Is a Prophylactic Central Compartment Neck Dissection Required in Papillary Thyroid Carcinoma Patients with Clinically Involved Lateral Compartment Lymph Nodes?

Can Unilateral Therapeutic Central Lymph Node Dissection Be Performed in Papillary Thyroid Cancer with Lateral Neck Metastasis?

Objectives

Unilateral or bilateral prophylactic central neck dissection (CND) in papillary thyroid cancer (PTC) is still controversial. We aimed to evaluate the risk factors for contralateral paratracheal lymph node metastasis and whether CND might be performed unilaterally.

Methods

Prospectively collected data of patients who underwent bilateral CND and lateral neck dissection (LND) with thyroidectomy due to PTC with lateral metastases, between January 2012 and November 2019, were evaluated retrospectively. The patients were divided into two groups according to the presence (Group 1) and absence (Group 2) of metastasis in the contralateral paratracheal region.A total of 42 patients (46 ±15.7 years) were operated. In the contralateral paratracheal region, Group 1 (35.7%) had metastases, while Group 2 (64.3%) had no metastases. In groups 1 and 2, metastasis rates were 100% vs 77.8% (p=0.073), 46.7% vs 18.5% (p=0.078), and 80% vs 40.7% (p=0.023) for the ipsilateralparatracheal, prelaryngeal and pretracheal lymph nodes, respectively.The number of metastatic lymph nodes in the central region was significantly higher in Group 1 compared to Group 2 as; 10.7±8.4 vs. 2.6±2.4 (p=0.001) in bilateral central region material; 8.3±7.4 vs. 2.9±2.7 (p=0.001) in lateral metastasis with ipsilateral unilateral central region; 3.8±3.4 vs. 1.9±1.9 (p=0.023) in ipsilateralparatracheal area; and 3.7±4.6 vs. 0.6±0.9 (p=0.001) in pretracheal region, respectively. However, no significant difference was found regarding the prelaryngeal region material (0.9±1.8 vs. 0.2±0.4 (p=0.71)).

Results

>2 metastatic central lymph nodes in unilateral CND material (AUC: 0.814, p<0.001, J=0.563) can estimate contralateral paratracheal metastasis with 93% sensitivity, 63% specificity, while >2 pretracheal metastatic lymph nodes (AUC: 0.795, p<0.001, J: 0.563) can estimate contralateral paratracheal metastasis with 60% sensitivity and 96.3% specificity.

Conclusion

In patients with lateral metastases, the rate of ipsilateralparatracheal metastasis is 85%, while the rate of contralateral paratracheal metastasis is 35.7%. The number of ipsilateral central region or pretracheal lymph node metastases may be helpful in predicting contralateral paratracheal lymph node metastases. Notably, unilateral CND may be performed in the presence of ≤ 2 metastases in the ipsilateral central region.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSION

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

Predictive factors for nodal recurrence in differentiated thyroid cancers

INTRODUCTION

Differentiated thyroid carcinoma usually has a good prognosis. Primary treatment is surgery, followed by radioactive iodine ablation based on risk stratification. The incidence of local and distant recurrence is 30%. Recurrence can be managed surgically or with multiple cycles of radioactive iodine ablation. There are multiple risk factors for structural disease recurrence proposed by the American Thyroid Association. In this study, we attempted to study the risk factors of structural recurrence in differentiated carcinoma thyroid and the pattern of recurrence in patients with node negative thyroid cancer who underwent total thyroidectomy.

METHODOLOGY

This study selected a retrospective cohort of 1498 patients with differentiated thyroid cancer: out of these, 137 patients who presented after thyroidectomy with cervical nodal recurrence from January 2017 to December 2020 were included. The risk factors for central and lateral lymph node metastasis were analysed by univariate and multivariate analyses, including age, gender, T-stage, extrathyroidal extension, multifocality and high-risk variants. In addition, the presence of TERT/BRAF mutations was studied as a risk factor for central and lateral nodal recurrence.

RESULTS

Out of 1498 patients, 137 who fit the inclusion criteria were analysed. Majority were female (73%); mean age was 43.1 years. Lateral compartment neck nodal recurrence was more common (84%), while isolated central compartment nodal recurrence occurred only in 16%. Most recurrences were seen in the first 1 year (23.3%) or after 10 years post-total thyroidectomy (35.7%). On univariate variate analysis, multifocality, extrathyroidal extension and high-risk variants stage were significant factors for nodal recurrence. However, on multivariate analysis for lateral compartment recurrence, multifocality, extrathyroidal extension and age were found to be significant. On multivariate analysis, multifocality, extrathyroidal extension and presence of high-risk variants were significant predictors of central compartment nodal metastasis. ROC curve analysis showed AUC for ETE (AUC-0.795), multifocality (AUC-0.860), presence of high-risk variants (AUC-0.727) and T-stage (AUC-0.771) as sensitive predictive factors for central compartment. 69 percent patients with very early recurrences (<6 month) had TERT/BRAF V600 E mutations.

CONCLUSION

In our study, we have noted extrathyroidal extension and multifocality as significant risk factors for nodal recurrence. BRAF and TERT mutations are associated with aggressive clinical course and early recurrences. There is limited role of prophylactic central compartment node dissection.

Extent of cervical lymph node dissection: Recommendations from the Francophone Association for Endocrine Surgery, the French Society of Endocrinology and the French Society of Nuclear Medicine

When metastatic ipsilateral central lymph nodes from thyroid cancer are identified pre- or intraoperatively (cN1a), ipsilateral central lymph node dissection should be performed concomitantly with thyroidectomy. When the patient is N1a on one side, contralateral prophylactic central lymph node dissection can also be considered. Prophylactic ipsilateral lymph dissection is not recommended. Ipsilateral compartment lymph node dissection is recommended in the corresponding sector for treatment of thyroid cancer with lymph node involvement (cN1b). Lymph node dissection can be limited to sectors III and IV when one of these sectors (or both) is involved and ultrasound does not demonstrate involvement of the other lateral sectors. Associated prophylactic lymph node dissection of sectors IIA and IIB is not recommended, while lymph node dissection of sector V (and exceptionally sector I) is indicated only when metastatic lymph nodes are proven. Prophylactic lymph node dissection of sector VB can be considered when positive lymph nodes are identified in sectors II, III and IV. When isolated metastatic lateral lymph nodes are identified (cN1b), prophylactic central (sector VI) lymph node dissection is recommended on the same side as the lateral compartment in addition to ipsilateral lateral lymph node compartment dissection. The level of evidence is insufficient to recommend prophylactic lateral lymph node dissection on the contralateral side for unilateral cN1b tumors. This type of lymph node dissection can be discussed for tumors that are at high risk of recurrence, bilateral tumors, in case of ipsilateral lateral lymph nodes > 3cm or in presence of > 4 metastatic lymph nodes in the central compartment.

The proposed modification of TNM staging and therapeutic strategy for skip metastasis in papillary thyroid carcinoma: A multicenter retrospective cohort study

BACKGROUND

Skip metastasis is a special type of lateral lymph node metastasis, which is not classified definitely by the eighth edition of the AJCC TNM staging system. The aim of the research was to study the prognosis of skip metastasis in PTC patients, and carry out a more appropriate N staging for skip metastasis.

METHODS

Study subjects were 3167 patients with papillary thyroid carcinoma (PTC), who underwent thyroidectomy at three clinical centers from 2016 to 2019. We identified two well-balanced cohorts matched on the basis of propensity score.

RESULTS

During a median follow-up of 42 months, recurrence occurred in 68 (4.3%) patients with lymph node metastasis. 34 cases recurred in 1120 patients with central lymph node metastasis (N1a), and 34 recurred in 461 patients with lateral lymph node metastasis (N1b), among which 73 patients were diagnosis with skip metastasis. The RFS of N1a was significantly lower than that of N1b (p < 0.001). After propensity-score matching, recurrence rate was significantly lower in the skip metastasis group than in the LLNM group (p = 0.039), whereas the rate was similar in the skip metastasis groups and the CLNM group (p = 0.29).

CONCLUSIONS

In conclusion, our study indicated that, among patients with LLNM, those with positive skip metastasis showed significantly lower recurrence, exhibiting a similar rucurrence tendency as patients with CLNM. Thus, skip metastasis could be categorized into N1a stage rather than N1b stage based on the AJCC TNM staging system. The downstaging of skip metastasis may reveal more conservative treatment strategy.

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.

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

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

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.

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.

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.

Predictors of Central Compartment Involvement in Patients with Positive Lateral Cervical Lymph Nodes According to Clinical and/or Ultrasound Evaluation

Lymph node neck metastases are frequent in papillary thyroid carcinoma (PTC). Current guidelines state, on a weak level of evidence, that level VI dissection is mandatory in the presence of latero-cervical metastases. The aim of our study is to evaluate predictive factors for the absence of level VI involvement despite the presence of metastases to the lateral cervical stations in PTC. Eighty-eight patients operated for PTC with level II–V metastases were retrospectively enrolled in the study. Demographics, thyroid function, autoimmunity, nodule size and site, cancer variant, multifocality, Bethesda and EU-TIRADS, number of central and lateral lymph nodes removed, number of positive lymph nodes and outcome were recorded. At univariate analysis, PTC location and number of positive lateral lymph nodes were risk criteria for failure to cure. ROC curves demonstrated the association of the number of positive lateral lymph nodes and failure to cure. On multivariate analysis, the protective factors were PTC located in lobe center and number of positive lateral lymph nodes < 4. Kaplan–Meier curves confirmed the absence of central lymph nodes as a positive prognostic factor. In the selected cases, Central Neck Dissection (CND) could be avoided even in the presence of positive Lateralcervical Lymph Nodes (LLN+).

Surgical Skills and Technological Advancements to Avoid Complications in Lateral Neck Dissection for Differentiated Thyroid Cancer

Neck dissection is a surgical procedure reserved for thyroid cancer cases with clinically evident lymphatic invasion. Although neck dissection is a reliable and safe procedure, it can determine a significant morbidity involving a variety of structures of nervous, vascular and endocrine typology. A careful pre-operative study is therefore essential to better plan surgery. Surgical experience, combined with accurate surgical preparation and merged with adequate and specific techniques, can certainly help reduce the percentage of complications. In recent years, however, technology has also proved to be useful. Its crucial role was already recognized in the safeguard of the integrity of the laryngeal nerve through neuro-monitoring, but new technologies are emerging to help the preservation also of the parathyroid glands and other structures, such as the thoracic duct. These surgical skills combined with the latest technological advancements, that allow us to reduce the incidence of complications after neck dissection for thyroid cancer, will be reported in the present article. This topic is of significant interest for the endocrine and metabolic surgeons' community.