Predictive Value of Estimated Tumor Volume Measured by Ultrasonography for Occult Central Lymph Node Metastasis in Papillary Thyroid Carcinoma

Correlation between EpCAM expression and cervical lymph node metastasis in papillary thyroid carcinoma: a study integrating ultrasonographic features

OBJECTIVES

The epithelial cell adhesion molecule (EpCAM) is a transmembrane glycoprotein that is overexpressed in various epithelial tumors and has been associated with tumor aggressiveness and unfavorable prognosis. This study aimed to explore the association between ultrasonic characteristics and EpCAM expression in papillary thyroid carcinoma (PTC), as well as the value in predicting the risk of cervical lymph node metastasis (CLNM).

METHODS

Participants with suspected thyroid cancer underwent conventional and contrast-enhanced ultrasonography (CEUS) before surgery. Age, sex, and nodule features in ultrasound were recorded. Participants were classified based on the presence of CLNM. EpCAM expression was detected using immunohistochemistry. The risk predictors of CLNM were evaluated by using univariate and multivariate Cox model.

RESULTS

The final dataset included 53 participants, of whom 27(50.94%) had CLNM, while 26(49.06%) did not. The EpCAM-positive area (p < 0.001), score (p < 0.001), and nuclear expression (p = 0.027) were significantly different between the CLNM and non-CLNM groups. Receiver operating characteristic curve analysis showed that EpCAM score with 4.5 had sensitivity and specificity of 85.2% and 76.9%, respectively, for diagnosing CLNM. Multivariate logistic regression results showed that overexpression EpCAM (score ≧ 4.5) [OR:46.54, p = 0.007], tumor size ≧ 1.05 cm [OR:14.21,p = 0.01] and extrathyroidal extension (ETE) on CEUS [OR:113.33, p = 0.01] were independent risk factors of CLNM. Overexpression of EpCAM (62.07%, 18/29) correlated with ETE of PTC confirmed by postoperative pathology (p = 0.01, 0.027). No significant difference in PTC histological variants was detected based on EpCAM expression (p = 0.05).

CONCLUSIONS

EpCAM overexpression demonstrated a significant association with ETE and CLNM in PTC. The integration of ultrasonography with EpCAM expression profiling offers A promising multiparameter diagnostic model to enhance predictive accuracy. Further studies evaluating EpCAM expression in fine-needle aspiration biopsy (FNAB) samples are required to determine its possible preoperative predictive value.

Comparison of Tumor Diameter and Tumor Volume in Terms of Aggressive Tumor Behavior and Prognosis in Papillary Thyroid Cancer

BACKGROUND

Tumor diameter may not reflect tumor burden accurately in all cancers. In this study, we aimed to investigate the relationship between tumor volume (TV) and aggressive features and prognosis in papillary thyroid cancer (PTC).

METHODS

Patients diagnosed with single foci PTC were recruited for the study. The largest tumor diameter was considered as the primary tumor diameter. TV was calculated using the formula for an ellipsoid shape, considering the three pathologically specified dimensions. Primary tumor diameter and TV were compared in terms of aggressive tumor characteristics and prognosis.

RESULTS

The data of 118 patients were analyzed. There was no significant relationship between primary tumor diameter and lymph node metastasis (LNM), extrathyroidal extension (ETE), and vascular invasion (p > 0.05 for each). In patients with tumor diameter >2 cm, TV was negatively associated with LNM (p = 0.015). One-unit increase in TV was associated with 1.629 times greater likelihood of absence of LNM (95% CI: 1.099-2.415). When the TV was ≤5.26 cm3, the sensitivity and specificity for the presence of LNM were 88.9% and 75.8%, respectively. Again in this group, the sensitivity for the occurrence of ETE was 100.0% and specificity was 45.7% when the TV was ≤9.49 cm3. There was no significant difference in the five-year disease-free survival between tumor diameter and TV.

CONCLUSIONS

In contrary to studies with other cancer types in the literature, there was a significant but negative relationship between TV and LNM. Further large-scale studies are needed to determine whether TV can be used as a prognostic factor in PTC.

Predictive Values of Clinical Features and Multimodal Ultrasound for Central Lymph Node Metastases in Papillary Thyroid Carcinoma

Papillary thyroid carcinoma (PTC), the predominant pathological type among thyroid malignancies, is responsible for the sharp increase in thyroid cancer. Although PTC is an indolent tumor with good prognosis, 60-70% of patients still have early cervical lymph node metastasis, typically in the central compartment. Whether there is central lymph node metastasis (CLNM) or not directly affects the formulation of preoperative surgical procedures, given that such metastases have been tied to compromised overall survival and local recurrence. However, detecting CLNM before operation can be challenging due to the limited sensitivity of preoperative approaches. Prophylactic central lymph node dissection (PCLND) in the absence of clinical evidence of CLNM poses additional surgical risks. This study aims to provide a comprehensive review of the risk factors related to CLNM in PTC patients. A key focus is on utilizing multimodal ultrasound (US) for accurate prognosis of preoperative CLNM and to highlight the distinctive role of US-based characteristics for predicting CLNM.

A nomogram based on clinicopathological and ultrasound characteristics to predict central neck lymph node metastases in papillary thyroid cancer

Purpose

Papillary thyroid cancer (PTC) has grown rapidly in prevalence over the past few decades, and central neck lymph node metastasis (CNLNM) is associated with poor prognoses. However, whether to carry out preventive central neck lymph node dissection (CNLND) is still controversial. We aimed to construct a prediction model of CNLNM to facilitate making clinical surgical regimens.

Methods

A total of 691 patients with PTC between November 2018 and December 2021 were included in our study. Univariate and multivariate analyses were performed on basic information and clinicopathological characteristics, as well as ultrasound characteristics (American College of Radiology (ACR) scores). The prediction model was constructed and performed using a nomogram, and then discriminability, calibrations, and clinical applicability were evaluated.

Results

Five variables, namely, male, age >55 years, clinical lymph node positivity, tumor size ≥1 cm, and ACR scores ≥6, were independent predictors of CNLNM in the multivariate analysis, which were eventually included to construct a nomogram model. The area under the curve (AUC) of the model was 0.717, demonstrating great discriminability. A calibration curve was developed to validate the calibration of the present model by bootstrap resampling, which indicated that the predicted and actual values were in good agreement and had no differentiation from the ideal model. The decision curve analysis (DCA) indicated that the prediction model has good clinical applicability.

Conclusions

Our non-invasive prediction model combines ACR scores with clinicopathological features presented through nomogram and has shown good performance and application prospects for the prediction of CNLNM in PTCs.

Risk factors for recurrence of differentiated thyroid carcinoma in children and adolescents: A retrospective cohort study

This study aimed to provide a recent clinical evaluation of the outcome of treatment and the predictors of recurrence for Chinese children and adolescents with differentiated thyroid carcinoma (DTC). This is a retrospective cohort study at the Yunnan Cancer Hospital from May 2002 to August 2021. We analyzed several risk factors related to the recurrence of DTC in children and adolescents. The Chi-square test, Kaplan-Meier log-rank tests, and Cox regression analysis were used in the statistical analysis. A P-value <.05 was considered statistically significant. A total of 103 patients were enrolled, including 68 girls (66.0%) and 35 boys (34.0%) with a median age of 18 years (range: 7-20 years). All enrolled patients received standard treatment. Children (≤14years) tended to have multifocality and higher levels of thyroid imaging reporting and data system, higher pN stage, and higher American Thyroid Association (ATA) pediatric risk compared with adolescents (P < .05). The chief complaints and clinical treatment differed between children and adolescents. During a follow-up of 6 to 239 months (average 74.7 months, median 59 months), all patients survived, but recurrence occurred in 22 patients (22.4%). The disease-free survival rates at 1, 2, 5, and 10 years were 91.2%, 78.4%, 77.1%, and 77.1%, respectively. Univariate Cox regression and log-rank tests showed that positive preoperative thyroglobulin level, bilaterality, extrathyroidal extension, high pT/pN/pM stage, and high ATA pediatric risk were the risk factors for DTC recurrence in children and adolescents. Multivariate Cox regression found that extrathyroidal extension and ATA pediatric risk were independent risk factors for the recurrence of DTC in children and adolescents. Additionally, among the 38 cases with cN0 stage, one who had bilateral, and multifocal thyroid nodules experienced recurrence, while the remaining 37 cases with cN0 stage had no recurrence. In conclusion, compared with adolescents, children present with more highly malignant disease and are more prone to metastasis. The significant risk factors associated with the recurrence of DTC in children and adolescents were positive preoperative thyroglobulin level, bilaterality, high pT/pN/pM stage, extrathyroidal extension, and high ATA pediatric risk, with the latter 2 being independent risk factors. The surgical approach for cN0 patients should be personalized taking into account invasive features.

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.

Predictors of metastasis in cervical indeterminate lymph nodes after thyroid cancer ablation by long-term ultrasound follow-up

OBJECTIVES

To investigate the pattern of change over time and predictors for metastasis in indeterminate lymph nodes (LNs) among patients with thyroid cancer post-ablation.

METHODS

We enrolled patients who developed new cervical LNs after papillary thyroid carcinoma (PTC) ablation. Changes in the ultrasound characteristics of the indeterminate LN were recorded at months 1, 3, 6 and 12 after ablation. LN puncture pathology and long-term follow-up were standard of diagnosis. The indeterminate LNs were divided into benign and malignant groups, the differences between the two groups were compared, and the risk characteristics of malignant LNs were screened using generalized estimating equations (GEE).

RESULTS

In total, we included 138 LNs from 99 patients, of which 48 were indeterminate LNs. When following up indeterminate LNs, non-cervical lymph node metastasis (non-CLNM) lesions demonstrated a statistically significant gradual decrease in volume (p = 0.012), though there was no significant change in the volume of CLNM lesions (p = 0.779). Compared to non-CLNM lesions, the diagnostic efficiency was the highest for CLNM lesions at 1-3 months after ablation, when the LN volume changed by -0.08 to 0.12 mL (p = 0.048). The third month after ablation became an important time point for review. Moreover, GEE analysis showed that microcalcifications, cystic changes, and vascularity were strongly associated with CLNMs (p = 0.004, p = 0.002, and p = 0.010, respectively).

CONCLUSIONS

There is a pattern of volume change of indeterminate LNs after PTC ablation, which, together with microcalcifications, cystic changes, and vascularity, can be used as criteria for differentiating the benignity and malignancy of indeterminate LNs.

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.

Tumour volume is a predictor of lymphovascular invasion in differentiated small thyroid cancer

Objectives

For small thyroid cancers (≤2 cm), tumour volume may better predict aggressive disease, defined by lymphovascular invasion (LVI) than a traditional single measurement of diameter. We aimed to investigate the relationship between tumour diameter, volume and associated LVI.

Methods

Differentiated thyroid cancers (DTC) ≤ 2 cm surgically resected between 2007 and 2016 were analysed. Volume was calculated using the formula for an ellipsoid shape from pathological dimensions. A 'larger volume' cut-off was established by receiver operating characteristic (ROC) analysis using the presence of lateral cervical lymph node metastasis (N1b). Logistic regression was performed to compare the 'larger volume' cut-off to traditional measurements of diameter in the prediction.

Results

During the study period, 2405 DTCs were surgically treated and 523 met the inclusion criteria. The variance of tumour volume relative to diameter increased exponentially with increasing tumour size; the interquartile ranges for the volumes of 10, 15 and 20 mm diameter tumours were 126, 491 and 1225 mm^3, respectively. ROC analysis using volume to predict N1b disease established an optimal volume cut-off of 350 mm³ (area under curve = 0.59, P = 0.02) as 'larger volume'. 'Larger volume' DTC was an independent predictor for LVI in multivariate analysis (odds ratio (OR) = 1.7, P = 0.02), whereas tumour diameter > 1 cm was not (OR = 1.5, P = 0.13). Both the volume > 350 mm³ and dimension > 1 cm were associated with greater than five lymph node metastasis and extrathyroidal extension.

Conclusion

In this study for small DTCs ≤ 2 cm, the volume of >350 mm³ was a better predictor of LVI than greatest dimension > 1 cm.

Nomograms to predict ipsilateral and contralateral central lymph node metastasis in clinically lymph node-negative patients with solitary isthmic classic papillary thyroid carcinoma

BACKGROUND

Isthmus-originating papillary thyroid carcinoma has unique clinicopathological characteristics. There are no specific guidelines regarding the extent of surgery for isthmic papillary thyroid carcinoma. We aimed to evaluate the characteristics of clinically lymph node-negative patients with solitary isthmic papillary thyroid carcinoma and to determine the best surgical protocol for these patients.

METHODS

A total of 904 patients diagnosed with solitary papillary thyroid carcinoma who underwent surgery were retrospectively reviewed. These patients were divided into the isthmic group (246 patients) or lobar group (658 patients). We compared the 2 groups and conducted a multivariate analysis to assess risk factors for ipsilateral and contralateral central lymph node metastasis in isthmic papillary thyroid carcinoma patients. Nomograms for predicting central lymph node metastasis in isthmic papillary thyroid carcinoma patients were developed and internal calibration was performed for these models.

RESULTS

Isthmic papillary thyroid carcinoma patients have a significantly higher incidence of extrathyroidal extension and central lymph node metastasis than do lobar papillary thyroid carcinoma patients. For isthmic papillary thyroid carcinoma patients, sex, BRAF V600E mutation, chronic lymphocytic thyroiditis, tumor size, margin, and extrathyroidal extension were independent risk factors of ipsilateral central lymph node metastasis. Body mass index, BRAF V600E mutation, tumor size, location, and extrathyroidal extension were independent risk factors of contralateral central lymph node metastasis. All the above factors were incorporated into nomograms, which showed the perfect discriminative ability.

CONCLUSION

Based on the predictive nomograms, we proposed a risk stratification scheme and corresponding individualized surgical treatment based on different nomogram scores. In the debate about prophylactic central neck dissection among clinically lymph node-negative patients with solitary isthmic papillary thyroid carcinoma, our nomograms provide the balance to avoid overtreatment and undertreatment through personal risk assessment.

The impact of thyroid tumor features on lymph node metastasis in papillary thyroid carcinoma patients in head and neck department at KAMC: A retrospective cross-sectional study

Papillary thyroid carcinoma (PTC) is the most prevalent type of thyroid cancer. It is one of the most common types of malignancy of the thyroid that spreads to cervical lymph nodes. Lymph node metastasis (LNM) is an important factor when determining recurrence risk, and determining the extent of lymph node involvement can guide treatment. Our main objective is to evaluate the association between the size of the tumor and the number of lymph node metastases in patients with PTC. Methods: We conducted an electronic retrospective chart review of 125 patients with PTC followed in the Head and Neck Department at KAMC from 2009 to 2020. Twenty-two patients included in our study were pathologically and clinically diagnosed and confirmed to have LNM of PTC. Results: The study included 22 PTC patients who had undergone lymph node dissections. Patients had a median age of 38.8 years (IQR = 32.2–54.5), and the median tumor size was 20.5 mm. The most commonly affected level of the neck was IV (76.2%). Distant metastasis M1 was seen in only two patients (9.1%). Tumors sizes >30mm (75%) had ≥5 LNM. Most cases were the classic subtype PTC. For the site of the tumor, the site had a significant impact on the number of LNM (p = 0.004). Multifocality had a high impact on LNM (p = 0.019). Conclusions: This study showed no association between the size of PTC and the number of LNMs. The bilaterality of PTC was significantly associated with a high number of LNMs.

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Lymph nodes in level IV were the most common metastasis site for PTC.

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Bilateral and multifocal PTC were significantly associated with a higher number of lymph nodes metastasis.

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The size of the tumor was not significantly related to the number of lymph node metastasis.

Ultrasonographic Features, Nodule Size, Capsular Invasion, and Lymph Node Metastasis of Solitary Papillary Carcinoma of Thyroid Isthmus

Objective: This retrospective study aimed to analyze the ultrasound (US) imaging features of solitary papillary thyroid carcinoma (PTC) located in the isthmus and to assess the risk factors for lymph node metastasis (LNM) and tumor capsular invasion. Methods: We included a total of 135 patients with solitary PTC located in the isthmus. All the cases underwent US, total thyroidectomy, and prophylactic central lymph node dissection. Patients' demographic and thyroid isthmus nodules' US characteristics, as well as risk factors associated with LNM and tumor capsular invasion, were analyzed. Results: It was revealed that the occurrence of LNM was higher in male patients than in female patients (P < 0.001). As risk factors, the size of PTC in the isthmus was found to be associated with LNM and tumor capsular invasion (P = 0.005 and 0.000, respectively). The area under the receiver operating characteristic curve (AUC) of the size of the isthmus PTC was 0.64 [95% confidence interval (CI) = 0.55-0.72], indicating a probability for LNM. The AUC value for tumor capsular invasion was 0.77 (95% CI: 0.68-0.83). When the threshold was set to 1.1 cm, the larger size indicated that there was a probability of occurrence of LNM with sensitivity and specificity of 47.4 and 73.7%, respectively. When the threshold was set to 0.7 cm, the larger size indicated that there was potentially a tumor capsular invasion, with sensitivity and specificity of 80.6 and 56.3%, respectively. Wider-than-tall nodules were found to be significantly different from those in LNM and tumor capsular invasion (P = 0.038 and 0.030, respectively). There were significant differences in tumor capsular invasion in extrathyroidal extension (ETE) compared with smooth or ill-defined and lobulated or irregular nodules (P = 0.017). Conclusions: This study showed that the incidence of LNM in male patients was higher than that in female ones. When a US image shows a thyroid isthmus nodule with a wider-than-tall shape, LNM and tumor capsular invasion were likely to occur. When a US image shows a thyroid isthmus nodule with an ETE, tumor capsular invasion was likely to occur. ETE and wider-than-tall may be indicators of FNA under US guidance, even though the size of thyroid isthmus nodule may be <1 cm.

The relationship between central lymph node metastasis and the distance from tumor to thyroid capsule in papillary thyroid microcarcinoma without capsule invasion

Background

This study aims to explore the predictive factors of central lymph node metastasis (CLNM) in patients with papillary thyroid microcarcinoma (PTMC) without capsule invasion.

Methods

From January 2016 to October 2018, 1,622 patients with PTMC, who underwent surgical treatment at Zhejiang Cancer Hospital, were enrolled in the present study. A model of multivariate logistic regression was developed to find the variables that were independently associated with CLNM. The results were presented in the odds ratio (OR) with a 95% confidence interval (CI). The nomogram for predicting CLNM was developed based on the results of the multivariate logistic regression analysis. The distance (distance >0) from tumor to capsule is defined as the shortest distance from the tumor boundary to the capsule or trachea.

Results

The multivariate logistic regression analysis indicated that age, gender, tumor maximum diameter, tumor mean diameter, and tumor volume were independently associated with CLNM. In the 692 cases without capsular invasion, the distance from the capsule was not correlated to the CLNM. The joint model, which included age, gender, tumor volume, and capsular invasion, were analyzed using the ROC curve. The cut-off point for the prediction of CLNM was defined as a value of 0.208. The area under the ROC curve was 0.687, the sensitivity was 65.4%, and the specificity was 63.3%.

Conclusions

Gender, age, maximum diameter, mean diameter, tumor volume, and capsular invasion were independently associated with the CLNM. When there was no capsular invasion, the distance between the tumor and capsule was not correlated to the CLNM, suggesting that considering whether the tumor is close to the capsule may not be necessary for low-risk PTMC.

Diagnostic accuracy of single-source dual-energy computed tomography and ultrasonography for detection of lateral cervical lymph node metastases of papillary thyroid carcinoma

Background

Dual-energy computed tomography (DECT) imaging can generate iodine-based material decomposition (MD) images and spectral HU curve. This study aimed to investigate the diagnostic accuracy of single-source dual-energy CT (DECT) and ultrasonography (US) for detecting lateral cervical lymph node metastases of papillary thyroid carcinoma (PTC).

Methods

Thirty patients with PTC were enrolled in the study and underwent DECT and US examination before thyroidectomy and cervical lymph node dissection. The spectral parameters included iodine concentration (IC), normalized iodine concentration (NIC) and slope (λ_HU) of lymph nodes. The CT morphological parameters included maximal short diameter, shape, margin, calcification and cystic degeneration of lymph nodes. The US morphological parameters included maximal short diameter, calcification and cystic degeneration of lymph nodes. The diagnostic value of every single spectral parameter, combined gemstone spectral image (GSI) parameters, CT morphological parameters and US morphological parameters between metastatic and non-metastatic lymph nodes were statistically compared. Receiver operating characteristic (ROC) curves, sensitivity, and specificity were used to determine the diagnostic value.

Results

Ninety-nine lymph nodes from thirty patients were pathologically confirmed. Among them, 70 (70.7%) were metastatic. For single GSI parameters, ROC analysis showed that the area under the curve (AUC) for IC was the highest (AUC =0.937) but the difference was not statistically significant when compared with NIC or slope (λ_HU) (P>0.05). The optimal diagnostic threshold for IC was 2.56 mg/mL, with a sensitivity, specificity and accuracy of 87.1%, 93.1%, and 88.9%, respectively. The AUC for combined GSI parameter (AUC =0.942) was higher compared with the US morphological parameters (AUC =0.771, P<0.001), with a sensitivity, specificity, and accuracy of 92.9%, 86.2%, and 90.9%, respectively. However AUC did not differ significantly among combined GSI parameters, combined CT morphological parameters and a single application for spectral CT parameters IC (P>0.05).

Conclusions

Combined GSI parameters showed better diagnostic accuracy in lateral cervical lymph node metastasis of PTC compared with that of combined US morphological parameters. IC alone showed excellent diagnostic stability and could be performed easily.

A risk-based approach to identifying oligometastatic disease on imaging

Recognition of <3 metastases in <2 organs, particularly in cancers with a known predisposition to oligometastatic disease (OMD) (colorectal, prostate, renal, sarcoma and lung), offers the opportunity to focally treat the lesions identified and confers a survival advantage. The reliability with which OMD is identified depends on the sensitivity of the imaging technique used for detection and may be predicted from phenotypic and genetic factors of the primary tumour, which determine metastatic risk. Whole‐body or organ‐specific imaging to identify oligometastases requires optimization to achieve maximal sensitivity. Metastatic lesions at multiple locations may require a variety of imaging modalities for best visualisation because the optimal image contrast is determined by tumour biology. Newer imaging techniques used for this purpose require validation. Additionally, rationalisation of imaging strategies is needed, particularly with regard to timing of imaging and follow‐up studies. This article reviews the current evidence for the use of imaging for recognising OMD and proposes a risk‐based roadmap for identifying patients with true OMD, or at risk of metastatic disease likely to be OM.

Papillary thyroid carcinoma of the isthmus: Total thyroidectomy or isthmusectomy?

BACKGROUND

Papillary thyroid carcinoma (PTC) is the most common histological type of differentiated thyroid malignancy. Although the majority of PTC is located in the thyroid lobes, a small minority arise from the thyroid isthmus. The reported incidence of PTC arising in the thyroid isthmus ranges from 1% to 9.2%, probably reflecting variation in the study populations.

PURPOSE

This review aimed to analyze the data about the optimal management of PTC arising in the isthmus.

DATA SOURCES

We performed a systematic review of PubMed, MEDLINE, EMBASE, Scopus, and Cochrane Central Register of Controlled Trials to identify eligible studies analyzing surgical management strategies and published outcomes of isthmic PTC.

RESULTS

Most reports support that papillary thyroid carcinomas originating in the isthmus are more likely to have multiple foci, invasion of thyroid capsule and adjacent tissues with increased rate of central node involvement, compared to carcinomas located in other parts of the thyroid.

CONCLUSIONS

The extent of the surgical resection, the role of prophylactic central neck dissection and the extent of central neck dissection in surgery for isthmic PTC remain highly controversial. However, total thyroidectomy and central node dissection may be an appropriate treatment for these patients.

Lymph node metastasis characteristics of papillary thyroid carcinoma located in the isthmus: A single-center analysis

The frequency and pattern of lymph node metastasis and the extent of dissection for isthmic papillary thyroid carcinoma (PTC) remain unclear, and the aim of this present study was to evaluate these characteristics and to attempt to detect the best surgical protocol for isthmic PTCs. A total of 3185 consecutive patients with PTCs were reviewed. Of these patients, 47 with a single isthmic PTC were enrolled in our study, and matched 47 patients with a single PTC located in the unilateral lobe were randomly selected and added for comparison of their baseline tumor characteristics and lymph node metastasis characteristics. Univariate and multivariate analyses were performed to determine the risk factors for central lymph node metastasis in PTCs. The isthmic PTCs showed a higher rate of capsule invasion (P = .013) and advanced pathological N stage (P = .038) compared to the PTCs located in the lobe; meanwhile, pathological evidence of central lymph node metastasis (P = .040) was more frequent in the isthmic PTC group than in the control group. The univariate and multivariate analyses indicated that the tumors located in the isthmus (hazard ratio [HR]: 2.769; 95% confidence interval [CI]: 1.124-6.826; P = .027) and those with advanced (T2-4) pathological classifications (HR: 4.282; 95% CI: 1.224-14.976; P = .023) were independent risk factors for central lymph node metastasis in PTC patients. Due to the higher rate of pathological central lymph node metastasis and independent risk factors for central lymph node metastasis, total thyroidectomy, and bilateral central lymph node dissection should be considered the standard surgical protocol for isthmic PTCs.

The Prognostic Values of Preoperative Tumor Volume and Tumor Diameter in T1N0 Papillary Thyroid Cancer

Purpose

The current TNM staging system for papillary thyroid cancer (PTC), which is based on tumor diameter, may not precisely reflect the true tumor burden. Therefore, we investigated whether preoperative tumor volume might more accurately reflect tumor burden and predict prognosis in patients with T1N0 PTC than preoperative tumor diameter.

Materials and Methods

We retrospectively reviewed data from 1,659 patients with T1N0 PTC, and after exclusion, a total of 1,081 patients were ultimately included. Tumor volume (V) was calculated for all patients using preoperative ultrasonography, and patients were grouped according to tumor diameter (T1a vs. T1b) and tumor volume (V1a vs. V1b). The recurrence-free survival (RFS) rates were then compared for these groups.

Results

The mean follow-up time was 66.12±28.75 months, and 97.2% of the cohort experienced RFS. The optimal volume cut-off was defined as 0.545 cm³. There were no differences in RFS rates between T1a/T1b groups (all ages) and V1a/V1b groups (< 45 years of age). However, ≥ 45-year-old patients in the V1b group had a significantly poorer RFS rate than those in the V1a group. These results were confirmed by multivariate analysis.

Conclusion

Our results indicate that preoperative tumor volume may be more useful for predicting prognosis than tumor diameter in ≥ 45-year-old patients with T1N0 PTC.