Latero-cervical lymph node metastases (N1b) represent an additional risk factor for papillary thyroid cancer outcome

Associations of clinicopathologic features and mutation status with lateral lymph node metastasis as a predictor of disease-free survival in papillary thyroid carcinoma

BACKGROUND

Lateral lymph node metastasis (LLNM) is a significant risk factor for poor prognosis in papillary thyroid carcinoma (PTC). Data on the association between LLNM and genetic alterations in PTC remains limited. This study investigated clinicopathological and molecular predictive factors for LLNM in patients with PTC.

METHODS

We conducted a single-center retrospective analysis of 603 patients who underwent thyroid surgery between January 2018 and December 2023. Clinicopathological features and genetic mutations, including BRAFV600E and telomerase reverse transcriptase (TERT) promoter mutations, were assessed to identify predictors of LLNM. The impact of these features on disease-free survival (DFS) was analyzed using multivariable Cox regression.

RESULTS

LLNM was found in 154 (25.5 %) patients. Independent predictors of LLNM included age < 55 years (odds ratio [OR] = 2.491, 95 % confidence interval [CI]: 1.411-4.398), multifocality (OR = 2.056, 95 % CI: 1.254-3.370), lymphatic invasion (OR = 1.811, 95 % CI: 1.094-2.997), gross extrathyroidal extension (ETE) (OR = 2.611, 95 % CI: 1.333-5.115), central lymph node metastasis (CLNM) without extranodal extension (ENE) (OR = 12.060, 95 % CI: 4.205-34.595) or with ENE (OR = 68.060, 95 % CI: 23.224-199.453), and TERT promoter mutation (OR = 2.272, 95 % CI: 1.078-4.786). CLNM with ENE, LLNM with ENE and TERT promoter mutation were significantly correlated with shorter DFS.

CONCLUSIONS

LLNM is not rare in PTC and represents an adverse prognostic factor significantly associated with age, gross ETE, multifocality, lymphatic invasion, CLNM, and TERT promoter mutation.

FNA-Tg improves the diagnostic efficacy of FNAC for PTC lateral cervical LN metastasis

The detection of thyroglobulin in lymph node (LN) fine needle aspirates (FNA-Tg) is an effective supplement to ultrasound and fine needle aspiration cytology (FNAC) in diagnosis of cervical LN metastases for patients with papillary thyroid carcinoma (PTC). However, there is no unique cutoff value of FNA-Tg in practice. We aimed to determine the optimal cutoff of FNA-Tg and evaluate the interfering factors of FNA-Tg. A serial of 405 lateral cervical LN samples from 317 patients with PTC were analyzed retrospectively. Receiver operating characteristic (ROC) curve was used to determine the optimal cutoff of FNA-Tg. The factors that impact FNA-Tg were evaluated. Serum Tg, serum thyroglobulin antibody (TgAb) and serum thyroid stimulating hormone (TSH) level, and thyroid status did not differ between the malignant and benign LN groups. The median FNA-Tg was 3.81 ng/mL (0.16-33.40 ng/mL) in LNs without metastasis and 310.32 ng/mL (124.41-500.00 ng/mL) in LNs with metastasis, and the differences reached statistical significance (P < 0.01). The optimal cutoff of FNA-Tg was 36.22 ng/mL, and the values of area under the curve (AUC), sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) was 0.88, 0.89, 0.75, 0.91 and 0.71, respectively. The diagnostic accuracy of FNA-Tg cutoff of 36.22ng/mL was 85%. When FNAC and the present FNA-Tg cutoff of 36.22 ng/mL were combined together, the diagnostic sensitivity, specificity, PPV, NPV and diagnostic accuracy was 0.96, 0.75, 0.92, 0.87 and 91%, respectively. FNA-Tg improves the diagnostic efficacy of FNAC for PTC lateral cervical LN metastasis, and the optimal cutoff value of FNA-Tg was 36.22 ng/mL. FNA-Tg was affected by LN status but was not associated with serum Tg, serum TgAb, serum TSH and thyroid status.

Thyroid lobectomy for unilateral TNM T1 and T2 papillary thyroid carcinoma patients with lateral lymph node metastasis

BACKGROUND

This study aimed to evaluate the prognostic outcomes of thyroidectomy extent in unilateral TNM T1 or T2 papillary thyroid carcinoma with lateral lymph node metastasis.

METHODS

Retrospective data were collected from unilateral papillary thyroid carcinoma patients with unilateral lymph node metastasis who underwent surgery at Qilu Hospital of Shandong University from 2011 to 2022. Patients were categorized into 2 groups based on the extent of the thyroidectomy (total thyroidectomy versus lobectomy). The primary endpoint was recurrence-free survival. The secondary endpoint was the incidence of complications. The Cox proportional hazards model was used to explore independent risk factors for structural recurrence.

RESULTS

A total of 372 patients with unilateral TNM T1 or T2 papillary thyroid carcinoma and unilateral lymph node metastasis were followed for a median of 55 months. Among them, 119 patients underwent lobectomy, whereas 253 patients underwent total thyroidectomy. During the follow-up period, 11 patients experienced structural recurrence. Kaplan-Meier analysis found no significant difference in recurrence-free survival between the groups (P > .05). However, the total thyroidectomy group had higher rates of both transient and permanent hypoparathyroidism, as well as transient recurrent laryngeal nerve injury (P < .05). Multivariate analysis identified minor extrathyroidal extension and lymph nodes ratio >0.49 as independent risk factors for structural recurrence, whereas the extent of thyroidectomy was not.

CONCLUSION

This study suggests that lobectomy does not impact the prognosis in unilateral TNM T1 and T2 papillary thyroid carcinoma patients with unilateral lymph node metastasis. Minor extrathyroidal extension and lymph nodes ratio >0.49 are identified as independent risk factors for structure recurrence, and patients exhibiting these risk factors should be subjected to vigilant postoperative monitoring.

Pretreatment level of circulating tumor cells is associated with lymph node metastasis in papillary thyroid carcinoma patients with ≤ 55 years old

OBJECTIVE

To investigate the relationship of pretreatment of circulating tumor cells (CTCs) and cervical lymph node metastasis (LNM) (central LNM (CLNM) and lateral LNM (LLNM)) in papillary thyroid carcinoma (PTC) patients with ≤ 55 years old.

METHODS

Clinicopathological data (CTCs level, Hashimoto's thyroiditis, thyroid function, multifocal, tumor size, invaded capsule, clinical stage, and LNM) of 588 PTC patients with ≤ 55 years old were retrospectively collected. The relationship of CLNM, LLNM and the clinical features of patients was analyzed. Univariate and multivariate logistic regression analyses were used to evaluate the relationship between the CTCs and CLNM, LLNM.

RESULTS

There were 273(46.4%) and 89(15.1%) patients with CLNM and LLNM, respectively. Patients with CLNM had higher proportions of multifocality, tumor size > 1 cm, invaded capsule, and positive CTCs level than those without (all p < 0.05). Patients with LLNM had higher proportions of multifocality, tumor size > 1 cm, and invaded capsule than those without (all p < 0.05). Logistic regression analysis showed that multifocality (odds ratio (OR): 1.821, 95% confidence interval (CI): 1.230-2.698, p = 0.003), tumor size > 1 cm (OR: 3.444, 95% CI: 2.296-5.167, p < 0.001), invaded capsule (OR: 1.699, 95% CI: 1.167-2.473, p = 0.006), and positive CTCs level (OR: 1.469, 95% CI: 1.019-2.118, p = 0.040) were independently associated with CLNM; and multifocality (OR: 2.373, 95% CI: 1.389-4.052, p = 0.002), tumor size > 1 cm (OR: 5.344, 95% CI: 3.037-9.402, p < 0.001), and invaded capsule (OR: 2.591, 95% CI: 1.436-4.674, p = 0.002) were independently associated with LLNM.

CONCLUSIONS

Preoperative CTCs positive was associated with CLNM in PTC patients with ≤ 55 years old, but not LLNM.

The application of a clinical-multimodal ultrasound radiomics model for predicting cervical lymph node metastasis of thyroid papillary carcinoma

Background

PTC (papillary thyroid cancer) is a lymphotropic malignancy associated with cervical lymph node metastasis (CLNM, including central and lateral LNM), which compromises the effect of treatment and prognosis of patients. Accurate preoperative identification will provide valuable reference information for the formulation of diagnostic and treatment strategies. The aim of this study was to develop and validate a clinical-multimodal ultrasound radiomics model for predicting CLNM of PTC.

Methods

One hundred sixty-four patients with PTC who underwent treatment at our hospital between March 2016 and December 2021 were included in this study. The patients were grouped into a training cohort (n=115) and a validation cohort (n=49). Radiomic features were extracted from the conventional ultrasound (US), contrast-enhanced ultrasound (CEUS) and strain elastography-ultrasound (SE-US) images of patients with PTC. Multivariate logistic regression analysis was used to identify the independent risk factors. FAE software was used for radiomic feature extraction and the construction of different prediction models. The diagnostic performance of each model was evaluated and compared in terms of the area under the curve (AUC), sensitivity, specificity, accuracy, negative predictive value (NPV) and positive predictive value (PPV). RStudio software was used to develop the decision curve and assess the clinical value of the prediction model.

Results

The clinical-multimodal ultrasound radiomics model developed in this study can successfully detect CLNM in PTC patients. A total of 3720 radiomic features (930 features per modality) were extracted from the ROIs of the multimodal images, and 15 representative features were ultimately screened. The combined model showed the best prediction performance in both the training and validation cohorts, with AUCs of 0.957 (95% CI: 0.918-0.987) and 0.932 (95% CI: 0.822-0.984), respectively. Decision curve analysis revealed that the combined model was superior to the other models.

Conclusion

The clinical-multimodal ultrasound radiomics model constructed with multimodal ultrasound radiomic features and clinical risk factors has favorable potential and high diagnostic value for predicting CLNM in PTC patients.

Interplay of metabolic dysfunction-associated fatty liver disease and papillary thyroid carcinoma: insights from a Chinese cohort

PURPOSE

Thyroid cancer is one of a set of extrahepatic cancers that closely linked to metabolic dysfunction-associated fatty liver disease (MAFLD). However, the connection between MAFLD and the characteristics of papillary thyroid cancer (PTC) remains unexplored.

METHODS

Between Jan 2020 and Oct 2022, surgical cases of PTC patients were examined at the first Affiliated Hospital of Wenzhou Medical University. Clinical data extracted from the electronic medical system underwent a rigorous comparison between two groups, classified based on MAFLD criteria, using logistic regression analysis.

RESULTS

In this study of 4,410 PTC patients, 18.3% had MAFLD. MAFLD emerged as a distinct risk factor for lymph node metastasis (OR = 1.230, 95% CI 1.018-1.487) in this cohort, especially in females (OR = 1.321, 95% CI 1.026-1.702) and those with BMI ≥ 23 kg/m2 (OR = 1.232, 95% CI 1.004-1.511). The presence of MAFLD was found to significantly elevate the risk of BRAF V600E mutation in both subgroups characterized by FIB-4 score ≥ 1.3 (OR = 1.968, 95% CI 1.107-3.496) and BMI < 23 kg/m2 (OR = 2.584, 95% CI 1.012-6.601). Moreover, among the subset of individuals without non-alcoholic fatty liver disease (NAFLD), it was noted that MAFLD considerably increased the likelihood of tumor multifocality (OR = 1.697, 95% CI 1.111-2.592). Nevertheless, MAFLD did not exhibit any correlation with increased tumor size, extra-thyroidal extension (ETE), or later TNM stage in PTC.

CONCLUSION

In this cross-sectional study, we discovered a significant association between MAFLD and increased occurrences of lymph node metastasis. Furthermore, MAFLD was linked to a higher chance of BRAF V600E mutation and the presence of multiple tumors in certain subgroups.

Impact of thyroid carcinoma invasion of recurrent laryngeal nerve on cervical lymph node metastasis

PURPOSE

Papillary thyroid carcinoma (PTC) has a favorable prognosis. However, involvement of the recurrent laryngeal nerve (RLN) significantly increases the risk of recurrence. RLN invasion was an important factor in determining the extent of thyroid surgery. The purpose of this study was to compare clinicopathologic features and characterize risk factors of central and lateral lymph node metastasis (LLNM) of RLN invasion in patients with PTC.

METHODS

A retrospective review was conducted of 130 patients with PTCs who had exclusive tumor involvement of the RLN at our institution between January 2014 and February 2019. All patients underwent total thyroidectomy and high-dose radioactive iodine (RAI) therapy. The clinicopathologic factors and prognostic outcomes of the patients with solitary and multiple RLN involvements were compared. Kaplan-Meier method was performed to compare the outcomes of tumor recurrence. Univariate and multivariate logistic regression analyses were used to identify risk factors associated with LLNM.

RESULTS

The invasion of the RLN was similar on both sides, with 58.5% on the right, 40.0% on the left, and 1.5% on both sides. Significant differences were observed in tumor size (p < 0.001), lymph node metastasis classification (p = 0.002), RLN resection (p < 0.001), and thyroglobulin (p = 0.010) in the solitary and multiple groups. During the median follow-up of 67 months, 9 (6.9%) patients developed recurrence. There were no statistical differences in recurrence for age, tumor size, gender, multifocality, lymph node metastasis (LNM), and RLN resection. According to receiver operating characteristic (ROC) curve analyses, a cut-off of tumor size > 1.7 cm was identified as the most sensitive and specific predictor of RLN with multiple involvements or LNM invasion. Univariate and multivariate analyses revealed that central lymph node metastasis (CLNM) and RLN invasion by LNM can serve as independent risk factors for LLNM (p = 0.006 and p < 0.001, respectively).

CONCLUSION

Our results indicate that recurrence was comparable in patients with solitary and multiple RLN involvements. Multiple RLN involvement was associated with pathological features such as larger tumors, RLN resection, and LLNM. The presence of LNM invading RLN and multiple nerve involvement increases the risk of intraoperative RLN resection. A higher risk of multiple invasion or LNM invasion should be considered when tumor size > 1.7 cm. The presence of CLNM and RLN invaded by LNM were independent predictors for LLNM, which could aid surgeons in deciding on lateral lymph node dissection.

Single-center external validation and reconstruction of multiple predictive models for skip lateral lymph node metastasis in papillary thyroid carcinoma

Objective

The unique metastatic pattern of skip lateral lymph node metastasis (SLLNM) in PTC patients may lead to missed diagnosis of lateral cervical metastatic lymph nodes. Therefore, many different SLLNM prediction models were constructed. In this study, partially eligible models (Hu 2020, Wang 2020, and Zhao 2023 nomograms) were selected for external validation, and then new variables were incorporated for model reconstruction to extend clinical applicability.

Methods

576 PTC patients from our center were selected to evaluate the performance of the three nomograms using the receiver operating characteristic curve (ROC), calibration curves, and decision curve analyses (DCA). Three new variables were added to calibrate the model, including assessment of LN status on ultrasound (US-SLLNM), the distance from the tumor to the capsule (Capsular distance), and the number of central lymph node dissections (CLND number). Univariate and multivariate logistic regression analyses were used to screen independent predictors to reconstruct the model, and 1000 Bootstrap internal validations were performed.

Results

SLLNM were present in 69/576 patients (12.0%). In external validation, the area under the ROC curves (AUCs) for Hu 2020, Wang 2020, and Zhao 2023 nomograms were 0.695 (95% CI:0.633-0.766), 0.792 (95% CI=0.73-0.845), and 0.769 (95% CI:0.713-0.824), respectively. The calibration curves for the three models were overall poorly fitted; DCA showed some net clinical benefit. Model differentiation and net clinical benefit improved by adding three new variables. Based on multivariate analysis, female, age, and maximum tumor diameter ≤ 10 mm, located at the upper pole, Capsular distance < 0mm, US-SLLNM, CLND number ≤ 5 were identified as independent predictors of SLLNM and were used to construct the new model. After 1000 Bootstrap internal validations, the mean AUC of the model was 0.870 (95% CI:0.839-0.901), the calibration curve was close to the ideal curve, and the net clinical benefit was significant.

Conclusion

Overall, these nomograms were well differentiated and provided some net clinical benefit, but with varying degrees of underestimation or overestimation of the actual risk and high false-negative rates. New dynamic nomogram was constructed based on the addition of new variables and larger samples, showing better performance.

Malignancy risk of indeterminate lymph node at the central compartment in patients with thyroid cancer and concomitant sonographic thyroiditis

BACKGROUND

To evaluate the malignancy risk of sonographic (US) indeterminate lymph node (LN)s at the central compartment in thyroid cancer patients with US-thyroiditis (ST).

METHODS

Among the central compartments of suspicious, indeterminate, and probably benign LN US categories, the malignancy rates were compared between ST and non-US-thyroiditis (non-ST) groups. Those of indeterminate category were compared with suspicious and probably benign categories.

RESULTS

At 531 central compartments from 349 patients, the malignancy rate was lower in ST group (34.4% [44/128]) than non-ST group (43.4% [175/403]), although statistically not significant (p = 0.08). The malignancy rate of indeterminate category in ST group (35.7% [5/14]) was lower than non-ST group (71.9% [23/32]) (p = 0.047). Within ST group, the malignancy rate of indeterminate category (35.7% [5/14]) did not differ from probably benign category (29.1% [30/103]) (p = 0.756), but was lower than suspicious category (81.8% [9/11]) (p = 0.042).

CONCLUSIONS

The malignancy risk of US indeterminate LNs at the central compartment in thyroid cancer patients with US thyroiditis was lower than that in patients without US thyroiditis.

Risk factors analysis of lateral cervical lymph node metastasis in papillary thyroid carcinoma: a retrospective study of 830 patients

OBJECTIVE

The aim of this study is to investigate the risk factors for lateral cervical lymph node metastasis in papillary thyroid carcinoma (PTC).

METHODS

Clinicopathological data (age, gender, Hashimoto's thyroiditis, preoperative circulating tumor cells (CTCs), multifocal, maximum lesion diameter, invaded capsule, T stage, and lymph node metastasis) of 830 PTC patients diagnosed and treated in Meizhou People's Hospital from June 2021 to April 2023 were collected. The related factors of lateral cervical lymph node metastasis were analyzed.

RESULTS

There were 334 (40.2%), and 103 (12.4%) PTC patients with central lymph node metastasis, and lateral cervical lymph node metastasis, respectively. Compared with patients without lateral cervical lymph node metastasis, PTC patients with lateral cervical lymph node metastasis had a higher proportion of multifocal, maximum lesion diameter > 1 cm, invaded capsule, T3-T4 stage. Regression logistic analysis showed that male (odds ratio (OR): 2.196, 95% confidence interval (CI): 1.279-3.769, p = 0.004), age < 55 years old (OR: 2.057, 95% CI: 1.062-3.988, p = 0.033), multifocal (OR: 2.759, 95% CI: 1.708-4.458, p < 0.001), maximum lesion diameter > 1 cm (OR: 5.408, 95% CI: 3.233-9.046, p < 0.001), T3-T4 stage (OR: 2.396, 95% CI: 1.241-4.626, p = 0.009), and invaded capsule (OR: 2.051, 95% CI: 1.208-3.480, p = 0.008) were associated with lateral cervical lymph node metastasis.

CONCLUSIONS

Male, age < 55 years old, multifocal, maximum lesion diameter > 1 cm, T3-T4 stage, and invaded capsule were independent risk factors for lateral cervical lymph node metastasis in PTC.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSION

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

A review of contrast-enhanced ultrasound using SonoVue® and Sonazoid™ in non-hepatic organs

Contrast-enhanced ultrasound (CEUS) is a dependable modality for the diagnosis of various clinical conditions. A judicious selection of ultrasound contrast agent (UCA) is imperative for optimizing imaging and improving diagnosis. Approved UCAs for imaging the majority of organs include SonoVue, a pure blood agent, and Sonazoid, which exhibits an additional Kupffer phase. Despite the fact that the two UCAs are increasingly being employed, there is a lack of comparative reviews between the two agents in different organs diseases. This review represents the first attempt to compare the two UCAs in non-hepatic organs, primarily including breast, thyroid, pancreas, and spleen diseases. Through comparative analysis, this review provides a comprehensive and objective evaluation of the performance characteristics of SonoVue and Sonazoid, with the aim of offering valuable guidance for the clinical application of CEUS. Overall, further clinical evidences are required to compare and contrast the dissimilarities between the two UCAs in non-hepatic organs, enabling clinicians to make an appropriate selection based on actual clinical applications.

Predictive Factors Affecting the Development of Lateral Lymph Node Metastasis in Papillary Thyroid Cancer

Objectives

Lateral lymph node metastasis (LLNM) in papillary thyroid cancer (PTC) determines the extent of surgery to be performed and the prognosis of the disease. In this study, we aimed to evaluate the clinicopathological risk factors affecting the development of LLNM.

Methods

We retrospectively evaluated the demographic and clinicopathological data of 346 cases with PTC who were operated in our clinic between May 2012 and September 2020. The patients were divided into 2 groups as patients with LLNM (Group 1) and without LLNM (Group 2).

Results

Thirty-six (10.4%) patients out of 346 patients with PTC had LLNM. A statistically significant difference was found between Group 1 and Group 2 regarding the male gender (M/F: 38.9% vs. 21.6%; p=0.020), tumor size (2.30±1.99 cm vs. 1.31±1.40 cm; p=0.000), lymphovascular invasion (69.4 vs. 20.6%; p=0.000), multicentricity (69.4% vs. 35.5%; p=0.000), multifocality (p=0.000), aggressive variant (22.2% vs. 9.4%; p=0.000), extrathyroidal extension (50% vs. 16.1% p=0.000), central lymph node metastasis (CLNM) rates (75% vs. 6.5%; p=0.000), and ≥3 cm lymph node metastasis (48.5% vs. 0%, p=0.000), distant metastasis (2.1% vs. 0%, p=0.000), respectively. Multivariance analysis determined the presence of CLNM as an independent risk factor for the development of LLNM.

Conclusion

The presence of CLNM in patients with PTC was determined as an independent risk factor for the development of LLNM. Although there has been increasing debate about prophylactic central neck dissection (pCND) in LLNM, pCND should still be considered in these patients as the rate of CLNM is high in patients with LLNM. CLNM might be a reference for surgeons to determine the extent of surgery. In addition, the presence of CLNM is important for close follow-up for the early detection of LLNM recurrence.

Lymph node ratio as a tool to stratify patients with N1b papillary thyroid cancer

BACKGROUND

The prognostic significance of lymph node ratio (LNR) in N1b papillary thyroid cancer is unclear. Therefore, the impact of LNR on disease-specific mortality (DSM) and overall survival (OS) in patients with N1b papillary thyroid cancer (PTC) needs to be defined.

METHODS

We used the Surveillance, Epidemiology, and End Results (SEER) database of patients who had undergone thyroidectomy and lymph node dissection. Factors associated with DSM and OS were analyzed and identified using univariate and multivariate Cox proportional risk models. X-tile software was used to find the best cutoff value of LNR. Kaplan-Meier estimates for DSM were plotted for LNR and were compared with the log-rank test. The ROC curve evaluated the validity of the model.

RESULTS

A total of 3223 patients with N1b PTC were identified in the SEER database between 1975 and 2019. The best cutoff value for LNR was 0.6. The multivariate Cox proportional risk model showed that age, race, T3/T4 classification, distant metastasis, extent of surgery, number of metastatic lymph nodes, and LNR > 0.6 were independent risk factors for DSM (all p < 0.05). Age, sex, T4 classification, distant metastasis, extent of surgery, and LNR > 0.6 were independent risk factors for OS (all p < 0.05). The Kaplan-Meier method plotted a cumulative risk curve and showed that patients with LNR > 0.6 had a significantly higher risk of DSM than patients with LNR ≤ 0.6 (p = 0.002).

CONCLUSION

LNR was a powerful predictor of DSM and OS in N1b PTC patients. LNR could be a useful tool for the stratification of PTC patients with lateral neck metastases.

Vascularity depicted by contrast-enhanced ultrasound predicts recurrence of papillary thyroid cancer

PURPOSE

Although angiogenesis is crucial for the occurrence and development of solid tumors, the prognostic value of vascularity remains unclear in papillary thyroid cancer (PTC), due to the lack of effective techniques to evaluate vascularity. Contrast-enhanced ultrasound (CEUS) is an effective technique to evaluate vascularity. This study aimed to investigate whether vascularity depicted by CEUS was associated with structural recurrence in classic PTC.

METHODS

512 consecutive patients who underwent total thyroidectomy and central lymph node dissection for classic PTC larger than 1 cm between January 2015 and December 2018 and who were followed up for 12 months or longer were retrospectively enrolled. For this study, iso- and hyperenhancement were considered hypervascularity, whereas hypovascularity referred to hypoenhancement. Kaplan-Meier cumulative event curves for structural recurrence were compared using the log-rank test. The multivariate Cox proportional hazard regression analysis was used to estimate hazard ratios (HRs) of hypervascularity depicted by CEUS for structural recurrence.

RESULTS

61 (11.9 %) of 512 patients had structural recurrence. Hypervascular PTCs had a shorter recurrence-free survival rate than hypovascular PTCs (P < 0.001). In the multivariate analysis, hypervascularity (HR, 2.069; 95 % confidence interval [CI]: 1.087, 3.937), larger size (HR, 1.279; 95 % CI: 1.011, 1.618), multifocality (HR, 1.976; 95 % CI: 1.150, 3.396), extrathyroidal extension (HR, 2.276; 95 % CI: 1.026, 5.046), and lymph node metastasis (HR, 3.631; 95 % CI: 1.515, 8.701) were independently associated with structural recurrence.

CONCLUSION

Hypervascularity depicted by CEUS was independently associated with structural recurrence in patients with classic PTC.

Prospective study and proposal of an outcome predictive nomogram in a consecutive prospective series of differentiated thyroid cancer based on the new ATA risk categories and TNM

INTRODUCTION

The personalized management of differentiated thyroid cancer (DTC) is currently based on the postoperative TNM staging system and the ATA risk stratification system (RSS), both updated in 2018 and 2015, respectively.

PURPOSE

We aimed to evaluate the impact of the last two editions of TNM and ATA RSS in the prediction of persistent/recurrent disease in a large series of DTC patients.

PATIENTS AND METHODS

Our prospective study included 451 patients undergone thyroidectomy for DTC. We classified the patients according to TNM (both VIII and VII ed.) and stratified them according to the ATA RSS (both 2015 and 2009). We then evaluated the response to the initial therapy after 12-18 months according to the ATA "ongoing" risk stratification, and analyzed the variables associated with persistent/recurrent disease by multivariate analysis.

RESULTS

The performance of the last two ATA RSSs was not significantly different. By staging patients according to the VIII or VII TNM editions, we found significant differences only in the distribution of patients with structural disease classified in stages III and IV. At multivariate analysis, only T-status and N-status were independently associated with persistent/recurrent disease. Overall, ATA RSSs and TNMs showed low predictive power in terms of persistent/recurrent disease (by Harrell's test).

CONCLUSIONS

In our series of DTC patients, the new ATA RSS as well as the VIII TNM staging provided no additional benefit compared to the previous editions. Moreover, the VIII TNM staging system may underestimate disease severity in patients with large and numerous lymph node metastases at diagnosis.

Nomograms for the prediction of lateral lymph node metastasis in papillary thyroid carcinoma: Stratification by size

Background

Lateral lymph node metastasis (LLNM) is a risk factor of poor prognosis in papillary thyroid cancer (PTC). We aimed to determine predictive factors and develop the nomograms for LLNM in patients with papillary thyroid microcarcinoma (PTMC) and macro-PTC.

Methods

We reviewed the medical records of 1,106 patients who underwent surgery between January 2019 and January 2022. Patients were divided into a PTMC and a macro-PTC group. We developed preoperative and postoperative nomograms for predicting LLNM based on results of multivariate analysis. Internal calibration was performed for these models.

Results

The number of metastatic lymph nodes in lateral compartment was higher in macro-PTC patients. LLNM was independently associated with gender, the number of foci, location, shape, and central lymph node metastasis (CLNM) in PTMC patients. For macro-PTC patients, chronic lymphocytic thyroiditis, the number of foci, location, margin, CLNM, and central lymph node ratio were all independent predictors for LLNM. All the above factors were incorporated into nomograms, which showed the perfect discriminative ability.

Conclusion

The diameter of the tumor has an impact on the rate of LLNM. Separate predictive systems should be used for PTMC and macro-PTC patients for more accurate clinical assessment of lateral lymph node status. Through these nomograms, we can not only detect high-risk patients with occult LLNM preoperatively, but also form appropriate treatment protocols for postoperative management of PTC patients with different risks.

Long-term follow-up ultrasonography surveillance in a large cohort of patients with papillary thyroid carcinoma

OBJECTIVE

This study aimed to investigate the predictive factors as well as the time and age course of recurrence/persistence in a large cohort of postoperative patients with papillary thyroid carcinoma (PTC) based on the long-term ultrasonography (US) follow-up data.

METHODS

Between January 2007 and December 2016, 3106 patients underwent surgery for PTC and at least two postoperative US follow-up examination over more than three years. Tumor recurrence/persistence was confirmed based on the follow-up US data and histopathological results. Univariate and multivariate analyses were performed to evaluate the predictive factors of tumor recurrence/persistence. Kaplan-Meier survival analysis was used to evaluate the recurrence-/persistence-free survival curve based on the US results.

RESULTS

A total of 321(10.3%) patients developed tumor recurrence/persistence during 54.3 months of mean follow-up (range 36-135 months), including 268(83.5%) cases of lymph node recurrence/persistence, 37 (11.5%) cases of non-lymph node recurrence/persistence, and 16(5%) cases of both types. Recurrence/persistence was observed using US examination at a mean interval of 23.6 ± 21.6 months (range 1-135 months) after surgery and peak incidence was observed 1-2 years after initial treatment. Younger (20-30 years old) and older (70-80 years old) patients had a higher proportion of tumor recurrence/persistence. Multifocality, advanced T and advanced N stages were independent risk factors of tumor recurrence/persistence.

CONCLUSION

Tumor recurrence/persistence of PTC usually occurs during the early postoperative period. For patients with multifocal cancer, advanced T and N stage, the US surveillance examination should be cautiously performed, especially in younger and older patients.

Predictive value of metastatic lateral lymph node ratio for recurrence in pathologically lateral lymph node-positive papillary thyroid cancer patients with palpable lymph nodes

BACKGROUND

This study aimed to identify the predictive value of the extent of metastatic lymph nodes in the central and lateral neck compartment for recurrence in papillary thyroid cancer (PTC) patients with pathologically lateral lymph node metastasis (pN1b).

METHODS

This study enrolled 252 patients with pN1b from PTC.

RESULTS

During a mean follow-up of 17.6 years, 55 (21.8%) patients experienced recurrence. Patients with palpable lymph nodes were more likely to have a recurrence than those with nonpalpable lymph nodes (30.1% vs. 17.8%, relative risk 1.7, 95%CI: 1.1-2.7). For patients with palpable metastatic lymph nodes, lymph node ratio of lateral lymph nodes ≥0.5 (aHR = 2.906, 95%CI: 1.29-6.54) and age ≥55 years (aHR = 2.508, 95%CI: 1.12-5.63) were independent prognostic factors. For those without palpable nodes, age ≥55 years (aHR = 2.224, 95%CI: 1.08-4.60) and tumor size >4 cm (aHR = 2.168, 95%CI: 1.01-4.66) were independently predictive of worse RFS.

CONCLUSIONS

Palpable lymph nodes were approximately twice as likely to recur as nonpalpable nodes. Metastatic lateral lymph node ratio predicts recurrence in pN1b PTC patients with palpable lymph nodes, but not those without ones.

Analysis of the Clinical Value of Delphian Lymph Node Metastasis in Papillary Thyroid Carcinoma

Purpose

Delphian lymph node (DLN) is often involved in metastasis of malignant head and neck tumors. This study evaluates the predictive utility of the DLN and the clinicopathological factors related to DLN metastasis in individuals suffering from papillary thyroid carcinoma (PTC). Patients and Methods. A retrospective analysis was made on 969 PTC patients enrolled from 2017 to 2021. Among these patients, 522 PTC patients are DLN positive and 447 are negative. Comparisons of clinicopathological characteristics between the DLN-positive and DLN-negative patients were made.

Results

The DLN was detected in 53.9% (522/969) cases, and DLN metastasis occurred in 20.3% (106/522) cases. The independent predictors of DLN metastasis (DLNM) include tumor size >1 cm, tumor located in the upper third thyroid or isthmus, central lymph node metastasis (CLNM), and lateral lymph node metastasis (LLNM). DLN-positive individuals exhibited a higher incidence and the number of CLNM, contralateral CLNM (CCLNM), and LLNM as compared to DLN-negative patients. Whether it is cN0 or cN+, the CLNM incidence was increased among DLN-positive patients as compared to that of DLN-negative patients.

Conclusions

Positive DLN indicated an increased rate and number of metastases in the cervical lymph nodes. Intraoperative rapid freezing is recommended to assess the status of the DLN, and careful assessment of cervical lymph nodes is warranted when the DLN is involved to implement an appropriate surgical approach.

Role and Extent of Neck Dissection for Neck Lymph Node Metastases in Differentiated Thyroid Cancers

Differentiated thyroid cancers (DTC) consist of 95% of thyroid tumors and include papillary thyroid cancer (PTC), follicular thyroid cancer (FTC), and Hurthle cell thyroid cancer (HTC). Rates of lymph node metastases are different depending on histologic subtypes and <5% in FTC and between 5% and 13% in HTC. Lymph node metastasis is more frequent in PTC and while rate of clinical metastasis can be seen approximately 30% rate of routine micrometastasis can be seen up to 80%. Lymph node metastasis of DTC mostly develops first in the Level VI lymph nodes at the central compartment starting from the ipsilateral paratracheal lymph nodes and then spreading to the contralateral paratracheal lymph nodes. Spread to the Level VII is mostly after Level VI invasion. Subsequent spread is to the lateral neck compartments of Levels IV, III, IIA, and VB and sometimes to the Levels IIB and VA. Occasionally skip metastasis to the lateral neck compartments develop without spreading to the central compartments and this situation is more frequent in upper pole tumors. Although application of prophylactic central neck dissection (pCND) in DTC increases the rate of complication, due to its unclear effects on oncologic results and quality of life, the interest to the pCND is decreasing and debate on its surgical extent is increasing. pCND is not essential in DTC and characteristics of patient and tumor and experience of surgeon should be considered when deciding for pCND. Due to lower complication rate of one sided pCND compared to bilateral central neck dissection (CND), low possibility of contralateral central neck metastasis and low risk of recurrence, application of one-sided CND is logical. Although therapeutic CND (tCND) is the standart treatment when there is a clinically involved lymph node, extent of dissection is a matter of debate. A case-based decision for the extent of tCND can be made by considering patient and tumor characteristics and experience of the surgeon. Due to the higher complication risk of bilateral CND, unilateral tCND can be performed if there is no suspicious lymph node on the contralateral side and bilateral tCND can be applied when there is a suspicion for metastasis only on the contralateral side or there are features for risk of metastasis to the contralateral side. In patients with clinical central metastasis owing to intra-operative pathology results by frozen section procedure are compatible with post-operative pathology results, when there is a suspicion for contralateral metastasis, a decision for one- or two-sided dissection can be made using frozen section procedure. In DTC, it can be stated that there is a consensus in the literature about not performing prophylactic lateral neck dissection (LND), but performing therapeutic LND (tLND). In addition, there is a debate on the extent of tLND. In a meta-analysis about lateral metastasis, the rates of metastasis to the Levels IIA, IIB, III, IV, VA, and VB were 53.1%, 15.5%, 70.5%, 66.3%, 7.9%, and 21.5%, respectively. Ultrasonography (USG) is an effective procedure for detection of cervical nodal metastasis on lateral compartment. Pre-operative imaging with USG and/or combination with the fine needle aspiration biopsy (cytology/molecular test/Thyroglobulin test) can allow pre-operative detection and verification of lateral lymph node metastasis. Extent of tLND can be determined to minimize morbidity considering pre-operative USG findings, pre-operative tumor and clinical features of lateral metastasis. Especially in the presence of limited lateral metastases, limited selective LND such as Levels III, IV or Levels IIA, III, IV can be applied according to the patient. Levels IIB and VB should be added to the dissection in the presence of metastases in these regions. In cases that increase the risk of Level IIB involvement, such as presence of metastasis at Level IIA, extranodal tumor involvement, presence of multifocal tumor, and in cases that increase the risk of Level VB involvement such as macroscopic extranodal spread, and simultaneous metastases at Levels II, III, IV; Levels IIB and VB can be added to dissection material. Levels I and VA should be added to the dissection in the presence of clinically detected metastases.

Large-Volume Lateral Lymph Node Metastasis Predicts Worse Prognosis in Papillary Thyroid Carcinoma Patients With N1b

We aimed to evaluate the relevance of large-volume lateral lymph node metastases (LLNMs) at risk of recurrence/persistence in papillary thyroid carcinoma (PTC) with LLNMs (N1b). This retrospective study included 448 PTC patients, who had positive LLNMs confirmed by histology and suspected of LLNMs by preoperative ultrasound. According to the number of pathological LLNMs, patients were divided into large-volume LLNM (number of LLNMs >5) and low-volume LLNM (number of LLNMs ≤5). Risk factors of recurrence/persistence in PTC patients with N1b were analyzed. Preoperative ultrasound features of PTC with large-volume LLNM were analyzed. For the patients with a mean follow-up of 44.0 months, the risk of recurrence/persistence was 25.1% in PTC patients with N1b. The recurrence/persistence rate was significantly higher in patients with large-volume LLNM than in patients with low-volume LLNM by multivariate analysis (37.3% vs. 17.1%; HR = 2.451, 95% CI 1.41-4.261, p = 0.001). The 3-year and 5-year recurrence/persistence-free survival for those with large-volume LLNM were 93.2% and 47.2%, respectively. Moreover, we found that multilevel suspected LLNMs and loss of fatty hilum were independent preoperative indicative factors of large-volume LLNM (OR = 6.239, 95% CI 3.547-10.977, p < 0.001; OR = 5.149, 95% CI 1.859-14.261, p = 0.002). In conclusion, multilevel suspected LLNM and loss of fatty hilum on ultrasound tended to be more common in patients with large-volume LLNM. PTC patients with large-volume LLNM are at a higher recurrent/persistent risk than those with low-volume LLNM. Large-volume LLNM may be used to stratify the risk of recurrence/persistence in PTC.

Effectiveness of Lymphatic Contrast Enhanced Ultrasound in the diagnosis of Cervical Lymph node metastasis from papillary thyroid carcinoma

Cervical lymph node metastasis (CLNM) is common in patients with papillary thyroid carcinoma (PTC), which is responsible for tumor staging and surgical strategy. The accurate preoperative identification of CLNM is essential. In this study, twenty consecutive patients with PTC received a parenchyma injection of Sonazoid followed by contrast enhanced ultrasound (CEUS) to identify CLNM. The specific lymphatic CEUS (LCEUS) signs for diagnosing CLNM were summarized, which were further compared with the resected specimens to get the pathological basis. After the injection of contrast agent, lymphatic vessel and lymph node (LN) could be exclusively displayed as hyperperfusion on LCEUS. The dynamic perfusion process of contrast agent in CLNM over time can be clearly visualized. Perfusion defect and interruption of bright ring were the two characteristic LCEUS signs in diagnosing CLNM. After comparing with pathology, perfusion defect was correlated to the metastatic foci in medulla and interruption of bright ring was correlated to the tumor seeding in marginal sinus (all p values < 0.001). The diagnostic efficacies of these two signs were high (perfusion defect vs. interruption of bright ring: AUC, 0.899, 95% CI 0.752–1.000 vs. 0.904, 0.803–1.000). LCEUS has advantages in identifying CLNM from PTC. The typical LCEUS signs of CLNM correlated with pathology.

Hashimoto's Thyroiditis Is Associated With Central Lymph Node Metastasis in Classical Papillary Thyroid Cancer: Analysis from a High-Volume Single-Center Experience

PURPOSE

Central lymph node metastasis (CLNM) is regarded as a predictor for local recurrence in patients with papillary thyroid carcinoma (PTC) but the role of prophylactic central lymph node dissection (CLND) is controversial. Our study aims to identify the clinical factors associated with CLNM and develop a nomogram for making individualized clinical decisions.

METHOD

The perioperative data of 1,054 consecutive patients between Jan 2019 and April 2021, in our center, were reviewed and analyzed. A total of 747 patients with histopathologically confirmed classical PTC were included as the training cohort and 374 (50% training cases) patients were randomly selected to build a validating cohort via internal bootstrap analysis. Univariate and multivariate logistic regression were used to analyze the correlation between clinicopathological characteristics and CLNM.

RESULT

In the training cohort, 33.6% (251/747) of patients with classical PTC were confirmed with CLNM. And the CLNM was determined in 31.4% (168/535) of non-Hashimoto's thyroiditis (HT) patients versus 39.2% (83/212) in HT patients (p=0.043). Four factors including gender, age, size, and HT status were confirmed significantly associated with CLNM. The established nomogram showed good discrimination and consistency with a C-index of 0.703, supported by the internal validation cohort with a C-index of 0.701. The decision curve analysis showed the nomogram has promising clinical feasibility.

CONCLUSION

Our study suggested that classical PTC patients with features like male gender, age<55 years old, tumor size>1cm, and HT condition had a higher risk of CLNM. And the nomogram we developed can help surgeons make individualized clinical decisions in classical PTC patients during preoperative and intraoperative management.

PRDM16 Inhibits Cell Proliferation and Migration via Epithelial-to-Mesenchymal Transition by Directly Targeting Pyruvate Carboxylase in Papillary Thyroid Cancer

PRDM16 (known as MEL1), a member of the PR domain zinc finger family, has been implicated in multiple biological processes, including cancers. It is not clear yet whether PRDM16 is involved in tumor progress of papillary thyroid cancer (PTC). We identified the PRDM16 expression level in PTC tissues by qRT-PCR and analyzed its relationship with clinical characteristics in both Fudan University Shanghai Cancer Center (FUSCC) and TCGA cohorts. We tested the function of PRDM16 in PTC cells both in vivo and in vitro. We found a direct downstream target of PRDM16, pyruvate carboxylase (PC), by RNA-sequencing, rescue experiments, luciferase assay, and chromatin immunoprecipitation assay. PRDM16 was downregulated in papillary thyroid cancer tissues and was significantly related with lymph node metastases and extrathyroidal extension in both FUSCC and TCGA cohorts. Overexpression of PRDM16 could attenuate proliferation and migration of PTC cells via inhibiting the epithelial-to-mesenchymal transition process. PC was upregulated in papillary thyroid cancer tissues. Knockdown of PC could inhibit proliferation and migration in TPC-1 and K1 cells. The repression effect on cell proliferation and migration from PRDM16 was PC dependent. PRDM16 could directly bind to the PC promoter and inhibit its expression at the transcription level. Moreover, the mRNA expression level of PRDM16 and PC was negatively related in human PTC tissues. In conclusion, PRDM16 exhibited an antitumor effect and EMT inhibition function in PTC by directly binding with the PC promoter. PRDM16 may be a novel therapeutic target in papillary thyroid cancer.

Dynamic Nomogram for Predicting Lateral Cervical Lymph Node Metastasis in Papillary Thyroid Carcinoma

OBJECTIVE

To establish a dynamic nomogram based on preoperative clinical data for prediction of lateral lymph node metastasis (LLNM) of papillary thyroid carcinoma.

STUDY DESIGN

Retrospective study.

SETTING

The Sixth Affiliated Hospital of Sun Yat-Sen University.

METHODS

The data of 477 patients from 2 centers formed the training group and validation group and were retrospectively reviewed. Preoperative clinical factors influencing LLNM were identified by univariable and multivariable analysis and were to construct a predictive dynamic nomogram for LLNM. Receiver operating characteristic analysis and calibration curves were used to evaluate the predictive power of the nomogram.

RESULTS

The following were identified as independent risk factors for LLNM: male sex (odds ratio [OR] = 4.6, P = .04), tumor size ≥10.5 mm (OR = 7.9, P = .008), thyroid nodules (OR = 6.1, P = .013), irregular tumor shape (OR = 24.6, P = .001), rich lymph node vascularity (OR = 9.7, P = .004), and lymph node location. The dynamic nomogram constructed with these factors is available at https://zxh1119.shinyapps.io/DynNomapp/. The nomogram showed good performance, with an area under the curve of 0.956 (95% CI, 0.925-0.986), a sensitivity of 0.87, and a specificity of 0.91, if high-risk patients were defined as those with a predicted probability ≥0.3 or total score ≥200. The nomogram performed well in the external validation cohort (area under the curve, 0.915; 95% CI, 0.862-0.967).

CONCLUSIONS

The dynamic nomogram for preoperative prediction of LLNM in papillary thyroid carcinoma can help surgeons identify high-risk patients and develop individualized treatment plans.

Disease-free Survival of Patients with Differentiated Thyroid Cancer: A Study from a Tertiary Center in Oman

Objectives

As with global trends, the prevalence of differentiated thyroid cancer (DTC) has increased in recent years in Oman. However, to the best of our knowledge, no local studies have yet been published evaluating the prognosis of DTC cases in Oman. This study aimed to assess disease-free survival (DFS) and prognostic factors related to DTC among Omani patients attending a tertiary care center.

Methods

This retrospective, observational cohort study was conducted between January 2006 and May 2016 at the National Diabetes and Endocrine Center in Oman. Data related to DFS and prognostic factors were obtained from the electronic medical records of all ≥ 18-year-old patients diagnosed with DTC during the study period.

Results

A total of 346 DTC cases were identified. Overall, 82.7% of patients were disease-free at their last follow-up appointment. Univariate analysis indicated that various tumor characteristics including histological subtype (i.e., papillary carcinoma, Hurthle cell cancer, and minimally invasive follicular thyroid carcinoma), lymph node status, number of lymph node metastases, distant metastasis status, and TNM status (primary tumor (T), regional lymph node (N), distant metastasis (M) stage) were strong prognostic factors for DFS (p < 0.050). According to multivariate regression analysis, lymph node status, extrathyroidal extension, and angiovascular invasion were independent predictors of DFS (p < 0.050).

Conclusions

The overall prognosis of DTC among Omani patients was excellent. Treatment and follow-up strategies for patients with DTC should be tailored based on the individual’s risk factor profile.

Risk Factors and Prediction Model for Lateral Lymph Node Metastasis of Papillary Thyroid Carcinoma in Children and Adolescents

Purpose

Papillary thyroid carcinoma (PTC) in children and adolescents is prone to lateral lymph node metastasis (LNM), which is a high-risk factor for recurrence. However, few studies focused on identifying risk factors and establishing prediction models for lateral LNM of PTC in children and adolescents.

Patients and Methods

We retrospectively reviewed consecutive cases of children and adolescents with PTC undergoing thyroidectomy and cervical lymph node dissection between January 2009 and December 2019. The demographics and clinicopathologic features were collected and analyzed.

Results

A total of 102 children and adolescents with PTC were enrolled in our study; 51 of whom had lateral LNM (50%). After adjusting for other risk factors, the independent risk factors for lateral LNM were multifocality (odds ratio [OR]: 6.04; 95% confidence interval [CI]: 1.653–22.092; p=0.007), tumor size (OR: 1.752; 95% CI: 1.043–2.945; p=0.034), and the number of central LNM (OR: 1.23; 95% CI: 1.028–1.472; p=0.023). The formula of the combined predictor is: Multifocality + 0.31 × Tumor size + 0.115 × Number of central LNM. The area under the receiver operating characteristic curve of multifocality, tumor size, number of central LNM, and the combined predictor was 0.706, 0.762, 0.748, and 0.855, respectively. When the value of the combined predictor was ≥2.2744, lateral LNM could be predicted. The sensitivity and specificity of the predicted value were 82.4% and 74.5%, respectively.

Conclusion

The independent risk factors for lateral LNM in children and adolescents with PTC were multifocality, tumor size, and the number of central LNM. The prediction model can better predict the presence of lateral LNM.

Combination of Lymphatic and Intravenous Contrast-Enhanced Ultrasound for Evaluation of Cervical Lymph Node Metastasis from Papillary Thyroid Carcinoma: A Preliminary Study

The aim of this prospective study was to evaluate the value of the combination of lymphatic contrast-enhanced ultrasound (LCEUS) and intravenous contrast-enhanced ultrasound (IVCEUS) for the identification of cervical lymph node metastasis (CLNM) from papillary thyroid carcinoma (PTC). From November 2018 to March 2019, 24 consecutive patients with PTC were evaluated. All patients underwent routine US, LCEUS and IVCEUS. Pathology was used as the gold standard. After injection of a contrast agent into the thyroid parenchyma, lymphatic vessels and lymph nodes (LNs) could be exclusively displayed as hyper-enhancement on LCEUS. Benign LNs displayed a complete bright ring (100%) and homogeneous perfusion (88.9%) on LCEUS, while displaying centrifugal perfusion (66.7%) and homogenous enhancement (88.9%) on IVCEUS. Perfusion defects (94.9%) and interruption of the bright ring (71.8%) were the two characteristic LCEUS signs for diagnosing CLNM. On IVCEUS, CLNM appeared as centripetal perfusion (59.0%) and heterogeneous enhancement (59.0%). After comparison with pathology, perfusion defect was correlated to the metastatic foci in the medulla and interruption of the bright ring to the tumor seeding in the marginal sinus (all p values <0.05). LCEUS had more value (area under the receiver operating characteristic curve [AUC] = 0.850, 95% confidence interval [CI]: 0.682-1.000) in diagnosing CLNM than IVCEUS (AUC = 0.692, 95% CI: 0.494-0.890) and routine US (AUC = 0.581, 95% CI: 0.367-0.796). The combination of LCEUS and IVCEUS has the highest diagnostic value (AUC = 0.863, 95% CI: 0.696-1.000). LCEUS had higher diagnostic value than IVCEUS and US for CLNM from PTC. The combination of LCEUS and IVCEUS has the highest diagnostic value for CLNM.

Clinical Analysis of Cervical Lymph Node Metastasis Risk Factors and the Feasibility of Prophylactic Central Lymph Node Dissection in Papillary Thyroid Carcinoma

OBJECTIVE

To identify the risk factors for cervical lymph node metastasis (CLNM) and the feasibility of prophylactic central lymph node dissection.

METHODS

The characteristics of 1107 patients were extracted and analyzed. Univariate and multivariate analyses were used to identify risk factors associated with lymph node metastasis. The relationship between the central lymph node dissection (CLND) and lateral lymph node metastasis (LLNM) was analyzed using the correlation analysis.

RESULTS

The probability of CLNM was closely related to the male gender, age <55, and the increase of tumor size. Those patients with an increase in tumor size and CLNM were extremely prone to LLNM. Also, LLNM was more likely to happen in those with the more positive central lymph nodes. Routine prophylactic central lymph node dissection (P-CLND) did not increase the risk of complications.

CONCLUSION

P-CLND should be considered as a reasonable surgical treatment for PTC.

Clinical implications of Delphian lymph node metastasis in papillary thyroid carcinoma

Background

As is known, identifying risk factors precisely for lymph node metastasis (LNM) plays a vital role in initial treatment for papillary thyroid carcinoma (PTC). Nonetheless, whether Delphian lymph node (DLN) metastasis has value in predicting LNM remains an open question. This study covered a sample of 1,575 patients, which is the largest sample group so far, aiming to assess the predictive validity of DLN metastasis in PTC.

Methods

This retrospective cohort study was conducted with 1,575 eligible PTC patients who underwent thyroid operation between July 2013 and December 2018 and clinicopathologic parameters of patients with DLN metastasis were compared with those without DLN metastasis.

Results

The incidence of DLN metastasis, according to our research samples, is 24.4% (384/1,575 patients). And results show that DLN positivity was closely associated with adverse prognostic factors including younger age, larger tumor size, extrathyroid extension, tumor location in the isthmus or upper lobe of the thyroid, number of LNM >5, higher recurrence. After carefully adjusting important confounding factors, we find that in multivariate logistic regression analyses, DLN metastasis is an independent predictor for both central LNM (CLNM, adjusted OR =7.81, P<0.001) and lateral LNM (LLNM, adjusted OR =3.40, P<0.001). Moreover, the stratified analyses also show convincing evidence of a positive correlation between DLN metastasis and LNM in levels II-IV in the vast majority of subgroups.

Conclusions

The present study suggests that DLN metastasis is an independent risk factor for CLNM and LLNM of levels II-IV. The cervical lymph nodes should be meticulously evaluated to guide tailored treatment during operation in patients with DLN involvement.

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.

The impact of minimal extrathyroidal extension in the recurrence of papillary thyroid cancer patients

OBJECTIVE

We aimed to evaluate the impact of minimal extrathyroidal extension (mETE) alone on the risk of recurrence of papillary thyroid carcinoma (PTC). The impact of other factors, including multifocality, age, tumor size, and stimulated thyroglobulin (sTg) values was also assessed.

SUBJECTS AND METHODS

We retrospectively analyzed 1,108 PTC patients from a medical institution, who presented tumors ≤ 4 cm without any adverse characteristics other than mETE. Patients were classified according to their response to initial treatment 12 to 24 months after surgery as proposed by the 2015 American Thyroid Association (ATA) guideline. Statistical analysis was performed using multivariate logistic regression and receiver operating characteristic (ROC) curve.

RESULTS

In the multivariate logistic regression analysis, mETE did not have an impact on the response to initial treatment (p = 0.44), similar to multifocality, age, and tumor size. Initial Tg value was the only variable associated with a poor response (p < 0.01, odds ratio = 1.303, 95% confidence interval 1.25-1.36). The ROC analysis revealed that Tg was significant (area under curve = 0.8750); the cutoff value of sTg as a predictor of poor response was 10 ng/mL (sensitivity = 72.2%, specificity = 98.5%).

CONCLUSION

For low-risk PTC presenting mETE as the only aggressive feature, the initial sTg value is essential to identify patients who may have a poor response after initial treatment and benefit from further treatment. Arch Endocrinol Metab. 2020;64(3):251-6.

Machine Learning and Feature Selection Applied to SEER Data to Reliably Assess Thyroid Cancer Prognosis

Utilizing historical clinical datasets to guide future treatment choices is beneficial for patients and physicians. Machine learning and feature selection algorithms (namely, Fisher’s discriminant ratio, Kruskal-Wallis’ analysis, and Relief-F) have been combined in this research to analyse a SEER database containing clinical features from de-identified thyroid cancer patients. The data covered 34 unique clinical variables such as patients’ age at diagnosis or information regarding lymph nodes, which were employed to build various novel classifiers to distinguish patients that lived for over 10 years since diagnosis, from those who did not survive at least five years. By properly optimizing supervised neural networks, specifically multilayer perceptrons, using data from large groups of thyroid cancer patients (between 6,756 and 20,344 for different models), we demonstrate that unspecialized and existing medical recording can be reliably turned into power of prediction to help doctors make informed and optimized treatment decisions, as distinguishing patients in terms of prognosis has been achieved with 94.5% accuracy. We also envisage the potential of applying our machine learning strategy to other diseases and purposes such as in designing clinical trials for unmasking the maximum benefits and minimizing risks associated with new drug candidates on given populations.

Transoral endoscopic selective lateral neck dissection for papillary thyroid carcinoma: a pilot study

BACKGROUND

Transoral endoscopic thyroid surgery via the vestibular approach (TOETVA) has been gradually accepted worldwide due to its scar-free effect on the neck. Even central cervical lymphadenectomy has been performed in some cases of papillary thyroid carcinoma (PTC). However, there are few reports involving lateral neck dissection with TOETVA. In this study, we attempted to perform selective lateral neck dissection (SLND) for PTC via a transoral vestibular approach.

METHODS

This prospective study was conducted from January 2016 to December 2018 in twenty PTC patients with unilateral T1 tumors without capsular invasion and patients with abnormal level III and IV lymph nodes who underwent SLND via a transoral vestibular approach.

RESULTS

Endoscopic surgery was successfully accomplished in all 20 PTC patients. The mean age was 29.2 ± 5.5 (20-41) years. The mean operation time was 146.0 ± 18.7 (114-193) min. The average postoperative hospital stay was 6.8 ± 1.3 (5-10) days. The mean number of removed nodes was 7.4 ± 2.5 (4-12) in the central neck and 10.9 ± 2.8 (6-16) in the lateral neck, and the positive yield amounts were 2.0 ± 1.2 (0-4) and 2.7 ± 1.9 (0-6), respectively. No major complications occurred except for 1 case of transient unilateral recurrent laryngeal nerve palsy and two cases of effusion in the operative area. No evidence of persistent or recurrent disease was observed in these patients during a mean follow-up of 24.3 ± 9.1 (6-36) months. The cosmetic results and protection of personal privacy of this procedure were excellent.

CONCLUSION

Endoscopic SLND via the transoral vestibular approach is feasible, safe, and effective for selected PTCs. A multicenter large comparative study is necessary.

Preoperative Ultrasonographic Staging of Papillary Thyroid Carcinoma With the Eighth American Joint Committee on Cancer Tumor-Node-Metastasis Staging System

OBJECTIVE

The purpose of this study was to evaluate the performance of preoperative ultrasonography (US) in the staging of papillary thyroid carcinoma (PTC) according to the eighth AJCC TNM classification system, to determine the effect of the preoperative US staging in the management of PTC.

PATIENTS AND METHODS

Preoperative US was performed by 2 highly trained sonographers in 665 consecutive patients with PTC, and the T and N categories were determined preoperatively. The accuracy of preoperative US in clinical staging was evaluated based on the histopathological specimens according to the eighth AJCC TNM classification. Further analysis was performed to identify the high-risk factors of N1b stage.

RESULTS

Overall accuracy of preoperative US for T stage was 92.5% (615/665). The accuracy of sonographic evaluation for T was high except for the T4a. Overall accuracy of preoperative US for N stage was 59% (426/655). The accuracies of sonographic evaluation for N0, N1a, and N1b were 81.8% (274/335), 33.3% (70/250), and 87.5% (70/80), respectively. Of 250 N1a patients, 164 (65.6%) were underestimated by US. Univariate and multivariate analyses showed that larger tumor diameter, multifocality, and higher T stage significantly increase the risk of N1b stage (P < 0.01).

CONCLUSIONS

Preoperative US was useful for the evaluation in staging of PTC, but some limitations still existed. For higher-risk patients of N1b (larger tumor size, multifocality, and higher T stage), preoperative US examination for lateral neck region should be further emphasized, and prophylactic lateral nodal dissection should be determined based on both preoperative imaging results and intraoperative evaluation.

Risk of recurrence in patients with papillary thyroid carcinoma and minimal extrathyroidal extension not treated with radioiodine

PURPOSE

This study evaluated the recurrence rate in patients with papillary thyroid carcinoma (PTC) and minimal extrathyroidal extension (mETE) who had low thyroglobulin (Tg) after total thyroidectomy, and therefore, did not receive radioactive iodine (RAI).

METHODS

This was a prospective study including 182 patients with tumors ≤ 4 cm and mETE without aggressive histology or clinically apparent lymph node involvement (cN0pNx). After thyroidectomy, all patients had nonstimulated Tg ≤ 0.3 ng/ml, negative antithyroglobulin antibodies (TgAb), and neck ultrasonography (US) showing no anomalies. Because of these results, the patients were not submitted to RAI.

RESULTS

The time of follow-up ranged from 24 to 132 months (median 72 months). One hundred and seventy-eight patients (97.8%) continued to have nonstimulated Tg ≤ 0.3 ng/ml and negative US. Four patients (2.2%) exhibited an increase in Tg and lymph node metastases (structural recurrence). After surgery, these patients obtained nonstimulated Tg < 1 ng/ml and no apparent tumor was detected by the imaging methods.

CONCLUSION

The results suggest that patients with mETE and without other adverse features, who have low nonstimulated Tg and negative neck US after thyroidectomy, do not require ablation with RAI.

Recombinant Thyrotropin vs Levothyroxine Withdrawal in 131I Therapy of N1 Thyroid Cancer: A Large Matched Cohort Study (ThyrNod)

CONTEXT

Recombinant human thyrotropin (rhTSH) has been shown to be an effective stimulation method for radioactive iodine (RAI) therapy in differentiated thyroid cancer, including in those with nodal metastases (N1 DTC).

OBJECTIVES

To demonstrate the noninferiority of rhTSH vs thyroid hormone withdrawal (THW) in preparation to RAI regarding disease status at the first evaluation in the real-life setting in patients with N1 DTC.

DESIGN

This was a French multicenter retrospective study. Groups were matched according to age (<45/≥45 years), number of N1 nodes (≤5/>5 lymph nodes), and stage (pT1-T2/pT3).

RESULTS

The cohort consisted of 404 patients pT1-T3/N1/M0 DTC treated with rhTSH (n = 205) or THW (n = 199). Pathological characteristics and initially administrated RAI activities (3.27 ± 1.00 GBq) were similar between the two groups. At first evaluation (6 to 18 months post-RAI), disease-free status was defined by thyroglobulin levels below threshold and a normal ultrasound. Disease-free rate was not inferior in the rhTSH group (75.1%) compared with the THW group (71.9%). The observed difference between the success rates was 3.3% (-6.6 to 13.0); rhTSH was therefore considered noninferior to THW because the upper limit of this interval was <15%. At the last evaluation (29.7 ± 20.7 months for rhTSH; 36.7 ± 23.8 months for THW), 83.5% (rhTSH) and 81.5% (THW) of patients achieved a complete response. This result was not influenced by any of the known prognostic factors.

CONCLUSIONS

A preparation for initial RAI treatment with rhTSH was noninferior to that with THW in our series of pT1-T3/N1/M0-DTC on disease-free status outcomes at the first evaluation and after 3 years.

Risk factors for skip metastasis and lateral lymph node metastasis of papillary thyroid cancer

BACKGROUND

Lymph node metastases from papillary thyroid cancer is believed to disseminate sequentially, first to the central neck and later to the lateral neck. Skip metastases of papillary thyroid cancer, however, are defined as lateral lymph node metastasis without central lymph node metastasis. The aim of this study was to investigate the risk factors for skip metastases and lateral lymph node metastasis of papillary thyroid cancer.

METHODS

We reviewed 721 papillary thyroid cancer patients undergoing total thyroidectomy with central lymph node dissection and lateral lymph node dissection during 2013 to 2018. Multivariate logistic regression analysis was performed to identify clinicopathologic risk factors for skip metastasis and lateral lymph node metastasis of papillary thyroid cancer.

RESULTS

The rate of skip metastases was 7.4% (42 of 567 patients). Multivariate analysis showed that female sex and papillary thyroid microcarcinoma (≤ 1 cm) were independent risk factors for skip metastases, with odds ratios ([OR], 95% confidence interval [CI]) of 2.29 (1.02-5.16) and 2.84 (1.46-5.16), respectively. Intrathyroidal spread of papillary thyroid cancer and an increased number of central lymph nodes dissected were inversely associated with skip metastases with ORs (95% CI) of 0.13 (0.02-0.99) and 0.88 (0.83-0.94), respectively. In contrast, a greater tumor size, central lymph node metastasis, an increased number of central lymph nodes dissected, and an increased number of lateral lymph nodes dissected were associated with a lateral lymph node metastasis risk of papillary thyroid cancer, with ORs (95% CI) as follow: 1.67 (1.08-2.59), 3.07 (1.71-5.52), 1.25 (1.14-1.37), and 1.07 (1.04-1.10), respectively, by multivariate analysis.

CONCLUSION

Greater tumor size, central lymph node metastasis, and an increased number of both central lymph nodes and lateral lymph nodes dissected were predictors for lateral lymph node metastasis of papillary thyroid cancer. In addition, papillary thyroid microcarcinoma was an independent risk factor for skip metastases. A complete and comprehensive central compartment dissection may decrease the false-positive detection of skip metastases of papillary thyroid cancer.

Clinical analysis of cervical lymph node metastasis risk factors in patients with papillary thyroid microcarcinoma

PURPOSE

Lymph node metastasis (LNM) is a vital prognosis factor in patients with papillary thyroid microcarcinoma (PTMC). The study tried to identify clinicopathological factors for LNM of PTMC.

METHODS

The clinicopathological data of 1031 patients with PTMC were extracted and analyzed. Univariate and multivariate analyses were used to identify risk factors associated with cervical lymph node metastasis. ROC analysis was used to determine the ideal critical points of the sum of the maximum diameter of multifocal in a unilateral lobe.

RESULTS

The probability of LNM, central lymph node metastasis (CLNM) and lateral lymph node metastasis(LLNM)of PTMC patients were 35.6, 33.7 and 5.6%, respectively. In addition, 1.9% PTMC had LLNM only. Male, age ≤ 40 years, tumor largest diameter ≥ 5 mm, multifocal, non-uniform echoic distribution, the sum of the maximum diameter of multifocal in a unilateral lobe ≥ 8.5 mm, tumors in the lower pole location were prone to CLNM. Ultrasound mix-echo, the sum of the maximum diameter of the multifocal ≥ 10.75 mm, tumors in the upper pole location were extremely prone to LLNM. T3 were prone to LLNM or skip LLNM.

CONCLUSIONS

According to the clinicopathological characteristics of PTMC, the cervical lymph nodes should be correctly evaluated to guide the surgical treatment.

Time to Separate Persistent From Recurrent Differentiated Thyroid Cancer: Different Conditions With Different Outcomes

CONTEXT

Differentiated thyroid cancer (DTC) has an excellent prognosis, but up to 20% of patients with DTC have disease events after initial treatment, indistinctly defined as persistent/recurrent disease.

OBJECTIVE

To evaluate the prevalence and outcome of "recurrent" disease (relapse after being 12 months disease-free) compared with "persistent" disease (present ab initio since diagnosis).

DESIGN

Retrospective analysis of persistent/recurrent disease in patients with DTC (1990 to 2016) with 6.5 years of mean follow-up.

SETTING

Tertiary referral center for thyroid cancer.

PATIENTS

In total, 4292 patients all underwent surgery ± 131I treatment of DTC.

MAIN OUTCOME MEASURES

DTC cure of disease persistence or recurrence.

RESULTS

A total of 639 of 4292 (14.9%) patients had disease events after initial treatment, most (498/639, 78%) with persistent disease and 141 (22%) with recurrent disease. Relative to patients with recurrent disease, patients with persistent disease were significantly older (mean age 46.9 vs 45.7 years) and with a lower female to male ratio (1.9/1 vs 4.8/1). Moreover, in this group, structured disease was more frequent (65.7% vs 41.1%), and more important, distant metastases were significantly more frequent (38.4% vs 17.0%). At multivariate analysis, male sex (OR = 1.7), age (OR = 1.02), follicular histotype (OR = 1.5), T status (T3; OR = 3), and N status (N1b; OR = 7.7) were independently associated with persistent disease. Only the N status was associated with recurrent disease (N1b; OR = 2.5).

CONCLUSIONS

In patients with DTC not cured after initial treatment, persistent disease is more common and has a worse outcome than recurrent disease. Postoperative status evaluated during first-year follow-up may have important clinical implications for planning tailored treatment strategies and long-term follow-up procedures.

Meta-analysis of ultrasound for cervical lymph nodes in papillary thyroid cancer: Diagnosis of central and lateral compartment nodal metastases

PURPOSE

To evaluate the performance of preoperative ultrasound in the diagnosis of cervical lymph nodes metastases (CLNM) of papillary thyroid cancer (PTC) and its value in assisting cervical lymph node dissection (CLND).

METHODS

PubMed, EMBASE and Cochrane Library databases were searched to identify relevant studies up to Sep. 2017. Overall sensitivity, specificity, and diagnostic odds ratio (DOR) were used to assess the diagnostic efficacy of ultrasound in detecting central and lateral CLNM of PTC.

RESULTS

Nineteen studies comprising 4014 patients were included in the meta-analysis. The pooled sensitivity, specificity, DOR and area under curve (AUC) of ultrasound in detecting central CLNM were 0.33 (95% confidence interval (95% CI): 0.31-0.35), 0.93 (95% CI: 0.92-0.94), 5.63 (95% CI: 3.50-9.04), and 0.69, respectively; and lateral CLNM were 0.70 (95% CI: 0.68-0.72), 0.84 (95% CI: 0.82-0.85), 18.7 (95% CI: 10.3-33.9) and 0.88, respectively. We found that the rate of central CLNM of PTC was 48.0%, and 36.2% of the dissected lymph nodes were metastatic, meanwhile, the rate of lateral CLNM of PTC was 59.2%, and 46.6% of the dissected lymph nodes were metastatic in the meta-analysis.

CONCLUSIONS

Preoperative ultrasound demonstrates poor sensitivity in the diagnosis of central CLNM, and good diagnostic efficacy for lateral CLNM of PTC. Prophylactic central CLND is recommended to PTC patients due to the high incidence of central CLNM and low diagnostic efficacy of ultrasound.

Lymph node location is a risk factor for papillary thyroid cancer-related death

PURPOSE

Papillary thyroid cancer (PTC) has good prognosis with a very low chance of mortality. The prognostic role of metastatic lymph node location was judged controversial and more recently (TNM VIII ed.) was considered to have no impact on the prognosis of older patients. The aim of the study was to evaluate the role of metastasized node location on PTC-related mortality.

METHODS

PTC-related mortality was analysed in a consecutive retrospective series of 1653 PTC patients followed at our Thyroid Clinic (mean follow-up 5.9 years).

RESULTS

Sixteen out of 1653 patients (0.96%) died because of PTC. Average age was 68 years at presentation and 74.7 at death. F/M ratio was 1:1. The death rate increased in relation to the lymph node status: 0.2% in N0, 0.3% in N1a and 3.0% in N1b.

CONCLUSIONS

The presence of lymph node metastases in the N1b compartment should be considered as a risk factor for distant metastatic spread and for cancer-related death and included in post-surgery evaluation.

Clinicopathologic risk factors for right paraesophageal lymph node metastasis in patients with papillary thyroid carcinoma

OBJECTIVES

To investigate risk factors associated with right paraesophageal lymph node (RPELN) metastasis in patients with papillary thyroid carcinoma (PTC) and to determine the indications for right lymph node dissection.

METHODS

Clinicopathologic data from 829 patients (104 men and 725 women) with PTC, operated on by the same thyroid surgery team at the First Affiliated Hospital of Harbin Medical University from January 2013 to May 2017, were analyzed. Overall, 309 patients underwent total thyroidectomy with bilateral lymph node dissection, 488 underwent right thyroid lobe and isthmic resection with right central compartment lymph node dissection, and 32 underwent near-total thyroidectomy (ipsilateral thyroid lobectomy with contralateral near-total lobectomy) with bilateral lymph node dissection.

RESULTS

The overall rate of central compartment lymph node metastasis was 43.5% (361/829), with right central compartment lymph node and RPELN metastasis rates of 35.5% (294/829) and 19.1% (158/829), respectively. Tumor size, number, invasion, and location, lymph node metastasis, right central compartment lymph node metastasis, and right lateral compartment lymph node metastasis were associated with RPELN in the univariate analysis, whereas age and sex were not. Multivariate analysis identified tumors with a diameter ≥ 1 cm, multiple tumors, tumors located in the right lobe, right central compartment lymph node metastasis, and right lateral compartment lymph node metastasis as independent risk factors for RPELN metastasis.

CONCLUSIONS

Lymph node dissection, including RPELN dissection, should be performed for patients with PTC with a tumor diameter ≥ 1 cm, multiple tumors, right-lobe tumors, right central compartment lymph node metastasis, or suspected lateral compartment lymph node metastasis.