Predicting the factors associated with central lymph node metastasis in clinical node-negative (cN0) papillary thyroid microcarcinoma

The impact of age at diagnosis on central lymph node metastasis in clinically low-risk papillary thyroid microcarcinoma patients

BACKGROUND

Age is an independent risk factor for central lymph node metastasis (CLNM) in clinically negative lymph node (cN0) papillary thyroid microcarcinoma (PTMC) patients. The objective of this study was to investigate the impact of age on CLNM in clinically low-risk PTMC patients.

METHODS

A retrospective analysis was performed on patients with clinically low-risk PTMC who underwent surgery between January 2016 and December 2018. Logistic regression analysis was used to examine the impact of age on the risk of CLNM. The associations between age and pN1a and the lymph node ratio (LNR) were examined by a restricted cubic spline (RCS) curve with logistic regression models.

RESULTS

A total of 1352 patients (mean [range] age, 43[18-76] years; 325 males [24.0%]) were enrolled in this study. Logistic regression analysis revealed that age was a significant factor influencing the risk of CLNM (OR 0.95, 95% CI 0.94-0.96; p < 0.001). The RCS curve revealed a significant nonlinear association between age and pN1a status and the LNR. For patients under the age of 55, the risk of CLNM (OR 0.59, 95% CI 0.55-0.65, p < 0.001) and the LNR (beta - 0.23, 95% CI -0.27, -0.19, p < 0.001) significantly decreased as age increased. For patients aged ≥ 55 years, the risk of LNM (OR 1.03, 95% CI 0.81-1.32; p = 0.79) and the LNR (Beta - 0.03, 95% CI -0.07,0.13, p = 0.54) did not change with age.

CONCLUSIONS

This study confirmed that age was a significant factor influencing the risk and severity of CLNM in patients with low-risk PTMC. The risk and severity of LNM were lowest in patients aged ≥ 55 years.

Risk factors associated with lymph node metastasis in papillary thyroid cancer: a retrospective analysis based on 2,428 cases

Background

Papillary thyroid cancer (PTC) with lymph node metastasis (LNM) is associated with an increased risk of postoperative recurrence. Understanding the clinical characteristics of PTC patients can help surgeons assess the likelihood of LNM. This study aims to identify risk factors for LNM in PTC patients.

Methods

We retrospectively analyzed clinical data from 2,428 patients diagnosed with PTC who underwent initial thyroid surgery in our single center. Risk factors related to central lymph node metastasis (CLNM), lateral lymph node metastasis (LLNM), and skip metastasis were investigated by univariate and multivariate binary logistic regression analyses.

Results

Univariate analysis revealed that the following factors were associated with an increased likelihood of CLNM (P<0.05): male gender, age < 45 years, maximal axial diameter (MAD) > 1 cm, body mass index (BMI) ≥ 28 kg/m² and multifocality. Univariate analysis also revealed that patients with age < 45 years, MAD > 1 cm, BMI ≥ 28 kg/m², multifocality, and CLNM demonstrated a higher propensity for LLNM (P<0.05). Lower pole tumors were more likely to have CLNM than upper pole tumors, while upper pole tumors were more prone to present LLNM (P<0.05) and skip metastasis (P<0.05). Multivariable binary logistic regression analysis identified that gender (odds ratio [OR], 1.732; 95% CI, 2.113-2.577; P < 0.001), age (OR, 1.905; 95% CI, 1.596-2.273; P < 0.001), MAD (OR, 4.639; 95% CI, 3.639-5.913; P < 0.001), and multifocality (OR, 1.860; 95% CI, 1.453-2.381; P < 0.001) were independent risk factors for CLNM and MAD (OR, 5.289; 95% CI, 3.777-7.404; P<0.001), multifocality (OR, 1.858; 95% CI, 1.248-2.766; P=0.002), and CLNM (OR, 5.030; 95% CI, 3.347-7.561; P<0.001) for LLNM.

Conclusion

Despite the overall postoperative recurrence rate in PTC patients is low, identifying risk factors such as male gender, age < 45 years, MAD > 1 cm, multifocality, and CLNM can help predict LNM. In specific cases, selective lymphadenectomy in the central or lateral neck area may be warranted.

Can pre-operative ultrasound elastography predict aggressive features of solitary papillary thyroid carcinoma?

OBJECTIVE

To investigate whether pre-operative ultrasound elastography (USE) can be used to predict aggressive features of solitary papillary thyroid carcinomas (PTCs).

METHODS

Clinical and USE indices were retrospectively analyzed in 487 patients with surgically confirmed solitary PTCs. The patients were grouped per aggressive features on pathologic testing. Univariate and binary logistic regression analyses were performed to explore independent risk factors of aggressive features.

RESULTS

Univariate analysis revealed standard deviation (SD) values of the tumor shear-wave velocity (SWV) were associated with capsular invasion (p < 0.05). Further, shear-wave elasticity and SWV ratios correlated with extrathyroidal extension (all p < 0.05). The tumor shear-wave elasticity and SWV SD values were associated with cervical lymph node metastasis (CLNM) (all p < 0.05). Binary logistic regression analysis identified location and capsule contact as independent predictive risk factors for capsular invasion (all p < 0.05); size for extrathyroidal extension (all p < 0.05); and sex, age, margin, and suspected CLNM for CLNM (all p < 0.05). However, pre-operational USE indexes were not independent predictors of aggressive features (all p > 0.05).

CONCLUSION

Pre-operative USE indices were not independent risk factors of aggressive features of solitary PTCs. Thus, USE may have a limited value for predicting the aggressive features of PTC.

ADVANCES IN KNOWLEDGE

Pre-operative USE indices may have a limited value for predicting the aggressive features of PTC.

Prevalence of Occult Central Lymph Node Metastasis by Tumor Size in Papillary Thyroid Carcinoma: A Systematic Review and Meta-Analysis

BACKGROUND

While papillary thyroid carcinoma (PTC) is associated with high occult central neck metastasis (CNM) rates, prophylactic central neck dissection (pCND) is controversial. This meta-analysis aims to look at the occult CNM rate according to tumor size.

METHODS

A literature search was conducted in PubMed from inception to April 2023. Inclusion criteria were primary studies that determined occult CNM rates in cN0 PTC by tumor size. Heterogeneity, influential case diagnostics, and proportion data were evaluated with Cochran's Q-test, Baujat plots and Forest plots, respectively.

RESULTS

Fifty-two studies were included in this meta-analysis. The findings demonstrated an occult CNM rate of 30.3% for tumors ≤ 5 mm, 32.7% for tumors ≤ 1 cm, 46.0% for tumors between 1 and 2 cm, 43.1% for tumors between 2 and 4 cm, and 61.2% for tumors > 4 cm. The heterogeneity of each study group was high, though no publication bias was noted. While there was a trend towards increased occult CNM rates with larger tumors, comparisons between different size cutoffs varied in significance.

CONCLUSION

This comprehensive review affirms that occult CNM is high and that an ipsilateral pCND can be justified in all PTC patients for accurate differentiation between Stage I and Stage II disease and its clinical implications.

Correlation between Sonographic Features and Central Neck Lymph Node Metastasis in Solitary Solid Papillary Thyroid Microcarcinoma with a Taller-Than-Wide Shape

Purpose: This study aimed to investigate the correlation between sonographic features and central neck lymph node metastasis (CNLM) in solitary solid papillary thyroid microcarcinoma (PTMC) with a taller-than-wide shape. Methods: A total of 103 patients with solitary solid PTMC with a taller-than-wide shape on ultrasonography who underwent surgical histopathological examination were retrospectively selected. Based on the presence or absence of CNLM, patients with PTMC were divided into a CNLM (n = 45) or nonmetastatic (n = 58) group, respectively. Clinical findings and ultrasonographic features, including a suspicious thyroid capsule involvement sign (STCS, which is defined as PTMC abutment or a disrupted thyroid capsule), were compared between the two groups. Additionally, postoperative ultrasonography was performed to assess patients during the follow-up period. Results: Significant differences were observed in sex and the presence of STCS between the two groups (p < 0.05). The specificity and accuracy of the male sex for predicting CNLM were 86.21% (50/58 patients) and 64.08% (66/103 patients), respectively. The sensitivity, specificity, positive predictive value (PPV), and accuracy of STCS for predicting CNLM were 82.22% (37/45 patients), 70.69% (41/58 patients), 68.52% (37/54 patients), and 75.73% (78/103 patients), respectively. The specificity, PPV, and accuracy of the combination of sex and STCS for predicting CNLM were 96.55% (56/58 patients), 87.50% (14/16 patients), and 67.96% (70/103 patients), respectively. A total of 89 (86.4%) patients were followed up for a median of 4.6 years, with no patient having recurrence as detected on ultrasonography and pathological examination. Conclusions: STCS is a useful ultrasonographic feature for predicting CNLM in patients with solitary solid PTMC with a taller-than-wide shape, especially in male patients. Solitary solid PTMC with a taller-than-wide shape may have a good prognosis.

The risk of central nodal metastasis based on prognostic factors of the differentiated thyroid carcinoma: a systematic review and meta-analysis study

BACKGROUND AND AIM

Despite improving the 10-year disease-free-survival, prophylactic central neck dissection (pCND) in differentiated thyroid carcinoma (DTC) should only be considered in patients with high risk factors for lymph node (LN) metastasis due to the increases in the risk of postoperative complications. Our aim was to identify the risk factors for central lymph node metastasis (CLNM) in DTC.

METHOD

We searched PubMed, Scopus, Web of science, Cochrane library for eligible studies from inception to November 1, 2021 and a systematic review and meta-analysis were carried out to identify the risk factors for CLNM in DTC.

RESULTS

We included 41 studies with total of 27,741 patients in this study. The pooled results in this meta-analysis showed that these risk factors were significantly associated with CLNM: age < 45 years (odds ratio (OR) 1.64, 95% confidence interval (CI) 1.34-1.99, p < 0.00001), male sex (OR 1.73, 95% CI 1.54-1.93, p < 0.00001), multifocality (OR 1.87, 95% CI 1.59-2.19, p < 0.00001), bilateral disease (OR 1.43, 95% CI 1.15-1.78, p < 0.001), capsular invasion (OR 1.67, 95% CI 1.10-2.54, p < 0.02), lymphovascular invasion (OR 4.89, 95% CI 2.76-8.66, p < 0.00001) and extra-thyroidal extension (OR 2.43, 95% CI 1.97-3.00, p < 0.00001). In addition, young age (< 45 years), male sex, multifocality, and extra-thyroidal extension were significantly associated with large-volume CLNM in clinically N0 DTC patients. However, the presence of Hashimoto's thyroiditis was not a predictors of large-volume CLNM.

CONCLUSION

Young age (< 45 years), male sex, bilateral disease, multifocality, capsular invasion, lymphovascular invasion and extra-thyroidal extension are significantly associated with CLNM and pCND would be expected to have a higher yield in patients with these risk factors.

Preoperative strain ultrasound elastography can predict occult central cervical lymph node metastasis in papillary thyroid cancer: a single-center retrospective study

Objective

To determine whether preoperative ultrasound elastography can predict occult central cervical lymph node metastasis (CCLNM) in patients with papillary thyroid cancer.

Methods

This retrospective study included 541 papillary thyroid cancer patients with clinically negative lymph nodes prior to surgery between July 2019 and December 2021. Based on whether CCLNM was present on postoperative pathology, patients were categorized as CCLNM (+) or CCLNM (-). Preoperative clinical data, conventional ultrasound features, and ultrasound elastography indices were compared between the groups. Univariate and multivariate logistic regression analysis were performed to identify the independent predictors of occult CCLNM.

Results

A total of 36.60% (198/541) patients had confirmed CCLNM, while 63.40% (343/541) did not. Tumor location, bilaterality, multifocality, echogenicity, margin, shape, vascularity, capsule contact, extrathyroidal extension, aspect ratio, and shear wave elasticity parameters were comparable between the groups (all P > 0.05). Univariate analysis showed statistically significant differences between the two groups in age, sex, tumor size, calcification, capsule invasion, and strain rates ratio in strain ultrasound elastography (all P < 0.05). In multivariate logistic regression analysis, the independent predictors of occult CCLNM were age (OR = 0.975, 95% CI = 0.959-0.991, P = 0.002), sex (OR = 1.886, 95% CI = 1.220-2.915, P = 0.004), tumor size (OR = 1.054, 95% CI = 1.014-1.097, P = 0.008), and strain rates ratio (OR = 1.178, 95% CI = 1.065-1.304, P = 0.002).

Conclusion

Preoperative strain ultrasound elastography can predict presence of occult CCLNM in papillary thyroid cancer patients and help clinicians select the appropriate treatment strategy.

A novel tool for predicting the risk of central lymph node metastasis in patients with papillary thyroid microcarcinoma: a retrospective cohort study

Introduction

Central lymph node status in papillary thyroid microcarcinoma (PTMC) plays an important role in treatment decision-making clinically, however, it is not easy to predict central lymph node metastasis (CLNM). The present work focused on finding the more rational alternative for evaluating central lymph node status while identifying influencing factors to construct a model to predict CLNM incidence.

Methods

In this study, we retrospectively analyzed the typical sonographic and clinicopathologic features of 546 PTMC patients who underwent surgery, among which, the data of 382 patients were recruited in the training cohort and that of 164 patients in the validation cohort. Based on the outcome of the training cohort, significant influencing factors were further identified through univariate analysis and were considered as independent variables in multivariable logistic regression analysis and incorporated in and presented with a nomogram.

Results

In total, six independent predictors, including the age, sex, tumor size, multifocality, capsular invasion, Hashimotos thyroiditis were entered into the nomogram. Both internal validation and external validation revealed the favorable discrimination of our as-constructed nomogram. Calibration curves exhibited high consistency. As suggested by decision-curve analyses, the as-constructed nomogram might be applied in clinic. Besides, the model also distinguished patients according to risk stratification.

Conclusions

The novel nomogram containing remarkable influencing factors for CLNM cases was established in the present work. The nomogram can assist clinicians in clinical decision-making.

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

Background

The presence of central lymph node metastases (CLNM) has been suggested as a risk factor for poorer prognosis and recurrence in papillary thyroid microcarcinoma (PTMC). However, the clinicopathologic factors for CLNM in clinical node-negative (CN0) PTMC were not well defined. This study aimed to perform a systematic review and meta-analysis to investigate the significant clinicopathologic predictors of CLNM in CN0 PTMC.

Methods

A systematic literature search was performed in PubMed, Embase, Cochrane Library, and Web of Science. Case-control studies on the association of clinicopathologic risk factors with CLNM in CN0 PTMC were included.

Results

Thirteen eligible studies involving 6068 patients with CN0 PTMC were included. From the pooled analyses, male (odds ratio [OR]: 2.07, 95% CI: 1.49–2.87, P < 0.001), multifocality (OR: 1.88, 95% CI: 1.54–2.29, P < 0.001), tumor size > 5 mm (OR: 1.84, 95% CI: 1.55–2.18, P < 0.001), and extrathyroidal extension (OR: 1.96, 95% CI: 1.30–2.95, P = 0.001) are significantly associated with increased risk of CLNM in CN0 PTMC. A sample size with a cutoff point of 200 was identified as the source of heterogeneity for sex according to meta-regression (t = 3.18, P = 0.033). Then, the subgroup analysis of male was performed, which illustrated that male increased the risk of CLNM in the small sample group (SG) and the large sample group (LG) by 6.11-folds and 2.01-folds, respectively (SG: OR, 6.11, 95% CI, 3.16–11.81, P < 0.001; LG: OR, 2.01, 95% CI, 1.65–2.46, P < 0.001).

Conclusions

Male, multifocality, tumor size > 5 mm, and extrathyroidal extension may be reliable clinical predictors of CLNM in CN0 PTMC. Moreover, prophylactic central lymph node dissection should be considered in surgical decision-making for CN0 PTMC patients, who are male, multifocal, with tumor size > 5 mm, and with extrathyroidal extension.

Trial registration

CRD42021242211 (PROSPERO)

Supplementary Information

The online version contains supplementary material available at 10.1186/s12957-022-02573-7.

A Nomogram Based on Clinicopathological and Ultrasound Imaging Characteristics for Predicting Cervical Lymph Node Metastasis in cN0 Unilateral Papillary Thyroid Microcarcinoma

Objective: The aim of this study was to establish a practical nomogram for preoperatively predicting the possibility of cervical lymph node metastasis (CLNM) based on clinicopathological and ultrasound (US) imaging characteristics in patients with clinically node-negative (cN0) unilateral papillary thyroid microcarcinoma (PTMC) in order to determine a personal surgical volume and therapeutic strategy. Methods: A total of 269 consecutive patients diagnosed with cN0 unilateral PTMC by postoperative pathological examination from January 2018 to December 2020 were retrospectively analyzed. All the patients underwent lobectomy or thyroidectomy with routine prophylactic central lymph node dissection (CLND) and were divided into a CLNM group and a non-CLNM group. Using logistic regression, the least absolute shrinkage and selection operator (LASSO) regression analysis was applied to determine the risk factors for CLNM in patients with unilateral cN0 PTMC. A nomogram including risk-factor screening using LASSO regression for predicting the CLNM in patients with cN0 unilateral PTMC was further developed and validated. Results: Risk factors identified by LASSO regression, including age, sex, tumor size, presence of extrathyroidal extension (ETE), tumor diameter/lobe thickness (D/T), tumor location, and coexistent benign lesions, were potential predictors for CLNM in patients with cN0 unilateral PTMC. Meanwhile, age (odds ratio [OR] = 0.261, 95% CI.104-0.605; P = 0.003), sex (men: OR = 3.866; 95% CI 1.758-8.880; P < 0.001), ETE (OR = 3.821; 95% CI 1.168-13.861; P = 0.032), D/T (OR = 72.411; 95% CI 5.483-1212.497; P < 0.001), and coexistent benign lesions (OR = 3.112 95% CI 1.407-7.303; P = 0.007) were shown to be significantly related to CLNM by multivariant logistic regression. A nomogram for predicting CLNM in patients with cN0 unilateral PTMC was established based on the risk factors identified by the LASSO regression analysis. The receiver operating characteristic (ROC) curve for predicting CLNM by nomogram showed that the area under the curve (AUC) was 0.777 and exhibited an excellent consistency. Conclusions: A nomogram based on clinical and US imaging characteristics for predicting the probability of CLNM in patients with cN0 unilateral PTMC was developed, which showed a favorable predictive value and consistency. Further prospective research to observe the oncological outcomes is necessary to determine whether the nomogram could potentially guide a personalized surgical volume and surgical approach.

Influencing Factors and Cumulative Risk Analysis of Cervical Lymph Node Metastasis of Papillary Thyroid Microcarcinoma

Objective

To explore the influencing factors and cumulative risk of lymph node metastasis (LNM) in papillary thyroid microcarcinoma (PTMC) patients.

Methods

607 patients confirmed PTMC pathologically after thyroidectomy were enrolled in this retrospective study. The rate of LNM was calculated. Different clinicopathological characteristics were compared in PTMC patients with and without LNM and in different subgroups of LNM, respectively. Correlation between clinicopathological characteristics and LNM was analyzed and the cumulative risk of LNM according to different clinicopathological characteristics was calculated.

Results

(1) There were 228 cases (37.56%) of PTMC combined with LNM. Compared with the non-lymph node metastasis group, the proportion of age <55 years, male, multiple foci, bilateral foci, diameter>0.5cm, extracapsular invasion, HT and intermediate-to-high risk stratification for recurrence of the LNM group was significantly increased (all p<0.05);(2) Multivariate logistic regression analysis showed that age <55years, male, multiple foci, diameter>0.5cm,HT were independently positively correlated with LNM (all p <0.05); (3) Subgroup analysis showed that women aged <55 years combined with HT and aged≥55 years combined with BMI≥25 kg/m² were independently positively associated with LNM; (4) With the increase of the tumor diameter, the cumulative risk of LNM in group of age <55 years, males, and multiple foci increased gradually, and was higher than those of age≥55 years, females and single foci, respectively. (5) Among the 228 cases of LNM, the proportion of lymph nodes (LN) >5 and the positive rate of LN were both higher in male group than that in the female group. The proportion of multiple foci and HT in LLNM group was higher than that in CLNM group (all P<0.05).

Conclusion

Age <55 years, males, multiple foci, diameter >0.5cm and HT were independent risk factors of LNM; HT was an independent risk factor for LNM in female <55 years old, and BMI≥25 kg/m² was an independent risk factor for LNM in female ≥55 years old; The increase of tumor diameter in age <55 years, males, multiple foci, and bilateral foci increased the cumulative risk of LNM, respectively; The number of LNM and the positive rate of LNM were both higher in male, and patients with multiple foci or HT were more likely to develop into LLNM.

Reevaluation of Criteria and Establishment of Models for Total Thyroidectomy in Differentiated Thyroid Cancer

Introduction

After the publication of the 2015 American Thyroid Association (ATA) guidelines, the indication for total thyroidectomy (TT) was reported to be underestimated before surgery, which may lead to a substantial rate of secondary completion thyroidectomy (CTx).

Methods and Materials

We retrospectively analyzed differentiated thyroid cancer patients from Wuhan Union Hospital (WHUH). Univariate analysis was performed to evaluate all preoperative and intraoperative factors. New models were picked out by comminating and arranging all significant factors and were compared with ATA and National Comprehensive Cancer Network (NCCN) guidelines in the multicenter prospective Differentiated Thyroid Cancer in China (DTCC) cohort.

Results

A total of 5,331 patients from WHUH were included. Pre- and intraoperative criteria individually identified 906 (17.0%) and 213 (4.0%) patients eligible for TT. Among all factors, age <35 years old, clinical N1, and ultrasound reported local invasion had high positive predictive value to predict patients who should undergo TT. Accordingly, we established two new models that minorly revised ATA guidelines but performed much better. Model 1 replaced “nodule size >4 cm” with “age <35 years old” and achieved significant increase in the sensitivity (WHUH, 0.711 vs. 0.484; DTCC, 0.675 vs. 0.351). Model 2 simultaneously demands the presence of “nodule size >4 cm” and “age <35 years old,” which had a significant increase in the specificity (WHUH, 0.905 vs. 0.818; DTCC, 0.729 vs. 0.643).

Conclusion

All high-risk factors had limited predictive ability. Our model added young age as a new criterion for total thyroidectomy to get a higher diagnostic value than the guidelines.

Diagnostic Performance of Neck Ultrasonography in the Preoperative Evaluation for Extrathyroidal Extension of Suspicious Thyroid Nodules

BACKGROUND

A preoperative neck ultrasound (US) is recommended for all patients with suspected thyroid cancer, to identify features potentially changing surgical extent. The extrathyroidal extension (ETE) is considered an indication for total thyroidectomy, but there is limited consensus on its US definition, and the interobserver reliability is low. This study aimed to evaluate the predictive value of neck US for ETE before surgery and to estimate the diagnostic performance of different US findings, evaluated during real-time examinations.

METHODS

Patients referred to surgery between November 1, 2015, and May 31, 2019, for a suspicious thyroid cancer underwent a preoperative neck US, with systematic assessment for ETE. Three definitions were tested: very restrictive (capsular disruption with suspicious images of surrounding tissues invasion), restrictive (including also capsular abutment with evidence of capsular disruption), and nonrestrictive (capsular abutment is sufficient). Histopathology report of ETE involving at least soft tissues was considered positive. Sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) were calculated.

RESULTS

The study cohort included 128 patients, with 102 (79.7%) confirmed malignancies, and 44 (43.1%) histological ETE. The nonrestrictive definition had good sensitivity (86.4%) but low specificity (29.8%), with an NPV of 80.6%; the restrictive definition had higher specificity (81%), while the very restrictive had specificity and PPV of 100%.

CONCLUSIONS

A more extensive surgical approach should not be based on US suspicion of ETE alone, with the possible exception of gross invasion appearance. The absence of any sign of ETE, on the other hand, has a substantial negative predictive value.

Web-Based Ultrasonic Nomogram Predicts Preoperative Central Lymph Node Metastasis of cN0 Papillary Thyroid Microcarcinoma

BACKGROUND

Many clinicians are facing the dilemma about whether they should apply the active surveillance (AS) strategy for managing Clinically Node-negative (cN0) PTMC patients in daily clinical practice. This research plans to construct a dynamic nomogram based on network, connected with ultrasound characteristics and clinical data, to predict the risk of central lymph node metastasis (CLNM) in cN0 PTMC patients before surgery.

METHODS

A retrospective analysis of 659 patients with cN0 PTMC who had underwent thyroid surgery and central compartment neck dissection. Patients were randomly (2:1) divided into the development cohort (439 patients) and validation cohort (220 patients). The group least absolute shrinkage and selection operator (Group Lasso) regression method was used to select the ultrasonic features for CLNM prediction in the development cohort. These features and clinical data were screened by the multivariable regression analysis, and the CLNM prediction model and web-based calculator were established. Receiver operating characteristic, calibration curve, Clinical impact curve and decision curve analysis (DCA) were used to weigh the performance of the prediction model in the validation set.

RESULTS

Multivariable regression analysis showed that age, tumor size, multifocality, the number of contact surface, and real-time elastography were risk factors that could predict CLNM. The area under the curve of the prediction model in the development and validation sets were 0.78 and 0.77, respectively, with good discrimination and calibration. A web-based dynamic calculator was built. DCA proved that the prediction model had excellent net benefits and clinical practicability.

CONCLUSIONS

The web-based dynamic nomogram incorporating US and clinical features was able to forecast the risk of preoperative CLNM in cN0 PTMC patients, and has good predictive performance. As a new observational indicator, NCS can provide additional predictive information.

Nomogram for Preoperative Estimation of Cervical Lymph Node Metastasis Risk in Papillary Thyroid Microcarcinoma

OBJECTIVE

Accurate preoperative identification of cervical lymph node metastasis (CLNM) is essential for clinical management and established of different surgical protocol for patients with papillary thyroid microcarcinoma (PTMC). Herein, we aimed to develop an ultrasound (US) features and clinical characteristics-based nomogram for preoperative diagnosis of CLNM for PTMC.

METHOD

Our study included 552 patients who were pathologically diagnosed with PTMC between January 2015 and June 2019. All patients underwent total thyroidectomy or lobectomy and divided into two groups: CLNM and non-CLNM. Univariate and multivariate analysis were performed to examine risk factors associated with CLNM. A nomogram comprising the prognostic model to predict the CLNM was established, and internal validation in the cohort was performed.

RESULTS

CLNM and non-CLNM were observed in 216(39.1%) and 336(60.9%) cases, respectively. Seven variables of clinical and US features as potential predictors including male sex (odd ratio [OR] = 1.974, 95% confidence interval [CI], 1.243-2.774; P =0.004), age < 45 years (OR = 4.621, 95% CI, 2.160-9.347; P < 0.001), US-reported CLN status (OR = 1.894, 95% CI, 0.754-3.347; P =0.005), multifocality (OR = 1.793, 95% CI, 0.774-2.649; P =0.007), tumor size ≥ 0.6cm (OR = 1.731, 95% CI,0.793-3.852; P =0.018), ETE (OR = 3.772, 95% CI, 1.752-8.441;P< 0.001) and microcalcification (OR = 2.316, 95% CI, 1.099-4.964; P < 0.001) were taken into account. The predictive nomogram was established by involving all the factors above used for preoperative prediction of CLNM in patients with PTCM. The nomogram model showed an AUC of 0.839 and an accuracy of 77.9% in predicting CLNM. Furthermore, the calibration curve demonstrated a strong consistency between nomogram and clinical findings in prediction CLNM for PTMC.

CONCLUSIONS

The nomogram achieved promising results for predicting preoperative CLNM in PTMC by combining clinical and US risk factor. Our proposed prediction model is able to help determine an individual's risk of CLNM in PTMC, thus facilitate reasonable therapy decision making.