Prophylactic central lymph node dissection in cN0 patients with papillary thyroid carcinoma: A retrospective study in China

Explainable machine learning model for predicting paratracheal lymph node metastasis in cN0 papillary thyroid cancer

Prophylactic dissection of paratracheal lymph nodes in clinically lymph node-negative (cN0) papillary thyroid carcinoma (PTC) remains controversial. This study aims to integrate preoperative and intraoperative variables to compare traditional nomograms and machine learning (ML) models, developing and validating an interpretable predictive model for paratracheal lymph node metastasis (PLNM) in cN0 PTC patients. We retrospectively selected 3213 PTC patients treated at the First Affiliated Hospital of Chongqing Medical University from 2016 to 2020. They were randomly divided into the training and test datasets with a 7:3 ratio. The 533 PTC patients treated at the Guangyuan Central Hospital from 2019 to 2022 were used as an external test sets. We developed and validated nine ML models using 10-fold cross-validation and grid search for hyperparameter tuning. The predictive performance was evaluated using ROC curves, decision curve analysis (DCA), calibration curves, and precision-recall curves. The best model was compared to a traditional logistic regression-based nomogram. The XGBoost model achieved AUC values of 0.935, 0.857, and 0.775 in the training, validation, and test sets, respectively, significantly outperforming the traditional nomogram model with AUCs of 0.85, 0.844, and 0.769, respectively. SHapley Additive exPlanations (SHAP)-based visualization identified the top 10 predictive features of the XGBoost model, and a web-based calculator was created based on these features. ML is a reliable tool for predicting PLNM in cN0 PTC patients. The SHAP method provides valuable insights into the XGBoost model, and the resultant web-based calculator is a clinically useful tool to assist in the surgical planning for paratracheal lymph node dissection.

Risk stratification for central lymph node metastasis in mono-focal papillary thyroid carcinoma patients with encapsulated tumor as confirmed by preoperative ultrasound: a multi-center analysis

PURPOSES

Mono-focal papillary thyroid carcinoma (PTC) patients with encapsulated tumor have traditionally been considered as low central lymph node metastasis (CLNM) risk subgroup. The aim of the research was to quantitatively predict the probability of CLNM for mono-focal PTC patients with encapsulated tumor as confirmed by preoperative ultrasound based on pre- and post-operative indexes respectively to guide the selection of prophylactic central lymph node dissection (CLND) and follow-up strategies.

METHODS

A total of 1014 mono-focal PTC patients with encapsulated tumor as confirmed by preoperative ultrasound from three medical centers were retrospectively analyzed, with 534 patients served as Training group and 480 patients as Validation group.

RESULTS

Multivariate analyses showed that age < 55 years old, male, clinical maximum tumor diameter (cMTD) > 0.5 cm, pathological maximum tumor diameter (pMTD) > 0.5 cm, and the presence of microscopic thyroid capsular invasion (mTCI) were independent CLNM risk factors. These were used to construct two nomograms that can effectively predict the central neck involvement in mono-focal PTC patients with encapsulated tumor. The first nomogram (pre-model) provides quantitative assessment on the necessity of prophylactic CLND, while the second nomogram (post-model) informs postoperative follow-up strategies.

CONCLUSIONS

Meticulous and comprehensive stratification flow charts that quantitatively evaluate the risk of central lymph node metastasis both pre- and post-operatively were constructed for mono-focal PTC patients with encapsulated tumor as confirmed by preoperative ultrasound, which may benefit both clinical decision-making of prophylactic CLND and postoperative follow-up strategies for the management of neck regions.

The role of parathyroid autotransplantation for hypoparathyroidism following total thyroidectomy with bilateral central neck dissection

Background

Hypoparathyroidism is the most common complication for patients who undergo total thyroidectomy (TT) with bilateral central lymph node dissection (BCLND). The objective of this retrospective study was to investigate the relationship between parathyroid autotransplantation (PA) and postoperative hypoparathyroidism.

Materials and Methods

Four hundred and sixty-five patients with papillary thyroid carcinoma (PTC) who underwent TT with BCLND (including prophylactic and therapeutic BCLND) by the same surgeon were enrolled in this retrospective study. They were divided into five groups based on the number of PAs. Group 0 was defined as no PA, while Group 1, 2, 3, and 4 were considered as 1, 2, 3, and 4 PAs during TT with BCLND, respectively.

Results

Transient and permanent hypoparathyroidism occurred in 83 (17.8%) and 2 (0.4%) patients who underwent TT and BCLND, respectively. The incidence of transient hypoparathyroidism increased gradually with an increase in the number of PAs. Compared with the previous group, Groups 2 and 3 had significantly more cases of transient hypoparathyroidism (p=0.03 and p=0.04, respectively). All cases of permanent hypoparathyroidism occurred in the patients without PA. Compared with Group 0, there were more removed central lymph nodes (RCLNs) in patients with one PA. Furthermore, Group 2 had more metastatic central lymph nodes(MCLNs) and RCLNs than Group 1.The number of PAs was the only identified risk factor for transient hypoparathyroidism after the multivariate logistic regression analysis. The median parathyroid hormone level recovered to the normal range within 1 month after surgery.

Conclusion

With an increasing number of PAs, the possibility of transient hypoparathyroidism also increases in patients with PTC who undergo TT and BCLND. Considering the rapid recovery of transient hypoparathyroidism in 1 month, two PAs during TT and BCLND could be a good choice, leading to an increase in the central lymph node yield and no permanent hypoparathyroidism. However, this conclusion should be validated in future multicenter prospective studies.

Prospective application of a prediction model for lateral lymph node metastasis in papillary thyroid cancer patients with central lymph node metastasis

Objective

This study aimed to develop and apply a prediction model to estimate the probability of lateral lymph node metastasis (LLNM) in patients with cN0 unilateral papillary thyroid carcinoma (PTC) with central lymph node metastasis (CLNM).

Setting

All study data were collected from a single tertiary hospital.

Methods

Univariable and multivariable logistic regression analyses were used to explore independent predictors of LLNM in the derivation and internal validation cohorts, which were used to construct and validate a nomogram. Another 96 patients were included prospectively to evaluate the efficacy of this nomogram.

Results

Maximum tumor diameter greater than 1.0 cm (OR, 2.712; 95% CI, 1.412-5.210), multifocality (OR, 2.758; 95% CI, 1.120-6.789), the number of CLNM ≥3 (OR, 2.579; 95% CI, 1.315-5.789), CLNM ratio ≥0.297 (OR, 2.905; 95% CI, 1.396-6.043), and tumors located in the upper portion (OR 2.846, 95% CI 1.151-7.039) were independent predictors associated with LLNM. The prediction model showed excellent discrimination with an AUC of 0.731 (95% CI, 0.635-0.827). Novel risk stratification for LLNM was constructed based on this nomogram. In the prospective cohort, we stratified these patients into three risk subgroups: low-, moderate-, and high-risk subgroups and we found that the probability of LLNM was positively correlated with the total points from the nomogram.

Conclusion

This nomogram was applied in prospective clinical practice and distinguished PTC patients with a genuinely high risk of LLNM. Surgeons can use our nomogram to tailor the surgical plan and to credibly determine further postoperative therapy.

Constructing a nomogram based on the distribution of thyroid nodules and suspicious lateral cervical lymph nodes in fine-needle aspiration biopsies to predict metastasis in papillary thyroid carcinoma

Purpose

Elevated concentrations of thyroglobulin eluent is a risk factor for lateral cervical lymph node metastasis (LLNM) in patients with papillary thyroid cancer (PTC). We aimed to develop a practical nomogram based on the distribution of thyroid nodules and the presence of suspicious lateral cervical lymph nodes in fine-needle aspiration biopsies (LN-FNABs), including the cytopathology and the suspicious lateral cervical lymph node (LLN) thyroglobulin eluent (Tg), to predict the possibility of LLNM preoperatively in patients with PTC.

Methods

The clinical data of PTC patients who were admitted to the Third Affiliated Hospital of Soochow University from January 2022 to May 2023 to undergo fine-needle aspiration biopsy (FNAB) were included in this study. A total of 208 patients in 2022 served as the training set (70%), and 89 patients in 2023 served as the validation set (30%). The clinical characteristics and LN-FNAB results were collected to determine the risk factors of LLNM. A preoperative nomogram was developed for predicting LLNM based on the results of the univariate and multivariate analyses. Internal calibration, external calibration, and decision curve analysis (DCA) were performed for these models.

Results

The multivariate logistic regression analysis showed that the maximum thyroid nodule diameter (Odds Ratio (OR) 2.323, 95% CI 1.383 to 3.904; p = 0.001), Tg level (OR 1.007, 95% CI 1.005 to 1.009; p = 0.000), Tg divided by serum thyroglobulin, (Tg/sTg) [odds ratio (OR) 1.005, 95% CI 1.001 to 1.008; p = 0.009], and cytopathology (OR 9.738, 95% CI 3.678 to 25.783; p = 0.000) (all p <  0.05) had a significant impact on the LLNM of patients with suspicious LLNs. The nomogram showed a better predictive value in both the training cohort [area under the curve, (AUC) 0.937, 95% CI 0.895 to 0.966] and the validation cohort (AUC 0.957, 95% CI 0.892 to 0.989). The nomogram also showed excellent internal and external calibration in predicting LLNM. According to the DCA, the diagnostic performance of this model was dependent on the following variables: maximum thyroid nodule diameter, Tg level, Tg/sTg, and cytopathology.

Conclusion

Based on the aforementioned risk factors, we believe that it is necessary to establish a personalized LLNM model for patients with PTC. Using this practical nomogram, which combines clinical and Tg risk factors, surgeons could accurately predict the possibility of LLNM preoperatively. The nomogram will also help surgeons to establish personalized treatment plans before surgery.

Prevalence of Occult Central Lymph Node Metastasis by Tumor Size in Papillary Thyroid Carcinoma: A Systematic Review and Meta-Analysis

BACKGROUND

While papillary thyroid carcinoma (PTC) is associated with high occult central neck metastasis (CNM) rates, prophylactic central neck dissection (pCND) is controversial. This meta-analysis aims to look at the occult CNM rate according to tumor size.

METHODS

A literature search was conducted in PubMed from inception to April 2023. Inclusion criteria were primary studies that determined occult CNM rates in cN0 PTC by tumor size. Heterogeneity, influential case diagnostics, and proportion data were evaluated with Cochran's Q-test, Baujat plots and Forest plots, respectively.

RESULTS

Fifty-two studies were included in this meta-analysis. The findings demonstrated an occult CNM rate of 30.3% for tumors ≤ 5 mm, 32.7% for tumors ≤ 1 cm, 46.0% for tumors between 1 and 2 cm, 43.1% for tumors between 2 and 4 cm, and 61.2% for tumors > 4 cm. The heterogeneity of each study group was high, though no publication bias was noted. While there was a trend towards increased occult CNM rates with larger tumors, comparisons between different size cutoffs varied in significance.

CONCLUSION

This comprehensive review affirms that occult CNM is high and that an ipsilateral pCND can be justified in all PTC patients for accurate differentiation between Stage I and Stage II disease and its clinical implications.

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.

Incidental Node Metastasis as an Independent Factor of Worse Disease-Free Survival in Patients with Papillary Thyroid Carcinoma

INTRODUCTION

Papillary thyroid carcinoma (PTC) have high node metastasis rates. Occasionally after thyroidectomy, the pathological report reveals node metastasis unintentionally resected. The present study aimed to evaluate the prognosis of these patients.

METHODS

A retrospective cohort of patients submitted to thyroidectomy with or without central compartment neck dissection (CCND) due to PTC with a minimum follow-up of five years.

RESULTS

A total of 698 patients were included: 320 Nx, 264 pN0-incidental, 37 pN1a-incidental, 32 pN0-CCND and 45 pN1a-CCND. Patients with node metastasis were younger, had larger tumors, higher rates of microscopic extra-thyroidal extension, and angiolymphatic invasion and most received radioiodine therapy. Treatment failure was higher in patients pN1a-incidental and pN1a-CCND (32% and 16%, respectively; p < 0.001-Chi-square test). Disease-free survival (DFS) was lower in patients pN1a-incidental compared to patients Nx and pN0-incidental (p < 0.001 vs. Nx and pN0-incidental and p = 0.005 vs. pN0-CCND) but similar when compared to patients pN1a-CCND (p = 0.091)-Log-Rank test. Multivariate analysis demonstrated as independent risk factors: pT4a (HR = 5.524; 95%CI: 1.380-22.113; p = 0.016), pN1a-incidental (HR = 3.691; 95%CI: 1.556-8.755; p = 0.003), microscopic extra-thyroidal extension (HR = 2.560; 95%CI: 1.303-5.030; p = 0.006) and angiolymphatic invasion (HR = 2.240; 95%CI: 1.077-4.510; p = 0.030).

CONCLUSION

Patients that were pN1a-incidental were independently associated with lower DFS.

Guideline for the Surgical Management of Locally Invasive Differentiated Thyroid Cancer From the Korean Society of Head and Neck Surgery

The aim of this study was to develop evidence-based recommendations for determining the surgical extent in patients with locally invasive differentiated thyroid cancer (DTC). Locally invasive DTC with gross extrathyroidal extension invading surrounding anatomical structures may lead to several functional deficits and poor oncological outcomes. At present, the optimal extent of surgery in locally invasive DTC remains a matter of debate, and there are no adequate guidelines. On October 8, 2021, four experts searched the PubMed, Embase, and Cochrane Library databases; the identified papers were reviewed by 39 experts in thyroid and head and neck surgery. The Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach was used to assess the quality of evidence, and to develop and report recommendations. The strength of a recommendation reflects the confidence of a guideline panel that the desirable effects of an intervention outweigh any undesirable effects, across all patients for whom the recommendation is applicable. After completing the draft guidelines, Delphi questionnaires were completed by members of the Korean Society of Head and Neck Surgery. Twenty-seven evidence-based recommendations were made for several factors, including the preoperative workup; surgical extent of thyroidectomy; surgery for cancer invading the strap muscles, recurrent laryngeal nerve, laryngeal framework, trachea, or esophagus; and surgery for patients with central and lateral cervical lymph node involvement. Evidence-based guidelines were devised to help clinicians make safer and more efficient clinical decisions for the optimal surgical treatment of patients with locally invasive DTC.

Preoperative strain ultrasound elastography can predict occult central cervical lymph node metastasis in papillary thyroid cancer: a single-center retrospective study

Objective

To determine whether preoperative ultrasound elastography can predict occult central cervical lymph node metastasis (CCLNM) in patients with papillary thyroid cancer.

Methods

This retrospective study included 541 papillary thyroid cancer patients with clinically negative lymph nodes prior to surgery between July 2019 and December 2021. Based on whether CCLNM was present on postoperative pathology, patients were categorized as CCLNM (+) or CCLNM (-). Preoperative clinical data, conventional ultrasound features, and ultrasound elastography indices were compared between the groups. Univariate and multivariate logistic regression analysis were performed to identify the independent predictors of occult CCLNM.

Results

A total of 36.60% (198/541) patients had confirmed CCLNM, while 63.40% (343/541) did not. Tumor location, bilaterality, multifocality, echogenicity, margin, shape, vascularity, capsule contact, extrathyroidal extension, aspect ratio, and shear wave elasticity parameters were comparable between the groups (all P > 0.05). Univariate analysis showed statistically significant differences between the two groups in age, sex, tumor size, calcification, capsule invasion, and strain rates ratio in strain ultrasound elastography (all P < 0.05). In multivariate logistic regression analysis, the independent predictors of occult CCLNM were age (OR = 0.975, 95% CI = 0.959-0.991, P = 0.002), sex (OR = 1.886, 95% CI = 1.220-2.915, P = 0.004), tumor size (OR = 1.054, 95% CI = 1.014-1.097, P = 0.008), and strain rates ratio (OR = 1.178, 95% CI = 1.065-1.304, P = 0.002).

Conclusion

Preoperative strain ultrasound elastography can predict presence of occult CCLNM in papillary thyroid cancer patients and help clinicians select the appropriate treatment strategy.

Effects of Patient and Tumor Characteristics on Central Lymph Node Metastasis in Papillary Thyroid Cancer: A Guide for Selective Node Dissection

BACKGROUND

Prophylactic central lymph node dissection (CLND) in papillary thyroid carcinoma (PTC) is still controversial. This study aimed to analyze the factors related to the patient and tumor characteristics affecting central lymph node metastasis (CLNM) in PTC patients and to evaluate the contribution of the results to shaping the surgical treatment algorithm.

METHODS

Two hundred and fifty-five PTC patients who underwent total thyroidectomy and CLND were evaluated retrospectively. Histopathology reports were examined to reveal tumor characteristics. The CLNM ratio and the relationship between CLNM with clinicopathological and demographic characteristics were analyzed.

RESULTS

The incidence of CLNM was 54.9% (95 CI%: 49-60.8). Male gender (P=0.027), age<45 years (P=0.016), tumor size≥9.5 mm (P<0.001), lymphovascular invasion (P<0001) and extracapsular invasion (P=0.007) were factors that increased the risk of metastasis. The follicular variant decreased the risk (P=0.010). There was no relationship between CLNM and focality (P=0.054). A low-to-moderate correlation was found between tumor diameter and the metastatic lymph node (MLN) number/total lymph node number ratio (r=0.396, P<0.001).

CONCLUSION

A selective prophylactic CLND strategy can be applied in cN0 patients. As the tumor diameter increases in PTC, both the risk of CLNM and the number of MLN increase. Lymphovascular and extracapsular invasion are other factors that increase the risk. The follicular variant is associated with a lower risk of CLNM. Male patients who are under the age of 45 and have a tumor diameter of 9.5 mm or more are definite candidates for prophylactic CLND.

Extreme gradient boosting model to assess risk of central cervical lymph node metastasis in patients with papillary thyroid carcinoma: Individual prediction using SHapley Additive exPlanations

BACKGROUND AND OBJECTIVES

Central cervical lymph node metastasis (CLNM) is considered a risk factor for recurrence in patients with papillary thyroid carcinoma (PTC). Traditional machine learning models suffered from "black-box" problems, which could not exactly explain the interactive effects of the risk factors. We aimed to develop an eXtreme Gradient Boosting (XGBoost) model to assess CLNM, including positive and negative effects.

METHODS

1,122 patients with PTC admitted at Tianjin First Central Hospital from 2016 to 2020 were retrospectively selected. They were randomly divided into the training and test datasets with an 8:2 ratio. 108 patients with PTC admitted at Binzhou Medical University Hospital in 2020 served as the validation dataset. The XGBoost model was used to assess CLNM. The 10-fold cross-validation was utilized for model selection, and the metric used to evaluate classification performance was the average area under the curve (AUC) of 10-fold cross-validation. Interpretation and transparency of the "black-box" problem were performed. SHapley Additive exPlanations (SHAP) and local interpretable model-agnostic explanation (LIME) were used to ensure the stability and reliability of the model.

RESULTS

The XGBoost model based on ultrasound and dual-energy computed tomography images of the solitary primary lesion had an excellent performance for assessing CLNM, with average AUCs of 0.918, 0.903, and 0.881 in the training, test, and validation datasets, respectively. SHAP plots showed the influence of each parameter on the XGBoost model, including positive (i.e., capsular invasion, diameter, iodine concentration in the venous phase, and calcification) and negative (i.e., sex and age) impacts. For all cases, the capsular invasion prediction weight was the highest; for individual cases, different predictors were assigned different weights. Moreover, the performance of the XGBoost model was better than classical machine-learning models.

CONCLUSIONS

This study developed and validated an XGBoost model for assessing CLNM in patients with PTC. The ability to visually interpret the positive and negative effects made the XGBoost model an effective tool for guiding clinical treatment.

Analysis of the Clinical Value of Delphian Lymph Node Metastasis in Papillary Thyroid Carcinoma

Purpose

Delphian lymph node (DLN) is often involved in metastasis of malignant head and neck tumors. This study evaluates the predictive utility of the DLN and the clinicopathological factors related to DLN metastasis in individuals suffering from papillary thyroid carcinoma (PTC). Patients and Methods. A retrospective analysis was made on 969 PTC patients enrolled from 2017 to 2021. Among these patients, 522 PTC patients are DLN positive and 447 are negative. Comparisons of clinicopathological characteristics between the DLN-positive and DLN-negative patients were made.

Results

The DLN was detected in 53.9% (522/969) cases, and DLN metastasis occurred in 20.3% (106/522) cases. The independent predictors of DLN metastasis (DLNM) include tumor size >1 cm, tumor located in the upper third thyroid or isthmus, central lymph node metastasis (CLNM), and lateral lymph node metastasis (LLNM). DLN-positive individuals exhibited a higher incidence and the number of CLNM, contralateral CLNM (CCLNM), and LLNM as compared to DLN-negative patients. Whether it is cN0 or cN+, the CLNM incidence was increased among DLN-positive patients as compared to that of DLN-negative patients.

Conclusions

Positive DLN indicated an increased rate and number of metastases in the cervical lymph nodes. Intraoperative rapid freezing is recommended to assess the status of the DLN, and careful assessment of cervical lymph nodes is warranted when the DLN is involved to implement an appropriate surgical approach.

Analysis of risk factors for posterior laryngeal recurrent nerve metastasis in micropapillary thyroid carcinoma

Posterior recurrent laryngeal nerve (RLN) lymph node dissection remains controversial in the operation of thyroid cancer, especially in cases of papillary thyroid microcarcinoma (PTMC). The present study aimed to evaluate the risk factors for posterior RLN lymph node metastasis in patients with PTMC. Two hundred and thirty-nine patients pathologically diagnosed with PTMC after surgery between June 2016 and June 2017 were included. Risk factors including age, sex, tumor diameter, multiple tumor focus, membrane invasion and lateral cervical lymph node metastasis condition, were analyzed, and their corresponding OR values were calculated. The results indicated that posterior RLN lymph node metastasis was pathologically identified in 27/239 patients. Membrane invasion (p = 0.024), VIa lymph node metastasis (p < 0.01), and lateral cervical lymph node metastasis (p < 0.01) were considered to be risk factors for posterior RLN lymph node metastasis. It is concluded that membrane invasion, VIa lymph node metastasis, and lateral cervical lymph node metastasis significantly increased the incidence of posterior RLN lymph node metastasis. Complete dissection of the posterior RLN lymph node was essential for patients with these risk factors.

The Application Value of the Central Lymph Node Metastasis Risk Assessment Model in Papillary Thyroid Microcarcinoma of Stage cN0: A Study of 828 Patients

BACKGROUND

The aim of this study is to build a risk assessment system for central lymph node metastasis (CLNM) in papillary thyroid microcarcinoma (PTMC) of stage cN0 and to explore its application value in clinical practice.

METHODS

A total of 500 patients with PTMC who underwent thyroid operation from 2013 to 2015 in Ningbo First Hospital were selected as the model group. Independent risk factors related to CLNM in PTMC were analyzed and determined, and a risk assessment system for CLNM was preliminarily established. Furthermore, the clinicopathological data from 328 PTMC patients with the same conditions as the model group from 2016 to 2017 were further collected as the validation group to verify the diagnostic value of the risk assessment system.

RESULTS

The risk assessment system was based on the score rating (score ≤ 5 was classified as low risk, 6-8 was classified as medium risk, and ≥9 was classified as high-risk). The area under the receiver operating characteristic curve (ROC) was 0.687 (95% CI: 0.635-0.783). According to the risk assessment system, 328 PTMC patients in the validation group were scored. Among the low-risk group, the moderate-risk group, and the high-group, 96.8%, 58.1%, and 43.2% were the CLNM (-) patients, and 3.1%, 41.9%, and 65.8% were CLNM (+) patients, respectively. The area under ROC was 0.837 (95% CI: 0.778-0.869).

CONCLUSIONS

The risk assessment system in this study is of diagnostic value and can provide a theoretical foundation for intraoperative decision-making of prophylactic central neck dissection (pCND).

Risk Factor Analysis for Central Lymph Node Metastasis in Papillary Thyroid Microcarcinoma

Purpose

Although the prognosis of papillary thyroid microcarcinoma (PTMC) is excellent, cervical lymph node metastasis (CLNM) is commonly observed in PTMC. This study aimed to investigate the incidence and risk factors for CLNM in PTMC.

Patients and Methods

Altogether, 687 patients with PTMC who initially underwent unilateral thyroidectomy with unilateral central lymph node dissection or bilateral thyroidectomy with bilateral central lymph node dissection between January 2014 and June 2018 at our hospital were included. The patients were divided into two groups: PTMC with CLNM and PTMC with no CLNM. The clinicopathologic characteristics and ultrasound features were compared between the groups. Univariate and multivariate logistic regression analyses were used to identify the risk factors for CLNM.

Results

CLNM was observed in 121/687 (17.6%) patients with PTMC. PTMC patients aged <55 years exhibited a greater incidence of CLNM (87.6% vs 12.4%) than those aged ≥55 years. PTMC patients with CLNM were more likely to have capsular extension (24.0% vs 15.4%) and extension to the adjacent structures (9.9% vs 4.2%). Patients with microcalcification on ultrasound images were more likely to have CLNM (66.1% vs 47.9%). Multivariate logistic regression analysis revealed that microcalcification (odds ratio [OR]: 2.066, 95% confidence interval [CI]: 1.361-3.135, P<0.001), age <55 years (OR: 2.341, 95% CI: 1.309-4.187, P=0.004), capsular invasion (OR: 1.772, 95% CI: 1.082-2.879, P=0.023), and invasion of the adjacent tissues (OR: 2.872, 95% CI: 1.355-4.187, P=0.004) were significant risk factors for CLNM.

Conclusion

Microcalcification, age <55 years, capsular invasion, and invasion of the adjacent tissues were significant risk factors for CLNM in PTMC.

Nomogram to assess risk of central cervical lymph node metastasis in patients with cN0 papillary thyroid carcinoma

OBJECTIVE

This study developed and validated an individualized prediction risk model for the need for central cervical lymph node dissection in patients with cN0 papillary thyroid carcinoma (PTC) diagnosed by ultrasound.

METHODS

Upon retrospective review, derivation and internal validation cohorts comprised 1585 consecutive patients with PTC treated from January 2017 to December 2019 at Hospital A. The external validation cohort consisted of 406 consecutive patients treated at Hospital B from January 2016 to June 2020. Independent risk factors for central cervical lymph node metastasis (CLNM) were determined through univariable and multivariable logistic regression analysis. An individualized risk prediction model was constructed and illustrated as a nomogram, which was internally and externally validated.

RESULTS

The following risk factors of CLNM were established: the solitary primary thyroid nodule's diameter, shape, calcification, and capsular abutment-to-lesion perimeter ratio. The areas under the receiver operating characteristic curves of the risk prediction model for the internal and external validation cohorts were 0.921 and 0.923, respectively. The calibration curve showed good agreement between the nomogram-estimated probability of CLNM and the actual CLNM rate in the three cohorts. The decision curve analysis confirmed the clinical usefulness of the nomogram.

CONCLUSION

This study developed and validated a model for predicting risk of CLNM in the individual patient with cN0 PTC, which should be an efficient tool for guiding clinical treatment.

Impacto del fenómeno de migración de estadio ganglionar en la supervivencia y la recurrencia de pacientes con cáncer papilar de tiroides sometidos a vaciamiento ganglionar profiláctico

Introducción. Dado que un ensayo clínico aleatorio es irrealizable, el rol del vaciamiento ganglionar profiláctico en pacientes con cáncer papilar de tiroides sin comprobación clínica de compromiso ganglionar metastásico (cN0) es controversial. El vaciamiento ganglionar profiláctico acarrea un proceso de reclasificación de pacientes, al hacer evidente la positividad ganglionar micrometastásica antes ignorada, lo que genera una aparente pero falsa mejoría en los desenlaces de los grupos de estadificación, mientras el pronóstico individual y total de la población no cambia, fenómeno conocido como migración de estadio o fenómeno de Will Rogers. Métodos. Se ejecutaron simulaciones de poblaciones con cáncer papilar de tiroides con compromiso ganglionar metastásico clínicamente evidente (cN+) y cN0, para determinar el impacto del fenómeno de migración de estadio en los pacientes sometidos a vaciamiento ganglionar profiláctico. Resultados. Con la simulación de las poblaciones y sus estadios ganglionares, se observa cómo la migración de estadio ganglionar genera una aparente mejoría en los desenlaces de recurrencia loco regional y supervivencia, sin cambiar los desenlaces de la población total ni individuales. Discusión. El fenómeno de migración de estadio es uno de los sesgos más importantes que limitan el uso de grupos históricos de control en ensayos de tratamiento experimental. De acuerdo con nuestros resultados, este fenómeno podría explicar los beneficios observados con el vaciamiento ganglionar profiláctico en algunos de los estudios agregativos publicados hasta el momento, hallazgos que no han sido documentados para el cáncer papilar de tiroides.

Value of Combining Clinical Factors, Conventional Ultrasound, and Contrast-Enhanced Ultrasound Features in Preoperative Prediction of Central Lymph Node Metastases of Different Sized Papillary Thyroid Carcinomas

Purpose

Early and accurate preoperative diagnosis of central lymph node metastasis (CLNM) is crucial to improve surgical management of patients with clinical lymph node-negative papillary thyroid carcinoma (PTC). Towards improving diagnosis of CLNM, we assessed the value of combining preoperative clinical characteristics, conventional ultrasound, and contrast-enhanced ultrasound (CEUS) in preoperative prediction of CLNM of different sized PTCs.

Patients and Methods

Patients were divided according to tumor size: a PTC group (>10 mm) and a papillary thyroid microcarcinoma (PTMC) group (≤10 mm). We retrospectively analyzed the clinical and ultrasonographic features of 120 PTC patients and 165 PTMC patients. Multivariate logistic regression analysis was used to screen independent risk factors and establish prediction models. Receiver operating characteristic curves were used to determine the best cut-off values for continuous variables and assess the performance of prediction models.

Results

Independent risk predictors of CLNM for the PTC group were extrathyroidal extension in CEUS (OR=7.923), tumor size >14 mm (OR=5.491), and multifocality (OR=3.235). For the PTMC group, the independent risk factors were the distance from the thyroid capsule =0 mm (OR=4.629), male (OR=3.315), tumor size >5 mm (OR=3.304), and microcalcification (OR=2.560). The predictive model of combined method had better performance in predicting CLNM of PTC compared with models based on CEUS and conventional ultrasound alone (area under the curve: 0.832 vs 0.739, P=0.0011; 0.832 vs 0.678, P=0.0012). For PTMC, comparing with CEUS, the combined method and conventional ultrasound performed better than CEUS alone in predicting CLNM (area under the curve: 0.783 vs 0.636, P=0.0016; 0.738 vs 0.636, P=0.0196).

Conclusion

The predictive models of combined method obtained from significant preoperative clinical and ultrasonographic features can potentially improve the preoperative diagnosis and individual treatment of CLNM in patients with PTC and PTMC. CEUS may be helpful in predicting CLNM of PTC, but CEUS would be ineffective in predicting CLNM of PTMC.

Predictive value of the Delphian lymph node in cervical lymph node metastasis of papillary thyroid carcinoma

INTRODUCTION

Delphian lymph node metastasis (DLNM) has proven to be a risk factor for a poor prognosis in head and neck malignancies. This study aimed to reveal the clinical features and evaluate the predictive value of the Delphian lymph node (DLN) in papillary thyroid carcinoma (PTC) to guide the extent of surgery.

METHODS

Tianjin Medical University Cancer Institute and Hospital pathology database was reviewed from 2017 to 2020, and 516 PTC patients with DLN detection were enrolled. Retrospective analysis was performed, while multivariate analysis was performed to identify the risk factors for DLNM.

RESULTS

Among the 516 PTC patients with DLN detection, the DLN metastasis rate was 25.39% (131/516). Tumor size >1 cm, location in the upper 1/3, central lymph node metastasis (CLNM), lateral lymph node metastasis (LLNM) and lymphovascular invasion were independent risk factors for DLNM. Patients with DLNM had a higher incidence of ipsilateral CLNM, contralateral CLNM (CCLNM) and LLNM, and larger numbers and size of metastatic CLNs than those without DLNM. The incidence of CLNM among cN0 patients with DLNM was higher than that among those without DLNM. The incidence of CCLNM among unilateral cN + patients with DLNM was similarly higher than that among patients without DLNM.

CONCLUSIONS

DLNM indicates a high likelihood and large number of cervical lymph nodes metastases in PTC patients. Surgeons are strongly recommended to detect DLN status during operation by means of frozen pathology, so as to evaluate the possibility of cervical nodal metastasis and decide the appropriate extent of surgery.

Risk Factors and a Prediction Model of Lateral Lymph Node Metastasis in CN0 Papillary Thyroid Carcinoma Patients With 1-2 Central Lymph Node Metastases

BACKGROUND

Papillary thyroid cancer (PTC) in clinically lymph node-negative (cN0) patients is prone toward lymph node metastasis. As a risk factor for tumor persistence and local recurrence, lateral lymph node metastasis (LLNM) is related to the number of central lymph node metastases (CLNMs).

METHODS

We performed LLNM risk stratification based on the number of CLNMs for cN0 PTC patients who underwent thyroidectomy and lymph node dissection between January 2013 and December 2018. A retrospective analysis was applied to the 274 collected patients with 1-2 CLNMs. We examined the clinicopathological characteristics of the patients and constructed a LASSO model.

RESULTS

In the 1-2 CLNM group, tumors >10 mm located in the upper region and nodular goiters were independent risk factors for LLNM. Specifically, tumors >20 mm and located in the upper region contributed to metastasis risk at level II. Hashimoto's thyroiditis reduced this risk (p = 0.045, OR = 0.280). Age ≤ 30 years and calcification (microcalcification within thyroid nodules) correlated with LLNM. The LASSO model divided the population into low- (25.74%) and high-risk (57.25%) groups for LLNM, with an AUC of 0.715.

CONCLUSIONS

For patients with 1-2 CLNMs, young age, calcification, nodular goiter, tumor >10 mm, and tumor in the upper region should alert clinicians to considering a higher occult LLNM burden. Close follow-up and therapy adjustment may be warranted for high-risk patients.

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.

The effectiveness of prophylactic ipsilateral central neck dissection in selected patients who underwent total thyroidectomy for clinically node-negative unilateral papillary thyroid carcinoma

Background

Prophylactic central neck dissection (CND) in clinically node-negative (cN0) papillary thyroid carcinoma (PTC) remains controversial. The purpose of this study was to evaluate the benefits of prophylactic ipsilateral CND compared with bilateral CND in total thyroidectomy for cN0 unilateral PTC.

Methods

We retrospectively enrolled 174 patients who underwent total thyroidectomies with prophylactic CND for cN0 unilateral PTC between January 2009 and May 2010. The prophylactic CND patients were divided into group 1, the ipsilateral CND group (n=74), and group 2, the bilateral CND group (n=100). The incidence of central lymph node metastasis (CLNM) and postoperative complications, such as hypoparathyroidism, recurrent laryngeal nerve injury, and recurrence were assessed.

Results

CLNM was found in 22 (29.8%) in group 1 and 69 (69%) in group 2. The incidence of postoperative severe hypocalcemia less than 7.0 was also significantly different (six patients [8.1%] in group 1 and 23 [23%] in group 2; p=0.009). Permanent hypoparathyroidism was significantly more frequent in group 2 (4.1% vs. 19%; p=0.005). However, the incidence of transient hypoparathyroidism, recurrence, and recurrent laryngeal nerve injury was not significantly different.

Conclusion

Prophylactic ipsilateral CND has advantage not only to reduce incidence of some complications but also to have similar recurrence rate compared with bilateral CND. We suggest that prophylactic ipsilateral CND may be safe and effective for selected patients undergoing total thyroidectomy for cN0 unilateral PTC.

Predictive Factors of Central-Compartment Lymph Node Metastasis for Clinical N0 Papillary Thyroid Carcinoma With Strap Muscle Invasion

Background: Papillary thyroid carcinoma (PTC) patients with anterior extrathyroidal extension (ETE) involving the strap muscle have a relatively better prognosis than those with posterior gross ETE involving the recurrent laryngeal nerve. Whether prophylactic central-compartment lymph node dissection (CLND) should be performed in PTCs with only strap muscle invasion (SMI) is still unclear. Methods: A retrospective cohort study was conducted in clinical N0 (cN0) PTC patients with SMI who underwent thyroid surgery from 2009 to 2017. A total of 152 patients were included, and predictive factors of central-compartment lymph node metastasis (CLNM) were determined. Results: Among the 281 PTCs patients with SMI, 152 (51.1%) did not clinically present with lymph node metastasis. Microscopic CLNM was identified in 77 (50.7%) cN0 PTC patients with SMI. According to the univariate and multivariate analyses, male patients and those aged <40 years were more likely to be diagnosed with CLNM than female patients and those aged >40 years (odds ratio [OR] = 6.22 [95% confidence interval (CI), 1.43-27.10], p = 0.02 vs. OR = 9.94 [95% CI, 2.79-35.44], p = 0.00). The CLNM positive rate of male patients aged <40 years was 87.5%, while that for female patients aged ≥55 years was 23.8%. However, risk factors associated with large-volume CLNM were not identified because of the small number of patients. Conclusions: Taken together, nearly half of PTC patients with SMI did not clinically present with lymph node metastasis. Male sex and patients aged <40 years were identified as the predictive factors of CLNM in cN0 PTCs with SMI. Hence, the results of this single-center study raise the possibility that prophylactic CLND may be more often considered for younger male PTC patients with SMI.

Silencing of FoxM1 blocks growth, migration and invasion of papillary thyroid carcinoma cells

The aim of the present study was to investigate the effect of Forkhead box transcription factor M1 (FoxM1)-silencing on the growth, migration and invasion of K1 human papillary thyroid carcinoma (PTC) cells. The effect of FoxM1-small interfering RNA (siRNA) in K1 cells was detected by western blot analysis. FoxM1-siRNA and control siRNA were transfected into K1 cells using Lipofectamine^® 2000 (transfection group, T) and the non-meaning sequence group (NM). K1 cells exposed to PBS solution comprised the blank control group (CON). Cell proliferation ability was detected using an MTT assay. Cell migration and invasion was detected by the single cell scratch test and Transwell invasion assay, respectively. Western blot analysis indicated that FoxM1 siRNA downregulated the expression of FoxM1 protein. Cell proliferation, migration and invasion were significantly lower in the T group compared with the NM and CON groups (P<0.05). These results indicated that silencing of FoxM1 expression could block growth, invasion and migration of K1 cells. This study may provide a novel target gene for targeted therapy of PTC.

Deciphering novel biomarkers of lymph node metastasis of thyroid papillary microcarcinoma using proteomic analysis of ultrasound-guided fine-needle aspiration biopsy samples

Thyroid papillary microcarcinoma is now a common clinical problem. Cervical lymph node metastasis is the main metastasis mode of PTMC. However, before operation, it is still difficult to determine exactly whether PTMC patient is suffering with cervical lymph node metastasis. To resolve this dilemma, for better selection of optimum treatment plans, it is necessary to investigate the overall changes in proteomes of PTMC, and evaluate the potential of biomarkers to predict lymph node metastasis. Tandem mass tags combined with multidimensional liquid chromatography and mass spectrometry analyses were used aiming to screen the proteomic profiles of fine-needle aspiration biopsy samples. Quantitative proteomic analysis, significant pathway and functional categories were investigated. In total, 3391 proteins of the 3793 protein groups identified were quantified. Bioinformatics analysis indicated that differentially expressed proteins were involved in multiple biological functions, metastasis-related pathways. Moreover, IFN-stimulated gene 15 proteins were found to be well distinguished between patients with lymph node metastatic and patients with nonmetastatic PTMC. Knocking down ISG15 with shRNA inhibited the xenografted tumor growth. This study provided a reference proteome map for lymph node metastatic PTMC. ISG15 probably is a prognosis marker of thyroid papillary microcarcinoma patients with lymph node metastasis. SIGNIFICANCE: Nowadays, thyroid cancer has become a widespread epidemic. The rate of thyroid cancer incidence has been faster than any other cancers, reported by the American Cancer Society. Papillary thyroid microcarcinoma (PTMC) is a subset of PTC defined as PTC measuring≤1 cm in size, which comprises nearly one-half of all the cases of PTCs. Actually, the rapidly increasing global incidence of PTC is mainly attributed to the corresponding increase in the diagnosis of PTMC. Scholars have figuratively compared the increase of PTMC to the "tsunami". The treatment scheme for PTMC is still not uniform, and the controversy is mainly focused on the necessity of surgery treatment. PTMCs often have an indolent course in the absence of evidence of metastatic cervical lymph nodes, distant metastases and extrathyroidal extension. Therefore, it is important for us to reliably differentiate the small number of PTMC patients developing significant metastases progression from the larger population of patients that harbor indolent PTMCs. The present study aimed to investigate the overall changes in proteomes of PTMC, and evaluate the potential of biomarkers to predict lymph node metastasis. Tandem mass tags (TMT) combined with multidimensional liquid chromatography and mass spectrometry analyses were used aiming to screen the proteomic profiles of fine-needle aspiration biopsy (FNAB) samples. Quantitative proteomic analysis, significant pathway and functional categories were investigated. Our results showed that some differential expression proteins were likely to be important resources for finding new diagnostic biomarkers.

Risk Factors for Predicting Lymph Nodes Posterior to Right Recurrent Laryngeal Nerve (LN-prRLN) Metastasis in Thyroid Papillary Carcinoma: A Meta-Analysis

OBJECTIVE

To evaluate the risk factors for predicting lymph nodes (LN) posterior to right recurrent laryngeal nerve metastasis in thyroid papillary carcinoma.

METHODS

PubMed, PMC, EMBASE, and the Cochrane Library were systematically searched for articles published spanning 30/06/2009-30/8/2018 using multiple search terms. Thirteen articles involving 10,014 patients were reviewed in our meta-analysis. Stata 15.1 software was used for the meta-analysis.

RESULTS

The rate of LN posterior to right recurrent laryngeal nerve (LN-prRLN) metastasis was 8.65%. Univariate analysis showed that age (P = 0.001), gender (P < 0.001), tumour size (P < 0.001), lateral LN metastasis (P < 0.001), extrathyroidal invasion (P < 0.001), multifocality (P = 0.005), capsule invasion (P < 0.001), tumour location (P = 0.076), lymph nodes anterior to right recurrent laryngeal nerve (LN-arRLN) metastasis (P < 0.001), and central LN metastasis (P < 0.001) were significantly associated with the increased incidence of LN-prRLN metastasis in thyroid papillary carcinoma.

CONCLUSION

PTC patients aged <45, male, and with tumours > 1 cm, lateral LN metastasis, extrathyroidal invasion, multifocality, capsule invasion, LN-arRLN metastasis, or central LN metastasis were significantly correlated with lymph nodes posterior to right recurrent laryngeal nerve metastasis, indicating LN-prRLN dissection.

Establishment and validation of the scoring system for preoperative prediction of central lymph node metastasis in papillary thyroid carcinoma

Early preoperative diagnosis of central lymph node metastasis (CNM) is crucial to improve survival rates among patients with papillary thyroid carcinoma (PTC). Here, we analyzed clinical data from 2862 PTC patients and developed a scoring system using multivariable logistic regression and testified by the validation group. The predictive diagnostic effectiveness of the scoring system was evaluated based on consistency, discrimination ability, and accuracy. The scoring system considered seven variables: gender, age, tumor size, microcalcification, resistance index >0.7, multiple nodular lesions, and extrathyroid extension. The area under the receiver operating characteristic curve (AUC) was 0.742, indicating a good discrimination. Using 5 points as a diagnostic threshold, the validation results for validation group had an AUC of 0.758, indicating good discrimination and consistency in the scoring system. The sensitivity of this predictive model for preoperative diagnosis of CNM was 4 times higher than a direct ultrasound diagnosis. These data indicate that the CNM prediction model would improve preoperative diagnostic sensitivity for CNM in patients with papillary thyroid carcinoma.

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.