Metastatic Lymph Node Ratio of Central Neck Compartment Has Predictive Values for Locoregional Recurrence in Papillary Thyroid Microcarcinoma

The relationship between lateral cervical lymph node positivity rate and recurrence after comprehensive treatment in differentiated thyroid carcinoma: a single-center retrospective cohort study from China

Introduction

The lateral cervical lymph node positivity rate has been hypothesized to correlate with the recurrence risk in differentiated thyroid carcinoma (DTC) patients. However, the extent of this association within the Chinese population remains understudied. This study seeks to elucidate the potential causal link between the lymph node positivity rate and DTC recurrence.

Methods

We conducted a retrospective cohort study, examining clinical records of 4,731 DTC patients who received surgical treatment at the First Medical Center of the General Hospital of the Chinese People's Liberation Army from January 2015 to May 2020. The study variables encompassed demographic and clinical characteristics, including sex, age, tumor size, location, laterality, capsular invasion, lymph node metastasis counts, lymph node positivity rates, histological subtypes, Hashimoto's thyroiditis co-occurrence, and the timing of iodine-131 therapy post-surgery. After applying strict inclusion criteria, 1,074 patients were selected for analysis. Recurrence was defined as structural incomplete response (SIR), confirmed by imaging or histological means. The lymph node positivity rate was calculated as the proportion of positive lymph nodes to the total lymph node count.

Results

Multivariate analysis revealed a nonlinear association between the lateral cervical lymph node positivity rate and post-treatment recurrence, with a significant threshold at 0.5. The recurrence risk was substantially elevated with a positivity rate below this threshold (HR: 27.48, 95% CI: 7.21-104.70, P<0.0001), while no significant association was observed above it (HR: 0.17, 95% CI: 0.02-1.57, P=0.119). Subgroup analysis within the high-risk cohort did not yield a significant association between the positivity rate and recurrence risk (HR=0.43, 95% CI: 0.10-1.79, P=0.246).

Discussion

In conclusion, this study identifies a nonlinear relationship between the lateral cervical lymph node positivity rate and the risk of DTC recurrence post-treatment. A positivity rate of less than 0.5 is positively associated with recurrence, while this association diminishes in significance among high-risk patients. This differs from the results previously reported. Further studies are needed to determine the potential mechanisms of the associations observed in observational studies.

FAM20C Promotes Papillary Thyroid Cancer Proliferation and Metastasis via Epithelial-Mesenchymal Transition

Thyroid cancer (TC) is the prevailing malignancy that impacts the endocrine system, accounting for 1% of all recently diagnosed malignancies in humans. The incidence of TC has been continuously increasing, which can be attributed to advancements in clinical diagnostic technology. However, the mechanisms behind the development of TC are still not well understood. TC is classified into four pathological forms: medullary thyroid cancer, papillary thyroid cancer (PTC), follicular thyroid cancer, and poorly differentiated TC. PTC constitutes more than 80% of all TC cases globally. Current research indicates that complex genetic and cellular processes could be responsible for the growth and spread of TC. Next-generation sequencing (RNA-seq) of 79 PTC samples and their corresponding normal thyroid tissues was performed to investigate the molecular mechanisms of PTC. An analysis of RNA-seq data from a local cohort from The Cancer Genome Atlas (TCGA) revealed that, compared with normal tissues, PTC tissues presented elevated FAM20C expression levels. In vitro, the function of FAM20C was validated with small interfering RNA (siRNA). Gene set enrichment analysis (GSEA) revealed the pathways influenced by FAM20C. A western blot experiment was used to investigate protein expression levels associated with epithelial‒mesenchymal transition (EMT). In conclusion, by regulating EMT, FAM20C facilitates PTC cell proliferation and metastasis.

The expression of CCL17 and potential prognostic value on tumor immunity in thyroid carcinoma based on bioinformatics analysis

Although CCL17 has been reported to exert a vital role in many cancers, the related studies in the thyroid carcinoma have never reported. As a chemokine, CCL17 plays a positive role by promoting the infiltration of immune cells into the tumor microenviroment (TME) to influence tumor invasion and metastasis. Therefore, this study is aimed to investigate the association of CCL17 level with potential prognostic value on tumor immunity in the thyroid carcinoma (THCA) based on the bioinformatics analysis. GEPIA database was applied to analyze CCL17 mRNA expression in THCA data from TCGA database. Through the collection of the data, totally 500 tumor and 57 normal tissue samples were taken for the study. According to survival status and survival time in 500 tumor samples and CCL17 expression from RNA-seq data, all patients were categorized as high- expression (n = 64) and low-expression (n = 436) groups using X-tile program. Next, the association of CCL17 with survival in the thyroid carcinoma patients was examined by using the Kaplan-Meier plotter database. Then, weighted gene co-expression network (WGCNA) was employed to analyze the 1424 DEGs to classify 9 modules. Besides, STRING database was used to obtain the hub genes. GO and KEGG database were employed to explore blue module genes enrichment situations. In addition, TISIDB was used to analyze the relationship of CCL17 expression with tumor-infiltrating lymphocytes proportion, immunostimulators, and major histocompatibility complexes in THCA. The correlation of CCL17 with 22 TIIC subtypes was evaluated by ESTIMATE and CIBERSORT databases. The association of CCL17 level with gene marker of immune cells in THCA was analyzed by GEPIA and TIMER databases. Finally, immunohistochemistry was applied to validate CCL17 expression in 21 tumor and para-carcinoma tissue samples. CCL17 expression in tumors was significantly up-regulated relative to non-carcinoma samples. Patients from CCL17 high-expression group had significantly decreased overall survival compared with low-expression group, which has a significantly importantly potential prognostic value. Moreover, CCL17 and clinical characteristics were analyzed, suggesting that CCL17 expression significantly increased among patients of advanced stage, with advanced T classification, advanced N classification, and higher CCR4 expression. Based on WGCNA, expression of 1424 DEGs in blue module with 258 genes was negatively related to dismal survival and clinical lymph node metastasis in THCA patients. Moreover, CCR4 and CCL17 genes were identified as hub genes within blue module. CCL17 high-expression had greater ImmuneScore, StromalScore and ESTIMATEScore, while lower TumorPurity compared to the CCL17 low-expression. Then, GO and KEGG database were used to analyze blue module genes enrichment situations. The result showed that genes in blue module were associated with cytokine-cytokine receptor interaction, chemokine, and PI3K - Akt pathways. The results of tumor-infiltrating lymphocytes proportion, immunostimulators, and major histocompatibility complexes were significantly positive in CCL17 high-expression. Our findings showed that B cells naïve, T cells CD4 memory resting, T cells CD8, T cells regulatory (Tregs), and dendritic cells resting were the main immune components of THCA tumor microenvironment (TME). CCL17 high-expression in TC was significantly positively related to expression of immune cell gene markers. The result of immunohistochemistry demonstrated that CCL17 expression in tumor tissues significantly increased compared with para-carcinoma tissues. CCL17 high-expression was significantly positively associated with age and advanced N classification, suggesting that CCL17 could accelerate tumor progression by promoting the lymph node metastasis. CCL17 high-expression in THCA tumor microenvironment (TME) accelerates local infiltration of immune cells and enhances anticancer immunity, resulting in worse survival of patients and exerting potential prognostic value on tumor immunity in THCA.

Lymph node ratio in lateral neck is an independent risk factor for recurrence-free survival in papillary thyroid cancer patients with positive lymph nodes

BACKGROUND

The purpose of this study was to explore the impact of the lymph node ratio on prognosis in papillary thyroid cancer patients with lymph node metastasis.

METHODS

Data from papillary thyroid cancer patients with positive nodes who were initially treated at our institution during 2015-2016 were analysed. Univariate and multivariate Cox proportional hazard models were adopted to predict prognostic factors. A receiver operating characteristic (ROC) curve was used to find the best cut-off value of the lymph node ratio (LNR). Kaplan-Meier curves were used to show the relationship between the LNR in the lateral neck and recurrence-free survival.

RESULTS

The median follow-up time was 64.6 months, and recurrence occurred in 16 of 662 patients (2.27%). Univariate analysis showed that male sex, primary tumour size (&gt;17 mm), visible extrathyroidal extension, LNR in the central neck (&gt;0.5), LNR in the lateral neck (&gt;0.10), and visible extranodal extension were significantly correlated with recurrence-free survival (RFS) (p &lt; 0.05). Multivariate analysis using the Cox proportional hazards model showed that the LNR in the lateral neck was an independent risk factor for RFS (p = 0.039; HR 14.76).

CONCLUSION

The LNR in the lateral neck was an independent risk factor for recurrence-free survival. For patients with a high lymph node ratio in the lateral neck, more frequent follow-up might be needed.

Bibliometric insights in advances of papillary thyroid microcarcinoma: Research situation, hot points, and global trends

BACKGROUND

Thyroid cancer has been on the rise over the last decade. Papillary thyroid microcarcinoma (PTMC) accounts for more than half of all thyroid cancers. Micropapillary carcinoma of the thyroid is a common but non-fatal form of thyroid cancer. To better comprehend, nearly two decades of scientific outputs were analyzed and summarized using bibliometric methods in this study.

METHODS

Approximately 1098 publications from 2000 and 2021 were included in WoS database through systematic retrieval. The general information was characterized, and developmental skeleton and research frontiers were explored. CiteSpace, VOSviewer, and R, Tableau were used to evaluate and visualize the results.

RESULTS

A total of 1098 publications from across 75 countries were identified. The annual number of publications showed an increasing trend in the past 21 years. China, Korea, the United States of America (USA), Italy, and Japan made remarkable contributions to the research of PTMC. Thyroid was the most productive journal. Miyauchi Akira published maximum articles. The utmost productive institution was the University of Ulsan. Risk stratification, active surveillance, and thermal ablation garnered the attention of researchers leading to novel approaches in the clinical diagnosis and treatment of micropapillary thyroid carcinoma.

CONCLUSIONS

This bibliometric study provides a comprehensive analysis of global productivity, collaboration, and research hotspots within PTMC field, which will aid in directing research toward PTMC in the coming years.

Factors Affecting Central Node Metastasis and Metastatic Lymph Node Ratio in Papillary Thyroid Cancer

OBJECTIVE

Despite the growing evidence that metastatic lymph node ratio (MLNR) is a valuable predictor for the prognosis of papillary thyroid carcinoma, it has not yet been fully determined which factors give the ratio predictive value independent of the number of metastatic lymph nodes (MLNs).

STUDY DESIGN

Retrospective cohort study.

SETTING

A comprehensive cancer center.

METHODS

Recurrence and clinicopathologic factors were analyzed in 2409 patients with papillary thyroid carcinoma who underwent total thyroidectomy and central node dissection.

RESULTS

Cutoff values of MLNs ≥2 and MLNR ≥28.2% increased the recurrence risk (hazard ratio [95% CI], 9.97 [4.73-21.0] and 11.4 [5.53-23.3], respectively). Younger age, male sex, multifocality, tumor size, lymphatic and vascular invasion, and gross extrathyroidal extension positively correlated with MLN and MLNR (all P < .05). Meanwhile, lymphocytic thyroiditis negatively correlated with MLNR in female patients (P < .001), by increasing total lymph node yields as compared with papillary thyroid carcinoma without lymphocytic thyroiditis. In multivariate analysis, younger age, tumor size, and lymphatic invasion remained significant in male and female patients for MLN and MLNR; lymphocytic thyroiditis was also significantly correlated with MLNR in female patients.

CONCLUSION

Our study demonstrates that MLN and MLNR are independently observed prognostic markers for tumor recurrence. However, lymphocytic thyroiditis in female patients seems to have lower MLNR by increasing total lymph node yields. In light of their association, a different cutoff for MLNR needs to be applied according to the presence or absence of underlying lymphocytic thyroiditis in the use of MLNR for predicting the recurrence.

LEVEL OF EVIDENCE

4.

Risk factors of suprasternal lymph node metastasis in papillary thyroid carcinoma with clinical lateral cervical lymph node metastasis

Background

Metastatic lymph nodes are occasionally found in suprasternal lymph nodes in patients with papillary thyroid cancer (PTC). However, limited studies have examined these lymph nodes thus far. Therefore, we investigated the frequency and risk factors of suprasternal lymph node metastasis in patients with PTC and lateral cervical lymph node metastasis.

Methods

A total of 85 patients with cN1b PTC underwent total thyroidectomy, central neck dissection, and ipsilateral selective neck dissection including suprasternal lymph node dissection. We analyzed the correlation between suprasternal lymph node metastasis and sex, age, tumor characteristics, and cervical lymph node metastasis status.

Results

Eleven (12.9%) patients had pathological suprasternal lymph node metastasis. Suprasternal lymph node metastasis was associated with tumors located in the inferior pole of the thyroid gland and level IV lymph node metastasis (P=0.005 and 0.014, respectively). Receiver operating characteristic curve analysis indicated that two or more level IV metastatic lymph nodes had the best predictive value for suprasternal lymph node metastasis (P<0.001).

Conclusions

In patients with cN1b PTC, especially those with tumors in the inferior pole of the thyroid gland or level IV lymph node metastasis, greater attention should be paid to the suprasternal lymph nodes and suprasternal lymph node dissection should be routinely included as part of selective neck dissection.

EGR1/GADD45α Activation by ROS of Non-Thermal Plasma Mediates Cell Death in Thyroid Carcinoma

Simple Summary

Recent studies have identified new anti-cancer mechanisms of nonthermal plasma (NTP) in several cancers. However, the molecular mechanisms underlying its therapeutic effect on thyroid cancer have not been elucidated. The objective of this study was to understand the anticancer effects of NTP-activated medium (NTPAM) on thyroid cancer cells and elucidate the signaling mechanisms responsible for NTPAM-induced thyroid cancer cell death.

Abstract

(1) Background: Nonthermal plasma (NTP) induces cell death in various types of cancer cells, providing a promising alternative treatment strategy. Although recent studies have identified new mechanisms of NTP in several cancers, the molecular mechanisms underlying its therapeutic effect on thyroid cancer (THCA) have not been elucidated. (2) Methods: To investigate the mechanism of NTP-induced cell death, THCA cell lines were treated with NTP-activated medium -(NTPAM), and gene expression profiles were evaluated using RNA sequencing. (3) Results: NTPAM upregulated the gene expression of early growth response 1 (EGR1). NTPAM-induced THCA cell death was enhanced by EGR1 overexpression, whereas EGR1 small interfering RNA had the opposite effect. NTPAM-derived reactive oxygen species (ROS) affected EGR1 expression and apoptotic cell death in THCA. NTPAM also induced the gene expression of growth arrest and regulation of DNA damage-inducible 45α (GADD45A) gene, and EGR1 regulated GADD45A through direct binding to its promoter. In xenograft in vivo tumor models, NTPAM inhibited tumor progression of THCA by increasing EGR1 levels. (4) Conclusions: Our findings suggest that NTPAM induces apoptotic cell death in THCA through a novel mechanism by which NTPAM-induced ROS activates EGR1/GADD45α signaling. Furthermore, our data provide evidence that the regulation of the EGR1/GADD45α axis can be a novel strategy for the treatment of THCA.

Brn3a/Pou4f1 Functions as a Tumor Suppressor by Targeting c-MET/STAT3 Signaling in Thyroid Cancer

BACKGROUND

Brn3a/Pou4f1 is a class IV POU domain-containing transcription factor and has been found to be expressed in a variety of cancers. However, the mechanism and action of Brn3a in thyroid cancer has not been investigated.

PURPOSE

To investigate the role of Brn3a in thyroid cancer progression and its clinical implication.

METHODS

We examined Brn3a expression status in patients with thyroid cancer and analyzed relationships between Brn3a expression and clinicopathological findings using The Cancer Genome Atlas (TCGA) database. For functional in vitro analysis, proliferation, migration, invasion assay, and Western blotting were performed after overexpression or suppression of Brn3a.

RESULTS

The promoter hypermethylation of Brn3a was found in patients with aggressive thyroid cancer and Brn3a was downregulated in tissues of patients with thyroid cancer. In TCGA database, the low-Brn3a-expression group revealed a more aggressive phenotype, including T stage and extrathyroid extension when compared with the high-Brn3a-expression group. Overexpression of Brn3a suppressed cell migration and invasion via regulation of epithelial-mesenchymal transition (EMT)-associated proteins in thyroid cancer cell lines. Brn3a overexpression also downregulated signal transducer and activator of transcription 3 (STAT3) signaling through suppression of tyrosine-protein kinase Met (c-MET). In contrast, knockdown of Brn3a by small interfering ribonucleic acid (siRNA) significantly increased cell migration and invasion through upregulation of c-MET/STAT3. These results imply that Brn3a suppresses tumor metastasis via c-MET/STAT3 inhibition and EMT suppression in thyroid cancer.

CONCLUSIONS

Our findings show that Brn3a is a potential tumor suppressor that leads to reduced cancer cell migration and invasion in thyroid cancer. Elucidation of the Brn3a-regulated cancer pathways may therefore provide novel therapeutic strategies to control thyroid cancer metastasis.

Lymph Node Metastasis and Extrathyroidal Extension in Papillary Thyroid Microcarcinoma in Cyprus: Suspicious Subcentimeter Nodules Should Undergo FNA When Multifocality is Suspected

OBJECTIVE

To determine the prevalence of lymph node (LN) metastasis and extrathyroidal extension (ETE) in patients with papillary thyroid microcarcinoma (PTMC) in Cyprus and to evaluate the role of preoperative ultrasound (U/S) examination.

METHODS

A retrospective study of 102 patients who underwent thyroidectomy for PTMC in a 2-year period. Preoperatively, all patients had a thyroid and neck U/S examination with LN mapping. Tumor size according to the largest diameter, number of foci, LN metastasis, and ETE data was collected from the histopathological report and was compared to the preoperative U/S reports.

RESULTS

LN metastasis was present in 23.5% of patients. 15.7% had central, 3.9% had lateral, and 3.9% had both central and lateral LN metastasis. ETE was present in 27.5% of patients. 21.6% had multifocal disease, and in this group, 40.9% had LN metastasis and 36.4% had ETE. Multifocality (p = 0.03), size of tumor (p = 0.05), and ETE (p ≤ 0.001) were significantly associated with LN metastasis. The prevalence of LN metastasis in multifocal PTMC ≤5 mm was the same with multifocal PTMC >5 mm. The preoperative U/S sensitivity for the suspicious lateral neck and central LN was 100%, and the specificity was 100%. The preoperative U/S sensitivity for nodules suspicious for ETE was 53.6%, and the specificity was 100%.

CONCLUSION

The presence of LN metastasis and ETE in our PTMC patients in Cyprus is frequent. Neck U/S mapping is a highly reliable and accurate tool in identifying metastatic nodes. LN metastasis is associated with ETE and multifocality. Suspicious subcentimeter nodules should undergo FNA irrespective of size when multifocality is suspected.

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.

Randomized trial of prophylactic ipsilateral central lymph node dissection in patients with clinically node negative papillary thyroid microcarcinoma

PURPOSE

This study aimed to evaluate the role of prophylactic ipsilateral central neck dissection (pCND) in patients with clinically node-negative (cN0) papillary thyroid microcarcinoma (PTMC).

METHODS

In this randomized control trial, a total of 164 consecutive patients were enrolled. By double-blinded randomization protocol, patients were allocated into hemithyroidectomy with pCND (n = 82) or without pCND (n = 82). With intention-to-treat analysis, post-surgical pathological and clinical course, surgery-related complications, causes and clinical course of protocol-violated cases and 5-year recurrence-free survival were compared.

RESULTS

Operation time, hospital stay, and post-surgical complication were not significantly different between the two groups. In the pCND (+) group, occult lymph node metastasis rate was 50.0%, and lymph node ratio (metastatic/harvested lymph nodes) was 45.2%. Ten patients in the pCND (+) group had converted to undergo onsite or staged completion total thyroidectomy due to the presence of metastatic central lymph nodes and/or positive resection margin. Until last follow-up (mean 73.4 months), one regional recurrence developed in the pCND (-) group, and three regional recurrences occurred in the pCND (+) group. Five-year recurrence-free survival was similar between the two groups.

CONCLUSION

Although ipsilateral pCND could clear occult lymph node metastasis in the central compartment, it failed to provide any oncological benefit for cN0 PTMC patients.

Radioactive Iodine Ablation Decrease Recurrences in Papillary Thyroid Microcarcinoma with Lateral Lymph Node Metastasis in Chinese Patients

Introduction

We aimed to carry out a retrospective study from a single institution to determine whether radioactive iodine (RAI) ablation decreases the risk of recurrence of papillary thyroid microcarcinoma (PTMC) patients that presented with lateral lymph node metastasis (LLNM).

Methods

We retrospectively analyzed a total of 6361 consecutive PTMC patients who initially underwent surgery for the treatment of thyroid carcinoma at the First Hospital of Jilin University, between January 2005 and February 2015. Altogether, 137 patients with PTMC with LLNM have been enrolled in our study.

Results

The disease-free survival period was significantly shorter for the RAI (−) patients than for the RAI (+) patients (p = 0.0074 by the log-rank test). The disease-free survival rates at 5 and 10 years were 93.02 and 87.5%, respectively, in the RAI (−) group and 100 and 96.81%, respectively, in the RAI (+) group. CLNM ratio and LLNM ratio were factors identified for multivariate analysis by Cox’s proportional hazards method yielding risk ratios of 7.281 [CI 1.804–17.554; p = 0.010] and 1.157 [CI 1.0125–9.381; p = 0.048] in the RAI (−) group.

Conclusion

Taken together, RAI may be beneficial for PTMC with LLNM, especially when CLNM ratio or LLNM ratio was greater than 0.5.

LAMB3 mediates metastatic tumor behavior in papillary thyroid cancer by regulating c-MET/Akt signals

Laminin subunit beta-3 (LAMB3) encodes one of the three subunits of LM-332, a protein of the extracellular matrix secreted by cultured human keratinocytes. While LAMB3 is involved in the invasive and metastatic abilities of several tumor types, including those found in the colon, pancreas, lung, cervix, stomach, and prostate, its mechanism of action in thyroid cancer has not been investigated previously. Our results show that LAMB3 is up-regulated in papillary thyroid cancer, and that its suppression reduces cell migration/invasion via down-regulation of epithelial‒mesenchymal transition-associated proteins (N-cadherin, vimentin, slug) and inhibition of matrix metalloproteinase 9. LAMB3 suppression also significantly decreases Akt phosphorylation and inhibits the transcription of c-MET, reducing its activation. These results suggest that LAMB3 leads to tumor invasion via Akt activation induced by the HGF/c-MET axis in papillary thyroid cancer cells. Our findings reveal a novel mechanism of action for LAMB3 in papillary thyroid cancer cells.

Nodal Factors Predictive of Recurrence After Thyroidectomy and Neck Dissection for Papillary Thyroid Carcinoma

BACKGROUND

Lymph node (LN) yield and ratio are considered important predictors of post-treatment outcomes for several human cancers. This study examined the association between nodal factors, including the LN yield and ratio, with recurrence after thyroidectomy plus central compartment neck dissection (ND) for papillary thyroid carcinoma (PTC).

MATERIALS AND METHODS

This retrospective study involved 2384 consecutive patients who underwent a thyroidectomy plus central compartment ND combined with (n = 440) or without lateral compartment ND at the authors' tertiary referral center between 2006 and 2012. The number of harvested LNs, as well as other tumor and nodal findings, were carefully reviewed. Univariable and multivariable Cox proportional hazards regression models were conducted to predict recurrence and its association with clinicopathologic variables.

RESULTS

All nodal factors, including the positive number of LNs, ratio, and extranodal extension, were significantly associated with nodal and any-site recurrence after thyroidectomy, as well as the tumor size and multifocality (p < 0.01). The multivariable analysis showed that tumor size, multifocality, LN ratio, and extranodal extension were independent factors predictive of post-treatment recurrence (p < 0.05). The LN yield was higher in patients with nodal recurrence but did not significantly affect the nodal recurrence. Patients with a LN ratio >0.3 exhibited a 1.7-fold higher risk of post-treatment nodal recurrence than their counterparts (p < 0.01).

CONCLUSIONS

LN ratio is an independent determinant predictive of nodal and any-site recurrence following thyroidectomy for PTC.

Latero-cervical lymph node metastases (N1b) represent an additional risk factor for papillary thyroid cancer outcome

PURPOSE

Papillary thyroid carcinoma (PTC), the most common thyroid cancer histotype, has a good prognosis even when spread to the neck lymph node (LN). The prognostic role of LN metastases' location is still controversial. The aim of the present study was to evaluate the clinical relevance of the number and location of LN metastases at presentation in PTCs.

METHODS

This retrospective study included a consecutive series of 1653 PTC patients followed for a mean period of 5.9 years in a referral thyroid cancer clinic. All patients have undergone thyroidectomy with the dissection of at least six LNs. According to the LN status, patients were subdivided into 569 N0 (34.4%), 644 N1a (39.0%, central compartment) and 440 N1b (26.6%, latero-cervical compartment).

RESULTS

Age at diagnosis was significantly lower in N1b (39.8, IQR 30.7-51.6) and N1a (40.1, IQR 31.3-50.1) than in N0 (44.7, IQR 36.6-55.0 yrs). The male gender was more prevalent in N1b than in N1a and N0 (F/M = 1.9/1, 4.0/1 and 5.5/1, respectively). Persistent/recurrent disease at last control was significantly more frequent in N1b (29.8%) than in N1a (14.3%), and in N1a than in N0 (4.2%) (p < 0.01 for all). Also, distant metastases were significantly (p < 0.001) more frequent in N1b (14.1%) than in N1a (4.3%) and N0 (1.6%). LN metastases' number (>5) was a significant risk factor for persistent/recurrent disease only for N1a patients.

CONCLUSIONS

These data indicate that persistent/recurrent disease and distant metastases are significantly more frequent in patients with latero-cervical LN (N1b) metastases and that the LN location should be used for a better postsurgical risk stratification.

Number of Metastatic Lymph Nodes and Ratio of Metastatic Lymph Nodes to Total Number of Retrieved Lymph Nodes Are Risk Factors for Recurrence in Patients With Clinically Node Negative Papillary Thyroid Carcinoma

OBJECTIVES

The number of metastatic lymph nodes (LNs) and the ratio between the number of metastatic LNs and the total number of retrieved LNs (the LN ratio [LNR]) have been proposed as risk factors for recurrence of papillary thyroid carcinoma (PTC). However, the significance of the number of LNs and the LNR in patients with clinically node negative PTC has not been clearly determined. The purpose of this study is to evaluate their significance.

METHODS

We retrospectively analyzed 382 patients with PTC who had undergone total thyroidectomy with prophylactic central neck dissection (CND) between January 2000 and December 2010. We excluded patients with lobectomy, concurrent lateral compartment neck dissection, a follow-up period less than at least 2 years, number of harvested central LNs less than or equal to one, clinically positive LN, distant metastasis, recurrent cancer or other types of malignancy. The correlations between recurrence and various clinicopathologic characteristics including tumor size, extrathyroidal extension (ETE), stage, number of metastatic central LNs, and the LNR were investigated.

RESULTS

After a mean follow-up period of 82.2±26.4 months, recurrence occurred in 14 patients (3.7%). Tumor size ≥20 mm, maximal ETE, presence of central LN metastasis, number of metastatic LNs ≥2, and LNR ≥0.31 correlated with recurrence in the univariate analysis. However, tumor size ≥20 mm, maximal ETE, number of metastatic LNs ≥2, and LNR ≥0.31 were significantly associated with recurrence in the multivariate analysis (hazard ratio=6.61, 7.17, 3.43, and 11.23, respectively).

CONCLUSION

The LNR and the number of metastatic LNs are independent prognostic risk factors for recurrence in patients with clinically node negative PTC, and these factors can be used to guide postoperative adjuvant therapy and follow-up strategy after prophylactic CND.

Influence of tumor extent on central lymph node metastasis in solitary papillary thyroid microcarcinomas: a retrospective study of 1092 patients

Background

The morbidity of papillary thyroid microcarcinomas is increasing worldwide. Surgery is the main treatment for papillary thyroid microcarcinomas, and the choice of surgical method partly depends on the T stage of the tumor. However, according to the American Joint Commission on Cancer staging system (7th edition), the T stage of papillary thyroid microcarcinomas with different tumor extent is unclear. We aimed to study the effect of tumor extent and other factors on central lymph node metastasis to explore the relationship between tumor extent and T stage and to identify the risk factors predicting central lymph node metastasis in papillary thyroid microcarcinomas.

Methods

We included 1092 patients diagnosed with solitary papillary thyroid microcarcinomas between July 2011 and April 2016. The tumor extent and other central lymph node metastasis risk factors were retrospectively analyzed.

Results

Univariate analysis revealed that capsule invasion and extracapsular extension (P = 0.013, <0.001; respectively) were significantly correlated with central lymph node metastasis. On multivariate analysis, extracapsular extension was independent central lymph node metastasis predictors (odds ratio 3.092, 95% CI 1.744–5.484), while capsule invasion was not (odds ratio 1.212, 95% CI 0.890–1.651). In addition, multivariate analysis revealed that male sex, tumor size >5 mm, and age <45 years were independent central lymph node metastasis predictors (odds ratio 2.072, 2.356, 2.302; 95% CI 1.483–2.894, 1.792–3.099, 1.748–3.031; respectively).

Conclusions

This study supported that capsule invasion and tumor limited to the thyroid in papillary thyroid microcarcinomas were suitable for the lower T1, that is, capsule invasion in papillary thyroid microcarcinomas might not belong to the minimal extrathyroid extension included in T3 of TNM staging. In addition, patients with risk factors of extrathyroid extension, male sex, age <45 years, or tumor size >5 mm in papillary thyroid microcarcinomas should consider a more aggressive surgical treatment.

Extranodal extension of lymph node metastasis as a prognostic indicator of recurrence and survival in papillary thyroid carcinoma

BACKGROUND AND OBJECTIVES

Stratification of extranodal extension (ENE) extent has the potential to improve the accuracy of risk estimations in papillary thyroid carcinoma (PTC). This study examined the prognostic importance of nodal factors, including ENE, in PTC patients.

METHODS

This study enrolled 2071 consecutive patients with treatment-naïve PTC who underwent thyroidectomy between 2006 and 2010. Microscopic/macroscopic ENE was determined by pathological and operative findings. Univariate and multivariate analyses were used to identify the relationship of factors with recurrence and survival in all study patients and in the node-positive subset.

RESULTS

Of 2071 patients, 975 (47.1%) had positive lymph nodes, and 271 (13.1%) and 70 (3.4%) had microscopic and macroscopic ENE, respectively. During a median follow-up of 96 months, 114 (5.5%) patients had post-treatment recurrence. Multivariate analyses showed that, in all patients, the number of positive nodes, lymph node ratio, ENE status, and ATA risk group were independent variables affecting recurrence (P < 0.05). T4 and macroscopic ENE were independent variables associated with shorter overall survival (P < 0.05). Macroscopic ENE was significantly associated with macroscopic extrathyroidal extension.

CONCLUSION

Macroscopic ENE has a significant adverse impact on recurrence and survival after treatment for PTC. ENE is considered a high risk factor for recurrence.

Differences in the Recurrence and Survival of Patients with Symptomatic and Asymptomatic Papillary Thyroid Carcinoma: An Observational Study of 11,265 Person-Years of Follow-Up

BACKGROUND

Papillary thyroid carcinoma (PTC) generally has an indolent course and favorable prognosis. However, an optimal treatment strategy for asymptomatic PTC is not clear. We compared the recurrence and survival outcomes of patients with asymptomatic and symptomatic PTC and identified the associated risk factors.

MATERIALS AND METHODS

Patients with previously untreated PTC of size ≤2 cm and who underwent curative surgery were included in this analysis. Asymptomatic PTC was defined as a tumor detected only by ultrasonography, computed tomography (CT), magnetic resonance imaging, and/or ¹⁸F-fluorodeoxyglucose positron emission tomography/CT. Clinical factors, operative and pathologic findings, and posttreatment outcomes were compared between the aforementioned two groups. Univariate and multivariate analyses were performed to identify the factors associated with recurrence-free survival (RFS) and overall survival (OS).

RESULTS

Out of 1419 patients, 1259 patients (88.7%) were asymptomatic. Patients with symptomatic PTC had significantly larger tumor size, palpability, extrathyroidal extension, high tumor and node stages, and were more likely to undergo treatment with radioactive iodine therapy compared with patients with asymptomatic PTC (p < 0.05 each). Recurrence was significantly higher in the symptomatic PTC group than in the asymptomatic group (p < 0.001). Asymptomatic PTC was an independent predictor of RFS and OS and had higher five-year rates than those associated with symptomatic tumors: 97.3% and 90.6% for RFS (p < 0.001) and 99.4% and 96.9% for OS (p < 0.001), respectively.

CONCLUSION

Symptomatic PTC is associated with higher recurrence and lower overall survival rates than asymptomatic PTC. Symptomatic PTC may require total thyroidectomy and close posttreatment surveillance.