independent t-test and Chi-square test. Multivariate logistic regression analysis was performed to identify the independent factors associated with lymph node metastasis. Tumors with lymph node metastasis (n = 117) had significantly higher entropy compared to those without lymph node metastasis (n = 244) (mean±standard deviation, 6.268±0.407 vs. 6.171±.0.405; P = .035). No additional histogram parameters showed differences in mean values according to lymph node metastasis. Entropy was not independently associated with lymph node metastasis on multivariate logistic regression analysis (Odds ratio, 0.977 [95% confidence interval (CI), 0.482-1.980]; P = .949). Younger age (Odds ratio, 0.962 [95% CI, 0.940-0.984]; P = .001) and lymph node metastasis on US (Odds ratio, 7.325 [95% CI, 3.573-15.020]; P < .001) were independently associated with lymph node metastasis. Texture analysis was not useful in predicting lymph node metastasis in patients with PTMC.

Preoperative predictors of lateral neck lymph node metastasis in papillary thyroid microcarcinoma

Lateral lymph node metastasis (LNM) is not uncommon in papillary thyroid microcarcinoma (PTMC). Our present study aimed to investigate the risk factors associated with lateral LNM in PTMC.We retrospectively collected data pertaining to 366 patients with PTMC who underwent surgery at our center from 2010 to 2015. These patients were divided into the following 2 groups: a lateral LNM-positive group and a lateral LNM-negative group. Clinical and ultrasound data were compared between the 2 groups to determine the risk factors associated with lateral LNM.Univariate and multivariate analyses indicated that capsule invasion (OR = 3.995, 95% CI, 2.148-7.430) and upper portion location (OR = 4.541, 95% CI, 2.444-8.438) were significant risk factors for lateral LNM of PTMC and that capsule invasion (AUC = 0.666) and upper portion location (AUC = 0.678) could be used to predict lateral LNM of PTMC. Moreover, the patients in lateral LNM positive group exhibited significantly higher rates of tumor recurrence or metastasis than the patients in lateral LNM negative group (P = 0.027).Patients with PTMC located in the upper portion or exhibiting capsule invasion should receive meticulous preoperative evaluations for lateral LNM, prophylactic lateral LND may be considered.

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.

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.

A Meta-analysis of Central Lymph Node Metastasis for Predicting Lateral Involvement in Papillary Thyroid Carcinoma

OBJECTIVE

Whether central lymph node metastasis is a reliable indicator of lateral lymph node metastasis in papillary thyroid carcinoma remains obscure. To investigate the value of central lymph node metastasis for predicting lateral compartment involvement, we performed a meta-analysis of published studies.

DATA SOURCES

A systematic literature search of PubMed, EMBASE, and Chinese National Knowledge Infrastructure databases was completed, and the reference lists of the identified articles and prior relevant reviews were examined.

REVIEW METHODS

Two reviewers extracted data and assessed the quality of eligible studies independently. Odds ratios and 95% confidence intervals were pooled through a random effects meta-analysis model.

RESULTS

Twenty-one studies were eligible and further analyzed in this meta-analysis. The risk of lateral lymph node metastasis was significantly higher in the central lymph node-positive group than in the negative group (odds ratio = 7.64, 95% confidence interval: 5.59-10.44), with moderate heterogeneity across studies (P = .007, I(2) = 48.6%). Subgroup analyses and sensitivity analysis suggested that the results were consistent and credible. However, Begg's funnel plot and Egger linear regression test revealed a likelihood of publication bias (P = .000).

CONCLUSION

This meta-analysis suggests that central lymph node metastasis is valuable for predicting lateral compartment involvement in patients with papillary thyroid carcinoma. For those patients with central lymph node metastasis, additional attention should be paid to the lateral neck, as the risk of lateral lymph node metastasis was significantly higher in the central lymph node-positive group than in the negative group. Further studies regarding appropriate management for patients with high risk of lateral involvement are needed.

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.

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.