Lobectomy and prophylactic central neck dissection for papillary thyroid microcarcinoma: do involved lymph nodes mandate completion thyroidectomy?

Histologic parameters driving completion thyroidectomy for papillary thyroid carcinoma in a high-volume institution: A retrospective observational study

BACKGROUND

When the histological examination indicates papillary thyroid carcinoma (PTC), there is no unanimity on the need to proceed with completion thyroidectomy (CT). This study aims to assess the histologic parameters that influenced the decision to perform CT.

MATERIALS AND METHODS

This study included PTC patients who underwent thyroid lobectomy between 2019 and 2022. Group A included patients who underwent thyroid lobectomy without further treatments, whereas Group B included those who underwent CT based on histological findings. Differences in terms of histologic parameters were analyzed.

RESULTS

Group A included 291 patients (68.3 ​%), whereas Group B 135 patients (31.7 ​%). Multivariate analysis identified associations between CT and tumor size (p ​< ​0.001), aggressive variant (p ​= ​0.009), and vascular invasion (p ​< ​0.001). ROC curve analysis established a tumor size cut-off of 21 ​mm for CT. At ROC curve analysis, the cut-off number of aggressive factors required for CT was 2.

CONCLUSION

A thorough comprehensive assessment encompassing all pathological characteristics might be necessary in case of PTC with aggressive histologic features after thyroid lobectomy.

Transoral endoscopic thyroidectomy with or without central neck dissection

PURPOSES

Minimally invasive thyroid surgeries are universally accepted. We report on one, transoral endoscopic thyroidectomy with or without central neck dissection.

METHODS

A case series of 103 patients were operated on between December 2018 and December 2021. We performed transoral endoscopic thyroidectomy vestibular approach (TOETVA) for 76 patients with a benign nodule, and 27 with papillary thyroid carcinoma (PTC). The patients with malignant nodules also underwent ipsilateral central neck dissection. The extent of surgery, operative time and operative complications were analyzed.

RESULT

No cases were converted to open surgery. Average tumor size was 3.8 ± 1.62 cm, mean operative time was 116.5 ± 41.7 min, median blood loss 40.1 ± 49 mL. There were 95 patients with lobectomy and 8 patients with total thyroidectomy. Temporary hoarseness occurred in 9 patients (8.7 %). No patients developed permanent hoarseness. Twelve patients had middle chin numbness.

CONCLUSION

The transoral endoscopic thyroidectomy vestibular approach, with or without central neck dissection, is a safe, effective and highly aesthetic treatment.

[Hemithyroidectomy or total thyroidectomy for low-risk papillary thyroid cancer? : Surgical criteria for primary and secondary choice of treatment in an interdisciplinary treatment concept]

The increase in small intrathyroid papillary thyroid cancer (PTC) observed worldwide over the past two decades, with no increase in cancer-specific mortality, has challenged the previous concept of total thyroidectomy as a one-size-fits-all panacea. After exclusion of papillary microcarcinomas, a systematic review of 20 clinical studies published since 2002, which compared hemithyroidectomy (HT) to total thyroidectomy (TT), found comparable long-term oncological outcomes for low-risk papillary thyroid cancer (LRPTC) 1-4 cm in diameter, whereas postoperative complication rates were markedly lower for HT. To refine individual treatment plans, HT should be combined with ipsilateral central lymph node dissection and intraoperative frozen section analysis for staging. Based on recent evidence from studies and in consideration of individual risk factors, patients with LRPTC can be offered the concept of HT as an alternative to the standard TT. A prerequisite for the treatment selection and decision is a comprehensive patient clarification of the possible advantages and disadvantages of both approaches.

Completion Total Thyroidectomy Is Not Necessary for Papillary Thyroid Microcarcinoma with Occult Central Lymph Node Metastasis: A Long-Term Serial Follow-Up

Simple Summary

The necessity of completion total thyroidectomy is unclear in patients with papillary thyroid microcarcinoma (PTMC) with only pathological central lymph node metastasis (pCLNM). The aim of our study was to determine the necessity of completion total thyroidectomy after an initial surgery by comparing the prognosis according to the presence of pCLNM during a long-term follow-up. We retrospectively compared the pathological central lymph node (pCLN)-positive group of 165 patients who underwent thyroid lobectomy with the pCLN-negative group of 711 patients and found no difference between the two groups in the recurrence rate and disease-free survival rates. Therefore, PTMC patients who underwent thyroid lobectomy with prophylactic central compartment neck dissection and were diagnosed with pCLNM after surgery do not require completion total thyroidectomy.

Abstract

The necessity of completion total thyroidectomy in patients with papillary thyroid microcarcinoma (PTMC) and pathological central lymph node metastasis (pCLNM) who underwent thyroid lobectomy with central compartment neck dissection (CCND) is unclear. We determined the necessity of completion total thyroidectomy by retrospectively comparing the prognosis according to the presence of pCLNM during a long-term follow-up. We enrolled 876 patients with PTMC who underwent thyroid lobectomy with prophylactic CCND from January 1986 to December 2009. Patients were divided according to central lymph node (CLN) metastasis: 165 (18.8%) and 711 (81.2%) in the CLN-positive and CLN-negative groups, respectively. Medical records were reviewed retrospectively, and clinicopathologic characteristics and recurrence rates were analyzed. The CLN-positive group was associated with male sex (p = 0.001), larger tumor size (p < 0.001), and more microscopic capsular invasion (p < 0.001) compared with the CLN-negative group. There was no significant difference between the two groups’ recurrence (p = 0.133) or disease-free (p = 0.065) survival rates. Univariate and multivariate analyses showed no factors associated with tumor recurrence except male sex (hazard ratio = 3.043, confidence interval 1.117–8.288, p = 0.030). Patients who were diagnosed with pCLNM after undergoing thyroid lobectomy with prophylactic CCND do not require completion total thyroidectomy; however, frequent follow-up is necessary for patients with PTMC and pCLNM.

Clinicopathologic factors and preoperative ultrasonographic characteristics for predicting central lymph node metastasis in papillary thyroid microcarcinoma: a single center retrospective study

Introduction

The treatment of papillary thyroid microcarcinoma remains controversial. Central lymph node metastasis is common in papillary thyroid microcarcinoma and it is an important consideration in treatment strategy selection.

Objective

The aim of this study was to investigate clinicopathologic risk factors and thyroid nodule sonographic characteristics for central lymph node metastasis in papillary thyroid microcarcinoma.

Methods

We retrospectively reviewed the data of 599 papillary thyroid microcarcinoma patients who underwent surgery from 2005 to 2017 at a single institution. Univariate and multivariate analyses were used to identify the clinicopathologic factors and preoperative sonographic features of central lymph node metastasis. A receiver-operating characteristic, ROC curve analysis, was performed to identify the efficacy of ultrasonographic features in predicting central lymph node metastasis. A nomogram based on the risk factors was established to predict central lymph node metastasis.

Results

The incidence of central lymph node metastasis was 22.4%. The univariate and multivariate analyses suggested that gender, age, multifocality, extrathyroidal invasion, and lateral lymph node metastasis were independent risk factors for central lymph node metastasis. The univariate and multivariate analyses revealed that nodular shape, margin, and calcification were independently associated with central lymph node metastasis. The ROC curve analysis revealed that the combination of shape, margin and calcification had excellent accuracy in predicting central lymph node metastasis. The nomogram was developed based on the identified risk factors for predicting central lymph node metastasis, and the calibration plot analysis indicated the good performance and clinical utility of the nomogram.

Conclusions

Central lymph node metastasis is associated with male gender, younger age (<45 years), extrathyroidal invasion, multifocality and lateral lymph node metastasis in papillary thyroid microcarcinoma patients. The ultrasongraphic features, such as irregular shape, ill-defined margin and calcification, may improve the efficacy of predicting central lymph node metastasis. Surgeons and radiologists should pay close attention to the patients who have these risk factors. The nomogram may help guide surgical decision making in papillary thyroid microcarcinoma.

The Effect of Prophylactic Central Neck Dissection During Hemithyroidectomy on Locoregional Recurrence in Patients With Papillary Thyroid Carcinoma: A Meta-Analysis

Objectives.

Hemithyroidectomy is commonly performed in patients with low- to intermediate-risk papillary thyroid carcinoma. The purpose of this meta-analysis was to evaluate the effect of prophylactic central neck dissection on locoregional recurrence in patients undergoing hemithyroidectomy.

Methods.

A meta-analysis was performed of full-text publications published in English retrieved from the Embase database.

Results.

The rate of regional recurrence in the central compartment after hemithyroidectomy, with or without prophylactic central neck dissection, was 0.17% and 1.78%, respectively. This difference was statistically significant. Recurrence in the lateral compartment or contralateral thyroid was not affected by prophylactic central neck dissection; the overall rate of recurrence was 1.3% and 5.4%, respectively.

Conclusion.

Prophylactic central neck dissection significantly reduced the risk of recurrence in the central compartment in patients undergoing hemithyroidectomy.

Recurrence following hemithyroidectomy in patients with low- and intermediate-risk papillary thyroid carcinoma

BACKGROUND

This study evaluated the incidence, patterns and risk factors for recurrence after hemithyroidectomy in patients with low- and intermediate-risk papillary thyroid carcinoma (PTC), and verified the predictive role of the risk staging systems in current use.

METHODS

The clinicopathological characteristics and risk categories were analysed according to recurrence in patients who underwent hemithyroidectomy for low- and intermediate-risk conventional PTC, and were followed up for at least 24 months. Five risk staging systems were used to stratify risk: the 2015 American Thyroid Association (ATA) system; Age, Metastases, Extent and Size (AMES) system; Metastases, Age, Complete resection, Invasion and Size (MACIS) system; Grade, Age, Metastases, Extent and Size (GAMES) system; and the eighth AJCC system.

RESULTS

The study included 561 patients; 93·9 per cent of the study population (527 of 561) had a papillary thyroid microcarcinoma 1 cm or smaller in size. At a mean follow-up of 83 months, 25 patients (4·5 per cent) had recurrence; among these patients, 23 (92%) presented with a remaining thyroid lobe. Multifocality was significantly associated with recurrence in univariable and multivariable analyses (adjusted hazard ratio 3·16, 95 per cent c.i. 1·25 to 7·98; P = 0·015). Disease-free survival (DFS) varied according to multifocality (P = 0·010). The five risk staging systems were not associated with recurrence, and their Harrell's C-index ranged from 0·500 to 0·531. DFS rates did not differ between the risk categories in each system.

CONCLUSION

Although the recurrence rate after hemithyroidectomy in patients with low- and intermediate-risk PTC was low, meticulous follow-up focusing on the remaining thyroid lobe is needed for early detection and timely management of recurrence. The risk scoring systems in current use have no predictive role in these patients.

Effect of chronic lymphocytic thyroiditis on the efficacy and safety of ultrasound-guided radiofrequency ablation for papillary thyroid microcarcinoma

BACKGROUND

Chronic lymphocytic thyroiditis (CLT) is an autoimmune disease commonly associated with papillary thyroid carcinoma characterized by a smaller primary tumor size at presentation. The efficacy and safety of ultrasound-guided radiofrequency ablation (RFA) for papillary thyroid microcarcinoma (PTMC) coexisting with CLT is still unknown.

METHODS

Sixty patients with unifocal PTMC were enrolled and classified into PTMC and PTMC+CLT groups (n = 30/group). CLT was diagnosed histopathologically. The ablation area exceeded the tumor margins, and was evaluated by US and contrast-enhanced US (CEUS) for residual tumor to prevent recurrence. Three months after ablation, US-guided core-needle biopsy was performed to assess the presence of residual and recurrent cancer. Preoperative and postoperative data on patients and tumors were recorded and analyzed.

RESULTS

There were no differences between groups in age, sex, preoperative tumor volume, ablation time, or ablation power (P > 0.05). There was also no significant difference in postoperative ablation zone volume between the groups at the 1-, 3-, 6-, 12-, and 18-month follow-ups (P > 0.05). The volume reduction rate significantly differed between the two groups at month 3 (P = 0.03). The ablation area could not be identified on US and CEUS at 9.8 ± 5.0 and 10.0 ± 4.8 months in the PTMC and PTMC + CLT groups, respectively (P = 0.197). No serious complications occurred during and after ablation. No residual cancer cells were found on biopsy after ablation.

CONCLUSIONS

RFA was effective in patients with PTMC+CLT, and its therapeutic efficacy and safety were similar to those in patients with PTMC without CLT.

Routine Prophylactic Central Neck Dissection May Not Obviously Reduce Lateral Neck Recurrence for Papillary Thyroid Microcarcinoma

BACKGROUND

The role of routine prophylactic central compartment neck dissection (pCCND) for papillary thyroid microcarcinoma (PTMC) remains controversial. The lateral neck recurrence-free survival (LRFS) advantages achieved by pCCND are still under investigation.

METHODS

The records of 2,074 consecutive patients with papillary thyroid carcinoma (PTC) at the time of surgery from 1996 to 2009 were retrospectively reviewed. A total of 611 consecutive patients were included in the final analyses. We used R version 3.5.1 to match patients with total thyroidectomy (TT)/lobectomy + pCCND with patients with TT/lobectomy alone and analyzed the following factors with a potential influence: age at diagnosis, sex, extrathyroid extension, and primary tumor multifocality and bilaterality. LRFS was analyzed. Moreover, the data were reanalyzed after separating the pairs of patients with pN1a from those with pN0.

RESULTS

We were able to select 159 pairs sharing the major prognostic risk factors as listed. Overall, there was no difference in the LRFS, although patients with pCCND more often had recurrence. Moreover, the central lymph node metastasis status had no significant influence on the risk of recurrence.

CONCLUSION

Routine pCCND was not a protective factor for LRFS in PTMC patients with cN0. The difference in LRFS between pN0 and pN1a was not statistically significant (p > 0.05).

Deciphering novel biomarkers of lymph node metastasis of thyroid papillary microcarcinoma using proteomic analysis of ultrasound-guided fine-needle aspiration biopsy samples

Thyroid papillary microcarcinoma is now a common clinical problem. Cervical lymph node metastasis is the main metastasis mode of PTMC. However, before operation, it is still difficult to determine exactly whether PTMC patient is suffering with cervical lymph node metastasis. To resolve this dilemma, for better selection of optimum treatment plans, it is necessary to investigate the overall changes in proteomes of PTMC, and evaluate the potential of biomarkers to predict lymph node metastasis. Tandem mass tags combined with multidimensional liquid chromatography and mass spectrometry analyses were used aiming to screen the proteomic profiles of fine-needle aspiration biopsy samples. Quantitative proteomic analysis, significant pathway and functional categories were investigated. In total, 3391 proteins of the 3793 protein groups identified were quantified. Bioinformatics analysis indicated that differentially expressed proteins were involved in multiple biological functions, metastasis-related pathways. Moreover, IFN-stimulated gene 15 proteins were found to be well distinguished between patients with lymph node metastatic and patients with nonmetastatic PTMC. Knocking down ISG15 with shRNA inhibited the xenografted tumor growth. This study provided a reference proteome map for lymph node metastatic PTMC. ISG15 probably is a prognosis marker of thyroid papillary microcarcinoma patients with lymph node metastasis. SIGNIFICANCE: Nowadays, thyroid cancer has become a widespread epidemic. The rate of thyroid cancer incidence has been faster than any other cancers, reported by the American Cancer Society. Papillary thyroid microcarcinoma (PTMC) is a subset of PTC defined as PTC measuring≤1 cm in size, which comprises nearly one-half of all the cases of PTCs. Actually, the rapidly increasing global incidence of PTC is mainly attributed to the corresponding increase in the diagnosis of PTMC. Scholars have figuratively compared the increase of PTMC to the "tsunami". The treatment scheme for PTMC is still not uniform, and the controversy is mainly focused on the necessity of surgery treatment. PTMCs often have an indolent course in the absence of evidence of metastatic cervical lymph nodes, distant metastases and extrathyroidal extension. Therefore, it is important for us to reliably differentiate the small number of PTMC patients developing significant metastases progression from the larger population of patients that harbor indolent PTMCs. The present study aimed to investigate the overall changes in proteomes of PTMC, and evaluate the potential of biomarkers to predict lymph node metastasis. Tandem mass tags (TMT) combined with multidimensional liquid chromatography and mass spectrometry analyses were used aiming to screen the proteomic profiles of fine-needle aspiration biopsy (FNAB) samples. Quantitative proteomic analysis, significant pathway and functional categories were investigated. Our results showed that some differential expression proteins were likely to be important resources for finding new diagnostic biomarkers.

Comparison of endoscopic thyroidectomy via a modified axillo-breast approach with the conventional breast approach for treatment of unilateral papillary thyroid microcarcinoma

Endoscopic thyroidectomy (ET) via an axillo-breast (ABA), axillary or breast approach (BA) is effective for treatment of unilateral papillary thyroid microcarcinoma (PTMC). However, several disadvantages still exist, including inconvenience for using endoscopic instruments and poor cosmetic results. Here, we introduced a modified ABA (MABA) to overcome these disadvantages and evaluated its therapeutic outcomes by comparison with conventional BA.Fifty-five patients undergoing ET via MABA (n = 22) or BA (n = 33) for PTMC were retrospectively enrolled between June 2012 and June 2015. Surgical outcomes, including the operation time, blood loss, amount of drainage, number of dissected lymph nodes, complications, cosmetic satisfaction and prognosis (recurrence and survival), were analyzed.The operation time (87.1 ± 9.3 min vs 93.2 ± 8.3 min; P = .014) and drainage tube removal time (4.4 ± 1.0 days vs 5.1 ± 1.1 days; P = .018) were shorter in the MABA group than those in the BA group. There was less postoperative drainage (54.3 ± 35.7 mL vs 137.6 ± 87.0 mL; P < .01) in the MABA group compared with the BA group. No significant differences in the blood loss (15.9 ± 7.5 mL vs 19.2 ± 11.7 mL, P = .243) and the number of dissected lymph nodes (1.8 ± 1.5 vs 2.3 ± 2.1, P = .309) were observed between the 2 groups. Subcutaneous ecchymosis occurred more frequently in the BA group than that in the MABA group (33.3% vs 9.1%; P = .038). Patients treated by MABA were more satisfied with their cosmetic results than those undergoing BA (100% vs 81.8%; P = .034). At the last follow-up time, all patients were alive although 1 patient in the BA group developed cervical lymph node recurrence ipsilateral to the original tumor at 4 years after surgery. Multivariate logistic regression analysis showed MABA surgery was a protective factor for postoperative complications (OR = 0.209, 95% confidence interval [CI] = 0.054-0.817, P = .024).ET via the MABA strategy may be a good choice for unilateral PTMC because of shorter operation time, fewer complications, greater cosmetic satisfaction, and excellent prognosis.

A meta-analysis on the effect of operation modes on the recurrence of papillary thyroid microcarcinoma

Whether total thyroidectomy reduces the recurrence rate in patients with papillary thyroid microcarcinoma (PTMC) is currently controversy. Conclusions of sporadic, inconsistent, and mono-institutional studies need a meta-analysis to evaluate. 525 relevant studies were obtained from initial search on PubMed, 511 studies were excluded by inclusion and exclusion criteria. Eligible data were extracted from each included study. The Odds ratios (ORs) and 95% confidence interval (CI) were used to assess the difference in the recurrence rates between PTMC patients treated with total thyroidectomy and non-total thyroidectomy. OR and 95% CI were calculated using a fixed-effects or a random-effects model. The Q statistic was used to evaluate homogeneity and Beggs test was used to assess publication bias. 14 studies meeting the inclusion criteria were included in this meta-analysis. The over all recurrence rates of pooled patients with total thyroidectomy and non-total thyroidectomy were 2.83% and 2.84% respectively. Primary random-effects model analysis showed, no significant difference of recurrence rates existed between two operation modes (OR = 0.732, 95% CI: 0.444 - 1.208), while, high heterogeneity among studies was found, I-squared index (I2) = 40.2%. After remove one study with high heterogeneity, the OR of the pooled recurrence rates of the total thyroidectomy and the non-total thyroidectomy groups was 0.786 (95% CI: 0.363 - 1.701), further suggesting no significant difference of the recurrence rate exists between two operation modes. Our meta-analysis demonstrated postoperative recurrence of PTMC is not reduced by total thyroidectomy, non-total thyroidectomy is also a good choice to treat PTMC patients.

The incidence and risk factors for central lymph node metastasis in cN0 papillary thyroid microcarcinoma: a meta-analysis

Although there have been many studies identifying clinical and pathologic factors that may predict central lymph node metastases (CLNM) in papillary thyroid microcarcinoma (PTMC) patients without clinically cervical lymph node metastasis (cN0), the results were inconsistent. And whether prophylactic central lymph node dissection (pCLND) should be performed in cN0 PTMC remains controversial. The EMBASE, PubMed, MEDLINE and the Cochrane Library were searched until Oct 2015 to identify relevant studies. Primary outcomes were clinical and pathologic factors for CLNM. Secondary outcomes included CLNM rate, surgical complications of hypocalcaemia and recurrent laryngeal nerve(RLN) injury and neck recurrences. Statistical analysis was performed using Stata 12.0. Fourteen eligible studies enrolling 4573 patients were included in this meta-analysis. The overall incidence of CLNM was 33 % (95 % CI 29-37). An elevated risk of CLNM was significantly associated with male gender (OR 2.33, 95 % CI 1.71-3.17), age <45 years (OR 1.27, 95 % CI 1.08-1.48), tumor size >5 mm (OR 2.16, 95 % CI 1.87-2.50), multifocality (OR 1.73, 95 % CI 1.45-2.05), extrathyroidal extension (OR 1.99, 95 % CI 1.66-2.37) and lymphovascular invasion (OR 3.87, 95 % CI 1.64-9.10), but not with thyroid bilaterality (OR 1.41, 95 % CI 0.89-2.22) and chronic lymphocytic thyroiditis (OR 0.98, 95 % CI 0.66-1.47). The pooled frequency of permanent hypocalcaemia, permanent RLN injury and neck recurrences was 1.1, 0.5 and 2.8 %, respectively. cN0 PTMC patients have a considerable CLNM rate and have a low pooled incident of surgical complications and neck recurrences with pCLND. Six unfavorable clinical and pathologic factors, which were significantly associated with CLNM, were identified. These findings may help guide the application of pCLND or subsequent treatment in cN0 PTMC.

Changing trends in the management of well-differentiated thyroid carcinoma in Korea

A questionnaire administered in 2009 found that members of the Korean Association of Thyroid-Endocrine Surgeons (KATES) favored more aggressive treatment of well-differentiated thyroid carcinoma (WDTC) than physicians from other countries. This study assessed the changes in practical management of WDTC in Korea from the previous survey. Questionnaires were sent by e-mail to KATES members. A total of 101 members completed the questionnaire. Their responses were compared with response for the 2009 survey. Of the respondents, 53.5% and 80.2% indicated that they would perform fine-needle aspiration cytology on nodules that were <0.5 cm and 0.5-1.0 cm in diameter, respectively. If the cytology was positive, a large number of respondents favored surgical treatment, regardless of tumor size. Compared with the 2009 survey, a slightly higher percentage favored observation for patients with tumors that were <0.5 cm in diameter, and a larger percentage recommended less-than-total thyroidectomy for patients with T1 cancers. Respondents in 2014 favored aggressive lymph node dissection less, irrespective of tumor size, preferring short-term treatment with thyroid stimulating hormone suppressors. The percentage preferring postoperative high-dose radioactive iodine therapy slightly increased, whereas the percentage favoring external irradiation decreased, in 2014 compared with 2009. The management of Korean patients with WDTC changed from 2009 to 2014. In 2009, Korean respondents favored more aggressive treatment of WDTC compared with respondents from other countries. In 2014, however, Korean respondents favored a more conservative approach, especially in patients with microcarcinomas.

Evaluating the influence of prophylactic central neck dissection on TNM staging and the recurrence risk stratification of cN0 differentiated thyroid carcinoma

OBJECTIVE

The purpose of this study was to explore the risk factors that were associated with central lymph node metastasis (CLNM) in patients with clinical nodal negative differentiated thyroid carcinoma (cN0 DTC) after prophylactic central neck dissection (pCND). The influence of pCND on TNM staging and recurrence risk stratification (RRS) in patients with cN0 DTC was also evaluated in our study.

METHODS

A total of 153 cN0 DTC patients in Guangdong general hospital who underwent thyroidectomy with pCND from March 2014 to October 2014 were enrolled in this study. The relations of CLNM with clinicopathologic characteristics of cN0 DTC were analyzed by univariate and multivariate logistic regression. The influence of pCND on migration of TNM staging and RRS in cN0 DTC was observed.

RESULTS

In the present study, CLNM was found in 42.5% (65 of 153 cases) of patients with cN0 DTC. On univariate analysis, the age less than 45 years old, tumor size more than 2cm, pT staging, and a total number of central lymph nodes dissected more than 3 were significantly associated with CLNM (P<0.05); however, gender, tumors affecting both lobes, multifocality, capsular invasion, and Hashimoto's thyroiditis were not related with CLNM (P>0.05). On multivariate logistic regression, age<45 years (P=0.001) and a total number of central lymph nodes dissected >3 (P=0.002) were significantly associated with CLNM. Because of the identification of CLNM in the implementation of pCND, 15 (9.8%) of 153 cN0 DTC patients were upgraded in TNM staging; all these patients were older than 45 years. Fifty-six patients (36.6%) developed higher RRS (from low to intermediate) after pCND.

CONCLUSIONS

For younger patients (age<45 years), careful preoperative assessment of the lymph node status must be done; surgeons should consider this risk factor when deciding whether to perform pCND. Thorough lymphadenectomy in the implementation of pCND can avoid residual lymph node metastasis and help to increase the incidence of CLNM. pCND can indentify occult CLNM which allows more precise TNM staging (for patients with age≥45 years) and RRS.