Prophylactic Central Neck Dissection for Papillary Thyroid Carcinoma with Clinically Uninvolved Central Neck Lymph Nodes: A Systematic Review and Meta-analysis

Comparison of US-guided thermal ablation and surgery for papillary thyroid cancer: a systematic review and meta-analysis

OBJECTIVE

We conducted the systematic review and meta-analysis to comprehensively compare ablation and surgery in terms of effectiveness, safety and multiple factors affecting life quality of patients with papillary thyroid cancer (PTC).

METHODS

PubMed, Embase, Scopus, Web of Science and EBSCO were searched for relevant studies published between January 1980 and September 2023. Two reviewers independently extracted data according to the PRISMA recommendations and assessed the quality of each study with the Cochrane Risk of Bias Tool. Pooled analyses were performed using random or fixed-effects models, as appropriate.

RESULTS

A total of 4829 patients with PTC from 19 eligible studies were included. Through the meta-analysis, similar tumor progression (OR: 1.07; 95% CI 0.78, 1.48; p = 0.66) and recurrence-free survival (OR: 0.86; 95% CI, 0.55, 1.34; p = 0.50) were found between the patients undergoing ablation and those undergoing surgery. More strikingly, the lower risk of major complications (OR: 0.31; 95% CI 0.24, 0.41; p < 0.001), the shorter hospital stay (MD = 3.67 d; 95% CI, -4.89, -2.44; p < 0.001), the abbreviated procedure time (MD: -66.33 min, 95% CI, -77.08, -55.59; p < 0.001), the less intraoperative blood loss (MD: -27.43 ml, 95% CI, -34.60, -20.27; p < 0.001) and the lower treatment cost (MD: -860.42 USD, 95% CI, -1008.03, -712.81; p < 0.001) were noticed in ablation techniques compared to surgical operation. Thermal ablation has shown multiple advantages by virtue of its percutaneous puncture compared with surgical resection.

CONCLUSION

As an effective, safe, minimally invasive and economical modality, thermal ablation might be a promising alternative to existing PTC management options.

The 2024 revised clinical guidelines on the management of thyroid tumors by the Japan Association of Endocrine Surgery

The Japan Association of Endocrine Surgery published the first edition of the "Clinical guidelines on the management of thyroid tumors" in 2010 and the revised edition in 2018. The guideline presented herein is the English translation of the revised third edition, issued in 2024. The aim is to enhance health outcomes for patients suffering from thyroid tumors by facilitating evidence-based shared decision-making between healthcare providers and patients, as well as standardizing the management of thyroid tumors. The focus is on adult patients with thyroid tumors, addressing clinically significant issues categorized into areas such as an overview of the diagnosis and treatment of thyroid nodules, treatment strategies by histological type, radioactive iodine therapy, treatment of advanced differentiated carcinoma, pharmacotherapy, and complications and safety management associated with thyroid surgery. Thirty-two clinical questions were established in these areas. Following a comprehensive search of the literature and systematic review to evaluate the overall evidence, we aimed to present optimal recommendations by considering the balance of benefits and harms from the patient's perspective. We integrated evidence and clinical experience to determine the "Certainty of evidence" and "Strength of recommendations". Based on these, we illustrated overall flows of care as "Clinical algorithms". Necessary background knowledge of diseases and established clinical procedures for understanding the recommendations are presented in "Notes", while information that may be clinically useful but for which evidence remains insufficient is included in "Columns", based on the current state of evidence. Finally, future challenges for the next revision are presented as "Future research questions".

Prophylactic central neck dissection in clinically node-negative papillary thyroid carcinoma: 10-year impact on surgical and oncologic outcomes

BACKGROUND

The role of prophylactic central compartment lymph node dissection in clinically node-negative papillary thyroid carcinoma is debated. This study presents the findings from a 10-year follow-up of a single-institution randomized controlled trial assessing the role of prophylactic central compartment lymph node dissection in clinically node-negative papillary thyroid carcinoma.

METHODS

Between 2008 and 2010, a total of 196 patients with clinically node-negative papillary thyroid carcinoma were randomly assigned to 2 groups in a 1:1 ratio to undergo total thyroidectomy (group A) or total thyroidectomy with prophylactic central compartment lymph node dissection (group B). Patients received low-dose radioactive iodine treatment (30 mCi) postoperatively, with additional doses as needed. Monitoring included serum thyroglobulin, thyroglobulin antibodies, and neck ultrasound imaging.

RESULTS

At the end of the follow-up, 151 patients were analyzed, after 28 from group A and 17 from group B were excluded. The 2 groups were similar in age at diagnosis (P = .643), sex distribution (P = .735), body mass index (P = .134), ultrasound-estimated thyroid volume (P = .650), and histologic tumor features. After >10 years (12.9 ± 2 years), no significant differences were observed in surgical and oncologic outcomes. The mean thyroglobulin levels were 0.1 ± 0.1 ng/mL in group A and 0.3 ± 1.3 ng/mL in group B (P = .146). Both groups showed similar findings in the need for further surgery (P = .917), for additional radioactive iodine (P = .979), and mean radioactive iodine dosage (P = .822). No difference was documented in permanent recurrent laryngeal nerve palsy (P = .640), permanent hypocalcemia (P = .238), and serum calcium level (P = .181). The only observed distinction was more parathyroid removal in prophylactic central compartment lymph node dissection cases based on histologic examination (P = .005).

CONCLUSION

Prophylactic central compartment lymph node dissection does not significantly affect surgical and oncologic outcomes in patients with clinically node-negative small papillary thyroid carcinoma after long-term follow-up.

Postoperative and permanent hypocalcemia after indocyanine green (ICG) angiography-guided total thyroidectomy and central neck dissection: A retrospective cohort study

BACKGROUND

This study aimed to compare the rates of postoperative and permanent hypocalcemia between postthyroidectomy indocyanine green angiography and indocyanine green angiography-guided thyroidectomy performed intraoperatively for identification and preservation of the parathyroids.

METHODS

We undertook a retrospective study of 2 cohorts of patients with thyroid cancer undergoing total thyroidectomy and central neck dissection. The first cohort (control group) included patients who underwent postthyroidectomy indocyanine green angiography to predict parathyroid function by scoring the degree of fluorescence (0, black; nonvascularized; 1, gray/heterogeneous: partially vascularized; and 2, white: well vascularized), and the second cohort (angiography-guided thyroidectomy) included patients undergoing initially indocyanine green angiography-guided thyroidectomy to identify the feeding vessels of the parathyroid glands followed by postthyroidectomy indocyanine green angiography.

RESULTS

There were 54 patients (97 sides) in the control group and 43 (71 sides) in the angiography-guided thyroidectomy group. The superior glands were significantly better preserved (indocyanine green score of 2) in the angiography-guided thyroidectomy group as compared with the control group (53.7% vs 34.5%, P = .026). The final parathyroids with an indocyanine green ICG score of 2 was greater in the angiography-guided thyroidectomy group than in the control group (47.8% vs 26.6%, P = .016). Postoperative hypocalcemia was significantly more common in the control group than in the angiography-guided thyroidectomy group (31.5% vs 7.0%, P = .007) as well as permanent hypocalcemia (11.1% vs 0%, P = .032).

CONCLUSION

Indocyanine green angiography-guided thyroidectomy allowing identification of the vascular supply of the parathyroid glands contributes to preserve functioning glands and to prevent postsurgical hypocalcemia.

Clinical characteristics, risk stratifications, and long-term follow-up of childhood differentiated thyroid cancer: a single-center experience

PURPOSE

Guidelines of the Pediatric American Thyroid Association (ATA) serve as a vital reference for managing the rare thyroid cancers in childhood. This study evaluates differentiated thyroid cancer (DTC) patients using the ATA guidelines, dynamic risk stratification (DRS), and other established risk classification systems.

METHODS

Pediatric patients with DTC under observation after total thyroidectomy were included in the study. We assessed preoperative and postoperative features based on the ATA guidelines, other risk scoring systems (TNM; De Groot staging; metastasis, age, completeness of resection, invasion, and tumor size; and combined risk), and the DRS.

RESULTS

A total of 41 patients was enrolled in the study, with a median follow-up duration of 5.14±3.94 years. Of the patients who underwent total thyroidectomy, 33 were diagnosed with papillary carcinoma and 8 with follicular thyroid carcinoma. During follow-up, cervical metastases were detected in 27 patients, and one had distant metastasis. All patients underwent total thyroidectomy, and 68% received lymph node dissection. Additionally, 16 patients received radioactive iodine therapy. Of the postoperative patients, 85.3% were classified as low risk. Based on DRS, patients were classified as having no evidence of disease (n=29, 70.7%), biochemical evidence of persistent disease (n=5, 12.2%), structural evidence of persistent disease (n=6, 14.6%), and recurrent disease (n=1, 2.5%). Notably, 98% of the patients showed no evidence of disease during their latest follow-up.

CONCLUSION

Persistent disease in patients classified as low risk according to the ATA guidelines resolved following radioactive iodine therapy, emphasizing the importance of risk stratification in postoperative care.

Clinically Significant Central Lymph Node Metastasis is Not Common in Patients with Clinically N0 Papillary Thyroid Carcinoma on Both Ultrasonography and CT

Background: The necessity of prophylactic central lymph node dissection (p-CLND) in patients with clinically node-negative papillary thyroid carcinoma (PTC) is unclear. The present study evaluated the central lymph node (LN) metastases status in patients with clinically node-negative PTC on both preoperative thyroid ultrasonography (USG) and neck computed tomography (CT) who underwent p-CLND. Methods: This retrospective cohort study included 3002 clinically node-negative patients diagnosed with PTC who had undergone thyroidectomy with p-CLND from January 2000 to September 2022. Clinically node-negative was defined as the absence of suspicious metastatic LNs on preoperative USG and neck CT. Low-risk central LN metastases were defined as LN metastases <2 mm in size with metastatic LNs ≤5. The median follow-up duration was 4.52 (interquartile range [IQR]: 1.6-7.5) years. Results: Of the 3002 patients, 1194 (39.7%) had central LN metastases, whereas 1808 (60.3%) did not. The 1194 patients with central LN metastases included 507 (16.9%) with intermediate-risk metastases and 610 (20.3%) with low-risk LN metastases, with a total of 2428 (80.5%) patients having low-risk LN metastases or no central LN metastases. High-risk metastases were observed in only 77 (2.5%) patients. Of the 584 patients with intermediate-/high-risk metastases, 577 (98.8%) had central LN metastases <1 cm in size, whereas only 7 (1.2%) had central LN metastases ≥1 cm. The disease recurrence rates for the no LN metastases, low-risk LN metastases, and intermediate-/high-risk LN metastases groups were 0.4%, 1.1%, and 1.9%, respectively (p = 0.012). Factors independently associated with intermediate-/high-risk central LN metastases included age <55 years (odds ratio [OR] = 2.29), male sex (OR = 2.33), tumor size >1 cm on USG (OR = 1.94), and the presence of extrathyroidal extension on CT scans (OR = 1.53), with p < 0.001 for all factors. Conclusions: Most LNs confirmed after CLND in cN0 PTC patients assessed by USG and CT were either metastasis-free or classified as low-risk metastatic LNs. Furthermore, the majority of metastatic LNs were small in size, typically measuring <1 cm. p-CLND may be unnecessary if preoperative thyroid USG and neck CT show no evidence of central neck LN metastaes.

The necessity of prophylactic central lymph node dissection in clinically n0 papillary thyroid carcinoma: perspective from the endemic region

BACKGROUND

Prophylactic central lymph node dissection (pCND) in papillary thyroid carcinoma (PTC) is still a matter of debate. Therefore, we aimed to identify the factors affecting central lymph node metastasis (CLNM) in patients with clinically node-negative (cN0) PTC.

METHODS

This retrospective study included 248 patients with cN0 PTC who underwent total thyroidectomy (TT) or TT + pCND. Clinicopathological associations among CLNM, complication rates and the effect of pCND on staging were assessed. Risk factors (RFs) and the pattern of lymph node metastasis (LNM) in PTC patients were studied via multivariate analysis.

RESULTS

A total of 216 patients underwent pCND, and 58.8% (127/216) had positive CLNM. Male patients, aged < 41 years, and those with lymphatic invasion were identified as RFs for CLNM, with odds ratios of 2.59, 2.26, and 4.09, respectively. Among the 216 patients, 65 (30%) had transient hypoparathyroidism (HPT), and 20 (9.3%) had permanent HPT. Transient recurrent laryngeal nerve (RLN) palsy occurred in 15 (6.9%) patients, and permanent RLN palsy occurred in 3 (1.4%) patients. Over 55 years of age, 46.7% of patients were upstaged according to the American Joint Committee on Cancer (AJCC) TNM staging system, and 14.2% (n = 18) of the 127 patients with CLNM were upgraded according to the American Thyroid Association (ATA) risk stratification system (RSS).

CONCLUSION

Taken together, in terms of the high incidence rate of CLNM in cN0 PTC patients; We believe that routine pCND, which can be performed with low morbidity rates, is optimal for cN0 PTC patients during their first treatment, especially for those with RFs for CLNM.

CLINICAL TRIALS NUMBER

NCT05873283.

Detection of Central Compartment Lymph Node Metastasis of Thyroid Cancer: Usefulness of Intraoperative Thyroglobulin Measurement in Fine Needle Aspiration Washout with and Without Blue Dye Injection

Background/Objectives: The management of lymph node metastases of the central neck compartment (CNC) in differentiated thyroid carcinoma is debated. The intraoperative measurement of thyroglobulin (Tg) has gained attention in accurately detecting metastases, reducing unnecessary CNC dissections. Methods: A total of 37 patients underwent surgery. An intraoperative assay of thyroglobulin from fine needle aspiration (Tg-FNA) was performed on CNC lymph nodes, identified by blue dye injection in 15 patients (23 nodes, group A) and by palpation in 22 patients (35 nodes, group B). The Tg-FNA values were compared with histology to calculate the diagnostic accuracy. Results: In group A, the blue dye diffused widely, complicating lymph node identification: 2 were metastatic and 21 non-metastatic, with median Tg-FNA levels of 6236 ng/mL and 99.20 ng/mL, respectively. In group B, 8 were metastatic and 27 benign, with median Tg-FNA levels of 4063 ng/mL and 121 ng/mL (p < 0.0001), respectively. ROC analysis identified 500 ng/mL as a cutoff, achieving 100% sensitivity and 74% specificity in group B and 90% sensitivity and 70% specificity overall. Finally, among the non-metastatic lymph nodes, group A exhibited some cases of very high Tg-FNA values compared to group B, with lower accuracy for the cutoff, suggesting that colorant injection might lead to increased Tg-FNA levels. Conclusions: Blue dye injection showed low accuracy. Intraoperative Tg-FNA was reliable in detecting CNC metastases, although a higher cutoff is needed in this compartment compared to what has been reported for lateral lymph nodes. Lymphatic drainage and surgical manipulation might explain these findings. The careful interpretation of Tg-FNA in CNC should be adopted.

Effectiveness of prophylactic central compartment neck dissection following hemithyroidectomy in papillary thyroid cancer: a meta-analysis

INTRODUCTION

In this study, we aimed to assess the effect of prophylactic central compartment neck dissection (pCCND) in conjunction with hemithyroidectomy (HT) for clinically low-risk node-negative (cN0) papillary thyroid carcinoma (PTC).

METHODS

A thorough literature search was performed utilizing PubMed and EMBASE for articles published until October 2023. Subsequently, a meta-analysis was performed on studies involving patients with cN0 PTC, with postoperative locoregional recurrence (LRR) and survival data, treated with HT + pCCND or HT. The study was registered with PROSPERO (CRD42024560962).

RESULTS

We included seven studies in this meta-analysis, including 2132 patients who met the inclusion criteria: six retrospective cohort studies and one randomized controlled trial. The HT + pCCND group consisted of 1090 cases, and the HT group had 1042 cases. The LRR rates after HT with or without pCCND were similar (3.58% vs. 4.51%; odds ratio (OR) = 0.65; 95% confidence interval (CI) = 0.41-1.03). Five of the seven studies provided prognostic and survival data, particularly the log hazard ratio (log HR) of disease-free survival (DFS) between the two groups. There was also no significant difference in terms of DFS between the HT + pCCND and HT groups (OR = 0.67; 95% CI = 0.42-1.07).

CONCLUSIONS

There was no significant difference in LRR and DFS between the HT + pCCND and HT groups. pCCND did not demonstrate significant efficacy in improving oncological outcomes for low-risk patients with cN0 PTC. Therefore, for patients with low-risk cN0 PTC, thyroid surgeons should make reasonable and individualized decisions regarding the extent of surgical removal.

Meta-analysis of prediction models for predicting lymph node metastasis in thyroid cancer

BACKGROUND

The purpose of this systematic review and meta-analysis is to assess the efficacy of various machine learning (ML) techniques in predicting preoperative lymph node metastasis (LNM) in patients diagnosed with papillary thyroid carcinoma (PTC). Although prior studies have investigated the potential of ML in this context, the current evidence is not sufficiently strong. Hence, we undertook a thorough analysis to ascertain the predictive accuracy of different ML models and their practical relevance in predicting preoperative LNM in PTC patients.

MATERIALS AND METHODS

In our search, we thoroughly examined PubMed, Cochrane Library, Embase, and Web of Science, encompassing their complete database history until December 3rd, 2022. To evaluate the potential bias in the machine learning models documented in the included studies, we employed the Prediction Model Risk of Bias Assessment Tool (PROBAST).

RESULTS

A total of 107 studies, involving 136,245 patients, were included. Among them, 21,231 patients showed central LNM (CLNM) and 4,637 had lateral LNM (LLNM). The meta-analysis results revealed that the c-index for predicting LNM, CLNM, and LLNM were 0.762 (95% CI: 0.747-0.777), 0.762 (95% CI: 0.747-0.777), and 0.803 (95% CI: 0.773-0.834) in the training set, and 0.773 (95% CI: 0.754-0.791), 0.762 (95% CI: 0.747-0.777), and 0.829 (95% CI: 0.779-0.879) in the validation set, respectively. A total of 134 machine learning-based prediction models were included, covering 10 different types. Logistic Regression (LR) was the most commonly used model, accounting for 81.34% (109/134) of the included models.

CONCLUSIONS

Machine learning methods have shown a certain level of accuracy in predicting preoperative LNM in PTC patients, indicating their potential as a predictive tool. Their use in the clinical management of PTC holds great promise. Among the various ML models investigated, the performance of logistic regression-based nomograms was deemed satisfactory.

Factors associated with occult lateral lymph node metastases in patients with clinically lymph node negative papillary thyroid carcinoma: a systematic review and meta-analysis

Background

It remains unclear which category of patients with clinically lymph node negative (cN0) papillary thyroid carcinoma (PTC) might have higher risk of occult lateral lymph node metastasis (OLLNM) due to the conflicting results in previous studies. This systematic review and meta-analysis aimed to investigate factors associated with OLLNM in patients with cN0 PTC.

Methods

PubMed, EMBASE, Cochrane Library and Web of Science were comprehensively searched by two independent investigators to 15 August 2022. Odds ratios (ORs) and 95% confidence intervals (CIs) were calculated for the pooled analysis. This systematic review and meta-analysis was registered in PROSPERO (CRD42022353567).

Results

Fifteen eligible studies involving 8369 patients with cN0 PTC were included in this meta-analysis. We found 7 factors significantly associated with OLLNM, including male (OR, 1.47; 95% CI, 1.30 to 1.66; P < 0.001), age<45y (OR, 1.65; 95% CI, 1.31 to 2.06; P < 0.001), tumor size > 10mm (OR, 3.17; 95% CI, 2.04 to 4.93; P <0.001), tumor located in upper pole (OR, 1.81; 95% CI, 1.44 to 2.27; P <0.001), bilaterality (OR, 1.66; 95% CI, 1.37 to 2.02; P <0.001), extrathyroidal extension (ETE) (OR, 2.52; 95% CI, 1.72 to 3.68; P <0.001) and increased number of central lymph node metastasis (CLNM) (OR, 6.84; 95% CI, 5.66 to 8.27; P <0.001). The results of sensitivity analysis and subgroup analysis were similar to the pooled results. No significant publication bias was observed.

Conclusions

The systematic review and meta-analysis identified 7 factors associated with OLLNM in patients with cN0 PTC. Future studies are needed to validate our results.

Systematic review registration

https://www.crd.york.ac.uk/prospero, identifier CRD42022353567.

The impact of intraoperative neural monitoring during papillary thyroid cancer surgery on completeness of thyroidectomy and thyroglobulin response: a propensity-score matched study

BACKGROUND

Intraoperative neural monitoring (IONM) has been utilized for a variety of thyroid pathologies, including papillary thyroid carcinoma (PTC). Remnant thyroid tissue following total thyroidectomy (TT) in patients with PTC is associated with increased recurrence. The aim of this study is to investigate whether the use of IONM in PTC surgery has an impact on the completeness of thyroidectomy.

METHODS

Retrospectively, patients with preoperative diagnosis of PTC, who underwent TT in a tertiary center were reviewed. They were grouped based on the IONM usage, and 1:1 propensity-score match was performed. Primary outcome was the completeness of thyroidectomy, determined by measuring postoperative stimulated thyroglobulin levels (sTg).

RESULTS

Among 274 clinically node-negative PTC patients who underwent TT and ipsilateral prophylactic central lymph-node dissection, a total of 170 patients (85:85) were matched. Postoperative sTg levels were significantly lower in the IONM group (1 ng/dL vs. 0.4 ng/dL; p < 0.01) with higher percentage of the patients with sTg levels <1 ng/ml (50.6% vs. 69.4%; p = 0.01). More patients in the no-IONM group received RAI ablation with significantly higher doses (mean mci: 120 vs. 102; p = 0.02).

CONCLUSION

The use of IONM during thyroidectomy provides improvement in the completeness of thyroidectomy and reduction in postoperative sTg levels which can be used as a guide by clinicians to avoid RAI ablation in selected PTC patients and to adjust low ablative doses in patients who are scheduled for remnant ablation.

An Online Model for Central Lymph Node Metastases in Papillary Thyroid Carcinoma With BRAF V600E Mutation

OBJECTIVE

To construct a predictive model to direct the dissection of the central lymph nodes in papillary thyroid cancer (PTC) with BRAF V600E mutation by identifying the risk variables for central lymph node metastases (CLNM).

METHODS

Data from 466 PTC patients with BRAF V600E mutations underwent thyroid surgery was collected and analyzed retrospectively. For these patients, we conducted univariate and multivariate logistic regression analysis to find risk variables for CLNM. To construct a nomogram, the independent predictors were chosen. The calibration, discrimination, and clinical utility of the predictive model were assessed by training and validation data.

RESULTS

CLNM was present in 323/466 PTC patients with BRAF V600E mutations. By using univariate and multivariate logistic regression, we discovered that gender, age, tumor size, multifocality, and pathological subtype were all independent predictors of CLNM in PTC patients with BRAF V600E mutations. A predictive nomogram was created by combining these variables. In both training and validation groups, the nomogram demonstrated great calibration capacities. The training and validation groups' areas under the curve (AUC) were 0.772 (specificity 0.694, sensitivity 0.728, 95% CI: 0.7195-0.8247) and 0.731 (specificity 0.778, sensitivity 0.653, 95% CI: 0.6386-0.8232) respectively. According to the nomogram's decision curve analysis (DCA), the nomogram might be beneficial. As well, an online dynamic calculator was developed to make the application of this nomogram easier in the clinic.

CONCLUSION

An online nomogram model based on the 5 predictors included gender, age, pathological subtype, multifocality, and tumor size was confirmed to predict CLNM and guide the central lymph nodes dissection in PTC patients with BRAF V600E mutations.

Impact of age on central lymph nodes involvement in papillary thyroid cancer

BACKGROUND

Total thyroidectomy is the main line of treatment for papillary thyroid cancer. Central lymph node dissection (CLND) is still debatable. In this study, we aimed to correlate the central lymph node status with the age of patients.

METHODS

This is a retrospective study including patients with papillary thyroid cancer (PTC) who underwent total thyroidectomy and CLND at a tertiary cancer center during the period from January 2012 to September 2022. Patients were subdivided into 3groups: patients younger than 20 years old, patients between 20 and 40 years old, and patients older than 40 years old. Correlation between central lymph node status, lateral lymph node status, and harvest count with each other and between age groups was done.

RESULTS

315 patients were included. The younger the age group the higher the possibility of harboring positive central nodes, however, the positivity of lateral nodes was similar. Neither central nodal harvest nor positive central node count significantly differed between groups. The lateral nodal harvest was significantly higher in the < 20 years group with no affection to the number of positive nodes retrieved. The younger the age group the longer the disease-free survival (DFS).

CONCLUSION

We can conclude that patients younger than twenty years had a higher probability of harboring malignancy in central nodes and higher lateral node harvest on dissection. In contrast, they do have a lower incidence of recurrence.

Central node dissection from the perspective of lateral neck node metastasis in papillary thyroid carcinoma

OBJECTIVES

Controversy exists on how to handle central lymph nodes in papillary thyroid carcinoma, particularly regarding indications for prophylactic central neck dissection (CND). Central node metastases are more difficult to diagnose preoperatively than lateral node metastases.

METHODS

We enrolled 493 patients with papillary thyroid carcinoma treated at our department in the past 22 years. Metastatic lymph nodes were diagnosed preoperatively mainly by ultrasonography. In principle, CND was performed for all cases; ipsilateral CND was performed for hemithyroidectomy, and bilateral CND was performed for total thyroidectomy. Lateral neck dissection (levels II to V; LND) was performed for metastases to lateral neck lymph nodes (clinical node (cN) 1b).

RESULTS

The cN stage was cN0 in 365 patients, cN1a in 10, and cN1b in 118. Of the 357 patients with stage cN0 who underwent CND, 42.9 % had pathologically positive nodes (pN+) in level VI, and of the 118 with stage cN1b who underwent CND, 78.0 % had pN+ in level VI. Cases with advanced T stage were significantly more common with pN+ in level VI. Level VI metastases were significantly associated with pN+ in level IV. As the total number of pN+ at each level of the lateral neck increased, the rate of patients with pN+ in level VI increased, and in patients with 3 or more pN+, about 85 % had level VI metastases.

CONCLUSION

Because about half of the patients with cN0 patients had pN+ in level VI, and the rate of pN+ in level VI in each clinical T stage was 46 to 65 %, prophylactic CND should be performed, considering the various clinical benefits. Central nodes will have metastases in about 80 % of cases with lateral node metastases, requiring more accurate dissection. In lateral node metastases, there is a significant association between metastases in levels IV and VI.

Demographic, clinical, and surgical features of patients undergoing thyroidectomy due to thyroid lesions in Southern Iran: A cross-sectional study

Background and Aims

The incidence of thyroid cancer has witnessed a significant global increase and stands as one of the most prevalent cancers in Iran. This surge is primarily attributed to the escalating incidence of papillary thyroid cancer (PTC), with overdiagnosis emerging as an equally noteworthy factor. Consequently, this study aims to ascertain the incidence of thyroid cancer, along with its clinical presentation, demographic characteristics, and surgical features in patients undergoing thyroid surgery.

Methods

This cross-sectional study involved the evaluation of patient files from referral centers in Shiraz spanning the years 2015-2020. Demographic and clinical information pertaining to thyroid cancer was extracted and subsequently analyzed using SPSS software.

Results

A total of 533 documented cases of thyroid cancer undergoing surgery revealed an annual rate of 89 cases in our location. The average age of the patients was 43.9 ± 13.4 years (ranging from 13 to 92), with females constituting 429 (83.5%) of the cases, and 278 (54.1%) being malignant. Conventional PTC emerged as the most prevalent pathology, accounting for 239 (45.0%) of the cases. Patients with thyromegaly exhibited significantly higher incidences of nonmalignant tumors (p = 0.01), while those with malignant tumors were notably younger than those with nonmalignant tumors (p = 0.001).

Conclusion

Our study revealed a progressive rise in the number of patients undergoing thyroidectomy over the years, with PTC constituting the majority of cases. Malignant cases were more frequently observed in younger patients, and in smaller lesion sizes, highlighting the importance of early screening and optimizing detection methods, especially in high-risk populations.

Development of a nomogram for prediction of central lymph node metastasis of papillary thyroid microcarcinoma

BACKGROUND

Papillary thyroid carcinoma (PTC) is the most frequent malignant tumor in thyroid carcinoma. The aim of this study was to explore the risk factors associated with central lymph node metastasis in papillary thyroid microcarcinoma (PTMC) and establish a nomogram model that can assess the probability of central lymph node metastasis (CLNM).

METHODS

The clinicopathological data of 377 patients with cN0 PTMC were collected and analyzed from The Second Affiliated Hospital of Fujian Medical University from July 1st, 2019 to December 30th, 2021. All patients were examined by underwent ultrasound (US), found without metastasis to central lymph nodes, and diagnosed with PTMC through pathologic examination. All patients received thyroid lobectomy or total thyroidectomy with therapeutic or prophylactic central lymph node dissection (CLND). R software (Version 4.1.0) was employed to conduct a series of statistical analyses and establish the nomogram.

RESULTS

A total of 119 patients with PTMC had central lymph node metastases (31.56%). After that, age (P < 0.05), gender (P < 0.05), tumor size (P < 0.05), tumor multifocality (P < 0.05), and ultrasound imaging-suggested tumor boundaries (P < 0.05) were identified as the risk factors associated with CLNM. Subsequently, multivariate logistic regression analysis indicated that the area under the receiver operating characteristic (ROC) curve (AUC) of the training cohort was 0.703 and that of the validation cohort was 0.656, demonstrating that the prediction ability of this model is relatively good compared to existing models. The calibration curves indicated a good fit for the nomogram model. Finally, the decision curve analysis (DCA) showed that a probability threshold of 0.15-0.50 could benefit patients clinically. The probability threshold used in DCA captures the relative value the patient places on receiving treatment for the disease, if present, compared to the value of avoiding treatment if the disease is not present.

CONCLUSION

CLNM is associated with many risk factors, including age, gender, tumor size, tumor multifocality, and ultrasound imaging-suggested tumor boundaries. The nomogram established in our study has moderate predictive ability for CLNM and can be applied to the clinical management of patients with PTMC. Our findings will provide a better preoperative assessment and treatment strategies for patients with PTMC whether to undergo central lymph node dissection.

Carbon nanoparticles beneficial for prophylactic central compartment lymph node dissection in cN0 papillary thyroid carcinoma

Objective

This study explored prophylactic central compartment lymph node dissection (pCCLND) for patients with cN0 papillary thyroid carcinoma (PTC) and the effect of carbon nanoparticles (CNP) on surgical outcomes.

Methods

This retrospective study reviewed PTC cases treated at our tertiary medical institution between January 2019 and December 2022. Only patients with indications for total thyroidectomy and cN0 disease were included. CNP has been associated with a higher number of harvested lymph nodes and a lower rate of accidental parathyroid gland (PTG) removal. Patients who used CNP in this study were classified as group 1, while those who denied its use were classified as group 2.

Results

In total, 116 cases were included, with 80 patients in group 1 and 36 in group 2. Most patients were in stage T1, with 68 (85.0 %) patients in group 1 and 31 (86.1 %) in group 2. Postoperative hoarseness occurred in 3 (3.8 %) patients in group 1 and 1 (2.8 %) in group 2, which recovered within two months. In group 2, 250 nodes were harvested, 72 (28.8 %) of which were metastatic; in group 1, 889 nodes were harvested, 316 (35.5 %) of which were metastatic; the difference regarding the rates of metastatic lymph nodes between the 2 groups was statistically significant (P = 0.047). Differences in postoperative blood calcium and parathyroid hormone levels between the two groups were statistically significant (P = 0.035 and P = 0.034, respectively). There were symptoms of hypocalcemia in 6 (16.7 %) patients in group 2 but in only 2 (2.5 %) in group 1, all of which recovered within three months; the difference was statistically significant (p = 0.017).

Conclusion

pCCLND is worth undertaking for cN0 PTC. CNP is beneficial for achieving more thorough dissection and reducing temporary hypoparathyroidism.

Lymph node imaging for thyroid cancer

Cervical lymph nodes (LNs) in the central (level VI) and lateral (levels II-V) compartments of the neck are the most common sites of locoregional metastases associated with thyroid cancer. Prophylactic nodal dissections are uncommon in modern thyroid surgery and are not routinely performed due to concern for increased morbidity and do not offer improved survival. Therefore, a selective approach for LN dissections is increasingly important. Preoperatively, this is most frequently assessed with cervical ultrasound (US). Contrast-enhanced computed tomography (CT) of the neck can also be used for preoperative assessment. Both US and CT imaging can be used to characterise LNs in levels II-VI and their risk of malignancy based on size, morphology, and growth. US-guided fine-needle aspiration of equivocal LN with thyroglobulin (Tg) washout can also determine if a LN harbours malignancy. For postoperative surveillance after total thyroidectomy, both US and CT continue to play an important role at 6-12 months intervals. These patients may also benefit from additional biochemical data such as Tg levels in addition to LN and thyroid bed imaging. Thyroid uptake scans may also play a role in LN surveillance postoperatively for well-differentiated thyroid carcinoma in certain clinical contexts. Less commonly, positron emitted tomography may play a role, but is typically reserved for patients with aggressive or radioactive iodine refractory disease.

Long-term impact of prophylactic central neck dissection in non-invasive classic papillary thyroid carcinoma

BACKGROUND

The utilization of prophylactic central neck dissection (pCND) in cases of non-invasive clinical node-negative (cN0) papillary thyroid carcinoma (PTC) remains a topic of debate, with a dearth of long-term evidence.

MATERIALS AND METHODS

We retrospectively reviewed 1181 cN0 PTC patients from 1997 to 2011. Of these, 641 underwent pCND (pCND + group) and 540 did not (pCND-group). Propensity score matching (PSM) was used to identify similar patients. Event-free survival and long-term complications including permanent hyperparathyroidism and permanent recurrent laryngeal nerve (RLN) paralysis were analyzed after PSM.

RESULTS

The pCND + group had more aggressive characteristics. In the matched cohort after PSM, the 5-year, 10-year, and 15-year EFS rates were 98.9 %, 98.2 %, and 97.1 % for the pCND + group, and 97.7 %, 97.1 %, and 97.1 % for the pCND-group, respectively. There was no statistically significant difference in EFS rates between the two groups (Log Rank P = 0.38). There was no statistically significant difference in the incidence of permanent hyperparathyroidism (3.3 % vs. 1.5 %, P = 0.08) and permanent RLN paralysis (1.7 % vs. 0.9 %, P = 0.13) between the pCND+ and pCND- groups.

CONCLUSION

Our study, with a median follow-up duration of 107 months, indicates that pCND does not lead to a significant reduction in nodal recurrence among non-invasive cN0 PTC patients.

Optimal range of lymph node dissection in patients with unilateral papillary thyroid carcinoma with lateral cervical lymph node metastasis

Background

Whether patients with unilateral papillary thyroid carcinoma (PTC) with lateral cervical lymph node metastasis (LLNM) require prophylactic central regional lymph node dissection (CLND) remains unclear. Herein, we investigated the independent risk factors associated with contralateral central lymph node metastasis (cCLNM) in unilateral PTC with LLNM and analyzed the optimal extent of lymph node dissection by comparing the 5-year recurrence-free survival rates.

Materials and methods

We retrospectively analyzed 695 patients with unilateral papillary thyroid carcinoma and lateral cervical lymph node metastasis. Factors including sex, age, multifocal, location of primary tumor, tumor diameter, capsule invasion, thyroid nodular goiter, Hashimoto thyroiditis, ipsilateral central lymph node metastasis(iCLNM), and lateral cervical lymph node metastasis were analyzed using univariate and multivariate logistic regression analyses to explore the independent risk factors of cCLNM. Propensity scores were matched to compare the 5-year recurrence-free survival rates in patients divided by different lymph node metastases and dissections.

Results

Of all patients who underwent bilateral (b)CLND, 52% (149/286) had cCLNM. Receiver operating characteristic (ROC) curve analysis was performed on 286 patients who underwent bCLND, for which a tumor diameter of 20.5 mm and number of LLNM of 3.5 were used as the thresholds for predicting cCLNM. The 5-year recurrence-free survival (RFS) rates in the cCLN-negative and cCLN-positive groups were 98.6% and 91.2%, with statistically significant differences (P=0.034). The 5-year RFS rates showed no significant difference between the ipsilateral (i)CLND and bCLND groups (P=0.235). Multifactorial regression analysis showed that tumor diameter >2 cm, presence of iCLNM, and number of LLNM >3 were independent risk factors of cCLNM.But male sex, young age (<45 years), multifocality, location of primary tumor, capsule invasion, thyroid nodular goiter, and Hashimoto thyroiditis were not associated with cCLNM.

Conclusion

Not all unilateral PTC with LLNM require prophylactic cCLND; however, prophylactic cCLND is necessary in cases which display high-risk factors for cCLNM, including primary diameter >2 cm, iCLNM, and number of LLNM >3.

Lymph Node Metastases in Papillary Thyroid Carcinoma can be Predicted by a Convolutional Neural Network: a Multi-Institution Study

OBJECTIVES

The presence of nodal metastases in patients with papillary thyroid carcinoma (PTC) has both staging and treatment implications. However, lymph nodes are often not removed during thyroidectomy. Prior work has demonstrated the capability of artificial intelligence (AI) to predict the presence of nodal metastases in PTC based on the primary tumor histopathology alone. This study aimed to replicate these results with multi-institutional data.

METHODS

Cases of conventional PTC were identified from the records of 2 large academic institutions. Only patients with complete pathology data, including at least 3 sampled lymph nodes, were included in the study. Tumors were designated "positive" if they had at least 5 positive lymph node metastases. First, algorithms were trained separately on each institution's data and tested independently on the other institution's data. Then, the data sets were combined and new algorithms were developed and tested. The primary tumors were randomized into 2 groups, one to train the algorithm and another to test it. A low level of supervision was used to train the algorithm. Board-certified pathologists annotated the slides. HALO-AI convolutional neural network and image software was used to perform training and testing. Receiver operator characteristic curves and the Youden J statistic were used for primary analysis.

RESULTS

There were 420 cases used in analyses, 45% of which were negative. The best performing single institution algorithm had an area under the curve (AUC) of 0.64 with a sensitivity and specificity of 65% and 61% respectively, when tested on the other institution's data. The best performing combined institution algorithm had an AUC of 0.84 with a sensitivity and specificity of 68% and 91% respectively.

CONCLUSION

A convolutional neural network can produce an accurate and robust algorithm that is capable of predicting nodal metastases from primary PTC histopathology alone even in the setting of multi-institutional data.

Predictive Factors Affecting the Development of Lateral Lymph Node Metastasis in Papillary Thyroid Cancer

Objectives

Lateral lymph node metastasis (LLNM) in papillary thyroid cancer (PTC) determines the extent of surgery to be performed and the prognosis of the disease. In this study, we aimed to evaluate the clinicopathological risk factors affecting the development of LLNM.

Methods

We retrospectively evaluated the demographic and clinicopathological data of 346 cases with PTC who were operated in our clinic between May 2012 and September 2020. The patients were divided into 2 groups as patients with LLNM (Group 1) and without LLNM (Group 2).

Results

Thirty-six (10.4%) patients out of 346 patients with PTC had LLNM. A statistically significant difference was found between Group 1 and Group 2 regarding the male gender (M/F: 38.9% vs. 21.6%; p=0.020), tumor size (2.30±1.99 cm vs. 1.31±1.40 cm; p=0.000), lymphovascular invasion (69.4 vs. 20.6%; p=0.000), multicentricity (69.4% vs. 35.5%; p=0.000), multifocality (p=0.000), aggressive variant (22.2% vs. 9.4%; p=0.000), extrathyroidal extension (50% vs. 16.1% p=0.000), central lymph node metastasis (CLNM) rates (75% vs. 6.5%; p=0.000), and ≥3 cm lymph node metastasis (48.5% vs. 0%, p=0.000), distant metastasis (2.1% vs. 0%, p=0.000), respectively. Multivariance analysis determined the presence of CLNM as an independent risk factor for the development of LLNM.

Conclusion

The presence of CLNM in patients with PTC was determined as an independent risk factor for the development of LLNM. Although there has been increasing debate about prophylactic central neck dissection (pCND) in LLNM, pCND should still be considered in these patients as the rate of CLNM is high in patients with LLNM. CLNM might be a reference for surgeons to determine the extent of surgery. In addition, the presence of CLNM is important for close follow-up for the early detection of LLNM recurrence.

Lymph node metastasis in cancer progression: molecular mechanisms, clinical significance and therapeutic interventions

Lymph nodes (LNs) are important hubs for metastatic cell arrest and growth, immune modulation, and secondary dissemination to distant sites through a series of mechanisms, and it has been proved that lymph node metastasis (LNM) is an essential prognostic indicator in many different types of cancer. Therefore, it is important for oncologists to understand the mechanisms of tumor cells to metastasize to LNs, as well as how LNM affects the prognosis and therapy of patients with cancer in order to provide patients with accurate disease assessment and effective treatment strategies. In recent years, with the updates in both basic and clinical studies on LNM and the application of advanced medical technologies, much progress has been made in the understanding of the mechanisms of LNM and the strategies for diagnosis and treatment of LNM. In this review, current knowledge of the anatomical and physiological characteristics of LNs, as well as the molecular mechanisms of LNM, are described. The clinical significance of LNM in different anatomical sites is summarized, including the roles of LNM playing in staging, prognostic prediction, and treatment selection for patients with various types of cancers. And the novel exploration and academic disputes of strategies for recognition, diagnosis, and therapeutic interventions of metastatic LNs are also discussed.

Predicting central lymph node metastasis in patients with papillary thyroid carcinoma based on ultrasound radiomic and morphological features analysis

OBJECTIVES

To build a combined model based on the ultrasound radiomic and morphological features, and evaluate its diagnostic performance for preoperative prediction of central lymph node metastasis (CLNM) in patients with papillary thyroid carcinoma (PTC).

METHOD

A total of 295 eligible patients, who underwent preoperative ultrasound scan and were pathologically diagnosed with unifocal PTC were included at our hospital from October 2019 to July 2022. According to ultrasound scanners, patients were divided into the training set (115 with CLNM; 97 without CLNM) and validation set (45 with CLNM; 38 without CLNM). Ultrasound radiomic, morphological, and combined models were constructed using multivariate logistic regression. The diagnostic performance was assessed by the area under the curve (AUC) of the receiver operating characteristic curve, accuracy, sensitivity, and specificity.

RESULTS

A combined model was built based on the morphology, boundary, length diameter, and radiomic score. The AUC was 0.960 (95% CI, 0.924-0.982) and 0.966 (95% CI, 0.901-0.993) in the training and validation set, respectively. Calibration curves showed good consistency between prediction and observation, and DCA demonstrated the clinical benefit of the combined model.

CONCLUSION

Based on ultrasound radiomic and morphological features, the combined model showed a good performance in predicting CLNM of patients with PTC preoperatively.

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.

Prophylactic central neck dissection for cN0 papillary thyroid carcinoma: is there any difference between western countries and China? A systematic review and meta-analysis

Background

Recommendations for the performance of prophylactic central neck dissection (pCND) in patients with clinically node-uninvolved (cN0) papillary thyroid carcinoma (PTC) are not the same. This meta-analysis set out to compare the effectiveness of pCND with total thyroidectomy (TT) in different countries and regions, mainly between western countries and China.

Methods

The electronic databases PubMed, EMBASE, and Cochrane Library were searched for studies published until August 2022. The incidence rate of cervical lymph node metastases (LNMs), locoregional recurrences (LRRs), and postoperative complications were pooled by a random-effects model. Subgroup analyses based on different countries and regions were performed.

Results

Eighteen studies involving 5,346 patients were analyzed. In the subgroup of western countries, patients undergoing pCND with TT had a significantly lower LRR rate [69/1,804, 3.82% vs. 139/2,541, 5.47%; odds ratio (OR) = 0.56; 95% CI 0.37-0.85] and a higher rate of temporary hypoparathyroidism (HPT) (316/1,279, 24.71% vs. 194/1,467, 13.22%; OR = 2.23; 95% CI 1.61-3.08) than that of the TT alone group, while no statistically significant difference was found in the rate of permanent HPT and temporary and permanent recurrent laryngeal nerve (RLN) injury. In the Chinese subgroup, the pCND with TT group had a significantly higher incidence rate of both temporary HPT (87/374, 23.26% vs. 36/324, 11.11%; OR = 2.24; 95% CI 1.32-3.81) and permanent HPT (21/374, 5.61% vs. 4/324, 1.23%; OR = 3.58; 95% CI = 1.24-10.37) than that of the TT alone group, while no significant difference was detected in the rate of LRR and temporary and permanent RLN injury.

Conclusion

Compared with the TT alone for cN0 PTC patients, pCND with TT had a significantly lower LRR rate while having a higher temporary HPT rate in Europe, America, and Australia; however, it showed no significant difference in decreasing LRR rate while having a significantly raised rate of temporary and permanent HPT in China. More population-based results are required to advocate precision medicine in PTC.

Systematic review registration

https://www.crd.york.ac.uk/PROSPERO/, identifier CRD42022358546.

Scope of prophylactic lymph node dissection in the surgical treatment of differentiated thyroid cancer. Recommendations of the AFCE (Association francophone de chirurgie endocrinienne) with the SFE (Société française d'endocrinologie) and the SFMN (Société française de médecine nucléaire)

Prophylactic lymph node dissection is considered only for papillary cancers. It is not indicated for vesicular cancers or oncocytic cancers, nor should it entail a secondary surgical intervention in the event of an incidental discovery of papillary cancer on a thyroidectomy specimen. Prophylactic lymph node dissection means a cervical lymph node dissection in the absence of any pre- or intraoperative evidence (biological, cytological, histological, clinical or ultrasound) of lymph node metastases. There is currently no evidence in the literature that prophylactic central dissection improves overall survival, which is similar for N0 and NX patients. Yet although prophylactic lymph node dissection is not justified by overall survival, it does seem to reduce the risk of locoregional recurrence in the case of micro-N1, and it allows occult metastases to be detected and a tumour to be reclassified. This enables patients at risk of recurrence to be more surely identified and therapeutic strategy and follow-up adapted accordingly. Prophylactic homolateral central lymph node dissection is warranted for papillary cancers with largest ultrasound diameter 4cm and above and/or with intraoperative macroscopic evidence of perithyroid tissue invasion. The benefits and risks of lymph node dissection must be assessed and discussed on a case-by-case basis. Only a central lymph node dissection homolateral to the tumour is recommended, except for bilateral or isthmic cancers, for which a prophylactic bilateral central lymph node dissection may be considered. This bilateral lymph node dissection incurs an increased risk of complications (parathyroids, recurrent laryngeal nerve). Prophylactic lateral lymph node dissection is not recommended.

Nomogram prediction for cervical lymph node metastasis in multifocal papillary thyroid microcarcinoma

Aim

Accurate preoperative prediction of cervical lymph node metastasis (LNM) in patients with mPTMC provides a basis for surgical decision making and the extent of tumor resection. This study aimed to develop and validate an ultrasound radiomics nomogram for the preoperative assessment of LN status.

Methods

A total of 450 patients pathologically diagnosed with mPTMC were enrolled, including 348 patients in the modeling group and 102 patients in the validation group. Univariate and multivariate logistic regression analyses were performed on the basic information, ultrasound characteristics, and American College of Radiology Thyroid Imaging Reporting and Data System (ACR TI-RADS) scores of the patients in the modeling group to identify independent risk factors for LNM in mPTMC and to construct a logistic regression equation and nomogram to predict the risk of LNM. The validation group data were used to evaluate the predictive performance of the nomogram.

Results

Male sex, age <40 years, a single lesion with a maximum diameter >0.5 cm, capsular invasion, a maximum ACR score >9 points, and a total ACR score >19 points were independent risk factors for the development of cervical LNM in mPTMC. Both the area under the curve (AUC) and concordance index (C-index) of the prediction model constructed from the above six factors were 0.838. The calibration curve of the nomogram was close to the ideal diagonal line. Furthermore, decision curve analysis (DCA) demonstrated a significantly greater net benefit of the model. The external validation demonstrated the reliability of the prediction nomogram.

Conclusions

The presented radiomics nomogram, which is based on ACR TI-RADS scores, shows favorable predictive value for the preoperative assessment of LNs in patients with mPTMC. These findings may provide a basis for surgical decision making and the extent of tumor resection.

Recent Advances in the Surgical Management of Thyroid Cancer

A growing incidence of differentiated thyroid cancer (DTC) has been reported in most developed countries, corresponding mainly to incidentally discovered small papillary thyroid carcinomas. Given the excellent prognosis of most patients with DTC, optimal therapeutic management, minimizing complications, and preserving patient quality of life are essential. Thyroid surgery has a central role in both the diagnosis, staging, and treatment of patients with DTC. Thyroid surgery should be integrated into the global and multidisciplinary management of patients with DTC. However, the optimal surgical management of DTC patients is still controversial. In this review article, we discuss the recent advances and current debates in DTC surgery, including preoperative molecular testing, risk stratification, the extent of thyroid surgery, innovative surgical tools, and new surgical approaches.

ESTIMation of the ABiLity of prophylactic central compartment neck dissection to modify outcomes in low-risk differentiated thyroid cancer: a prospective randomized trial

BACKGROUND

Prophylactic central neck dissection in clinically low-risk cT1bT2N0 papillary thyroid carcinoma is controversial, due to a large number of conflicting retrospective studies, some showing an advantage in terms of locoregional recurrence, others showing no advantage. These previous studies all show high rates of excellent response. We aim to demonstrate the non-inferiority of thyroidectomy alone as compared to total thyroidectomy with prophylactic central neck dissection in conjunction with adjuvant RAI 30 mCi with rTSH stimulation in terms of excellent response at 1 year.

TRIAL DESIGN AND METHODS

Prospective randomized open multicenter phase III trial including patients with 11-40-mm papillary thyroid carcinoma (Bethesda VI) or suspicious cytology (Bethesda V) confirmed malignant on intra-operative frozen section analysis, with no suspicious lymph nodes on a specialized preoperative ultrasound examination. Patients will be randomized 1:1 into two groups: the reference group total thyroidectomy with bilateral prophylactic central neck dissection, and the comparator group total thyroidectomy alone. All patients will receive an ablative dose of 30mCi of radioactive iodine (RAI) within 4 months of surgery. The primary outcome is to compare the rate of excellent response at 1 year after surgery between the groups, as defined by an unstimulated serum thyroglobulin (Tg) level ≤ 0.2 ng/mL with no anti-Tg antibodies, an normal neck ultrasound and no ectopic uptake on the post-RAI scintiscan. Non-inferiority will be demonstrated if the rate of patients with excellent response at 1 year after randomization does not differ by more than 5%. Setting the significance level at 0.025 (one-sided) and a power of 80% requires a sample size of 598 patients (299 per group). Secondary outcomes are to compare Tg levels at 8 +/- 2 postoperative weeks, before RAI ablation, the rate of excellent response at 3 and 5 years, the rate of other responses at 1, 3, and 5 years (biochemical incomplete, indeterminate, and structurally incomplete responses), complications, quality of life, and cost-utility.

DISCUSSION (POTENTIAL IMPLICATIONS)

If non-inferiority is demonstrated with this high-level evidence, prophylactic neck dissection will have been shown to not be necessary in clinically low-risk papillary thyroid carcinoma.

TRIAL REGISTRATION

NCT03570021. June 26,2018.

A Nod to the Nodes: An Overview of the Role of Central Neck Dissection in the Management of Papillary Thyroid Carcinoma

Lymph node metastasis in thyroid cancer is common and associated with an increased risk of locoregional recurrence (LRR). Although therapeutic central neck dissection is well established, prophylactic central node dissection (pCND) for microscopic occult nodal involvement is controversial and recommendations are based on low-level evidence. The potential benefits of pCND such as reducing LRR and re-operation, refining staging, and improving surveillance are enthusiastically debated and the decision to perform pCND must be weighed up against the increased risks of complications.

Risk staging with prophylactic unilateral central neck dissection in low-risk papillary thyroid carcinoma

OBJECTIVE

Current guidelines favor thyroid lobectomy for intrathyroidal cT1bT2cN0 papillary thyroid carcinoma. Prophylactic neck dissection (PND) is not recommended for these low-risk tumors due to the lack of high-level evidence on improvement in outcomes, but the information from PND may be used for staging. The aim of this study was to evaluate the rate of upstaging with ipsilateral PND.

MATERIALS AND METHODS

Retrospective study of patients with intrathyroidal unifocal cT1bT2cN0 papillary thyroid carcinoma from 2008 to 2021. All patients underwent total thyroidectomy and PND. Tumors were classified as low or intermediate risk based on the information from pathological analysis of the primary tumor and then from adding the analysis of the lymph nodes. The difference between the tumor-only and the PND-added risk staging was evaluated.

RESULTS

Three hundred three patients (241 women, median age 45, median tumor size 17 mm) were included. Microscopic extrathyroidal extension was found in 23.4%, aggressive histology in 6.6%, vascular invasion in 29.3%, and lymph node metastases in 37.3%. One hundred ten patients (36.3%) were intermediate-risk based on the primary tumor. An additional 26 (8.6%) were upstaged to intermediate-risk based on the ipsilateral PND and 2% based on the contralateral PND. Kaplan-Meier 10-year event-free survival in tumors upstaged with ipsilateral PND was not statistically different from intermediate-risk tumors based on the primary tumor characteristics (92% versus 90.9%, Log Rank p = 0.943).

CONCLUSIONS

Ipsilateral PND upstaged low-risk cT1bT2cN0 patients to intermediate risk in only 8.6% of cases, and contralateral PND in an additional 2%. Routinely performing PND may not be warranted.

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.

Effect of prophylactic central neck dissection following total thyroidectomy on surgical site wound infection, hematoma, and haemorrhage in subjects with clinically node-negative papillary thyroid carcinoma: A meta-analysis

We performed a meta-analysis to evaluate the effect of prophylactic central neck dissection following total thyroidectomy on surgical site wound infection, hematoma, and haemorrhage in subjects with clinically node-negative papillary thyroid carcinoma. A systematic literature search up to April 2022 was performed and 3517 subjects with clinically node-negative papillary thyroid carcinoma at the baseline of the studies; 1503 of them were treated with prophylactic central neck dissection following total thyroidectomy, and 2014 were using total thyroidectomy. Odds ratio (OR) with 95% confidence intervals (CIs) were calculated to assess the effect of prophylactic central neck dissection following total thyroidectomy on surgical site wound infection, hematoma, and haemorrhage in subjects with clinically node-negative papillary thyroid carcinoma using the dichotomous method with a random or fixed-effect model. The prophylactic central neck dissection following total thyroidectomy subjects had a significantly lower surgical site wound infection (OR, 0.40; 95% CI, 0.20-0.78, P = .007) in subjects with clinically node-negative papillary thyroid carcinoma compared with total thyroidectomy. However, prophylactic central neck dissection following total thyroidectomy did not show any significant difference in hematoma (OR, 0.08; 95% CI, 0.43-2.71, P = .87), and haemorrhage (OR, 0.72; 95% CI, 0.26-1.97, P = .52) compared with total thyroidectomy in subjects with clinically node-negative papillary thyroid carcinoma. The prophylactic central neck dissection following total thyroidectomy subjects had a significantly higher surgical site wound infection, and no significant difference in hematoma, and haemorrhage compared with total thyroidectomy in subjects with clinically node-negative papillary thyroid carcinoma. The analysis of outcomes should be with caution because of the low number of studies in certain comparisons.

En bloc resection of total thyroid and bilateral central compartment lymph nodes via a gasless transoral approach in papillary thyroid carcinoma

INTRODUCTION

The current study presents a preliminary exploration of en bloc resection via a gasless transoral approach in papillary thyroid carcinoma.

OBJECTIVE

This study aimed to summarize and explore the efficacy and safety of en bloc resection of total thyroid and bilateral central compartment lymph nodes via a gasless transoral approach in patients with papillary thyroid carcinoma.

METHODS

This study was conducted between January 2021 and December 2021. It involved 30 patients with bilateral papillary thyroid carcinoma who had undergone en bloc resection of the total thyroid and bilateral central compartment lymph nodes via a gasless transoral approach using a three-trocar and four-instrument technique at The First Affiliated Hospital of the University of Science and Technology of China. The key steps and difficulties of the operation were summarized, and the clinicopathological characteristics and surgical complications of patients were analyzed.

RESULTS

All operations were successful without conversion to open surgery. The pathological diagnosis was bilateral papillary thyroid carcinoma. The mean maximum tumor diameter was 0.85 ± 0.51 cm (range 0.3-2.5 cm). There was no case of gross capsular invasion. The mean number of harvested central compartment lymph nodes was 11.36 ± 5.36. Central compartment lymph node metastases were found in 16 patients (53.3%) with a mean of 1.53 ± 2.39. On the other hand, lymphocytic thyroiditis was observed in 12 cases (40%), and microscopic capsular invasion was observed in five cases (16.6%). All patients had normal parathyroid hormone levels after the operation. However, one patient developed hoarseness after the operation due to injury of the recurrent laryngeal nerve branch, but there was no numbness of the mandible and lower lip or infection of the oral incision.

CONCLUSION

The study revealed that the three-trocar and four-instrument technique can be used in the en bloc resection of total thyroid and bilateral central compartment lymph nodes via a gasless transoral approach without disconnecting the thyroid isthmus. As a result, the operation is considered effective and safe. Therefore, this technique may be a better surgical method for patients with bilateral thyroid cancer and cosmetic needs.

Evaluation of the role of prophylactic bilateral central neck lymph node dissection in patients with papillary thyroid carcinoma: a case controlled study

Thyroid cancer is the most common malignancy in the endocrine system. Papillary thyroid carcinoma (PTC) is the most common differentiated thyroid cancer. There are considerable discrepancies regarding the role and extent of prophylactic central lymph node dissection (PCLND) for patients with PTC. Our primary goal was the evaluation of CLN involvement based on the tumor features and staging on the eight version of the American Joint Committee on Cancer and also the TNM method. Our secondary aim was to evaluate the features of the CLNs with tumoral features and also features associated with the development of transient hypoparathyroidism. This prospective case-controlled study was performed among PTC patients. Total thyroidectomy and bilateral dissection of the CLNs of the central compartment of the neck was performed, and samples were sent for pathological evaluation. CLN involvement, tumoral features and transient hypoparathyroidism were cross-evaluated and analyzed with SPSS version 26.0. In this study, out of 61 patients, 11 (18%) were male, the average age was 37.3 ± 13.7 years, based on AJCC staging, 53 (86.9%) were stage I and 8 (13.1%) were stage II, and based on TNM staging, 39 patients (66.1%) were T1, including 13 (22.0%) T1a and 26 (44.1%) T1b, 15 patients (25.4%) were T2, and five patients (8.5%) were T3. Based on permanent pathology evaluation, the majority of patients (n = 48; 78.7%) had CLN involvement. None of the preoperative and tumor features had a significant association with CLN involvement. 75% of stage I and 100% of stage two cases, while 76.9% of T1, 86.7% of T2, and 80.0% of T3 cases had CLN involvement. There was no significant association between the involvement of CLN and the AJCC staging (P = 0.184) or TNM staging (P = 0.875). The involved to dissected CLN ratio was significantly higher in stage II patients compared to stage I (72.5 vs. 34.8%; P = 0.006), and also with higher T staging (0.009). There was a statistically significant association between the larger CLN size and older patients' age, higher postoperative thyroglobulin levels, and smaller tumor size. Higher postoperative thyroglobulin level was significantly associated with larger tumors size and thyroid capsule invasion. Also, 26 (44.8%) of patients developed transient hypoparathyroidism, which was significantly associated with vascular invasion (P = 0.048), bilateral location of tumor (P = 0.048) or on the right side (0.005), and larger size of the tumor (P = 0.016). Tumor features and staging were not associated with CLN involvement features. Therefore, full extent PCLND should be carried out to avoid reoperation or metastasis in PTC patients.

Microbubble contrast agent SonoVue: An efficient medium for the preoperative lymphatic mapping of thyroid carcinoma

Objective: To assess the value of microbubble contrast agent SonoVue in the thorough preoperative lymphatic mapping of patients with thyroid carcinoma, including the lymphatic drainage region, the detection of sentinel lymph node (SLN), and the diagnosis of lymph node metastasis (LNM). Materials and methods: 55 patients with 62 thyroid malignancies proved by surgical pathology (59 papillary thyroid carcinomas and three medullary thyroid carcinomas) who underwent preoperative lymphatic contrast-enhanced ultrasound (LCEUS) with microbubble contrast agent SonoVue were enrolled. All LNM were confirmed by pathology. The location of thyroid lesions, ultrasonic features of lymph nodes, lymphatic drainage region, and detection of SLN were assessed. The diagnostic performance (sensitivity, specificity, positive predictive value, negative predictive value and accuracy) of different parameters for the LNM diagnosis was calculated. Results: SonoVue effectively demonstrated the lymphatic drainage region for all enrolled thyroid carcinomas. The most common lymphatic drainage region for thyroid carcinomas was region VI (93.55%), followed by region III (62.90%), region IV (48.39%) and region II (4.84%). When divided by the lesion location, the most common lymphatic drainage regions for the nodule in isthmus, superior lobe and inferior lobe of the thyroid were region VI, region III, and region VI respectively. SLN was detected in 96.77% (60/62) of cases. The two cases without SLN demonstration had pathologically proven LNM. The most common sonographic sign of LNM was perfusion defect (54.17%). The diagnostic accuracy of SonoVue in central and lateral compartment LNM was 86.67% and 91.67%, respectively. Conclusion: Microbubble contrast agent SonoVue is a valuable imaging contrast medium for thorough preoperative lymphatic mapping in patients with thyroid carcinoma, including the lymphatic drainage region, the detection of SLN, and the diagnosis of LNM. LCEUS with SonoVue alone has limitations of false negatives when there is lymphatic vessel obstruction and may need to be combined with other ultrasound modalities.

SFE-AFCE-SFMN 2022 consensus on the management of thyroid nodules: Surgical treatment

The SFE-AFCE-SFMN 2022 consensus deals with the management of thyroid nodules, a condition that is a frequent reason for consultation in endocrinology. In more than 90% of cases, patients are euthyroid, with benign non-progressive nodules that do not warrant specific treatment. The clinician's objective is to detect malignant thyroid nodules at risk of recurrence and death, toxic nodules responsible for hyperthyroidism or compressive nodules warranting treatment. The diagnosis and treatment of thyroid nodules requires close collaboration between endocrinologists, nuclear medicine physicians and surgeons, but also involves other specialists. Therefore, this consensus statement was established jointly by 3 societies: the French Society of Endocrinology (SFE), French-speaking Association of Endocrine Surgery (AFCE) and French Society of Nuclear Medicine (SFMN); the various working groups included experts from other specialties (pathologists, radiologists, pediatricians, biologists, etc.). This section deals with the surgical management of thyroid nodules.

Evaluation of recurrence risk in patients with papillary thyroid cancer through tumor-node-metastasis staging: A single-center observational study in Taiwan

BACKGROUND

Many patients with papillary thyroid cancer (PTC) demonstrate satisfactory outcomes. However, 8%-28% of patients with PTC show tumor recurrence, which may affect prognosis. Therefore, identifying factors associated with tumor recurrence in patients with PTC may be helpful to refine therapeutic strategies.

METHODS

To identify factors associated with PTC recurrence, we retrospectively reviewed demographic features (sex and age), operation method, image character, serum thyroglobulin (Tg), accumulated radioactive iodine (I-131) therapeutic dose, I-131 uptake, and metastases at diagnosis in 829 patients with PTC. Patients were grouped into early (stage I and II; n = 698) and advanced (stage III and IV; n = 131) tumor-node-metastasis (TNM) stages. Recurrence rate, mortality rate, risk factors of recurrence, recurrent free survival and overall survival curve were compared between two groups.

RESULTS

Patients in the early stage demonstrated a lower recurrence rate (7.2%) than did those in the advanced stage (28.2%, p < 0.05). The mortality rate of patients with recurrence in the advanced stage was higher than that of those in the early stage (51.4% vs. 12.0%). The major impact factors on tumor recurrence in early TNM stage were distant metastasis and lymph node metastasis, while in advanced TNM stage were distant metastasis, male gender, total thyroidectomy with limited lymph node dissection, and a high serum Tg level.

CONCLUSIONS

Strategies to monitor tumor recurrence might be refined according to the TNM stages of PTC patients.

Impact of Lymph Node Dissection on Postoperative Complications of Total Thyroidectomy in Patients with Thyroid Carcinoma

Background: Lymph node dissection (LND) in primary treatment of differentiated thyroid carcinoma is controversial. The aim of our retrospective study was to analyse the risk factors of post-thyroidectomy complications and to assess the morbidity of lymph node dissection, especially in the central neck compartment, since prophylactic central lymph node dissection has not been proven to bring an overall survival benefit. Methods: We performed a retrospective analysis of postoperative complications from 1547 consecutive patients with differentiated thyroid carcinoma in an academic department of endocrine surgery over a period of 10 years. Results: A total of 535 patients underwent lymph node dissection, whereas the other 1012 did not. The rate of postoperative hypoparathyroidism was higher in patients with LND (17.6% vs. 11.4%, p = 0.001). No significant difference in the rate of permanent hypoparathyroidism (2.4% vs. 1.3%, p = 0.096) was observed between these two groups. A multivariate analysis was performed. Female gender, ipsilateral and bilateral central LND (CLND), parathyroid autotransplantation, and the presence of the parathyroid gland on the resected thyroid were associated with transient hypoparathyroidism. Bilateral CLND and the presence of the parathyroid gland on specimen were associated with permanent hypoparathyroidism. The rate of transient recurrent laryngeal nerve (RLN) injury (15.3% vs. 5.4%, p < 0.001) and permanent RLN injury (6.5% vs. 0.9%, p < 0.001) were higher in the LND group. In multivariate analysis, ipsilateral and bilateral lateral LND (LLND) were the main predictive factors of transient and permanent RLN injury. Bilateral RLN injury (2.6% vs. 0.4%, p < 0.001), chyle leakage (2.4% vs. 0%, p < 0.001), other nerve injuries (2.2% vs. 0%, p < 0.001), and abscess (2.4% vs. 0.5%, p = 0.001) were higher in the patients with LND. Conclusions: The surgical technique and the extent of lymph node dissection during surgery for thyroid carcinoma increase postoperative morbidity. A wider knowledge of lymph-node-dissection-related complications associated with thyroid surgery could help surgeons to carefully evaluate the surgical and medical therapeutic options.

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.

Predictors of impaired effectiveness of carbon nanoparticle-based central lymph node tracing in patients who underwent surgery for papillary thyroid cancer: A retrospective cohort study

Carbon nanoparticles (CNs) are used in papillary thyroid cancer (PTC) surgery to facilitate central lymph node dissection (CLND) and protect the parathyroid glands (PGs). However, some cases develop hypoparathyroidism after using CNs. This cohort study was undertaken to explore the predictors of the reduced effectiveness of CNs. Data on patients with PTC who underwent surgery wherein CNs were used during CLND were reviewed retrospectively. Patients who did not develop hypoparathyroidism and developed hypoparathyroidism were classified into Group A and B, respectively. Demographic and clinical characteristics were compared between the 2 groups. Univariate and multivariate logistic regression analysis were performed on related variables. The receiver operating characteristic curve was used to evaluate the predictors of the binary logistic model and the cutoff value of each predictor was obtained. A total of 265 patients were included. Compared with Group A, the patients in Group B had a higher body mass index (BMI) (P = .003), were more frequently associated with Hashimoto thyroiditis (HT) (P = .001), and tumors were larger in size (P = .026). Multivariate logistic regression analyses were performed on these variables and showed that HT (P = .001) and tumor size (P = .001) predicted the impaired role of CNs. CNs are not always useful in protecting PG function in patients who undergo CLND for PTC. In patients with coexisting HT (blood thyroid peroxidase antibody [TPOAb] level higher than 44.0 IU/mL or blood anti-thyroglobulin antibody [ATG] level higher than 125.0 IU/mL) or a tumor size exceeding 1.1 cm in diameter, the protective role of CNs may be impaired.

Central Lymph Node Ratio Predicts Recurrence in Patients with N1b Papillary Thyroid Carcinoma

Simple Summary

The lymph node ratio (LNR) is an emerging predictive marker for recurrence in papillary thyroid carcinoma (PTC). The purpose of this study was to investigate the association between LNR and disease-free survival (DFS) in patients with N1b PTC. Unlike that in the lateral or whole neck, LNR in the central compartment (CLNR) was found to have prognostic significance. The high-CLNR group (CLNR ≥ 0.7) had worse DFS and was 4.5 times more likely to experience recurrence in patients with N1b PTC.

Abstract

The lymph node ratio (LNR) indicates the number of metastatic lymph nodes (LNs) to the total number of LNs. The prognostic value of LNR in papillary thyroid carcinoma (PTC) and other solid tumors is known. This study aimed to investigate the relationship between LNR and disease-free survival (DFS) in patients with PTC with lateral LN metastases (N1b PTC). A total of 307 patients with N1b PTC who underwent total thyroidectomy and therapeutic central and lateral LN dissection were retrospectively analyzed. The DFS and recurrence risk in the patients with LNR, central-compartment LNR (CLNR), and lateral-compartment LNR (LLNR) were compared. The mean follow-up duration was 93.6 ± 19.9 months. Eleven (3.6%) patients experienced recurrence. Neither LNR nor LLNR affected the recurrence rate in our analysis (p = 0.058, p = 0.106, respectively). However, there was a significant difference in the recurrence rates between the patients with low and high CLNR (2.1% vs. 8.8%, p = 0.017). In the multivariate analysis, CLNR ≥ 0.7 and perineural invasion were independent predictors of tumor recurrence. High CLNR was associated with an increased risk of recurrence, and was shown to be a significant predictor of prognosis in patients with N1b PTC.

Role and Extent of Neck Dissection for Neck Lymph Node Metastases in Differentiated Thyroid Cancers

Differentiated thyroid cancers (DTC) consist of 95% of thyroid tumors and include papillary thyroid cancer (PTC), follicular thyroid cancer (FTC), and Hurthle cell thyroid cancer (HTC). Rates of lymph node metastases are different depending on histologic subtypes and <5% in FTC and between 5% and 13% in HTC. Lymph node metastasis is more frequent in PTC and while rate of clinical metastasis can be seen approximately 30% rate of routine micrometastasis can be seen up to 80%. Lymph node metastasis of DTC mostly develops first in the Level VI lymph nodes at the central compartment starting from the ipsilateral paratracheal lymph nodes and then spreading to the contralateral paratracheal lymph nodes. Spread to the Level VII is mostly after Level VI invasion. Subsequent spread is to the lateral neck compartments of Levels IV, III, IIA, and VB and sometimes to the Levels IIB and VA. Occasionally skip metastasis to the lateral neck compartments develop without spreading to the central compartments and this situation is more frequent in upper pole tumors. Although application of prophylactic central neck dissection (pCND) in DTC increases the rate of complication, due to its unclear effects on oncologic results and quality of life, the interest to the pCND is decreasing and debate on its surgical extent is increasing. pCND is not essential in DTC and characteristics of patient and tumor and experience of surgeon should be considered when deciding for pCND. Due to lower complication rate of one sided pCND compared to bilateral central neck dissection (CND), low possibility of contralateral central neck metastasis and low risk of recurrence, application of one-sided CND is logical. Although therapeutic CND (tCND) is the standart treatment when there is a clinically involved lymph node, extent of dissection is a matter of debate. A case-based decision for the extent of tCND can be made by considering patient and tumor characteristics and experience of the surgeon. Due to the higher complication risk of bilateral CND, unilateral tCND can be performed if there is no suspicious lymph node on the contralateral side and bilateral tCND can be applied when there is a suspicion for metastasis only on the contralateral side or there are features for risk of metastasis to the contralateral side. In patients with clinical central metastasis owing to intra-operative pathology results by frozen section procedure are compatible with post-operative pathology results, when there is a suspicion for contralateral metastasis, a decision for one- or two-sided dissection can be made using frozen section procedure. In DTC, it can be stated that there is a consensus in the literature about not performing prophylactic lateral neck dissection (LND), but performing therapeutic LND (tLND). In addition, there is a debate on the extent of tLND. In a meta-analysis about lateral metastasis, the rates of metastasis to the Levels IIA, IIB, III, IV, VA, and VB were 53.1%, 15.5%, 70.5%, 66.3%, 7.9%, and 21.5%, respectively. Ultrasonography (USG) is an effective procedure for detection of cervical nodal metastasis on lateral compartment. Pre-operative imaging with USG and/or combination with the fine needle aspiration biopsy (cytology/molecular test/Thyroglobulin test) can allow pre-operative detection and verification of lateral lymph node metastasis. Extent of tLND can be determined to minimize morbidity considering pre-operative USG findings, pre-operative tumor and clinical features of lateral metastasis. Especially in the presence of limited lateral metastases, limited selective LND such as Levels III, IV or Levels IIA, III, IV can be applied according to the patient. Levels IIB and VB should be added to the dissection in the presence of metastases in these regions. In cases that increase the risk of Level IIB involvement, such as presence of metastasis at Level IIA, extranodal tumor involvement, presence of multifocal tumor, and in cases that increase the risk of Level VB involvement such as macroscopic extranodal spread, and simultaneous metastases at Levels II, III, IV; Levels IIB and VB can be added to dissection material. Levels I and VA should be added to the dissection in the presence of clinically detected metastases.

Preoperative Prediction of Central Cervical Lymph Node Metastasis in Fine-Needle Aspiration Reporting Suspicious Papillary Thyroid Cancer or Papillary Thyroid Cancer Without Lateral Neck Metastasis

Purpose

No non-invasive method can accurately determine the presence of central cervical lymph node (CCLN) metastasis in papillary thyroid cancer (PTC) until now. This study aimed to investigate factors significantly associated with CCLN metastasis and then develop a model to preoperatively predict CCLN metastasis in fine-needle aspiration (FNA) reporting suspicious papillary thyroid cancer (PTC) or PTC without lateral neck metastasis.

Patients and Methods

Consecutive inpatients who were diagnosed as suspicious PTC or PTC in FNA and underwent partial or total thyroidectomy and CCLN dissection between May 1^st, 2016 and June 30^th, 2018 were included. The total eligible patients were randomly divided into a training set and an internal validation set with the ratio of 7:3. Univariate analysis and multivariate analysis were conducted in the training set to investigate factors associated with CCLN metastasis. The predicting model was built with factors significantly correlated with CCLN metastasis and validated in the validation set.

Results

A total of 770 patients were eligible in this study. Among them, 268 patients had histologically confirmed CCLN metastasis, while the remaining patients did not. Factors including age, BRAF mutation, multifocality, size, and capsule involvement were found to be significantly correlated with the CCLN metastasis in univariate and multivariate analysis. A model used to predict the presence CCLN metastasis based on these factors and US CCLN status yielded AUC, sensitivity, specificity and accuracy of 0.933 (95%CI: 0.905-0.960, p < 0.001), 0.816, 0.966 and 0.914 in the training set and 0.967 (95%CI: 0.943-0.991, p < 0.001), 0.897, 0.959 and 0.936 in the internal validation set.

Conclusion

Age, BRAF mutation, multifocality, size, and capsule involvement were independent predictors of CCLN metastasis in FNA reporting suspicious PTC or PTC without lateral neck metastasis. A simple model was successfully built and showed excellent discrimination to distinguish patients with or without CCLN metastasis.

Hemithyroidectomy and ipsilateral central neck dissection for T1 low-risk papillary thyroid cancer: single-institution retrospective observational study

OBJECTIVE

The aim of this study was to report the rationale and selection criteria for hemithyroidectomy and ipsilateral central neck dissection in patients with selected papillary thyroid cancer and to report the surgical and oncological outcomes.

DESIGN

Single-institution retrospective observational study.

METHODS

The clinical records of patients with a histopathological diagnosis of low-risk pT1 papillary thyroid cancer who underwent hemithyroidectomy with or without ipsilateral central neck dissection between March 2000 and April 2018 at a tertiary referral center were retrospectively reviewed. Demographic, clinical, and histopathological data were collected.

RESULTS

During the study period, 176 patients underwent hemithyroidectomy for PTC. Thirteen patients (13/176, 7.39%) were lost to follow-up and 74 patients (74/163 45.40%) underwent completion thyroidectomy within 1 month because they were classified intermediate ATA initial risk based on definitive pathology. The final study group was composed of 89 patients, who had a median follow-up of 5.3 years. The mean follow-up was 6.3 years (range: 36-207 months). Eighty-four patients (94.38%) did not experience recurrence in the follow-up period. A total of 5/89 patients (5.62%) underwent delayed completion thyroidectomy with or without neck dissection for recurrent malignancy in the residual lobe (3/5) or regional lymph nodes (2/5). The median time from surgery to recurrence was 24.8 months (range: 6-60). The follicular variant was an independent risk factor for recurrence.

CONCLUSIONS

Hemithyroidectomy with or without prophylactic ipsilateral central neck dissection is a valuable treatment option in selected low-risk papillary thyroid cancers and ensures a low risk of recurrence. Prophylactic ipsilateral central compartment dissection could have a role in improving cancer staging, and accurate ultrasonographic follow-up is essential to identify local recurrence.

Risk Factors for Central Lymph Node Metastases and Benefit of Prophylactic Central Lymph Node Dissection in Middle Eastern Patients With cN0 Papillary Thyroid Carcinoma

Background

Prophylactic central lymph node dissection (PCLND) for adult patients with papillary thyroid carcinoma (PTC) is still a matter of debate. Data on incidence, risk and benefits of PCLND in Middle Eastern patients is lacking. Therefore, we aimed to identify the incidence and predictive clinico-pathological and molecular marker of PCLND in adult patients with clinically node negative (cN0) Middle Eastern PTC.

Methods

This retrospective study included 942 adult Middle Eastern patients with cN0 PTC who underwent total thyroidectomy (TT) or TT+PCLND. Clinico-pathological associations of central lymph node metastasis (CLNM) were assessed. Multivariate analysis was performed using logistic regression and Cox proportional hazards model.

Results

213 patients underwent PCLND and 38.0% (81/213) had positive CLNM. Multivariate analysis demonstrated age ≤55 years (Odds Ratio (OR) = 7.38; 95% Confidence Interval (CI) = 1.59 – 34.31; p = 0.0108), tumor bilaterality (OR = 3.01; 95% CI = 1.01 – 9.21; p = 0.0483), lymphovascular invasion (OR = 2.92; 95% CI = 1.18 – 7.23; p = 0.0206) and BRAF mutation (OR = 3.24; 95% CI = 1.41 – 7.49; p = 0.0058) were independent predictors of CLNM in adult PTC. Furthermore, patients who underwent PCLND showed significant association with improved recurrence-free survival (RFS; p = 0.0379). Multivariate analysis demonstrated that PCLND was an independent predictor of improved recurrence-free survival.

Conclusions

cN0 Middle Eastern PTC patients treated with PCLND showed a significantly better prognosis. PCLND was effective in improving RFS in Middle Eastern PTC patients and should be encouraged for patients with potential risk factors for CLNM.

Prophylactic Central Neck Dissection for cN1b Papillary Thyroid Carcinoma: A Systematic Review and Meta-Analysis

Background

The value of prophylactic central neck dissection (PCND) for papillary thyroid carcinoma (PTC) with clinically evident lateral cervical lymph node metastases (cN1b) remains unclear. Therefore, a systematic review and meta-analysis was conducted to assess the efficacy and safety of PCND.

Methods

A comprehensive systematic search was conducted on PubMed, Web of Science, Cochrane library and Embase databases up to September 2021 to identify eligible studies. Controlled clinical trials assessing therapeutic effects and safety of PCND for cN1b PTC patients were included. The risk of bias for each cohort study was assessed using the Newcastle-Ottawa Scale (NOS). The primary outcomes were indexes related to the locoregional recurrence (LRR) and surgical complications. Review Manager software V5.4.0 was used for statistical analysis. A fixed effects model was adopted for the data without heterogeneity, otherwise a random effects model was used.

Results

We included 4 retrospective cohort studies, which comprised 483 PTC patients. There was no statistically significant difference in the central neck recurrence (CNR) (10.2% vs. 3.8%, relative risk (RR) = 1.82; 95%CI 0.90–3.67; P = 0.09), lateral neck recurrence (LNR) (5.1% vs. 7.7%, RR = 0.47; 95% CI 0.13–1.74; P = 0.26), and overall recurrence (OR) (18.9% vs. 16.9%, RR = 0.77; 95%CI 0.34–1.76; P = 0.54), between LND + PCND group and LND group. Simultaneously, PCND increased the risk of permanent hypoparathyroidism (11.4% vs. 4.5%, RR = 2.70, 95%CI 1.05–6.94; P = 0.04) and overall complications (17.0% vs. 5.3%, RR = 3.28; 95%CI 1.37–7.86; P = 0.008).

Conclusions

This meta-analysis showed that PCND did not have any advantage in preventing LRR for cN1b PTC. Meanwhile, PCND may result in the increased rate of surgical complications. However, the current evidence is limited and more clinical trials are still needed to further clarify the true role of PCND.

Systematic Review Registration

https://www.crd.york.ac.uk/PROSPERO/, CRD42021281825.