Central Lymph Node Metastasis in Papillary Thyroid Carcinoma

Predicting central lymph node metastasis in papillary thyroid cancer: A nomogram based on clinical, ultrasound and contrast‑enhanced computed tomography characteristics

Central lymph node (CLN) status is considered to be an important risk factor in patients with papillary thyroid carcinoma (PTC). The aim of the present study was to identify risk factors associated with CLN metastasis (CLNM) for patients with PTC based on preoperative clinical, ultrasound (US) and contrast-enhanced computed tomography (CT) characteristics, and establish a prediction model for treatment plans. A total of 786 patients with a confirmed pathological diagnosis of PTC between January 2021 to December 2022 were included in the present retrospective study, with 550 patients included in the training group and 236 patients enrolled in the validation group (ratio of 7:3). Based on the preoperative clinical, US and contrast-enhanced CT features, univariate and multivariate logistic regression analyses were used to determine the independent predictive factors of CLNM, and a personalized nomogram was constructed. Calibration curve, receiver operating characteristic (ROC) curve and decision curve analyses were used to assess discrimination, calibration and clinical application of the prediction model. As a result, 38.9% (306/786) of patients with PTC and CLNM(-) status before surgery had confirmed CLNM using postoperative pathology. In multivariate analysis, a young age (≤45 years), the male sex, no presence of Hashimoto thyroiditis, isthmic location, microcalcification, inhomogeneous enhancement and capsule invasion were independent predictors of CLNM in patients with PTC. The nomogram integrating these 7 factors exhibited strong discrimination in both the training group [Area under the curve (AUC)=0.826] and the validation group (AUC=0.818). Furthermore, the area under the ROC curve for predicting CLNM based on clinical, US and contrast-enhanced CT features was higher than that without contrast-enhanced CT features (AUC=0.818 and AUC=0.712, respectively). In addition, the calibration curve was appropriately fitted and decision curve analysis confirmed the clinical utility of the nomogram. In conclusion, the present study developed a novel nomogram for preoperative prediction of CLNM, which could provide a basis for prophylactic central lymph node dissection in patients with PTC.

Risk Factors That Influence Surgical Decision-Making for Patients with Low-Risk Differentiated Thyroid Cancer with Tumor Diameters of 1-4 cm

Background

There are several controversies between thyroid lobectomy and total thyroidectomy for surgical management of low-risk differentiated thyroid cancer (DTC) with a tumor diameter of 1–4 cm.

Patients and Methods

In this study, we explore the factors related to selection of type of surgical procedure for 103 low-risk DTC patients with a tumor diameter of 1–4 cm.

Results

Among 103 low-risk DTC patients with tumor diameters of 1–4 cm, 43 patients underwent total thyroidectomy and 60 patients underwent thyroid lobectomy based on postoperative pathology. A ROC curve showed that the optimal diagnostic threshold for selecting surgical modality was a tumor diameter of 2.15 cm. For these low-risk DTC patients, the sensitivity and specificity for predicting thyroid lobectomy when tumor diameter <2.15 cm while total thyroidectomy when tumor diameter ≥2.15 cm are 46.5% and 78.3%, respectively. There were significant differences between the selection of type of surgical procedure in patient groups with 1) tumors with multiple foci group vs a single focus (P<0.05), and 2) tumor diameter of ≥2.15 cm vs <2.15 cm (P<0.05). There was no significant difference between gender and age groups (P>0.05). Multivariate analysis confirmed that tumors with multiple foci and diameter ≥2.15 cm were the primary risk factors for implementation of total thyroidectomy (P<0.05).

Conclusion

The diameter and multifocal nature of low-risk DTC tumors are the primary factors related to preferred surgical modality. This study revealed that thyroid lobectomy is more applicable to patients with tumor diameter <2.15 cm and a single focus, whereas, total thyroidectomy was preferred in patients with tumor diameter ≥2.15 cm and/or multiple foci.

Using Diffusion-Weighted MRI to Predict Central Lymph Node Metastasis in Papillary Thyroid Carcinoma: A Feasibility Study

Objective: To investigate whether diffusion-weighted imaging (DWI) with multi b values can be used as a quantitative assessment tool to predict central lymph node metastasis (CLNM) in papillary thyroid carcinoma (PTC). Method: A total of 214 PTC patients were enrolled from January 2015 to April 2018. Each patient underwent multi b value DWI (300, 500, and 800 s/mm²) preoperatively and then clinical treatment of central LN dissection at the Thyroid Surgery Department. These patients were divided as two groups based on with and without CLNM. The corresponding apparent diffusion coefficients (ADCs) were evaluated with separated b value, i.e., 300, 500, or 800 s/mm². Clinicopathological variables and ADC values were analyzed retrospectively by using univariate and binary logistic regression. The corresponding obtained variables with statistical significance were further applied to create a nomogram in which the bootstrap resampling method was used for correction. Results: PTCs with CLNM had significantly lower ADC₃₀₀, ADC₅₀₀, and ADC₈₀₀ values compared with PTCs without CLNM. Using receiver operating characteristic (ROC) analysis, the ADC₅₀₀ value (0.817) showed a higher area under the curve (AUC) than those of the ADC₃₀₀ and ADC₈₀₀ values (0.610 and 0.641, respectively) in differentiating patients with CLNM and without CLNM. The corresponding cutoff value for ADC₅₀₀ was also determined (1.444 × 10^-3 mm²/s), with respective sensitivity and specificity of 88.6 and 66%. The nomogram was generated by binary logistic regression results, incorporating four variables: gender, primary tumor size, extrathyroidal extension (ETE), and ADC₅₀₀ value. The AUC of the nomogram was 0.894 in predicting CLNM. Moreover, as shown in the calibration curve between nomogram and clinical findings, a strong agreement was observed in the prediction of CLNM. Conclusions: In summary, the ADC value is a valuable noninvasive imaging biomarker for evaluating CLNM in PTCs. The nomogram, as a clinical predictive model, is able to provide an effective evaluation of CLNM risk in PTC patients preoperatively.

Overexpression of SET and MYND Domain-Containing Protein 2 (SMYD2) Is Associated with Tumor Progression and Poor Prognosis in Patients with Papillary Thyroid Carcinoma

Backgrounds

SET and MYND domain-containing protein 2 (SMYD2), which is identified as a protein-lysine methyltransferase, plays a crucial role in the progression of some tumors such as bladder carcinoma. However, the clinical significance of SMYD2 in patients with papillary thyroid carcinoma (PTC) has not been elucidated. In the present study, we aimed to investigate the expression and role of SMYD2 in human PTC.

Material/Methods

Clinicopathological analysis was performed in 107 patients with PTC. Expression of SMYD2 was determined by immunohistochemistry staining, quantitative RT-PCR, or Western blotting in PTC tissues, adjacent normal tissues, and PTC cells (K1 and B-CPAP). The prognostic value of SMYD2 in PTC patients was assessed by univariate and multivariate analysis. Clinical outcomes were evaluated by Kaplan-Meier log-rank tests. Cell proliferation was examined in PTC cells following overexpression or knockdown of SMYD2.

Results

SMYD2 was highly expressed in PTC tissues compared to adjacent thyroid tissues. Additionally, high expression of SMYD2 was significantly related to tumor size, lymph node metastasis, and TNM stage. Moreover, SMYD2 was identified as an independent prognosis factor by multivariate analysis. Using 2 PTC cell lines, K1 and B-CPAP, we demonstrated that high expression of SMYD2 can promote tumor cell proliferation.

Conclusions

SMYD2 expression was upregulated in PTC tissues and significantly related to the poorer prognosis of PTC patients. Our studies suggested the potential role of SMYD2 as a new therapeutic target and prognostic biomarker in human PTC.

Reconsideration of tumor size threshold for total thyroidectomy in differentiated thyroid cancer

BACKGROUND

The optimal extent of surgery for differentiated thyroid cancer may not be well recognized initially. Identification of intermediate-risk features on surgical pathology may prompt the need for completion thyroidectomy if a lobectomy is performed. In this study, we examined the factors in relation to the need for completion thyroidectomy.

METHODS

We studied consecutive patients who underwent thyroidectomy for differentiated thyroid cancer from 2008 to 2017. Total thyroidectomy was indicated when tumor size >4 cm, clinical extrathyroidal extension, clinical lymph node metastasis, or distant metastasis was present. The need for completion thyroidectomy was defined as the presence of aggressive histology, extrathyroidal extension, lymphovascular invasion, or non-low-risk nodal metastasis.

RESULTS

Among 771 patients, 155 (20%) were definitely indicated for total thyroidectomy. The need for completion thyroidectomy was identified in 273 (44%) of the 616 patients initially eligible for lobectomy. The proportions of patients requiring completion thyroidectomy were 18% and 57% for microcarcinomas and tumors of 1-4 cm, respectively. Receiver operating characteristic curve analysis indicated that tumor size ≥1.1 cm had the highest accuracy of prediction. Multivariate logistic regression revealed that tumor size and BRAF V600E mutation were independent factors predicting the risk of requiring completion thyroidectomy.

CONCLUSION

A substantial portion of patients with differentiated thyroid cancer who are preoperatively eligible for lobectomy would be found to have intermediate-risk pathologic features. This should be incorporated into the shared decision making before surgery.