Performing contralateral central lymph node dissection in papillary thyroid carcinoma: a decision approach

Machine learning algorithms for identifying contralateral central lymph node metastasis in unilateral cN0 papillary thyroid cancer

Purpose

The incidence of thyroid cancer is growing fast and surgery is the most significant treatment of it. For patients with unilateral cN0 papillary thyroid cancer whether to dissect contralateral central lymph node is still under debating. Here, we aim to provide a machine learning based prediction model of contralateral central lymph node metastasis using demographic and clinical data.

Methods

2225 patients with unilateral cN0 papillary thyroid cancer from Wuhan Union Hospital were retrospectively studied. Clinical and pathological features were compared between patients with contralateral central lymph node metastasis and without. Six machine learning models were constructed based on these patients and compared using accuracy, sensitivity, specificity, area under the receiver operating characteristic and decision curve analysis. The selected models were then verified using data from Differentiated Thyroid Cancer in China study. All statistical analysis and model construction were performed by R software.

Results

Male, maximum diameter larger than 1cm, multifocality, ipsilateral central lymph node metastasis and younger than 50 years were independent risk factors of contralateral central lymph node metastasis. Random forest model performed better than others, and were verified in external validation cohort. A web calculator was constructed.

Conclusions

Gender, maximum diameter, multifocality, ipsilateral central lymph node metastasis and age should be considered for contralateral central lymph node dissection. The web calculator based on random forest model may be helpful in clinical decision.

Comparison of prophylactic ipsilateral and bilateral central lymph node dissection in papillary thyroid carcinoma: a meta-analysis

OBJECTIVE

The scope of surgical resection for paratracheal (level VI) lymph nodes in patients with Papillary Thyroid Carcinoma (PTC) remains debatable. The aim of our study was to evaluate the effectiveness and safety of prophylactic ipsilateral Central Neck lymph node Dissection (CND) versus bilateral CND at the time of total thyroidectomy for Clinically Node-negative (cN0) unilateral PTC.

METHODS

A systematic retrieval of electronic databases, including Pubmed, Web of Science, and the China Journal Net, was conducted from January 1990 to September 2021. Outcome data of interest included transient hypoparathyroidism, permanent hypoparathyroidism, transient Recurrent Laryngeal Nerve (RLN) injury, permanent RLN injury and local recurrence. We constructed the summary Odds Ratios (ORs) and 95% Confidence Intervals (CIs) for every study with either fixed or random effect models.

RESULTS

A full total of 1792 patients from 6 studies were enrolled. Our meta-analysis showed that transient hypoparathyroidism was significantly more frequent in bilateral CND group (OR=0.58; 95% CI 0.44-0.76). The prevalence of permanent hypoparathyroidism was significantly higher in bilateral CND group patients compared to those in ipsilateral CND group (OR=0.26; 95% CI 0.15-0.45). On the other hand, our meta-analysis indicated that there were no significant differences in the incidence of transient RLN injury, permanent RLN injury and local recurrence.

CONCLUSIONS

Compared with bilateral CND, the rate of temporary and permanent hypoparathyroidism in ipsilateral CND is lower, but the local recurrence is similar. It may be presumptuous to suggest that ipsilateral CND is an adequate treatment for cN0 unilateral PTC.

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.

Ultrasound Echogenicity of Papillary Thyroid Cancer Is Affected by Tumor Growth Patterns and Tumor Fibrosis

BACKGROUND/AIM

The association between preoperative ultrasound (US) echogenicity and histopathological characteristics of papillary thyroid cancer (PTC) has been rarely investigated is not well characterized. This study evaluated a relationship between the clinical characteristics of PTC, histopathological phenomena including tumor growth patterns (TGPs) and tumor fibrosis (TF), and US echogenicity.

PATIENTS AND METHODS

In total, 170 patients with PTC (<2 cm) underwent total thyroidectomy with central neck dissection. Demographics, US echogenicity, tumor size, extra-thyroidal extension (ETE), lymph node metastasis (LNM) within the central and lateral neck, TGPs, and TF percentage were reviewed.

RESULTS

Patients with TGP II (encapsulated growth with partial pericapsular extension) and III (infiltrative growth) were more frequently burdened by ETE and lateral neck LNM compared to patients with TGP I (encapsulated growth with a well-defined cystic or solid characteristic). Older age was significantly deterministic of TGP III, and male gender and higher TF percentage were independent risk factors for lateral neck LNM. TGP III and TF were independent determining factors for marked hypoechogenicity on US.

CONCLUSION

PTC with TGP II and III and higher tumor fibrosis exhibited more aggressive clinicopathologic behaviors. TGP III and TF were determinants for marked hypoechogenicity.

Predictive Value of Delphian Lymph Node Metastasis in the Thyroid Cancer

OBJECTIVE/HYPOTHESIS

To evaluate the diagnostic accuracy of Delphian lymph node (DLN) metastasis for the prediction of central lymph node (CLN) metastasis and lateral lymph node (LLN) metastasis.

METHODS

Two authors independently reviewed the six databases (Cochrane database, Embase, Google Scholar, PubMed, SCOPUS, and Web of Science). Four parameters were extracted from each study: true positive, true negative, false positive, and false negative. The quality of the methodology was evaluated using the Quality Assessment of Diagnostic Accuracy Studies ver. 2 tool.

RESULTS

The diagnostic odds ratio of DLN in CLN metastasis was 8.859 (95% confidence interval [CI], 4.419; 16.578). The area under the summary receiver operating characteristic curve was 0.748. The diagnostic odds ratio of DLN in LLN metastasis was 7.61 (95% CI, 4.48; 12.94). The area under the summary receiver operating characteristic curve was 0.837. DLN metastasis was moderately predictive of CLN metastasis (sensitivity = 32%, specificity = 95%), LLN metastasis (sensitivity = 52%, specificity = 89%), and contralateral CLN metastasis (sensitivity = 46%, specificity = 85%). DLN metastasis had statistically significant correlation with specific clinicopathological characteristics, including younger age (< 45 years old), bilaterality, capsule invasion, extrathyroidal extension, lymphovascular invasion, male sex, multifocality, and tumor size (> 1 cm).

CONCLUSIONS

The higher specificities of DLN pathology may help predict central and lateral compartment involvement in patients with thyroid cancer.

LEVEL OF EVIDENCE

NA Laryngoscope, 131:1990-1996, 2021.

A Prediction Model for Contralateral Central Neck Lymph Node Metastases in Unilateral Papillary Thyroid Cancer

The health problems caused by the frequent relapse of papillary thyroid carcinoma (PTC) remain a worldwide concern since the morbidity rate of PTC ranks the highest among thyroid cancers. Residues from contralateral central lymph node metastases (con-CLNM) are the key reason for persistence or recurrence of unilateral papillary thyroid carcinoma (uni-PTC); however, the ability to assess the status of con-CLNM in uni-PTC patients is limited. To clarify the risk factors of con-CLNM, a total of 250 patients with uni-PTC who underwent total thyroidectomy and bilateral central lymph node dissection were recruited in this study. We compared the clinical, sonographic, and pathological characteristics of patients with con-CLNM to those without con-CLNM and established a nomogram for con-CLNM in uni-PTC. We found that male sex, without Hashimoto's thyroiditis, present capsular invasion, with ipsilateral lateral lymph node metastases, and the ratio of ipsilateral central lymph node metastases ≥0.16 were independent con-CLNM predictors of uni-PTC (ORs: 2.797, 0.430, 2.538, 2.202, and 26.588; 95% CIs: 1.182-6.617, 0.211-0.876, 1.223-5.267, 1.064-4.557, and 7.596-93.069, respectively). Additionally, a preoperative nomogram for the prediction of con-CLNM based on these risk factors showed good discrimination (C-index 0.881; 95% CI: 0.840-0.923; sensitivity 85.3%; specificity 76.0%) and good agreement via the calibration plot. Our study provided a way to quantitatively and accurately predict whether con-CLNM occurred in patients with uni-PTC, which may guide surgeons to evaluate the nodal status and perform tailored therapeutic central lymph node dissection.

Unilateral papillary thyroid carcinoma treated with contralateral central lymph node dissection: A nomogram to aid in decision-making

The central lymph nodes of the neck are the most common sites of papillary thyroid carcinoma (PTC) but cannot be easily diagnosed preoperatively. Prophylactic central lymph node dissection (CLND), especially contralateral CLND, is not recommended in various guidelines due to its high risk. The aim of our study was to establish an objective point score based on preoperative and intraoperative data to guide the selection of patients for contralateral CLND.We retrospectively evaluated 1085 consecutive patients with PTC treated by thyroidectomy for inclusion in this study (the training cohort). Variables of contralateral central lymph node macro-metastasis (CLNMM) were investigated using univariate and multivariate analyses; subsequently, nomograms were developed and then validated in an independent cohort of patients (n = 326, the validation cohort).Univariate and multivariate analyses indicated that preoperative fine needle aspiration-proven ipsilateral lateral lymph node metastasis (LNM) (odds ratio [OR] 4.888, 95% confidence interval [CI] 1.587-41.280, P < .001) and cases with frozen-section pretracheal LNM (OR 19.015, 95% CI 2.949-186.040, P < .001) or Delphian LNM (OR 4.494, 95% CI 1.503-54.128, P < .001) were the 3 risk factors for contralateral CLNMM. A receiver operating characteristic curve indicated a cutoff value of 1 for the frozen-section pretracheal LNM number or the Delphian LNM number as a predictor of contralateral central lymph node metastasis (CLNM). The nomogram was then generated according to the 3 risk factors and well validated in the external cohorts, and the intraoperative frozen-section results were highly consistent with the postoperative pathological results.The proposed nomogram based on the 3 factors showed a good prediction of contralateral CLNMM in PTC.

Pretracheal-laryngeal lymph nodes in frozen section predicting contralateral paratracheal lymph nodes metastasis

BACKGROUND

There has been an ongoing debate concerning the predictors of contralateral paratracheal lymph nodes metastasis (LNM) in unilateral papillary thyroid cancer (PTC). This study aimed to explore the value of pretracheal-laryngeal lymph nodes (LNs) in frozen section in predicting contralateral paratracheal LNM.

METHODS

A total of 242 patients with unilateral PTC were enrolled in this prospective study. Patients who underwent total thyroidectomy and bilateral central lymph nodes dissection (LND) were divided into two groups according to positive or negative contralateral paratracheal LNs. Patients' demographics and clinicopathological features were compared between the two groups. Validity indexes and consistency of pretracheal-laryngeal LNs in frozen sections were calculated.

RESULTS

LNM rates in central, ipsilateral paratracheal, pretracheal-laryngeal, and contralateral paratracheal regions were 55.37%, 47.03%, 23.55% and 14.05%, respectively. Only pretracheal-laryngeal LNM, regardless of whether detected in frozen or paraffin sections, were independent risk factors for contralateral paratracheal LNM (OR = 2.707; 95% CI 1.062-6.902; P = 0.037 in frozen section; OR = 3.072; 95% CI 1.248-7.560; P = 0.015 in paraffin section). The sensitivity, specificity, false-negative rate, false-positive rate, accuracy rate, and Kappa value of pretracheal-laryngeal LNM in frozen sections for predicting pretracheal-laryngeal LNM were 87.72%, 100%, 12.28%, 0%, 97.11% and 0.916 respectively, while those for predicting contralateral paratracheal LNM were 85,29%, 89.90%, 14.71%, 10.10%, 89.22%, and 0.618 respectively.

CONCLUSION

Pretracheal-laryngeal LNs in frozen section accurately predicted contralateral paratracheal LNM, which could allow the identification of patients who can benefit from an extended central LND.

The American Association of Endocrine Surgeons Guidelines for the Definitive Surgical Management of Thyroid Disease in Adults

OBJECTIVE

To develop evidence-based recommendations for safe, effective, and appropriate thyroidectomy.

BACKGROUND

Surgical management of thyroid disease has evolved considerably over several decades leading to variability in rendered care. Over 100,000 thyroid operations are performed annually in the US.

METHODS

The medical literature from 1/1/1985 to 11/9/2018 was reviewed by a panel of 19 experts in thyroid disorders representing multiple disciplines. The authors used the best available evidence to construct surgical management recommendations. Levels of evidence were determined using the American College of Physicians grading system, and management recommendations were discussed to consensus. Members of the American Association of Endocrine Surgeons reviewed and commented on preliminary drafts of the content.

RESULTS

These clinical guidelines analyze the indications for thyroidectomy as well as its definitions, technique, morbidity, and outcomes. Specific topics include Pathogenesis and Epidemiology, Initial Evaluation, Imaging, Fine Needle Aspiration Biopsy Diagnosis, Molecular Testing, Indications, Extent and Outcomes of Surgery, Preoperative Care, Initial Thyroidectomy, Perioperative Tissue Diagnosis, Nodal Dissection, Concurrent Parathyroidectomy, Hyperthyroid Conditions, Goiter, Adjuncts and Approaches to Thyroidectomy, Laryngology, Familial Thyroid Cancer, Postoperative Care and Complications, Cancer Management, and Reoperation.

CONCLUSIONS

Evidence-based guidelines were created to assist clinicians in the optimal surgical management of thyroid disease.

Long-term outcomes of central neck dissection for cN0 papillary thyroid carcinoma

OBJECTIVE

The risk-benefit ratio of central neck dissection (CND) in patients affected by papillary thyroid carcinoma (PTC) without clinical or ultrasonographic (US) evidence of neck lymph node metastasis (cN0) is currently debated. The aim of this study was to evaluate long-term outcome of CND on locoregional recurrence, distant metastasis, survival, and postoperative complications in a large series of patients with cN0-PTC.

STUDY DESIGN

Observational retrospective controlled study.

METHODS

Clinical records of patients (n=610) surgically treated for cN0-PTC at the Otolaryngology Unit of the Arcispedale Santa Maria Nuova-IRCCS, Reggio Emilia, Italy, from January 1984 to December 2008, were retrospectively reviewed. Study population was divided into three groups according to surgical treatment: Group A, total thyroidectomy (n=205); Group B, total thyroidectomy and elective ipsilateral CND (n=281); Group C, total thyroidectomy and bilateral CND (n=124).

RESULTS

Of a total of 610 patients, 305 (50%) were classified as low-risk, 278 (45.57%) as intermediate-risk, and 27 (4.43%) as high-risk. Response to initial therapy was excellent in 567 patients (92.95%), acceptable in 21 (3.44%), and incomplete in 22 (3.61%), with no significant differences among groups. Locoregional recurrence was detected in 32 (5.2%) out of 610 patients. Distant metastasis was found in 15 patients (2.5%). Statistical analysis showed no significant differences in the rates of locoregional recurrence (p=0.890) or distant metastasis (p=0.538) among groups. Disease-specific mortality and overall survival did not significantly differ among groups (p=0.248 and 0.223, respectively). Rate of permanent hypoparathyroidism was significantly higher in Group C patients compared to those in Groups A and B.

CONCLUSION

CND does not confer any clear advantage in the treatment of low-risk patients, regardless of surgical procedure. Instead, bilateral CND may be effective in limiting disease relapse and/or progression in patients at higher prognostic risk. Our data indicate that elective CND does not confer any clear advantage in terms of locoregional recurrence and long-term survival, as demonstrated by outcomes of the study Groups, regardless of their different prognostic risk. Elective CND allows a more accurate pathologic staging of central neck lymph nodes, despite its increasing the risk of permanent hypoparathyroidism. Intraoperative pathologic staging is a valuable tool to assess the risk of controlateral lymph node metastasis in the central neck compartment and to limit more aggressive surgery only to cases, otherwise understaged, with lymph node metastasis.

A nomogram predicting contralateral central neck lymph node metastasis for papillary thyroid carcinoma

BACKGROUND AND OBJECTIVES

Central compartment neck dissection (CCND) is recommended for patients with papillary thyroid carcinoma (PTC). However, whether to perform contralateral CCND remains unclear. An individualized estimation of the contralateral central neck metastasis (CNM) risk would assist in the tailoring of treatment for PTC patients.

METHODS

Consecutive patients who underwent bilateral CCND for unilateral PTC between 2012 and 2014 in a tertiary center were identified. The clinicopathological data of 142 patients were analyzed retrospectively. The variables that had clinical significance in the final multivariate logistic regression model were built into a nomogram to assess the risk of metastasis of the contralateral central compartment. This model was internally validated using bootstrap resampling.

RESULTS

This nomogram demonstrated good calibration and discrimination, with a concordance index of 0.834 (bootstrap corrected, 0.824). The variables with the greatest influence on the risk of contralateral CNM in this model included tumor size, the number of positive lymph nodes, and extranodal extension in the ipsilateral central neck.

CONCLUSIONS

This nomogram integrates three variables to estimate an individualized risk of contralateral CNM in unilateral PTC patients. This model may assist in individual decision-making regarding contralateral CCND and help avoid the over- and under-treatment of PTC. J. Surg. Oncol. 2016;114:703-707. © 2016 Wiley Periodicals, Inc.

Prophylactic "First-Step" Central Neck Dissection (Level 6) Does Not Increase Morbidity After (Total) Thyroidectomy

BACKGROUND

In terms of morbidity, prophylactic central neck dissection (CND; level 6) in potentially malignant thyroid disease is discussed controversially. The rates of (transient and permanent) hypoparathyroidism and palsy of the recurrent laryngeal nerve (RLN) after "first-step" (FS-)CND are analyzed in this study.

METHODS

Bilateral and unilateral FSCND, i.e., lymph node dissection along the RLN before (total) thyroidectomy, was performed bilaterally in 68 (group 1) and unilaterally in 44 patients (group 2), respectively. The rates of hypoparathyroidism and palsy of the RLN were documented prospectively and were compared to 237 patients of group 3 (controls) who underwent (total) thyroidectomy only.

RESULTS

Fifteen of 68 patients (22 %) of group 1 developed transient and one patient had permanent hypoparathyroidism. Transient unilateral palsy of the RLN was observed in ten patients (15 %); none were permanent. Transient hypoparathyroidism was monitored in 10 of 44 patients (23 %) of group 2 and permanent hypoparathyroidism in 1 (2 %). Six patients (14 %) developed temporary palsy of the RLN; one remained permanent. Palsy was seen in 3 patients on the contralateral side of unilateral FSCND. Transient and permanent hypoparathyroidism was observed in 50 (21 %) and 2 (1 %) of 237 controls. Transient palsy of the RLN was documented in 22 (9 %) of 237 controls and permanent palsy of the RLN in 4 (2 %).

CONCLUSIONS

In this single-center series, the overall permanent morbidity was low (1 %). Therefore, FSCND may be recommended (even prophylactically) for experienced high-volume surgeons in patients with thyroid nodules suspicious for malignancy.

Central neck dissection in the treatment of well-differentiated thyroid cancer

Therapeutic central compartment neck dissection (CCND) is required for confirmed nodal metastasis in patients with differentiated thyroid cancer. The need for routine prophylactic CCND in patients with papillary thyroid cancer is controversial. This article presents the current evidence to inform the debate against the background of the recommendations of US and British thyroid cancer guidelines. Potential advantages of pCCND include reduced local recurrence, preventing the need for further central compartment surgery and improved staging. Opponents claim that there is no proven patient benefit and that there is increased risk of recurrent laryngeal nerve injury and hypocalcemia.

Predictive factors and pattern of central lymph node metastasis in unilateral papillary thyroid carcinoma

OBJECTIVE

Prophylactic central neck dissection (CND) for papillary thyroid carcinoma (PTC) remains controversial. The aim of this study was to evaluate the patterns and predictive factors of central lymph node metastasis in cases of PTC that were clinically determined to be node negative.

METHODS

We studied 485 patients who have unilateral PTC without clinical lymph node metastasis and underwent total thyroidectomy and prophylactic bilateral CND from 2003 to 2012, retrospectively. The frequency, subsite and predictive factors of central lymph node metastasis were analyzed.

RESULTS

In total, 166 (32.4%) patients had occult central lymph node metastases. The most common subsite of central node metastases was the ipsilateral paratracheal lymph node (26.0%), followed by pretracheal (12.5%), prelaryngeal (5.0%), and contralateral paratracheal (3.9%) lymph nodes. The tumor size larger than 0.5cm (p=0.003), age under 45 (p<0.001) and extrathyroidal extension (p=0.028) were associated with ipsilateral central compartment metastasis in multivariate analysis. Contralateral central node metastasis was associated with tumor size >3cm, age under 45, and multifocality and ipsilateral central node metastasis in univariate analysis, but it was associated with only ipsilateral central node metastasis in multivariate analysis (p=0.001).

CONCLUSION

Prophylactic CND might be considered for PTC patients with large tumor size or extrathyroidal extension based on rates of lymph node metastasis. Unilateral CND might be appropriate as prophylactic CND due to the low metastatic rate to the contralateral paratracheal node.

Revisiting the guidelines issued by the Japanese Society of Thyroid Surgeons and Japan Association of Endocrine Surgeons: a gradual move towards consensus between Japanese and western practice in the management of thyroid carcinoma

BACKGROUND

In 2010, the Japanese Society of Thyroid Surgeons (JSTS) and Japanese Association of Endocrine Surgeons (JAES) established new guidelines entitled "Treatment of Thyroid Tumors." Since then, several new studies, including those that address the treatment of differentiated thyroid carcinoma (DTC) have been published, and the DTC treatment policy not only of Japanese physicians but those in Western countries has continued to evolve.

METHODS

We selected six clinical questions regarding the treatment of DTC and revisited them based on newly published data from Western countries and Japan.

RESULTS

More data have accumulated about treatment of low-risk papillary microcarcinoma. It has become clear that conservative treatment (observation) of low-risk papillary microcarcinoma in elderly patients is an acceptable alternative to immediate surgery. Total thyroidectomy versus hemithyroidectomy for low-risk papillary thyroid carcinoma (PTC) has become an important issue, and some publications after 2010 indicated that hemithyroidectomy is adequate for these low-risk patients. Unfortunately, no published manuscripts on prophylactic central node dissection offered good evidence regarding its indications or included a large number of patients. Also, it was not evident that prophylactic lateral node dissection improves cause-specific survival, although it might reduce lymph node recurrence especially in PTC patients with large tumors, distant metastases, or clinical central node metastases. Although completion total thyroidectomy was not recommended for minimally invasive follicular thyroid carcinoma in our guidelines, it may be better to perform it in elderly patients and those with a large tumor or extensive vascular invasion. Radioactive iodine (RAI) ablation after total thyroidectomy is still performed almost routinely in many Western institutions, although recent studies showed that ablation is not beneficial in low-risk patients. In Japan, because of legal restrictions, most patients did not undergo RAI ablation, and their prognoses are excellent.

CONCLUSIONS

Recently, policy for treating DTCs has changed not only in Western countries but also in Japan, resulting in a gradual move toward consensus between Western practice and ours. We will continue to present the best treatments for patients with thyroid carcinoma each time we revise our guidelines.

The total number of prelaryngeal and pretracheal lymph node metastases: is it a reliable predictor of contralateral central lymph node metastasis in papillary thyroid carcinoma?

BACKGROUND

Central lymph node (CLN) metastasis in papillary thyroid carcinoma (PTC) is common and being able to predict CLN metastasis helps surgeons determine individualized therapy. However, the relationship between contralateral CLN metastasis and the total number of positive lymph nodes (LNs) in the combined prelaryngeal and pretracheal region remains unclear. This study aimed to investigate whether the total number of positive LNs in the combined prelaryngeal and pretracheal region has clinical significance as a predictor for contralateral CLN metastasis.

METHODS

We prospectively enrolled 153 consecutive patients with unifocal PTC >1.0 cm without ultrasonographic evidence of nodal metastasis who underwent total thyroidectomy and prophylactic bilateral CLN dissection from July 2011-May 2013. Patients were divided into three groups according to the total number of positive LNs in the combined prelaryngeal and pretracheal region.

RESULTS

Rates of metastasis to ipsilateral and contralateral central compartments in PTC >1.0 cm were 84.3% and 24.2%, respectively. Multivariate analysis showed that ≥3 positive LNs in the combined prelaryngeal and pretracheal region were an independent predictive factor of contralateral CLN metastasis (P < 0.001; odds ratio, 8.585). After a mean follow-up of 24.1 mo, none of these patients had a recurrence in the central or lateral compartment.

CONCLUSIONS

Occult metastasis is highly prevalent in the ipsilateral central neck of patients with PTC >1.0 cm, and the total number of prelaryngeal and pretracheal LNs metastases may be a useful indicator to predict contralateral CLN metastasis in patients with unifocal PTC.

Ipsilateral Central Neck Dissection Plus Frozen Section Examination Versus Prophylactic Bilateral Central Neck Dissection in cN0 Papillary Thyroid Carcinoma

BACKGROUND

Ipsilateral central compartment node dissection (IpsiCCD) can reduce the morbidity of prophylactic bilateral central compartment node dissection (BilCCD) in papillary thyroid carcinoma (PTC) but it carries the risk of contralateral metastases being overlooked. Frozen section examination (FSE) of removed ipsilateral nodes has been proposed to intraoperatively assess nodal status. We compared IpsiCCD plus FSE and BilCCD in clinically unifocal and node negative PTC.

METHODS

One hundred patients were prospectively assigned to undergo total thyroidectomy (TT) plus BilCCD or TT plus IpsiCCD. In the IpsiCCD group, removed lymph nodes were sent for FSE. If FSE was positive for metastases, a BilCCD was accomplished.

RESULTS

The two groups included 50 patients each. Overall, occult lymph node metastases were found in 41 patients-20 in the IpsiCCD group and 21 in the BilCCD group. FSE correctly identified occult node metastases in 13 of 20 pN1a patients in the IpsiCCD group (overall accuracy 86 %). Seven node metastases were not detected at FSE-five were micrometastases (≤2 mm). Six of 13 patients in the IpsiCCD group who underwent BilCCD and 6 of 21 BilCCD pN1a patients had bilateral metastases. More patients in the BilCCD group showed transient hypocalcemia (27/50 vs. 18/50, respectively) [p = NS]. No patient experienced recurrent disease.

CONCLUSIONS

FSE of ipsilateral nodes is accurate in determining nodal status, allowing the extension of the central neck clearance to be reliably modulated. Routine IpsiCCD plus FSE of the ipsilateral nodes could be a valid alternative to prophylactic BilCCD since it allows accurate staging and may reduce morbidity.

Routine prophylactic central neck dissection for low-risk papillary thyroid cancer is not cost-effective

BACKGROUND

The role of routine prophylactic central neck dissection (CND) in papillary thyroid cancer (PTC) remains controversial. The aim of this study was to evaluate the cost utility of the addition of routine CND in patients with low-risk PTC compared with total thyroidectomy (TT) alone.

METHODS

A Markov model for low-risk PTC was constructed with a treatment algorithm based on the American Thyroid Association guidelines for well-differentiated thyroid carcinoma. Utilities and outcome probabilities were derived from published medical literature. US 2010 costs were examined from a society perspective using Medicare reimbursement rates and opportunity loss based on published US government data. Monte Carlo simulation and sensitivity analysis were used to examine the uncertainty of probability, cost and utility estimates.

RESULTS

Initial TT alone is more cost-effective than TT with CND, resulting in a cost savings of US $5763 per patient with slightly higher effectiveness per patient (0·03 QALY) for a cost savings of $285 per QALY. Sensitivity analysis shows that TT alone offers no advantage when radioactive iodine (RAI) becomes more detrimental to a patient's state of health, when the incidence of non-neck recurrence increases above 5% in patients undergoing TT alone or decreases below 3·9% in patients undergoing TT with CND or when the rate of permanent hypocalcaemia rises above 4%.

CONCLUSIONS

TT with CND is not a cost-effective strategy in low-risk PTC. Initial TT alone is favourable because of the low complication rates and low recurrence rates associated with the initial surgery. Alternative strategies such as unilateral prophylactic neck dissection require additional study to assess their cost-effectiveness.

Prophylactic level II neck dissection guided by frozen section for clinically node-negative papillary thyroid carcinoma: is it useful?

BACKGROUND

Prophylactic lateral neck dissection (PLND) is generally not performed for papillary thyroid carcinoma(PTC). When performed, occult metastases are found in upto 50 % of patients, although the incidence of occult level II nodes seems low. Our aim was to evaluate frozen section analysis-oriented elective level II PLND in patients with clinically node-negative (cN0) PTC.

METHODS

This retrospective study included patients with cN0 PTC treated with total thyroidectomy and prophylactic bilateral central and lateral neck dissection of ipsilateral levels III and IV. Frozen section analysis of PLND III and IV was performed. If positive, the PLND was extended to level II. We measured the accuracy of frozen section analysis, the incidence of occult level II metastasis, and oncologic outcomes.

RESULTS

A total of 295 patients were included. For frozen section analysis, the sensitivity was 71.0 %, specificity 99.6 %, positive predictive value 97.8 %, negative predictive value 92.4 %, overall accuracy 93.2 %. Definitive analysis found lateral node metastases in 63 of the 295(21 %) patients. Extension to level II was performed in 27 of 46 cases (59 %). Level II contained metastatic nodes in 12 of 27 (44 %) patients. There was no difference in total doses of 131I administered to patients with or without level II disease. Even when extension of PLND to level II was not performed, no cases of recurrent or persistent disease in level II occurred.

CONCLUSIONS

Frozen section analysis was highly accurate.The rate of occult metastases in level II was low. Detection of additional metastases in level II did not modify subsequent treatment or the rate of recurrence and is not useful for routine application.

Impact of prophylactic central neck dissection on oncologic outcomes of papillary thyroid carcinoma: a review

Prophylactic neck dissection (PND) for papillary thyroid carcinoma (PTC) is controversial. Our aim was to assess current levels of evidence (LE) according to the Oxford Centre for Evidence-based Medicine ( http://www.cebm.net/?O=1025 ) regarding the oncologic benefits of PND. Data were analyzed via MEDLINE keywords: PTC, differentiated thyroid carcinoma, PND, central lymph node metastases, central compartment, recurrence-free survival. There was conflicting evidence regarding the rate of reoperation for recurrence, with some studies showing a lower rate after PND with increased recurrence-free survival and a higher rate of undetectable pre- and post-ablation thyroglobulin levels (LE 4), whereas other studies did not show a difference (LE 4). Only one study (LE 4) showed improved disease-specific survival with PND. PND may improve recurrence-free survival, although this is supported by only a low LE. Current recommendations can only be based on low-level evidence.

Impact of prophylactic central compartment neck dissection on locoregional recurrence of differentiated thyroid cancer in clinically node-negative patients: a retrospective study of a large clinical series

BACKGROUND

In clinically node-negative patients with differentiated thyroid cancer (DTC), indications for routine central lymph node dissection (RCLD) are the subject of intensive research, and surgeons are divided between the pros and cons of this surgery. To better define the role of neck dissection in the treatment of DTC, we analyzed retrospectively the results in three centers in Italy.

METHODS

The clinical records of 752 clinically node-negative patients with DTC who underwent operative treatment between January 1998 and December 2005 in three endocrine surgery referral units were evaluated retrospectively. The complications and medium- and long-term outcomes of total thyroidectomy (TT) alone (performed in 390 patients: group A) and TT combined with bilateral RCLD (362 patients: group B) were analyzed and compared.

RESULTS

The incidence of permanent hypoparathyroidism and permanent unilateral vocal folds was 1% and 0.8% in group A and 3.6% and 1.7% in the group B, respectively. Bilateral temporary recurrent nerve palsy was observed in one of the 362 patients in group B. After a follow-up of 9.5 ± 3.5 years (mean ± SD), the locoregional recurrence rate with positive cervical lymph nodes was not substantially significantly different between the two groups.

CONCLUSION

In our series, TT combined with bilateral RCLD was associated with a greater rate of transient and permanent complications. Similar incidences of locoregional recurrence were reported in the two groups of patients. Considering the recent trend toward routine central lymphadenectomy, further studies are needed to evaluate the benefits of these different approaches.