Clinicopathologic predictors of central lymph node metastases in clinical node-negative papillary thyroid microcarcinoma: a systematic review and meta-analysis

The role of intraoperative central lymph node biopsy in the treatment of clinically low-risk PTMC

PURPOSE

To evaluate the role of intraoperative frozen biopsy of central lymph nodes in central neck dissection and thyroidectomy in patients of unilateral, clinically negative nodes (cN0) papillary thyroid microcarcinoma (PTMC) without extra-glandular invasion.

METHODS

The clinical data of 465 patients were collected retrospectively. Part of prelaryngeal, pretracheal and ipsilateral paratracheal lymph nodes were taken for frozen pathological examination during the operation. Then the thyroid lobe on the tumor side and isthmus were excised, and central neck dissection of the affected side was performed in all patients. The number of metastases in entire central lymph nodes of the affected side can be obtained by postoperative paraffin pathology. If the number of positive lymph nodes during surgery is ≥3, contralateral gland resection was performed.

RESULTS

In this group of 465 patients, there were 186 cases with central lymph node metastasis. The Kappa coefficient of consistency between frozen pathology and paraffin pathology in central lymph nodes was 0.605. The ROC curve for the number of intraoperative frozen metastases-postoperative pathological metastases over 5 showed that the AUC of the curve was 0.793, while the maximum Youden index was 0.5259, whose corresponding number of positive lymph nodes was 3.

CONCLUSION

Intraoperative central lymph nodes biopsy can be used as an important indicator for the status of central lymph node metastasis in unilateral cN0 PTMC patients without extra-glandular invasion and a determinant for central lymph node dissection. While the number of positive lymph nodes intraoperatively is ≥3, total thyroidectomy should be considered.

Application of ultrasound elastography and radiomic for predicting central cervical lymph node metastasis in papillary thyroid microcarcinoma

Objective

This study aims to combine ultrasound (US) elastography (USE) and radiomic to predict central cervical lymph node metastasis (CLNM) in patients with papillary thyroid microcarcinoma (PTMC).

Methods

A total of 204 patients with 204 thyroid nodules who were confirmed with PTMC and treated in our hospital were enrolled and randomly assigned to the training set (n = 142) and the validation set (n = 62). US features, USE (gender, shape, echogenic foci, thyroid imaging reporting and data system (TIRADS) category, and elasticity score), and radiomic signature were employed to build three models. A nomogram was plotted for the combined model, and decision curve analysis was applied for clinical use.

Results

The combined model (USE and radiomic) showed optimal diagnostic performance in both training (AUC = 0.868) and validation sets (AUC = 0.857), outperforming other models.

Conclusion

The combined model based on USE and radiomic showed a superior performance in the prediction of CLNM of patients with PTMC, covering the shortage of low specificity of conventional US in detecting CLNM.

Prediction of central lymph node metastasis in patients with papillary thyroid microcarcinoma by gradient-boosting decision tree model based on ultrasound radiomics and clinical features

Background

In recent years, the study of radiomics in thyroid diseases has developed rapidly. This study aimed to establish a preoperative radiomics prediction model for central compartment lymph node metastases (CLNMs) in papillary thyroid microcarcinoma (PTMC) patients using gradient-boosting decision tree (GBDT) model and evaluate the performance of the model.

Methods

A total of 274 patients with PTMC admitted for thyroid surgery at China-Japan Union Hospital of Jilin University from January 2020 to July 2022 were retrospectively analyzed. Patients were randomized into training and validation cohorts according to a ratio of 8:2. Radiomics features were extracted from the ultrasound (US) images of PTMC lesions. The open-source software Pyradiomics was used to extract radiomics features, and WEKA software was used to select CLNM-related radiomics features. Clinical risk factors for CLNM were screened by statistical methods. The GBDT model was constructed by combining radiomics features and clinical risk factors, and compared with the diagnostic efficacy of US-reported cervical lymph node status. Shapley Additive exPlanations (SHAP) was applied to visualize and analyze the GBDT model globally and locally.

Results

A total of seven radiomics features were significantly correlated with central lymph node status in the training and validation cohorts. The predictors in the GBDT model included the radiomics features, sex, age, and body mass index (BMI). The area under the curve (AUC) values of the GBDT model in the training and validation cohorts were 0.946 [95% confidence interval (CI): 0.920-0.972] and 0.845 (95% CI: 0.714-0.976), respectively, compared with 0.583 (95% CI: 0.508-0.659) and 0.582 (95% CI: 0.430-0.736) for US-reported lymph node status alone. The Delong test showed a significant difference between AUS in the training and validation cohorts (P<0.001, respectively). SHAP visual analysis showed the effect of each parameter on the GBDT model globally and locally. Decision curve analysis demonstrated the clinical utility of the GBDT model.

Conclusions

The prediction of CLNM by the GBDT model, based on US radiomics features and clinical factors, can be better than that by using US alone in patients with PTMC. Furthermore, the GBDT model may serve a guidance of clinical decision for patient's treatment strategy.

A prediction model for identifying high-risk lymph node metastasis in clinical low-risk papillary thyroid microcarcinoma

BACKGROUND

The presence of high-volume lymph node metastasis (LNM) and extranodal extension (ENE) greatly increases the risk of recurrence in patients with low-risk papillary thyroid microcarcinoma (PTMC). The goal of this research was to analyze the factors that contribute to high-risk lymph node metastasis in patients with low-risk PTMC.

METHODS

We analyzed the records of 7344 patients who were diagnosed with low-risk PTMC and treated at our center from January 2013 to June 2018.LNM with a high volume or ENE was classified as high-risk lymph node metastasis (hr-LNM). A logistic regression analysis was conducted to identify the risk factors associated with hr-LNM. A nomogram was created and verified using risk factors obtained from LASSO regression analysis, to predict the likelihood of hr-LNM.

RESULTS

The rate of hr-LNM was 6.5%. LASSO regression revealed six variables that independently contribute to hr-LNM: sex, age, tumor size, tumor location, Hashimoto's thyroiditis (HT), and microscopic capsular invasion. A predictive nomogram was developed by integrating these risk factors, demonstrating its excellent performance. Upon analyzing the receiver operating characteristic (ROC) curve for predicting hr-LNM, it was observed that the area under the curve (AUC) had a value of 0.745 and 0.730 in the training and testing groups showed strong agreement, affirming great reliability.

CONCLUSION

Sex, age, tumor size, tumor location, HT, and microscopic capsular invasion were determined to be key factors associated with hr-LNM in low-risk PTMC. Utilizing these factors, a nomogram was developed to evaluate the risk of hr-LNM in patients with low-risk PTMC.

Incidence and risk factors for occult lesions in low-risk papillary thyroid microcarcinoma patients with tumor characteristics appropriate for thermal ablation: A retrospective study

In recent years, thermal ablation has been increasingly employed for the treatment of low-risk papillary thyroid microcarcinoma (PTMC) across various institutions. Its use as a standard or initial treatment continues to be a subject of debate. Retrospective analyses of the surgical pathology in post-ablation patients have indicated that occult lesions are not uncommon. This retrospective study aimed to examine the incidence and risk factors of occult lesions via postoperative pathology in low-risk PTMC patients who fulfilled the criteria for thermal ablation therapy. We examined the medical records of patients who underwent thyroid surgery and had a Bethesda classification V or VI based on fine needle aspiration cytology between November 22, 2020, and December 31, 2022. A total of 413 patients with preoperative tumor characteristics appropriate for thermal ablation were included in this study. Occult lesions, encompassing ipsilateral or contralateral occult carcinoma or central lymph node metastases may have occurred in 34.7% of patients. Male gender (OR: 2.526, 95% CI: 1.521-4.195, P = .000), tumor location in the lower pole (OR: 1.969, 95% CI: 1.186-3.267, P = .009), multiple microcalcifications (OR: 5.620, 95% CI: 2.837-11.134, P = .000), and Hashimoto's thyroiditis (OR: 2.245, 95% CI: 1.292-3.899, P = .004) were independent risk factors for the presence of occult lesions. In low-risk PTMC patients exhibiting tumor characteristics amenable to thermal ablation, over one-third of the patients may present with occult lesions. Meticulous evaluation of the presence of additional lesions is necessary before performing thermal ablation, particularly in patients exhibiting high-risk factors for occult lesions.

Initial ablation ratio predicts the recurrence of low-risk papillary thyroid microcarcinomas treated with microwave ablation: a 5-year, single-institution cohort study

Objective

To assess the long-term efficacy and safety of microwave ablation (MWA) in treating low-risk papillary thyroid microcarcinomas (PTMC) and to identify predictive factors for the postoperative local tumor progression of PTMC.

Methods

A total of 154 low-risk PTMC patients treated with MWA who were followed up for at least 3 months were retrospectively recruited. Ultrasonography was performed after MWA to assess the local tumor progression. Adverse events associated with MWA were recorded. The ablated volume (Va) and initial ablation ratio (IAR) were measured to assess their influences on the recurrence risk of PTMC.

Results

The mean tumor volume of PTMC before MWA was 0.071 (0.039, 0.121) cm3, with a maximum diameter of 0.60 ± 0.18 cm. All PTMC patients were followed up for 6 (3, 18) months. Va increased immediately after MWA, then gradually decreased over time, till significantly smaller at 12 months than that before MWA (P < 0.05). The median volume reduction ratio at 24 months reached 100%, which was maintained during a 60-month follow-up. A total of 7 (4.55%) cases of local tumor progression were recorded during the follow-up. Kaplan-Meier survival analysis revealed that the rate of local tumor progression was significantly lower in PTMC patients with a maximum tumor diameter < 0.70 cm than in those with ≥0.70 cm (P = 0.031). A significant better prognosis was achieved in PTMC patients with IAR ≥ 15 than in those with IAR < 15 (P = 0.015). Sex, age (<55 years) and preoperative thyroid-stimulating hormone (>2.0 mU/L) of PTMC patients were not correlated with local tumor progression.

Conclusion

MWA is an effective therapeutic strategy for low-risk PTMC with high safety. The maximum tumor diameter and IAR are predictive factors for the local tumor progression of PTMC after MWA.

A nomogram for predicting lateral lymph node metastasis in cN0 unifocal papillary thyroid microcarcinoma

BACKGROUND

Identifying risk factors for occult lateral lymph node metastasis (LLNM) in papillary thyroid microcarcinoma (PTMC) can provide valuable insights into the necessity of lateral neck dissection (LND). The objective of this study was to develop a nomogram for predicting the probability of LLNM in patients with cN0 unifocal PTMC.

METHODS

We conducted a retrospective analyzed a total of 4872 patients with cN0 unifocal PTMC who were treated at our center from January 2013 to June 2018. Logistic regression analysis was used to determine the risk factors for LLNM, and a nomogram was constructed based on these risk factors.

RESULTS

The rate of LLNM was 3.2%. Tumors located in the upper lobe(odds ratio [OR] = 2.56, 95% confidence interval [CI] 1.80-3.62; p < 0.001) and size greater than 7 mm (OR = 2.59, 95% CI 1.85-3.62; p < 0.001) had a significantly higher risk of LLNM compared to tumors in the lower or middle lobe and size less than or equal to 7 mm. Tumors with extrathyroidal extension (ETE) had a significantly higher risk of LLNM (OR = 1.41, 95% CI 1.01-1.99; p = 0.044). The presence of three or more central lymph node metastases (CLNMs) (OR = 5.84, 95% CI 3.83-8.93; p < 0.001) or one or two CLNMs (OR = 2.91, 95% CI 1.93-4.42; p < 0.001) also increased the risk of LLNM compared to having no CLNMs. A nomogram incorporating these risk factors was developed, and the receiver operating characteristic (ROC) curve demonstrated an area under the curve (AUC) of 0.777, indicating a high degree of predictive accuracy.

CONCLUSION

Tumor location in the upper lobe, greater than 7 mm in size, ETE, and CLNMs, especially three or more, were independent risk factors for LLNM in cN0 unifocal PTMC. The nomogram based on these factors exhibited favorable predictive value and consistency.

Do Histologically Aggressive Subtypes of Papillary Thyroid Microcarcinoma have Worse Clinical Outcome than Non-Aggressive Papillary Thyroid Microcarcinoma Subtypes? A Multicenter Cohort Study

Histologically aggressive micropapillary thyroid carcinomas (PTMC) subtypes are thought to be associated with an aggressive clinical course. However, evidence for unfavorable clinical outcomes in patients with aggressive PTMC subtypes is not clear. In this study, we intended to determine the difference in clinical outcomes between patients with aggressive and non-aggressive PTMC subtypes. In this multicenter cohort study, the computer-recorded clinical and histopathological data of patients who underwent thyroid surgery between January 2000 - January 2021 in 9 referral centers and were diagnosed as PTMC were analyzed. A total of 1585 patients [female 1340 (84.5%), male 245 (15.5%), mean age 47.9±11.63 years), with a mean follow-up time of 66.55±37.16 months], were included in the study. Ninety-eight cases were diagnosed as aggressive and 1487 as non-aggressive subtypes. Persistent/recurrent disease was observed in 33 (33.7% )and 41 (2.8%) patients with aggressive and non-aggressive subtypes (p<0.001). Diseases-free survival rates were markedly lower in patients with aggressive than in those with non-aggressive PTMC subtypes (66.3 vs. 94.8%, log-rank p<0.001). Moreover, in multivariate analysis, aggressive histology was an independent predictor of persistent/recurrent disease, after controlling for other contributing factors (HR 5.78, 95% CI 3.32-10, p<0.001). Patients with aggressive PTMC subtypes had higher rates of incomplete biochemical and structural response than patients with non-aggressive subtypes as well (p<0.001). Aggressive PTMC subtypes share many characteristics with histologically identical tumors>1 cm in size. Therefore, the histopathological subtype of PTMC should be taken into consideration to tailor a personalized management plan.

A Nod to the Nodes: An Overview of the Role of Central Neck Dissection in the Management of Papillary Thyroid Carcinoma

Lymph node metastasis in thyroid cancer is common and associated with an increased risk of locoregional recurrence (LRR). Although therapeutic central neck dissection is well established, prophylactic central node dissection (pCND) for microscopic occult nodal involvement is controversial and recommendations are based on low-level evidence. The potential benefits of pCND such as reducing LRR and re-operation, refining staging, and improving surveillance are enthusiastically debated and the decision to perform pCND must be weighed up against the increased risks of complications.

Prophylactic Central Neck Lymph Node Dissection Adds No Short-Term Benefit to Total Thyroidectomy for Differentiated Thyroid Cancer

Background and Objectives: To answer the research question: "Is prophylactic central neck lymph node dissection (pCNLD) beneficial among differentiated thyroid carcinoma (DTC) patients?" Materials and Methods: This was a retrospective cohort study enrolling DTC patients treated at the University Hospital Kaspela, Bulgaria, from 30 January 2019 to October 2021. The predictor variable was presence of pCNLD (total thyroidectomy with vs. without pCNLD). The main outcome variables were postoperative complications (i.e., vocal cord paralysis, hypoparathyroidism, postoperative bleeding, and adjacent organ injury) and recurrence parameters. Appropriate statistics were computed with the significant level at p ≤ 0.05. Results: During the study period, 300 DTC patients (59.7% with pCNLD; 79.3% females) with an average age of 52 ± 2.8 years were treated. The mean follow-up period of the entire cohort was 45.8 ± 19.1 months. On bivariate analyses, TT with pCNLD, when compared to TT alone, required longer surgical time (mean difference: 9.4 min), caused nearly similar complications (except transient hypothyroidism: p = 0.04; relative risk, 1.32; 95% confidence interval, 1.0 to 1.73), and no significantly different recurrence events, time to recurrence, and recurrent sites. The benefit-risk analyses using the number needed to treat and to harm (NNT; NNH) also confirmed that TT plus pCNLD was not very beneficial in DTC management. Conclusion: The results of this study refute the benefit of pCNLD in DTC patient care with TT. Further well-designed studies in a larger cohort with a longer follow-up period are required to confirm this conclusion.

Exploring risk factors for cervical lymph node metastasis in papillary thyroid microcarcinoma: construction of a novel population-based predictive model

BACKGROUND

Machine learning was a highly effective tool in model construction. We aim to establish a machine learning-based predictive model for predicting the cervical lymph node metastasis (LNM) in papillary thyroid microcarcinoma (PTMC).

METHODS

We obtained data on PTMC from the SEER database, including 10 demographic and clinicopathological characteristics. Univariate and multivariate logistic regression (LR) analyses were applied to screen the risk factors for cervical LNM in PTMC. Risk factors with P < 0.05 in multivariate LR analysis were used as modeling variables. Five different machine learning (ML) algorithms including extreme gradient boosting (XGBoost), random forest (RF), adaptive boosting (AdaBoost), gaussian naive bayes (GNB) and multi-layer perceptron (MLP) and traditional regression analysis were used to construct the prediction model. Finally, the area under the receiver operating characteristic (AUROC) curve was used to compare the model performance.

RESULTS

Through univariate and multivariate LR analysis, we screened out 9 independent risk factors most closely associated with cervical LNM in PTMC, including age, sex, race, marital status, region, histology, tumor size, and extrathyroidal extension (ETE) and multifocality. We used these risk factors to build an ML prediction model, in which the AUROC value of the XGBoost algorithm was higher than the other 4 ML algorithms and was the best ML model. We optimized the XGBoost algorithm through 10-fold cross-validation, and its best performance on the training set (AUROC: 0.809, 95%CI 0.800-0.818) was better than traditional LR analysis (AUROC: 0.780, 95%CI 0.772-0.787).

CONCLUSIONS

ML algorithms have good predictive performance, especially the XGBoost algorithm. With the continuous development of artificial intelligence, ML algorithms have broad prospects in clinical prognosis prediction.

Evaluate the diagnostic and prognostic value of NUSAP1 in papillary thyroid carcinoma and identify the relationship with genes, proteins, and immune factors

Background

Nucleolar spindle-associated protein 1 (NUSAP1) is reported to be a useful diagnostic and prognostic marker for a variety of cancers, but relevant studies are lacking in papillary thyroid carcinoma (PTC).

Methods

The relationship between NUSAP1 expression and the overall survival (OS) of pan-cancer was examined by GEPIA and KMplot. We explored the relationship between NUSAP1 and clinical PTC data based on the THCA dataset of TCGA and the GEO dataset of NCBI; GO, KEGG analysis, and ceRNA networks were performed on co-expressed genes through LinkedOmics and Starbase. We assessed the relevance between NUSAP1 and the tumor microenvironment using ESTIMATE, correlations between NUSAP1 and immune cells with TIMER, the relationship between NUSAP1 and immunotherapy by TCIA, and small-molecule drugs targeting NUSAP1 that can be discovered using the CMap database.

Results

Higher expression of NUSAP1 in pan-cancer tissues was correlated with shorter OS. NUSAP1 was also significantly expressed in PTC tissues and was an independent prognostic risk factor. Compared to the NUSAP1 low expression group, the NUSAP1 high expression group was more likely to also have lymph node metastasis, pathological PTC type, shorter progression-free survival (PFS), and higher scores for immune checkpoint inhibitor treatment. The genes associated with NUSAP1 were mostly involved in the cell cycle, immune-related pathways, and AITD. Ten lncRNAs (GAS5, SNHG7, UCA1, SNHG1, HCP5, DLEU2, HOTAIR, TP53TG1, SNHG12, C9orf106), eleven miRNAs (hsa-miR-10a-5p, hsa-miR-10b-5p, hsa-miR-18a-5p, hsa-miR-18b-5p, hsa-miR-128-3p, hsa-miR-214-3p, hsa-miR-219a-2-3p, hsa-miR-339-5p, hsa-miR-494-3p, hsa-miR-545-3p, hsa-miR-769-5p), and one mRNA (NUSAP1) were constructed. NUSAP1 participated in the formation of the tumor microenvironment. CMap predicted the 10 most important small molecules about NUSAP1.

Conclusions

In PTC, NUSAP1 shows good diagnostic value and prognostic value; NUSAP1 impacts the cell cycle, immune-related pathways, and AITD and has a complex effect on the tumor microenvironment in PTC.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12957-022-02652-9.

Minimal extrathyroidal extension is associated with lymph node metastasis in single papillary thyroid microcarcinoma: a retrospective analysis of 814 patients

Background

Extrathyroidal extension (ETE) is considered a major prognostic factor in papillary thyroid carcinoma (PTC). Patients with gross ETE are at increased risk of recurrence and mortality. The importance of minimal ETE still remains controversial, especially in patients with papillary thyroid microcarcinoma (PTMC). The purpose of this study was to evaluate the association between ETE and lymph node (LN) metastasis in single PTMC.

Methods

A retrospective analysis was performed of 1994 patients underwent thyroidectomy for PTC between 2012 and 2016 in a single institution. Patients with combined thyroid carcinoma of other types and those who underwent completion thyroidectomy were excluded. After further exclusion of PTC larger than 1 cm and multifocal tumors, 814 patients with single PTMC were included in the study.

Results

72.9% patients had no ETE, 25.1% minimal ETE, and 2.1% gross ETE. ETE was associated with lymphatic invasion, perineural invasion, and vascular invasion. Patients with minimal and gross ETE were also more likely to have LN metastasis, including lateral neck metastasis, compared to those without ETE. In univariate analysis, LN metastasis was associated with male gender, conventional PTC, lymphatic invasion, perineural invasion, and ETE. In multivariate analysis, male gender (OR = 1.987; 95% CI 1.369–2.884), lymphatic invasion (OR = 4.389; 95% CI 1.522–12.658), perineural invasion (OR = 6.545; 95% CI 1.262–33.948), and minimal ETE (OR = 1.852; 95% CI 1.298–2.643) were found to be independent risk factors of LN metastasis.

Conclusions

Minimal ETE is associated with LN metastasis in single PTMC, compared to no ETE. Minimal ETE should be considered in the management of patients with single PTMC, whether surgical or during active surveillance.