Lymph node management in clinically node-negative patients with papillary thyroid carcinoma

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSION

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

The risk of central nodal metastasis based on prognostic factors of the differentiated thyroid carcinoma: a systematic review and meta-analysis study

BACKGROUND AND AIM

Despite improving the 10-year disease-free-survival, prophylactic central neck dissection (pCND) in differentiated thyroid carcinoma (DTC) should only be considered in patients with high risk factors for lymph node (LN) metastasis due to the increases in the risk of postoperative complications. Our aim was to identify the risk factors for central lymph node metastasis (CLNM) in DTC.

METHOD

We searched PubMed, Scopus, Web of science, Cochrane library for eligible studies from inception to November 1, 2021 and a systematic review and meta-analysis were carried out to identify the risk factors for CLNM in DTC.

RESULTS

We included 41 studies with total of 27,741 patients in this study. The pooled results in this meta-analysis showed that these risk factors were significantly associated with CLNM: age < 45 years (odds ratio (OR) 1.64, 95% confidence interval (CI) 1.34-1.99, p < 0.00001), male sex (OR 1.73, 95% CI 1.54-1.93, p < 0.00001), multifocality (OR 1.87, 95% CI 1.59-2.19, p < 0.00001), bilateral disease (OR 1.43, 95% CI 1.15-1.78, p < 0.001), capsular invasion (OR 1.67, 95% CI 1.10-2.54, p < 0.02), lymphovascular invasion (OR 4.89, 95% CI 2.76-8.66, p < 0.00001) and extra-thyroidal extension (OR 2.43, 95% CI 1.97-3.00, p < 0.00001). In addition, young age (< 45 years), male sex, multifocality, and extra-thyroidal extension were significantly associated with large-volume CLNM in clinically N0 DTC patients. However, the presence of Hashimoto's thyroiditis was not a predictors of large-volume CLNM.

CONCLUSION

Young age (< 45 years), male sex, bilateral disease, multifocality, capsular invasion, lymphovascular invasion and extra-thyroidal extension are significantly associated with CLNM and pCND would be expected to have a higher yield in patients with these risk factors.

The clinical significance of the features of the morphological study and immunohistochemical determination of pancytokeratin in the lymph nodes of the central zone in papillary thyroid cancer

Introduction. papillary thyroid cancer is increasingly being detected at early stages when regional and distant metastases are absent per clinical examination. However, lymph nodes of the central zone can carry hidden metastases. frequency of such metastases is 22.3–46.7 %. maximally accurate identification of hidden metastases after lymph node dissection remains an important problem.

Aim. тo evaluate the effect of histological examination characteristics and immunohistochemical measurement of pancytokeratin level on frequency of detection of papillary cancer hidden metastases in regional lymph nodes of the central zone in patients with clinical stage N0 papillary cancer.

Materials and methods. The main group included 50 patients with stage ст1–2N0М0 primary papillary thyroid cancer. Dissected central lymph nodes of the patients prior to formalin fixation were extracted from the sample and inserted in individual paraffin blocks. Apart from standard histological examination, pancytokeratin level was measured immunohistochemically in the lymph nodes. The control group consisted of 200 patients for whom dissected central cell tissue was sectioned into blocks after formalin fixation. The number of lymph nodes in the dissected sample was measured by a pathomorphologist.

Results. In the main group, the number of lymph nodes in the sample varied between 6 and 37 with mean of 20.7 ± 6.8; in the control group the number was lower: 3–25, mean 9.8 ± 5.1 (р = 0.000). In the main group, hidden metastases were detected more frequently than in the control group: in 30 (60 %) and 68 (34 %) cases, respectively (р = 0.001). In 20 (40 %) patients, immunohistochemical examination showed new metastases. use of this method allowed to detect 1 to 7 additional metastases (mean 2.4 ± 1.5 lymph node lesions).

Conclusion. use of targeted dissection with extraction of lymph nodes led to significant increase in their numbers in the samples, and immunohistochemical examination allowed to detect a large number of hidden metastases in the central lymph nodes.

Prediction of Cervical Lymph Nodes Metastasis in Papillary Thyroid Carcinoma (PTC) Using Nodal Staging Score (NSS)

Background

Cervical lymph node metastasis is commonly seen in papillary thyroid carcinoma. Surgery is the preferred treatment for PTC with cervical lymph node metastasis. There is no alternate ultrasound, neck CT, and thyroglobulin (Tg) methods to assess the occult lymph node metastasis. For moderate-and high-risk PTC, the number of lymph nodes to be dissected should be increased to remove the occult lymph node metastasis.

Objective

This study was designed to develop a nodal staging score model to predict the likelihood of lymph node metastasis in papillary thyroid carcinoma (PTC), and further guide the treatments. Material and Methods. Data were collected from the SEER database. Patients with PTC from 2000 to 2005 were selected. The beta-binomial model was adopted to establish a nodal staging score (NSS)-based model. The NSS-based model was built according to gender, age, extrathyroidal invasion, tumor multifocality, tumor size, and T stage of the patients. A total of 12,431 PTC patients were included in our study. Various types of lymph nodes were examined based on various categories (incidence, risk assessment) to evaluate the results.

Results

5,959 (47.9%) patients in the study were positive and 6,472 (52.1%) were confirmed negative for lymph node metastasis. The corrected incidence of lymph node metastasis was higher than that of direct calculation, regardless of the factors that affected lymph node metastasis. There were significant differences in the OS of PTC patients among the four groups and T stage (p is less than 0.05), indicating that cervical lymph node metastasis would have an impact on the prognosis of patients.

Conclusion

In conclusion, an NSS-based model base on a variety of clinicopathological factors can be used to predict lymph node metastasis. It is important to evaluate the risk of occult lymph node metastasis in the treatment of PTC.. Since, this statistical model can describe the risk of occult lymph node metastasis in patients; therefore, it can be used as basis for decision-making related to the number of lymph nodes that can be dissected in operations.

Paratracheal lymph node dissection during total (pharyngo-)laryngectomy: A systematic review and meta-analysis

OBJECTIVES

The objective of this review was to determine the rate and risk factors of paratracheal lymph node (PTLN) involvement during total laryngectomy (TL) or total pharyngolaryngectomy (TPL). In addition, we aimed to assess its prognostic significance in terms of survival and peristomal recurrence.

METHODS

A comprehensive electronic search was performed on PubMed, EMBASE, and CENTRAL databases. We searched for studies reporting outcomes of PTLN dissection during radical laryngeal surgery for squamous cell carcinoma of the larynx, hypopharynx or cervical oesophagus.

RESULTS

We included a total of ten studies (838 patients). The overall rate of PTLN dissection positivity was 18.6% (20.7% for primary TL, 8.7% for salvage TL). Random-effects meta-analysis identified T4 stage, N+ stage of the lateral neck, subglottis involvement and primary tumour arising from the hypopharynx or cervical oesophagus as significant risk factors for PTLN involvement.

CONCLUSIONS

This meta-analysis allowed to better define the risk of PTLN involvement during TL or TPL, in a bid to guide indication for PTLN dissection. There is a need for further large studies reporting rigorously the outcomes of PTLN dissection in order to establish stronger evidence-based recommendations.

A Narrative Review of Preventive Central Lymph Node Dissection in Patients With Papillary Thyroid Cancer - A Necessity or an Excess

Objective

This review article summarises the latest evidence for preventive central lymph node dissection in patients with papillary thyroid cancer taking into account the possible complications and risk of recurrence.

Background

Papillary thyroid cancer is the most frequent histological variant of malignant neoplasms of the thyroid gland. It accounts for about 80-85% of all cases of thyroid cancer. Despite good postoperative results and an excellent survival rate in comparison with many other malignant diseases, tumor metastases to the cervical lymph nodes are frequent. Most researchers agree that the presence of obvious metastases in the lymph nodes requires careful lymph node dissection. It was suggested to perform preventive routine lymphadenectomy in all patients with malignant thyroid diseases referred to surgery.

Methods

It was performed the literature review using the “papillary thyroid cancer”, “central lymph node dissection”, “hypocalcemia”, “recurrent laryngeal nerve paresis”, “metastasis”, “cancer recurrence” along with the MESH terms. The reference list of the articles was carefully reviewed as a potential source of information. The search was based on Medline, Scopus, Google Scholar, eLibrary engines. Selected publications were analyzed and their synthesis was used to write the review and analyse the role of preventive central lymph node dissection in patients with papillary thyroid cancer.

Conclusions

The necessity of preventive central lymph node dissection in patients with differentiated papillary thyroid carcinoma is still controversial. There is much evidence that it increases the frequency of transient hypocalcemia. Due to the fact that this complication is temporary, its significance in clinical practice is debatable. It can also be assumed that an extant of surgery in the neck area is associated with an increased risk of recurrent laryngeal nerve injury. However, most studies indicate that this injury is associated more with thyroidectomy itself than with lymph node dissection. Recurrent laryngeal nerve dysfunction is also a temporary complication in the vast majority of cases. At the same time, a large amount of data shows that central lymph node dissection reduces the risk of thyroid cancer recurrence in two times.

Prevalence of Central Compartment Lymph Node Metastases in Papillary Thyroid Micro-Carcinoma: A Retrospective Evaluation of Predictive Preoperative Features

Simple Summary

The present study focused on patients affected by stage pT1a papillary thyroid micro-carcinomas that were treated with surgery and central lymph node dissection. In this study, male sex, low age, and sub-capsular carcinoma localization resulted as independent predictive factors for central lymph node metastases.

Abstract

Papillary thyroid micro-carcinomas are considered relatively indolent carcinomas, often occult and incidental, with good prognosis and favorable outcomes. Despite these findings, central lymph node metastases are common, and are related to a poor prognosis for the patient. We performed a retrospective analysis on patients treated with surgery for stage pT1a papillary thyroid micro-carcinomas. One hundred ninety-five patients were included in the analyses. The presence of central lymph node metastases was identified and studied. A multivariate analysis employing binary logistic regression was used to calculate adjusted odds ratios with 95% confidence intervals of possible central lymph node metastases risk factors. In the performed multivariate analysis, male gender, younger age, and histopathological characteristics, such as a tumor sub-capsular localization, were significantly associated with central lymph node metastases in pT1a patients. Central compartment lymph node metastases are present in a non-negligible number of cases in patients with papillary thyroid micro-carcinoma undergoing surgical resection. Studying these factors could be an effective tool for predicting patients’ central lymph node metastases in papillary thyroid micro-carcinomas, defining a tailored surgical treatment in the future.

Dual-energy computed tomography could reliably differentiate metastatic from non-metastatic lymph nodes of less than 0.5 cm in patients with papillary thyroid carcinoma

Background

Dual-energy computed tomography (DECT) has been widely applied to detect lymph node (LN) and lymph node metastasis (LNM) in various cancers, including papillary thyroid carcinoma (PTC). This study aimed to quantitatively evaluate metastatic cervical lymph nodes (LNs) <0.5 cm in patients with PTC using DECT, which has not been done in previous studies.

Methods

Preoperative DECT data of patients with pathologically confirmed PTC were retrospectively collected and analyzed between May 2016 and June 2018. A total of 359 LNs from 52 patients were included. Diameter, iodine concentration (IC), normalized iodine concentration (NIC), and the slope of the energy spectrum curve (λ_HU) of LNs in the arterial and the venous phases were compared between metastatic and non-metastatic LNs. The optimal parameters were obtained from the receiver operating characteristic (ROC) curves. The generalized estimation equation (GEE) model was used to evaluate independent diagnostic factors for LNM.

Results

A total of 139 metastatic and 220 non-metastatic LNs were analyzed. There were statistical differences of quantitative parameters between the two groups (P value 0.000-0.007). The optimal parameter for diagnosing LNM was IC in the arterial phase, and its area under the curve (AUC), sensitivity, and specificity were 0.775, 71.9%, and 73.6%, respectively. When the three parameters of diameter, IC in the arterial phase, and NIC in the venous phase were combined, the prediction efficiency was better, and the AUC was 0.819. The GEE results showed that LNs located in level VIa [odds ratio (OR) 2.030, 95% confidence interval (CI): 1.134-3.634, P=0.017], VIb (OR 2.836, 95% CI: 1.597-5.038, P=0.000), diameter (OR 2.023, 95% CI: 1.158-3.532, P=0.013), IC in the arterial phase (OR 4.444, 95% CI: 2.808-7.035, P=0.000), and IC in the venous phase (OR 5.387, 95% CI: 3.449-8.413, P=0.000) were independent risk factors for LNM in patients with PTC.

Conclusions

DECT had good diagnostic performance in the differentiation of cervical metastatic LNs <0.5 cm in patients with PTC.

Prophylactic central lymph node dissection informs the decision of radioactive iodine ablation in papillary thyroid cancer

BACKGROUND

Prophylactic central lymph node dissection (CLND) in papillary thyroid cancer (PTC) is controversial. We aimed to investigate if prophylactic CLND aids risk stratification and contributes to the decision for postoperative RAI ablation.

METHODS

Patients undergoing thyroidectomy for PTC and prophylactic CLND were identified from an endocrine surgical unit database. Pathology reports where reviewed for number and size of lymph nodes and patients stratified by risk according to the ATA guidelines.

RESULTS

426 patients were identified with PTC ≤4 cm and prophylactic CLND. 96 patients (23%) had central lymph node metastasis (CLNM) that qualified them for the intermediate risk group. In 17 patients (4%), the CLNM data led to upgrading independently of other histopathological characteristics. Correcting for multiple variables, CLNM was an independent factor contributing to RAI treatment.

CONCLUSION

Prophylactic CLND provides information to aid the selection of RAI ablation independent of primary cancer histology for risk stratification in 4% of patients. This benefit should be carefully balanced with the risk of CLND and patient treatment choice when deciding on management of PTC ≤4 cm.

Central Compartment Nodal Bulk: A Predictor of Permanent Postoperative Hypocalcaemia

Central compartment clearance (CCC) for Papillary thyroid cancers (PTC) is one of the factors causing postoperative hypocalcaemia. We aimed to examine determinants of this major sequela. 41 patients treated for PTCs between 2014 and 2016 were studied. Surgical details, tumour and nodal characteristics, incidence of transient, temporary and permanent hypocalcaemia were noted. Central clearance was done bilaterally in 24 (58.5%) cases, ipsilaterally in 17 (41.6%). Central nodes were involved in 26 (63.4%) cases, unilaterally in 15 (36.6%), bilaterally in 11 (26.8%). Transient hypocalcaemia developed in 10 (24.4%) cases, temporary hypocalcaemia in 6 (14.6%) cases, and permanent hypocalcaemia in 2 (4.9%) cases. 17 (41%) patients were symptomatic. 9 (21.9%) patients received intravenous calcium. The only factor consistently associated with development of hypocalcaemia of all patterns, was the presence of matted central compartment nodes (p = 0.021). Matted nodes also related to a longer length of stay (p = 0.04) and requirement of intravenous calcium (p = 0.000). Extent of CCC, nodal yield, nodal positivity, perinodal extension, number of parathyroids identified, gender or pT size were not significantly associated. Symptomatic patients did not necessarily become permanently hypocalcaemic (p = 0.8). Patients requiring intravenous calcium were more likely to take oral calcium after discharge (p = 0.002). Postoperative hypocalcaemia is more likely in cases with bulky involved central nodes where extensive clearance is done. In routine CCC, even if done bilaterally, preservation of parathyroid function is possible. Permanent hypocalcaemia after CCC need not be taken as inevitable.

Evaluation of surgical risk and prognosis between thyroid nodules of size <1 and ≥1 cm

Background

The objective of this study was to evaluate the surgical risk and prognosis between thyroid nodules of size <1 and ≥1 cm and to explore whether it is reasonable generally to ignore the diagnosis and treatment of thyroid nodules and thyroid carcinoma <1 cm in wide areas of China.

Methods

A retrospective observational study included all first-time thyroid surgery patients between January 2005 and December 2016 of the First Affiliated Hospital of Harbin Medical University. All patients were divided into two groups (group A: <1 cm, group B: ≥1 cm) according to the maximum diameter of the nodules and demographics, surgery procedure, pathology, postoperative complications, morbidity, and mortality were analyzed.

Results

A total of 6,317 patients were reviewed and 3,424 (54.20%) of them were malignant; 2,128 patients in group A and 4,189 in group B. Patients in group A had better pathological diagnosis, inferior extent of lymph node metastasis, less surgical complexity, fewer postoperative complications, and longer disease-free survival (DFS).

Conclusions

Thyroid operations were safer and involved fewer postoperative complications when thyroid nodules were <1 cm and patients who were diagnosed with malignant thyroid disease had superior prognoses. Underdeveloped regions of China should diagnose and treat thyroid nodules <1 cm early.

Predictive Value of BRAFV600E Mutation for Lymph Node Metastasis in Papillary Thyroid Cancer: A Meta-analysis

BRAF^V600E mutation has been thought to be a valuable molecular marker that may predict a worse prognosis for papillary thyroid cancer (PTC). But whether BRAF^V600E mutation is associated with lymph node metastasis (LNM) remains controversial. Different surgical strategies may bring a bias in demonsstrating the association between them. In order to delineate a risk stratification to guide a tailored initial approach to tumors that express BRAF^V600E mutation, we performed this meta-analysis by using the articles in which total or near-total thyroidectomy plus bilateral central lymph node dissection was routinely performed to avoid the bias from the surgical strategy. We searched the Medline, Embase and CNKI database for eligible studies from January 2003 to May 2018. Meta-analysis was performed using the STATA 12.0 software. Odds ratios (ORs) and 95% confidence intervals (CIs) were calculated under fixed-effects or randomeffects models. Fifteen clinical studies were included with a total of 4909 PTC patients. Our meta-analysis results reported that BRAFV600E mutation was associated with LNM (OR=1.34; 95% CI: 1.09-1.65; P=0.005), as well as central LNM (OR=1.59; 95% CI: 1.35-1.88; P<0.00001). Moreover, in patients with papillary thyroid microcarcinoma, we also confirmed the predictive value of BRAF^V600E mutation for LNM (OR=3.49; 95% CI: 2.02-6.02; P<0.00001). This meta-analysis demonstrates that BRAF^V600E mutation is closely related to LNM in PTC patients. The results suggest that BRAF^V600E mutation can be considered as a risk factor for LNM in PTC. Moreover, combining BRAF^V600E mutation with other risk factors to determine the initial surgical treatment may bring benefits for PTC patients.

Persistent and recurrent disease in patients with papillary thyroid carcinoma with clinically apparent (cN1), but not extensive, lymph node involvement and without other factors for poor prognosis

OBJECTIVE

Lymph node metastases (LNM) are frequent in patients with papillary thyroid cancer (PTC). The risk of persistent disease (PD) and tumor recurrence (TR) is increased when factors for poor prognosis other than LNM exist, when LNM are numerous, large, detected by preoperative ultrasonography (US), or exhibit extranodal extension. This study evaluated the risk of PD and TR in patients with LNM not exhibiting these characteristics.

SUBJECTS AND METHODS

Eighty-six patients with 5 or fewer LNM detected during intraoperative inspection, but not by preoperative US, who had no other factors for poor prognosis [tumors > 4 cm, extensive extrathyroid invasion, vascular invasion, aggressive histological subtype, distant metastases, incomplete tumor resection], were studied. All patients underwent total thyroidectomy followed by radioiodine ablation. PD was defined as metastases on initial post-therapy whole-body scans (RxWBS) or detected by imaging methods up to 12 months after ablation. TR was defined as structural disease diagnosed more than one year after ablation in patients without PD.

RESULTS

PD was diagnosed in 3/86 patients (3.5%). TR was observed in 2/83 patients (2.5%) after 62 months of follow-up. There was no case of death due to the disease. A correlation was observed between pre-ablation Tg and PD or TR [1/48 (2%) with Tg ≤ 2 ng/mL versus 2/22 (9%) with Tg > 2 ≤ 10 ng/mL versus 2/7 (28.5%) with Tg ≥ 10 ng/ml)]. It is noteworthy that 38 patients had up to 3 positive LN and pre-ablation Tg ≤ 2 ng/ml, and none of them had PD or TR.

CONCLUSIONS

The frequency of PD and TR was low in patients with PTC with 5 or fewer LNM and without other factors for poor prognosis. Low postoperative stimulated Tg was predictive of the absence of PD and TR in these patients.

Significance of clearing differentiated thyroid carcinoma lymph node by high-frequency color Doppler ultrasonography

We compared the clinical effects and prognosis of patients receiving lymph node dissection after surgical removal of the thyroid tissues and those not receiving it after the removal. A total of 80 patients diagnosed with differentiated thyroid carcinoma (DTC) by our hospital from March 2012 to March 2014 were successively included in the study. The cases were divided into the control group (n=36 cases) and observation group (n=44 cases), and the two groups underwent total or subtotal resection of the thyroid. In the control group, patients underwent preoperative high-frequency color ultrasonography, and the most suspicious lymph node was removed. In the observation group, patients underwent preoperative high-frequency color ultrasonography, and the surgeons cleared the lymph node of the widest range. Difference in clinical effects and prognosis of the two groups were compared. After nearly a year's follow-up observation, the tumor recurrence rate of the observation group was significantly lower than that of the control group and the survival rate of the observation group was significantly higher than that of the control group (P<0.05). The rate of surgery complications and comparative difference of the two patient groups had no statistical significance (P>0.05). When comparing the data of lymphatic metastasis tested by preoperative high-frequency color ultrasonography with intraoperative diagnosed figures, sensitivity was 97.4%, specificity 33.3%, positive predictive value 90.2% and the negative predictive value 66.7%. In conclusion, removal of the lymph node for DTC patients having undergone thyroid tissue excision with preoperative high-frequency color ultrasonography can be beneficial to improve the effects along with reduction in the recurrence rate.

Predictors of metastasis to lymph nodes posterior to the right recurrent laryngeal nerve in differentiated thyroid carcinoma: A prospective study

OBJECTIVES

To study the clinicopathological characteristics and the risk factors of lymph nodes posterior to the right recurrent laryngeal nerve (LN-prRLN) metastasis in differentiated thyroid carcinoma; and to identify the indication for LN-prRLN dissection.

METHODS

We treated 145 patients with differentiated thyroid carcinoma with appropriate surgical intervention. The specimens were examined by the pathologists. The right paratracheal lymph nodes were divided into two groups: anterior or posterior to right recurrent laryngeal nerve (VIa or VIp compartment, respectively). We recorded the clinical characteristics, histopathological features of the primary tumors, and lymph node metastasis of the patients. The results were statistically analyzed.

RESULTS

There were 85 patients (58.6%) with central lymph node metastasis, of whom 61 (42.1%) had metastasis in VIa compartment; 16 patients (11.0%) had VIp subdistrict metastasis; and 25 patients had lateral lymph node metastasis. Multiplicity, larger tumor (≥1 cm), and coexistence of central lymph node metastasis, VIa compartment metastasis, and lateral lymph node metastasis were all significantly related with LN-prRLN metastasis, while sex, age, location of the tumor, and extrathyroid extension of the tumor showed no significant relation (p > 0.05).

CONCLUSION

The incidence of LN-prRLN metastasis was lower than other central lymph nodes, as well as lymph nodes anterior to right recurrent laryngeal nerve. When there were multiple foci of tumors, or the tumor was larger than 1 cm, or central or lateral LN metastasis was indicated by preoperative ultrasound or confirmed by intraoperative frozen sections, it is strongly recommended that exploration and dissection of the LN-prRLN should only be performed by experienced surgeons.

Prophylactic neck dissection for low-risk differentiated thyroid cancers: Risk-benefit analysis

BACKGROUND

The benefit of neck dissection is the subject of debate in differentiated thyroid cancer (DTC). We analyze the risk-benefit of neck dissection for low-risk DTC without detectable lymph nodes.

METHODS

We conducted a retrospective study from 1983 to 2003; which included 295 patients without detectable lymph nodes who were treated by thyroidectomy with (C+) or without (C-) neck dissection. All patients had iodine131 therapy. We compared the frequency of remission, disease progression, and permanent complications between groups.

RESULTS

Two hundred twelve patients comprised the C+ group, and 83 patients the C- group. Respectively for C+ versus C-, remission rates were 92% versus 89.2% (p = .40), and progressive disease observed was 3.3% versus 7.2% (p = .10). Permanent hypoparathyroidism occurred in 15.1% in C+ versus 3.6% in C- (p = .006).

CONCLUSION

The risk-benefit analysis of neck dissection in patients with low-risk DTC shows no benefit in terms of complete remission or occurrence of progression. However, risk of complications seems to be higher in patients with neck dissection. © 2016 Wiley Periodicals, Inc. Head Neck 38: 1091-1096, 2016.

The clinical prognosis of patients with cN0 papillary thyroid microcarcinoma by central neck dissection

BACKGROUND

Central lymph node metastasis of papillary thyroid microcarcinoma (PTMC) is common; however, prophylactic central lymph node dissection (CLND) is still controversial because of the possible increased morbidity. The purpose of this study is to determine the clinical outcome of patients with cN0 PTMC by central neck dissection.

METHODS

A retrospective cohort study was conducted on patients with PTMC without preoperative evidence of lymph node disease (cN0), and the outcomes were compared between patients undergoing total thyroidectomy (TT) alone (group A) and patients undergoing TT with CLND (group B).

RESULTS

In this study, 242 patients with cN0 PTMC were included. Group A had 108 patients and group B had 134 patients. During a follow-up of over 60 months, the long-term postoperative complications were equivalent between the two groups. In group B, the presence of involved central neck lymph nodes upstaged 16% of patients to stage III disease, which necessitated additional postoperative radioactive iodine treatment. More patients had recurrences in group A. The rate of reoperation in the central compartment was higher in group A than in group B (8.3% vs 2.2%, P < 0.01).

CONCLUSIONS

Prophylactic CLND does not increase long-term postoperative complications and reduces the risk of recurrence in the central compartment.

Predictive factors of central lymph node metastasis in papillary thyroid carcinoma

PURPOSE

The aim of this study was to evaluate the correlation between central lymph node (CLN) metastasis and clinicopathologic characteristics of papillary thyroid cancer (PTC). In addition, we investigated the incidence and risk factors for contralateral CLN metastasis in unilateral PTC. This study suggests the appropriate surgical extent for CLN dissection.

METHODS

A prospective study of 500 patients with PTC who underwent total thyroidectomy and prophylactic bilateral CLN dissection was conducted.

RESULTS

Of 500 patients, 255 had CLN metastases. The rate of CLN metastasis was considerably higher in cases of younger patients (<45 years old) (P < 0.001; odds ratio [OR], 2.357) and of a maximal tumor size greater than 1 cm (P < 0.001; OR, 3.165). Ipsilateral CLN metastasis was detected in 83.1% of cases (133/160) of unilateral PTC, only contralateral CLN metastases in 3.7% of cases (6/160), and bilateral CLN metastases in 13.1% of cases (21/160). The rate of contralateral CLN metastasis was considerably higher in cases of PTC with a large tumor size (≥1 cm) (P = 0.019; OR, 4.440) and with ipsilateral CLN metastasis (P = 0.047; OR, 2.613).

CONCLUSION

Younger age (<45 years old) and maximal tumor size greater than 1 cm were independent risk factors for CLN metastasis. Maximal tumor size greater than 1 cm and presence of ipsilateral CLN macrometastasis were independent risk factors for contralateral CLN metastasis. Therefore, both CLN dissections should be considered for unilateral PTC with a maximal tumor size greater than 1 cm or presence of ipsilateral CLN macrometastasis.

The pros and cons of routine central compartment neck dissection for clinically nodal negative (cN0) papillary thyroid cancer

Metastatic disease to regional lymph nodes (LNs) is common in papillary thyroid carcinoma (PTC). LN dissection is increasingly performed as part of the surgical management of PTC. The role of prophylactic central neck dissection (pCND) in PTC is unclear. There is limited evidence to support a routine pCND in clinical setting for nodal negative (cN0) PTC. The aim of this review was to examine the pros and cons of prophylactic neck dissection in cN0 PTC. In summary, the advantages of pCND are: removal of the central LNs that potentially harbor micro-metastases, more accurate staging of disease in order to plan more individualized management, reducing the need for re-operation to remove the metastatic LNs which have developed later and possible improvement in overall survival. The disadvantages are: an extensive surgery but lack of evidence of survival benefit, higher incidence of complications with little impact on local recurrence rate, possibility of over treating in cN0 patients and it does not sound like a cost effective approach in the management of small thyroid cancer. Considering low frequency of permanent morbidity, some authors believe that prophylactic neck dissection is safe in experienced hands even though its prognostic benefit has yet to be demonstrated.

The extent of lateral lymph node dissection in differentiated thyroid cancer in the N+ neck

The management of the lateral neck in metastatic differentiated thyroid cancer (DTC) varies widely. Most groups advocate dissection of nodal levels II-IV but many perform a more extensive dissection. We aimed to asses whether there was any evidence for a modified radical neck dissection over a selective neck dissection by looking at the extent to which DTC metastases to levels I and V. We performed a review of the current literature including adult and paediatric patients who underwent a lateral neck dissection for metastatic DTC. The primary endpoint was histological confirmation of metastases in nodal levels I and V. 650 abstracts were identified and reviewed. 23 papers were included in the study. The incidence of level V metastases during routine level V dissection in patients with DTC is 20 % and the incidence of level I metastases during routine level I dissection in patients with DTC is 8 %. Histologically proven metastases were found in 22.5 % of level V neck dissection of which 2.5 % were pre-operatively suspected of metastases. 20 % had histologically proven metastases to level I of which 12 % were pre-operatively suspected of metastases. Our study has shown a 20 % incidence of level V metastases in the N+ neck suggesting that level V should be part of a planned neck dissection. Evidence is lacking for routine dissection of level I. A future prospective study is required to asses the question of risk factors for lateral nodal metastases, recurrence and survival.

Impact of lymph node metastases identified on central neck dissection (CND) on the recurrence of papillary thyroid cancer: potential role of BRAFV600E mutation in defining CND

The impact of metastasized cervical lymph nodes (CLN) identified on central neck dissection (CND) on the recurrence/persistence of papillary thyroid cancer (PTC) and the extent of CND needed to reduce recurrence/persistence have not been firmly established. To assess the impact of CLN metastasis and BRAF mutation on the recurrence/persistence of PTC and the potential of BRAF mutation in assisting CND. Analyses of 379 consecutive patients with PTC who underwent thyroidectomy with (n=243) or without CND (n=136) at a tertiary-care academic hospital during the period 2001-2010 for their clinicopathological outcomes and BRAF mutation status. Increasingly aggressive tumor characteristics were found as the extent of CND was advanced following conventional risk criteria from non-CND to limited CND to formal CND. Disease recurrence/persistence rate also sharply rose from 4.7% to 15.7% and 40.5% in these CND settings respectively (P<0.0001). CLN metastasis rate rose from 18.0 to 77.3% from limited CND to formal CND (P<0.0001). An increasing rate of BRAF mutation was also found from less to more extensive CND. A strong association of CLN metastasis and BRAF mutation with disease recurrence/persistence was revealed on Kaplan-Meier analysis and BRAF mutation strongly predicted CLN metastasis. CLN metastases found on CND are closely associated with disease recurrence/persistence of PTC, which are both strongly predicted by BRAF mutation. Current selection of PTC patients for CND is appropriate but higher extent of the procedure, once selected, is needed to reduce disease recurrence, which may be defined by combination use of preoperative BRAF mutation testing and conventional risk factors of PTC.

Predictive factors for lateral occult lymph node metastasis in papillary thyroid carcinoma

Management of lateral no necks in papillary thyroid carcinoma (PTC) is very controversial. The aim of this study was to find predictive factors of lateral neck involvement in N0 PTC to help the clinician in his decision to treat the lateral compartment. We retrospectively analysed 173 patients who underwent thyroidectomy and lateral prophylactic neck dissection for PTC >10 mm. Predictive factors for occult lateral lymph node metastasis including sex, age, tumour size, multifocality and bilaterality, tumour extracapsular spread, vascular invasion and presence of a tumour capsule were examined by multivariate analysis. There were three independent predictive factors for occult lateral lymph node metastases in multivariate analysis: tumour extracapsular spread (p < 0.0001), vascular invasion (p < 0.001) and age <45 years (p < 0.027). When none of these factors was present, the risk of occult metastases was <5 %. The risk increased up to 56 % when at least two of these factors were present. These findings suggest that, in patients older than 45 years with neither tumour extracapsular spread nor vascular invasion on histopathological examination, occult lymph node metastases are very uncommon. In that case further discussion regarding the risks and benefits of lateral nodal dissection may be warranted.

The prognostic significance of nodal metastases from papillary thyroid carcinoma can be stratified based on the size and number of metastatic lymph nodes, as well as the presence of extranodal extension

BACKGROUND

Ultrasound and prophylactic dissections have facilitated identification of small-volume cervical lymph node (LN) metastases in patients with papillary thyroid carcinoma (PTC). Since most staging systems do not stratify risk based on size or number of LN metastases, even a single-microscopic LN metastasis can upstage a patient with low-risk papillary thyroid microcarcinoma (PMC) to an intermediate risk of recurrence in the American Thyroid Association (ATA) system and to an increased risk of death in the American Joint Committee on Cancer (AJCC) staging system (stage III if the metastatic node is in the central neck or stage IVA if the microscopic LN metastasis is identified in the lateral neck). Such microscopic upstaging may lead to potentially unnecessary or additional treatments and follow-up studies. The goal of this review is to determine if the literature supports the concept that specific characteristics (clinically apparent size, number, and extranodal extension) of LN metastases can be used to stratify the risk of recurrence in PTC.

SUMMARY

In patients with pathological proven cervical LN metastases (pathological N1 disease; pN1), the median risk of loco-regional LN recurrence varies markedly by clinical staging, with recurrence rates for patients who are initially clinically N0 (clinical N0 disease; cN0) of 2% (range 0%-9%) versus rates of recurrence for patients who are initially clinically N-positive (clinical N1 disease; cN1) of 22% (range 10%-42%). Furthermore, the median risk of recurrence in pN1 patients varies markedly by the number of positive nodes, <5 nodes (4%, range 3%-8%) vs. >5 nodes (19%, range 7%-21%). Additionally, the presence of extranodal extension was associated with a median risk of recurrence of 24% (range 15%-32%) and possibly a worse disease-specific survival.

CONCLUSION

Our previous paradigm assigned the same magnitude of risk for all patients with N1 disease. However, small-volume subclinical microscopic N1 disease clearly conveys a much smaller risk of recurrence than large-volume, macroscopic clinically apparent loco-regional metastases. Armed with this information, clinicians will be better able to tailor initial treatment and follow-up recommendations. Implications of N1 stratification for PTC into small-volume microscopic disease versus clinically apparent macroscopic disease importantly relate to issues of prophylactic neck dissection utility, need for pathologic nodal size description, and suggest potential modifications to the AJCC TNM (tumor, nodal disease, and distant metastasis) and ATA risk recurrence staging systems.

The role of prophylactic central neck dissection in differentiated thyroid carcinoma: issues and controversies

Prophylactic central neck dissection (pCND) in differentiated thyroid carcinoma (DTC) is one of the most controversial surgical subjects in recent times. To date, there is little evidence to support the practice of pCND in patients with DTC undergoing total thyroidectomy. Although the recently revised American Thyroid Association (ATA) guideline has clarified many inconsistencies regarding pCND and has recommended pCND in “high-risk” patients, many issues and controversies surrounding the subject of pCND in DTC remain. The recent literature has revealed an insignificant trend toward lower recurrence rate in patients with DTC who undergo total thyroidectomy and pCND than those who undergo total thyroidectomy alone. However, this was subjected to biases, and there are concerns whether pCND should be performed by all surgeons who manage DTC because of increased surgical morbodity. Performing a unilateral pCND may be better than a bilateral pCND given its lower surgical morbidity. Further studies in this controversial subject are much needed.

Clinical value of integrated [18F]fluoro-2-deoxy-D-glucose positron emission tomography/computed tomography in the preoperative assessment of papillary thyroid carcinoma: comparison with sonography

OBJECTIVES

The purpose of this study was to evaluate the clinical value of preoperative [(18)F]fluoro-2-deoxy-D-glucose (FDG) positron emission tomography/computed tomography (PET/CT) by comparing it to neck sonography in papillary thyroid carcinoma.

METHODS

The diagnostic accuracies of PET/CT and sonography for detecting cervical node metastasis were compared. The association between FDG uptake in the primary tumor and the prognostic factors of differentiated thyroid cancer, such as tumor size, multiplicity, extrathyroid extension, and lymph node metastasis, was also assessed.

RESULTS

Positron emission tomography/computed tomography showed lower sensitivity and higher specificity than sonography for detection of cervical node metastasis; however, no statistically significant difference was noted (P > .99). Only the tumor size was associated with FDG uptake in the primary tumor.

CONCLUSIONS

[(18)F]Fluoro-2-deoxy-d-glucose PET/CT could not provide additional information compared to neck sonography.

Clinical impact of cervical lymph node involvement and central neck dissection in patients with papillary thyroid carcinoma: a retrospective analysis of 368 cases

The impact of cervical lymph node metastases and the optimal surgical management of the neck in patients with papillary thyroid carcinoma (PTC) remain controversial. The objectives of this retrospective study were to determine, in patients with PTC, the predictive factors and the impact on tumor recurrence rate of cervical lymph node involvement, and to evaluate the oncologic results and the morbidity of central neck dissection (CND). We reviewed the records of patients who had undergone surgical treatment for PTC at our institution between 1990 and 2000. A total of 368 patients (86 men and 282 women) were included in this study. Young age (p = 0.02), tumor size (p = 0.001) and extrathyroidal tumor extension (p = 0.003) were significant predictive factors of cervical lymph node metastatic involvement (multivariate analysis). Initial metastatic cervical lymph node involvement was identified as an independent risk factor of tumor recurrence (multivariate analysis, p = 0.01). Metastatic lymph node(s) were found in prophylactic CND specimens in 31% of the patients. CND increased the risk of postoperative hypocalcemia (p = 0.008) and of permanent hypoparathyroidism (p = 0.002). In conclusion, cervical lymph node metastatic involvement at the time of initial surgery is an independent risk factor of tumor recurrence. CND provided an up-staging of more than 30% of patients with a clinically N0 neck, but was associated with significant morbidity regarding parathyroid function.

An individualized approach to the child with thyroid cancer

Children with differentiated thyroid cancer (DTC) often present with extensive disease that inclined clinicians in prior decades toward aggressive treatment including total thyroidectomy, radical neck dissection and universal prescription of radioactive iodine (RAI). Recent series with 40 years of follow-up have shown that fewer than 2% of children ultimately die from DTC, but they may have increased all-cause mortality from second malignancies that might be related to previous radiation exposure. In this article, we review data to support the notion that an individualized, risk-stratified approach to therapy should be used for children with DTC. Ideally this will provide aggressive therapy for those in whom aggressive treatment is warranted, but withhold aggressive and risk-associated therapy from those who are not likely to benefit.