Risk Factors for Predicting Lymph Nodes Posterior to Right Recurrent Laryngeal Nerve (LN-prRLN) Metastasis in Thyroid Papillary Carcinoma: A Meta-Analysis

Prediction model of lymph node metastasis posterior to the right recurrent laryngeal nerve

BACKGROUND

At present, it is still controversial whether lymph nodes posterior to the right recurrent laryngeal nerve (LN-prRLN) in papillary thyroid carcinoma (PTC) patients should be dissected. Failure to dissect metastatic lymph nodes results in continued metastasis from the positive lymph nodes to other regions. Our study aimed to establish a predictive model and predict the probability of metastasis of the lymph nodes posterior to the right recurrent laryngeal nerve (LNM-prRLN) in patients.

METHODS

A total of 309 patients underwent surgery for thyroid cancer between May 2019 and September 2022. The risk factors were identified by univariate and multivariate analyses, and statistically significant risk factors identified in the multivariate analysis were included in the nomogram. We used the calibration curve and the receiver operating characteristic (ROC) curve to verify the accuracy of the prediction model.

RESULTS

Multivariate analysis showed that irregular tumor margins (OR: 3.549, 95% CI 1.294-9.733, P = 0.014), extrathyroidal extension (OR: 4.507, 95% CI 1.694-11.993, P = 0.003), maximum tumor diameter > 1 cm (OR: 5.729, 95% CI 2.617-12.542, P < 0.001), overweight status (OR: 2.296, 95% CI 1.057-4.987, P = 0.036), high total cholesterol level (OR: 5.238, 95% CI 2.304-11.909, P < 0.001), and multifocality (OR: 11.954, 95% CI 5.233-27.305, P < 0.001) were independent risk factors for LNM-prRLN. The area under the ROC curve was 0.927. The calibration curve showed good agreement between the predicted and observed rates of LNM-prRLN.

CONCLUSION

The probability of LNM-prRLN could be predicted by a nomogram based on the statistically significant risk factors identified in the multivariate analysis. This nomogram can guide clinicians when preoperatively evaluating the status of the LN-prRLN with regard to LNM-prRLN in PTC patients. For patients at high risk for LNM-prRLN, the preventive dissection of LN-prRLNs can be considered.

Lymph Node Posterior to the Right Recurrent Laryngeal Nerve Metastasis in Right Lobe T1a Papillary Thyroid Carcinoma: A Retrospective Cohort Study

INTRODUCTION AND OBJECTIVES

This study analyzed the incidence and predictors of lymph node posterior to the right recurrent laryngeal nerve metastasis in T1a papillary thyroid carcinoma of the right lobe.

METHODS

This was a retrospective cohort study. Patients were selected from those who had received surgical treatment for primary papillary thyroid carcinoma between January 2019 and December 2020. The association between clinicopathologic variables and lymph node posterior to the right recurrent laryngeal nerve metastasis was assessed using univariate and multivariate analyses. Postoperative complications were also described.

RESULTS

Lymph node posterior to the right recurrent laryngeal nerve metastasis was present in 6.0% of the 402 study patients. It was the most likely to occur when there were other lymph node metastases, particularly in the lymph node anterior to the recurrent laryngeal nerve. Independent predictors for lymph node posterior to the right recurrent laryngeal nerve metastasis were a tumor size of ≥5.0 mm, a lower pole location, and lymph node anterior to the right recurrent laryngeal nerve metastasis. The rate of persistent vocal cord paralysis was .5%, and no patient developed permanent hypoparathyroidism.

CONCLUSIONS

Although lymph node posterior to the right recurrent laryngeal nerve metastases of the right lobe T1a papillary thyroid carcinoma is uncommon, the possibility of metastasis should be investigated when there is a positive lymph node anterior to the right recurrent laryngeal nerve in a tumor >5.0 mm in size located in the lower pole. Lymph node posterior to the right recurrent laryngeal nerve dissection is recommended for such tumors.

Surgical outcomes of different approaches to dissection of lymph nodes posterior to right recurrent laryngeal nerve: a retrospective comparative cohort study of endoscopic thyroidectomy via the areolar approach and via the axillo-breast approach

Background

The American Thyroid Association (ATA) points out that lymph nodes posterior to right recurrent laryngeal nerve (LN-prRLN) should be routinely dissected. Due to the high risk of nerve injury, the lymph nodes in this area are difficult to dissect thoroughly. Although there are many approaches to endoscopic thyroidectomy, no study has been conducted on which one is more suitable. The purpose of this study was to evaluate the safety, thoroughness, related trauma, and feasibility of two widely used endoscopic thyroidectomy approaches, so as to provide a basis for the surgeon to select a better surgical approach.

Methods

This retrospective study included patients who underwent ETA (n=26) and ETAB (n=36). All patients had a pathological diagnosis of papillary thyroid carcinoma (PTC) and underwent endoscopic right thyroidectomy from May 2015 to February 2022 in the Affiliated Hospital of Nantong University. The basic clinical data and surgical outcomes of the two groups were compared.

Results

There was no statistical difference between the two groups in basic clinical data and oncological characteristics, which meant that the baseline data of the two groups of patients were comparable. Significant statistical significance was observed in the operation duration (149.38±44.15 vs. 119.22±45.48 min, P=0.011), drainage volume 24 h after operation (95.54±16.79 vs. 54.46±15.11 mL, P<0.001), visual analog score (VAS) 24 h after operation (3.69±1.44 vs. 2.25±1.32, P<0.001), hospitalization duration after the operation (3.19±0.75 vs. 2.25±0.44 days, P<0.001), number of lymph node dissections after right recurrent laryngeal nerve resection (0.96±1.08 vs. 2.06±1.77, P=0.007), and number of lymph node metastases after right recurrent laryngeal nerve resection (0.12±0.33 vs. 0.58±1.00, P=0.025). Besides, there was no significant difference in the numbers of central lymph node dissections and central lymph node metastases.

Conclusions

Our study indicated that compared with ETA, ETAB may perform a more efficient dissection of the LN-prRLN based on less surgical trauma, which could provide a basis for the surgeon to select a better surgical approach.

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.

Infiltration pattern predicts metastasis and progression better than the T-stage and grade in pancreatic neuroendocrine tumors: a proposal for a novel infiltration-based morphologic grading

The advancing edge profile is a powerful determinant of tumor behavior in many organs. In this study, a grading system assessing the tumor-host interface was developed and tested in 181 pancreatic neuroendocrine tumors (PanNETs), 63 of which were <=2 cm. Three tumor slides representative of the spectrum (least, medium, and most) of invasiveness at the advancing edge of the tumor were selected, and then each slide was scored as follows. Well-demarcated/encapsulated, 1 point; Mildly irregular borders and/or minimal infiltration into adjacent tissue, 2 points; Infiltrative edges with several clusters beyond the main tumor but still relatively close, and/or satellite demarcated nodules, 3 points; No demarcation, several cellular clusters away from the tumor, 4 points; Exuberantly infiltrative pattern, scirrhous growth, dissecting the normal parenchymal elements, 5 points. The sum of the rankings on the three slides was obtained. Cases with scores of 3-6 were defined as "non/minimally infiltrative" (NI; n = 77), 7-9 as "moderately infiltrative" (MI; n = 68), and 10-15 as "highly infiltrative" (HI; n = 36). In addition to showing a statistically significant correlation with all the established signs of aggressiveness (grade, size, T-stage), this grading system was found to be the most significant predictor of adverse outcomes (metastasis, progression, and death) on multivariate analysis, more strongly than T-stage, while Ki-67 index did not stand the multivariate test. As importantly, cases <=2 cm were also stratified by this grading system rendering it applicable also to this group that is currently placed in "watchful waiting" protocols. In conclusion, the proposed grading system has a strong, independent prognostic value and therefore should be considered for integration into routine pathology practice after being evaluated in validation studies with larger series.

Pattern and Predictive Factors of Metastasis in Lymph Nodes Posterior to the Right Recurrent Laryngeal Nerve in Papillary Thyroid Carcinoma

OBJECTIVE

The right cervical central lymph nodes include lymph nodes anterior to the right recurrent laryngeal nerve (LN-arRLN) and lymph nodes posterior to the right recurrent laryngeal nerve (LN-prRLN), and are separated by the right recurrent laryngeal nerve (RLN). LN-prRLN is a common site of nodal recurrence after the resection of papillary thyroid carcinoma (PTC). However, the complexity in anatomical structure brings difficulties in determining the surgical scope, so it is necessary to assess the pattern and predictive factors of right cervical central lymph nodes, especially LN-prRLN metastasis in papillary thyroid carcinoma.

METHODS

A total of 562 diagnosed PTC patients who underwent right or total thyroidectomy were enrolled in this retrospective study. The clinicopathological features were collected, univariate and multivariate analyses were performed to determine predictive factors of the right central lymph node metastasis.

RESULTS

In this study, the metastatic rates of the right CLN, the LN-arRLN and the LN-prRLN were 59.6% (335/562), 51.8% (291/562) and 30.4% (171/562), respectively. And 22.6% (127/562) of patients had both LN-arRLN and LN-prRLN metastasis. Among patients without LN-arRLN metastasis, the rate of LN-prRLN metastasis was 16.2% (44/271), accounting for 25.7% of the LN-prRLN metastasis group. Factors associated with an increased risk of LN-arRLN metastasis include male, age below 55 years, tumor size > 1cm, extrathyroidal extension (ETE), clinical lymph nodes metastasis(cN1), lateral lymph node metastasis, and left CLN metastasis. In addition, ETE, lateral lymph node metastasis, and LN-arRLN metastasis were independent factors of LN-prRLN metastasis. The predictive factors of LN-prRLN in cN0 PTC were further explored, revealing that tumor size ≥1.5cm, ETE, and LN-arRLN metastasis were independent predictors of LN-prRLN metastasis in cN0 PTC.

CONCLUSION

The LN-prRLN should not be ignored in surgery because of its high rate of metastasis. Our findings indicate that thorough dissection of central lymph nodes, especially LN-prRLN is crucial in clinical work.

Unnecessity of Routine Dissection of Right Central Lymph Nodes in cN0 Papillary Thyroid Carcinoma Located at the Left Thyroid Lobe

Objective

The lymph node posterior to the right recurrent laryngeal nerve (LN-prRLN) is an important part of the central lymph nodes (LNs). We aimed to explore the rate and predictors of LN-prRLN metastasis in cN0 papillary thyroid carcinoma (PTC) located at the left thyroid lobe.

Methods

Patients with surgically treated primary left lobe PTC were retrospectively enrolled. The metastatic distribution of LN-prRLN and postoperative complications were assessed. The association between LN-prRLN metastasis and clinicopathological variables was evaluated by univariate and multivariate analyses.

Results

A total of 857 patients were included for the analysis. Central LN metastasis was noted in 310 (35.3%) cases. The most (27.6%) and least (1.7%) commonly involved LNs were the left paratracheal LN and the LN-prRLN. In the univariate analysis, the tumor size, multifocality, the extent of extrathyroidal extension (none vs. macroscopic vs. macroscopic maximal), and perineural invasion were associated with positive LN-prRLN. In the multivariate analysis, tumor size of >40.0 mm and macroscopic maximal invasion were found as the only two independent predictors. Transient and permanent hypoparathyroidism were noted in 90 (10.2%) and 13 (1.5%) patients, respectively. Voice change was noted in 40 (4.6%) patients, and 20 patients recovered.

Conclusions

In cN0 PTC located at the left lobe, LN-prRLN metastasis was very uncommon. We found that LN-prRLN dissection is not required routinely, but should be performed if the tumor size is >40.0 mm and macroscopic maximal extrathyroidal extension is present.

[A Meta-analysis of risk factors related to the lymph nodes posterior to the right recurrent laryngeal nerve in thyroid micropapillary carcinoma]

Objective:To evaluate the risk factors for metastasis of the lymph nodes posterior to the right recurrent laryngeal nerve in thyroid micropapillary carcinoma（PTMC） by Meta-analysis. Methods:We searched domestic and foreign databases for relevant studies published up to June, 2020. Two independent reⅥewers performed literature screening and data extraction according to the inclusion and exclusion criteria. Then, Meta-analysis was performed using Revman 5.3 software. Results:A total of 5 articles were included, with a total of 1884 subjects.The results of the study showed that the rate of lymph node metastasis in PTMC Ⅵb area was 10.8% （203/1884）. The risk factors for metastasis included patients' age <45 years old, male, right lobe tumor Diameter ≥0.5 cm, invading the envelope, Ⅵa lymph node metastasis. Conclusion:Ⅵb lymph node dissection is recommended when there exists age<45 years, male sex, right lobe tumor≥0.5 cm, capsular invasion or Ⅵa lymph node metastasis.

A Novel Scoring System for Predicting the Metastases of Posterior Right Recurrent Laryngeal Nerve Lymph Node Involvement in Patients With Papillary Thyroid Carcinoma by Preoperative Ultrasound

OBJECTIVE

Our goal was to investigate the correlation between papillary thyroid carcinoma (PTC) characteristics on ultrasonography and metastases of lymph nodes posterior to the right recurrent laryngeal nerve (LN-prRLN). There is still no good method for clinicians to judge whether a patient needs LN-prRLN resection before surgery, and we also wanted to establish a new scoring system to determine whether patients with papillary thyroid carcinoma require LN-prRLN resection before surgery.

PATIENTS AND METHODS

There were 482 patients with right or bilateral PTC who underwent thyroid gland resection from December 2015 to December 2017 recruited as study subjects. The relationship between the PTC characteristics on ultrasonography and the metastases of LN-prRLN was analyzed by univariate and logistic regression analyses. Based on the risk factors identified in univariate and logistic regression analysis, a nomogram-based LN-prRLN prediction model was established.

RESULT

LN-prRLN were removed from all patients, of which 79 had LN-prRLN metastasis, with a metastasis rate of 16.39%. Multivariate logistic regression analysis revealed that LN-prRLN metastasis was closely related to sex, age, blood supply, larger tumors (> 1 cm) and capsular invasion. A risk prediction model has been established and fully verified. The calibration curve used to evaluate the nomogram shows that the consistency index was 0.75 ± 0.065.

CONCLUSION

Preoperative clinical data, such as sex, age, abundant blood supply, larger tumor (> 1 cm) and capsular invasion, are positively correlated with LN-prRLN metastasis. Our scoring system can help surgeons non-invasively determine which patients should undergo LN-prRLN resection before surgery. We recommend that LN-prRLN resection should be performed when the score is above 103.1.

Predictive Factor of Large-Volume Central Lymph Node Metastasis in Clinical N0 Papillary Thyroid Carcinoma Patients Underwent Total Thyroidectomy

Large-volume central lymph node metastasis (large-volume CLNM) is associated with high recurrence rate in papillary thyroid carcinoma (PTC) patients. However, sensitivity in investigating large-volume CLNM on preoperative ultrasonography (US) is not high. The aim of this study is to investigate the clinical factors associated with large-volume CLNM in clinical N0 PTC patients. We reviewed 976 PTC patients undergoing total thyroidectomy with central lymph node dissection during 2017 to 2019. The rate of large-volume LNM was 4.1% (40 of 967 patients). Multivariate analysis showed that male gender and young age (age<45 years old) were independent risk factors for large-volume CLNM with odds ratios [(OR), 95% confidence interval (CI)] of 2.034 (1.015-4.073) and 2.997 (1.306-6.876), respectively. In papillary thyroid microcarcinoma (PTMC), capsule invasion was associated with large-volume CLNM with OR (95% CI) of 2.845 (1.110-7.288). In conventional papillary thyroid cancer (CPTC), tumor diameter (>2cm) was associated with large-volume CLNM, with OR (95% CI) 3.757 (1.061-13.310), by multivariate analysis. In ROC curve analysis on the diameter of the CPTC tumor, the Area Under Curve (AUC) =0.682(p=0.013), the best cut-off point was selected as 2.0cm. In conclusion, male gender and young age were predictors for large-volume CLNM of cN0 PTC. cN0 PTMC patient with capsule invasion and cN0 CPTC patient with tumor diameter >2cm were correlated with large-volume CLNM. Total thyroidectomy with central lymph node dissection may be a favorable primary treatment option for those patients.

Metastasis of cN0 Papillary Thyroid Carcinoma of the Isthmus to the Lymph Node Posterior to the Right Recurrent Laryngeal Nerve

OBJECTIVE

The association between metastasis to the lymph node posterior to the right recurrent laryngeal nerve (LN-prRLN) and cN0 papillary thyroid carcinoma (PTC) located in the thyroid isthmus remains unknown; therefore, our goal was to analyze the characteristics of LN-prRLN metastasis of cN0 PTCs of the thyroid isthmus and determine its potential predictors.

PATIENTS AND METHODS

This retrospective study included patients who underwent bilateral central neck dissection between January 2018 and January 2021. The specimen was divided into five groups of prelaryngeal lymph node (LN), pretracheal LN, left paratracheal LN, lymph node anterior to the right recurrent laryngeal nerve (LN-arRLN), and LN-prRLN. Univariate and multivariate analyses were used to assess the association between the clinical pathologic variables and LN-prRLN metastases. Surgical complications were presented descriptively.

RESULTS

A total of 357 patients were included, LN-prRLN metastasis occurred in 23 (6.4%) patients, and LN-prRLN was positive only when there were other LN metastases, especially LN-arRLN metastases. Other independent risk factors for LN-prRLN included foci numbers ≥2, tumor size ≥5.0 mm, and extrathyroidal extensions. The rates of permanent hypoparathyroidism and vocal cord paralysis were 1.1% and 2.0%, respectively.

CONCLUSION

LN-prRLN metastases should not be ignored in cN0 PTC located in the thyroid isthmus; however, its dissection is a safe procedure, and the status of LN-arRLN can be a reliable predictor for LN-prRLN metastases.

A NOVEL SCORING SYSTEM FOR THE RISK OF PAPILLARY THYROID CANCER METASTASES IN LYMPH NODES POSTERIOR TO THE RIGHT OF THE RECURRENT LARYNGEAL NERVE

OBJECTIVE

Some surgeons believe that dissection posterior to the right recurrent laryngeal nerve lymph node (PRRLN-LN) is unnecessary for the low metastasis rate and high complication risk. However, persistent metastatic lymph nodes may have a higher recurrence rate, surgical risk, and complications. Thus, it is important to distinguish patients who require PRRLN-LN dissection. To identify the risk factors for lymph nodes posterior to the right recurrent laryngeal nerve metastasis (LN-prRLN) and establish a scoring system to help determine whether PRRLN-LN dissection is required in patients with papillary thyroid carcinoma.

METHODS

821 participants were randomly allocated to the development and validation cohorts in a 2:1 ratio. A nomogram-based predictive model for LN-prRLN was established based on the risk factors identified in the development cohort.

RESULTS

LN-prRLN was diagnosed pathologically in 124 of 821 patients (15.1%) from the entire cohort. Multivariate analysis identified age (odds ratio [OR], 0.964; 95% CI, 0.945-0.983; P < .001), tumor size (OR, 1.536; 95% CI, 1.135-2.079; P = .005), extrathyroidal extension (OR 2.271, 95% CI, 1.368-3.770; P = .002), clinically involved right central compartment lymph node metastasis (OR 1.643, 95% CI, 1.055-2.559; P = .028), and right lateral lymph node metastasis (OR 4.271, 95% CI, 2.325-7.844; P < .001) as the predictors of LN-prRLN. A risk model was established and well validated. Calibration curves to evaluate the nomogram in both the development and validation cohorts revealed a concordance index of 0.756 ± 0.058 and 0.745 ± 0.042, respectively.

CONCLUSION

Our scoring system may be useful for helping the surgeons decide which patients should undergo the dissection of PRRLN-LN.

Clinical and sonographic features for the preoperative prediction of lymph nodes posterior to the right recurrent laryngeal nerve metastasis in patients with papillary thyroid carcinoma

OBJECTIVE

To evaluate clinical and sonographic features predictive of lymph nodes posterior to the right recurrent laryngeal nerve (LN-prRLN) metastasis in patients diagnosed with papillary thyroid carcinoma (PTC).

METHODS

We retrospectively reviewed the clinical records and ultrasound (US) images of 479 consecutive PTC patients who received total thyroidectomy or right lobectomy with central neck dissection (CND) between October 2017 and October 2019. Univariate and multivariate analyses were performed to identify clinical and sonographic features associated with LN-prRLN metastasis. Receiver operating characteristic (ROC) analysis was applied to evaluate the efficacy of clinical and sonographic features in the preoperative prediction of LN-prRLN metastasis.

RESULTS

Overall, 127 (26.5%) patients had LN-prRLN metastasis. Multivariate logistic regression analysis showed that age < 45 years (p = 0.005; OR 2.155; 95% CI 1.262-3.683), male sex (p = 0.043; OR 1.657; 95% CI 1.016-2.704), tumor diameter > 1 cm (p = 0.042; OR 1.702; 95% CI 1.019-2.842), microcalcifications (p = 0.022; OR 1.980; 95% CI 1.104-3.551), and US-detected lateral compartment lymph node (LLN) metastasis (p = 0.001; OR 2.578; 95% CI 1.500-4.430) were independent risk factors for LN-prRLN metastasis. ROC analysis revealed that the multivariate logistic regression model had good accuracy in predicting LN-prRLN metastasis, with an area under the ROC curve of 0.758.

CONCLUSIONS

Age less than 45 years, male sex, tumor diameter larger than 1 cm, microcalcifications, and US-detected LLN metastasis may preoperatively predict LN-prRLN metastasis.

Prophylactic lymph node dissection in clinically N0 differentiated thyroid carcinoma: example of personalized treatment

Considering the 'differentiated thyroid carcinoma (DTC) epidemic', the indolent nature of DTC imposes a treatment paradigm shift toward elimination of recurrence. Lymph node metastases in cervical compartments, encountered in 20-90% of DTC, are the main culprit of recurrent disease, affecting 5-30% of patients. Personalized risk-stratified cervical prophylactic lymph node dissection (PLND) at initial thyroidectomy in DTC with no clinical, sonographic or intraoperative evidence of lymph node metastases (clinically N0) has been advocated, though not unanimously. The present review dissects the controversy over PLND. Weighing the benefit yielded from PLND up against the PLND-related morbidity is so far hampered by the inconsistent profit yielded by PLND and the challenging patient selection. Advances in tailoring PLND are anticipated to empower optimal patient care.

A Comparison of Two Operation Methods Revealed the Risk Factors and the Necessity of LN-prRLN Dissection in Papillary Thyroid Carcinoma: A Retrospective Cohort Study in FUSCC

BACKGROUND

Although the American Thyroid Association (ATA) guidelines indicate that central lymph nodes posterior to the right recurrent laryngeal nerve (LN-prRLN) should be routinely dissected, pr-RLN dissection is often neglected due to the high risk of injury to the recurrent laryngeal nerve (RLN). The purpose of this study was to investigate the risk factors associated with LN-prRLN metastasis in patients with papillary thyroid carcinoma (PTC) by preoperative examination and the indications for LN-prRLN dissection.

METHODS

A total of 1487 consecutive patients with PTC who underwent total thyroidectomy or right lobectomy plus isthmic resection with central LN dissection (CLND) were divided into two groups: patients with LN-prRLN dissection (group A) and patients without LN-prRLN dissection (group B). Clinicopathologic data were reviewed of the patients who were operated on by the same thyroid surgery team in the Department of Head Neck Surgery, Fudan University Shanghai Cancer Center (FUSCC) between August 2011 and May 2019. The relationships of LN-prRLN metastasis with clinicopathologic characteristics were analyzed by univariate and multivariate logistic regression.

RESULTS

The incidence of LN-prRLN metastasis was 34.1% (129/378). Univariate analysis showed that sex (P ≤ 0.001), tumor size (P ≤ 0.001), extrathyroidal extension (P=0.002), concurrent Hashimoto's thyroiditis (P=0.009), cLNMa (central lymph nodes anterior to the right recurrent laryngeal nerve) (P ≤ 0.001), cLNMa number (P ≤ 0.001), and lateral LN metastasis (LLNM) (P ≤ 0.001) were significantly associated with LN-prRLN metastasis in PTC. Multivariate logistic regression analysis revealed that tumor size (P=0.039), cLNMa (P=0.001), and LLNM (P=0.025) were independent risk factors for LN-prRLN metastasis in patients with PTC. Although there was no significant difference between the two groups in recurrence, we found that 4 cases relapsed in the LN-prRLN compartment in group B, while none relapsed in group A.

CONCLUSION

LN-prRLN metastasis is often identified in patients with PTC. Patients with large tumor sizes, cLNMa and LLNM are at a high risk of LN-prRLN metastasis and should be recommended for careful LN-prRLN dissection.

Risk factors of metastasis to the lymph nodes posterior to the right recurrent laryngeal nerve in papillary thyroid carcinoma

PURPOSE

To investigate the risk factors of lymph node posterior to the right recurrent laryngeal nerve (LN-prRLN) metastasis in papillary thyroid carcinoma.

METHODS

Clinicopathologic feature data of 427 patients with right or double lobes who underwent surgery between January 2014 to August 2019 in the Department of General Surgery, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, were retrospectively analyzed. The risk factors of LN-prRLN metastasis were analyzed by the Chi-squared test and multivariate logistic regression.

RESULTS

LN-prRLN metastasis was detected in 96 patients. Univariate analysis showed that age, right-side tumor diameter, capsular invasion, comorbid adenoma, and VIa compartment LN metastasis were significantly associated with LN-prRLN metastasis (all P < 0.05). Multivariate logistic regression analysis showed that right-side tumor diameter, capsular invasion, and VIa compartment LN metastasis were independent risk factors of LN-prRLN metastasis (all P ≤ 0.001). The receiver operating characteristic curve showed that the cutoff value of the right tumor diameter for predicting LN-prRLN metastasis was 1.25 cm (sensitivity = 0.5, specificity = 0.819, area under the curve = 0.720, P < 0.001).

CONCLUSION

The incidence of LN-prRLN metastasis cannot be ignored, and our findings indicate that prophylactic LN-prRLN dissection should be performed in patients with right-side tumor diameter ≥ 1.25 cm, capsular invasion, and VIa compartment LN metastasis.