Machine learning algorithms for identifying contralateral central lymph node metastasis in unilateral cN0 papillary thyroid cancer

Purpose

The incidence of thyroid cancer is growing fast and surgery is the most significant treatment of it. For patients with unilateral cN0 papillary thyroid cancer whether to dissect contralateral central lymph node is still under debating. Here, we aim to provide a machine learning based prediction model of contralateral central lymph node metastasis using demographic and clinical data.

Methods

2225 patients with unilateral cN0 papillary thyroid cancer from Wuhan Union Hospital were retrospectively studied. Clinical and pathological features were compared between patients with contralateral central lymph node metastasis and without. Six machine learning models were constructed based on these patients and compared using accuracy, sensitivity, specificity, area under the receiver operating characteristic and decision curve analysis. The selected models were then verified using data from Differentiated Thyroid Cancer in China study. All statistical analysis and model construction were performed by R software.

Results

Male, maximum diameter larger than 1cm, multifocality, ipsilateral central lymph node metastasis and younger than 50 years were independent risk factors of contralateral central lymph node metastasis. Random forest model performed better than others, and were verified in external validation cohort. A web calculator was constructed.

Conclusions

Gender, maximum diameter, multifocality, ipsilateral central lymph node metastasis and age should be considered for contralateral central lymph node dissection. The web calculator based on random forest model may be helpful in clinical decision.

Cervical lymph node metastasis prediction from papillary thyroid carcinoma US videos: a prospective multicenter study

BACKGROUND

Prediction of lymph node metastasis (LNM) is critical for individualized management of papillary thyroid carcinoma (PTC) patients to avoid unnecessary overtreatment as well as undesired under-treatment. Artificial intelligence (AI) trained by thyroid ultrasound (US) may improve prediction performance.

METHODS

From September 2017 to December 2018, patients with suspicious PTC from the first medical center of the Chinese PLA general hospital were retrospectively enrolled to pre-train the multi-scale, multi-frame, and dual-direction deep learning (MMD-DL) model. From January 2019 to July 2021, PTC patients from four different centers were prospectively enrolled to fine-tune and independently validate MMD-DL. Its diagnostic performance and auxiliary effect on radiologists were analyzed in terms of receiver operating characteristic (ROC) curves, areas under the ROC curve (AUC), accuracy, sensitivity, and specificity.

RESULTS

In total, 488 PTC patients were enrolled in the pre-training cohort, and 218 PTC patients were included for model fine-tuning (n = 109), internal test (n = 39), and external validation (n = 70). Diagnostic performances of MMD-DL achieved AUCs of 0.85 (95% CI: 0.73, 0.97) and 0.81 (95% CI: 0.73, 0.89) in the test and validation cohorts, respectively, and US radiologists significantly improved their average diagnostic accuracy (57% vs. 60%, P = 0.001) and sensitivity (62% vs. 65%, P < 0.001) by using the AI model for assistance.

CONCLUSIONS

The AI model using US videos can provide accurate and reproducible prediction of cervical lymph node metastasis in papillary thyroid carcinoma patients preoperatively, and it can be used as an effective assisting tool to improve diagnostic performance of US radiologists.

TRIAL REGISTRATION

We registered on the Chinese Clinical Trial Registry website with the number ChiCTR1900025592.

Disease-free survival and response to therapy of clinically node- negative Papillary Thyroid Cancer treated without central neck dissection: Retrospective study of 321 patients

BACKGROUND AND OBJECTIVE

Nodal metastases in the central compartment are frequent in papillary thyroid cancer (PTC). However, they are mostly micrometastases with no impact on survival and their relevance on the risk of locoregional relapse is controversial. There is no consensus regarding optimal management of the central neck in patients with PTC cN0. In our center, we do not perform prophylactic central neck dissection (pCND). The objective of this study is to review our long-term results and compare them with the most recent literature.

PATIENTS AND METHODS

Retrospective review of patients with PTC who underwent total thyroidectomy (TT) without CND between 2005 and 2017. Primary result was disease-free survival in the neck (DFS).

RESULTS

321 patients were identified, mostly T1-T2 tumors (94.1%). Median follow-up was 90 months. DFS in the central compartment was excellent (96.1% at 10 year's follow-up). 19 patients had cervical recurrence, of which 15 underwent salvage surgery. On their last visit, including salvage surgery when appropriate, 77% of patients had excellent response, 18.7% had indeterminate response, 3.1% had biochemically incomplete response and 1.2% had morphologically incomplete response. Recurrent laryngeal nerve (RLN) paralysis after TT was transient in 4.7% of patients and permanent in 0.9% of patients. There were no RLN paralysis after salvage surgery. Permanent hypoparathyroidism occurred in 3.4% of patients. Only one patient had hypoparathyroidism after salvage surgery and it was permanent.

CONCLUSIONS

Based on long-term results and low rate of complications associated with salvage surgery in our experience, we consider routine pCND is not justified.

Impact of prophylactic central lymph node dissection on the complications and recurrence rates in papillary thyroid carcinoma-An AFCE (French-speaking Association of Endocrine Surgery) multicentre study based on the EUROCRINE® national data

BACKGROUND

Prophylactic central neck dissection (pCND) remains controversial during the initial surgery for preoperative and intraoperative node-negative (cN0) papillary thyroid carcinoma (PTC).

METHODS

Patients undergoing thyroidectomy with or without pCND (Nx) for PTC in nine French surgical departments, registered in the EUROCRINE® national data in France between January 2015 and June 2021, were included in a cohort study. Demographic and clinicopathological characteristics, complications, and recurrence rates were compared using multivariate regression analysis.

RESULTS

A total of 1905 patients with cN0 PTC were enrolled, including 1534 who had undergone pCND and 371 who hadn't (Nx). Of these, 1546 (81.2%) were female, and the median age was 49 years (range: 15-89 years). Patients who had undergone pCND were more likely to have multifocal tumors (n = 524 [34.2%] vs. n = 68 [18.3%], p < .001) and larger tumors (15.3 vs. 10.2 mm, p = .01) than patients with Nx. Of the patients with pCND, 553 (36%) had positive central LN (N1a), with a median of 1 N1 (IQR 0-5). pCND was associated with a higher temporary hypocalcemia rate (n = 25 [8%] vs. n = 15 [4%], p < .001). The rates of permanent hypocalcemia and temporary and permanent recurrent laryngeal nerve (RLN) palsy were not significantly different between the two groups (p > .2). After adjusting for covariates (age, sex, multifocality, and pathological T stage) in a multivariable Cox PH model, the performance of lymph node dissection (pCND vs. no-pCND) was not associated with PTC recurrence (p = .2).

CONCLUSION

pCND in PTC does not reduce recurrence and is associated with a two-fold increase in the incidence of transient hypoparathyroidism. These data should be considered while issuing further guidelines regarding the treatment of patients with cN0 PTC.

Intraoperative pathologic evaluation of central compartment lymph nodes in patients undergoing lobectomy for unilateral papillary thyroid carcinoma

BACKGROUND/OBJECTIVE

Although papillary thyroid carcinoma (PTC) has an excellent prognosis, it can cause central lymph node metastasis (CLNM) which can increase local recurrence. Intraoperative pathologic evaluation (IOPE) can provide evidence regarding CLNM and help surgeons determine the appropriate surgical approach. The aim of this study was to evaluate the efficacy of IOPE and to determine risk factors associated with CLNM in unilateral PTC without preoperative clinical evidence of CLNM.

METHODS

Medical charts of 227 patients who had unilateral PTC without clinical lymph node metastasis preoperatively were reviewed retrospectively. They were scheduled for thyroid lobectomy and prophylactic central lymphadenectomy (CND) from January 1, 2017 to December 31, 2017.

RESULTS

Total follow-up period was 47.6 ± 10.6 months. CLNM was identified in 57 (25.1%) patients during IOPE and in 72 (31.7%) patients during final pathological analysis. The sensitivity and specificity of IOPE were 76.4% and 98.7%, respectively. IOPE through central lymph node dissection was safely performed with low complications (vocal cord palsy, 5.7%; hypoparathyroidism, 22.8%). Age < 55 years, echogenic foci on preoperative ultrasonography, and extrathyroidal extension at final pathological report were significantly associated with an increased risk of CLNM (p = 0.006, p < 0.001, and p < 0.001, respectively). In terms of oncological outcomes, there was no significant difference between the true negative and false negative results in IOPE.

CONCLUSION

IOPE can safely provide accurate information for determining disease status and surgical extent. Further long-term studies are needed to evaluate clinical benefits of IOPE.

Long-term impact of prophylactic central neck dissection in non-invasive classic papillary thyroid carcinoma

BACKGROUND

The utilization of prophylactic central neck dissection (pCND) in cases of non-invasive clinical node-negative (cN0) papillary thyroid carcinoma (PTC) remains a topic of debate, with a dearth of long-term evidence.

MATERIALS AND METHODS

We retrospectively reviewed 1181 cN0 PTC patients from 1997 to 2011. Of these, 641 underwent pCND (pCND + group) and 540 did not (pCND-group). Propensity score matching (PSM) was used to identify similar patients. Event-free survival and long-term complications including permanent hyperparathyroidism and permanent recurrent laryngeal nerve (RLN) paralysis were analyzed after PSM.

RESULTS

The pCND + group had more aggressive characteristics. In the matched cohort after PSM, the 5-year, 10-year, and 15-year EFS rates were 98.9 %, 98.2 %, and 97.1 % for the pCND + group, and 97.7 %, 97.1 %, and 97.1 % for the pCND-group, respectively. There was no statistically significant difference in EFS rates between the two groups (Log Rank P = 0.38). There was no statistically significant difference in the incidence of permanent hyperparathyroidism (3.3 % vs. 1.5 %, P = 0.08) and permanent RLN paralysis (1.7 % vs. 0.9 %, P = 0.13) between the pCND+ and pCND- groups.

CONCLUSION

Our study, with a median follow-up duration of 107 months, indicates that pCND does not lead to a significant reduction in nodal recurrence among non-invasive cN0 PTC patients.

Optimal range of lymph node dissection in patients with unilateral papillary thyroid carcinoma with lateral cervical lymph node metastasis

Background

Whether patients with unilateral papillary thyroid carcinoma (PTC) with lateral cervical lymph node metastasis (LLNM) require prophylactic central regional lymph node dissection (CLND) remains unclear. Herein, we investigated the independent risk factors associated with contralateral central lymph node metastasis (cCLNM) in unilateral PTC with LLNM and analyzed the optimal extent of lymph node dissection by comparing the 5-year recurrence-free survival rates.

Materials and methods

We retrospectively analyzed 695 patients with unilateral papillary thyroid carcinoma and lateral cervical lymph node metastasis. Factors including sex, age, multifocal, location of primary tumor, tumor diameter, capsule invasion, thyroid nodular goiter, Hashimoto thyroiditis, ipsilateral central lymph node metastasis(iCLNM), and lateral cervical lymph node metastasis were analyzed using univariate and multivariate logistic regression analyses to explore the independent risk factors of cCLNM. Propensity scores were matched to compare the 5-year recurrence-free survival rates in patients divided by different lymph node metastases and dissections.

Results

Of all patients who underwent bilateral (b)CLND, 52% (149/286) had cCLNM. Receiver operating characteristic (ROC) curve analysis was performed on 286 patients who underwent bCLND, for which a tumor diameter of 20.5 mm and number of LLNM of 3.5 were used as the thresholds for predicting cCLNM. The 5-year recurrence-free survival (RFS) rates in the cCLN-negative and cCLN-positive groups were 98.6% and 91.2%, with statistically significant differences (P=0.034). The 5-year RFS rates showed no significant difference between the ipsilateral (i)CLND and bCLND groups (P=0.235). Multifactorial regression analysis showed that tumor diameter >2 cm, presence of iCLNM, and number of LLNM >3 were independent risk factors of cCLNM.But male sex, young age (<45 years), multifocality, location of primary tumor, capsule invasion, thyroid nodular goiter, and Hashimoto thyroiditis were not associated with cCLNM.

Conclusion

Not all unilateral PTC with LLNM require prophylactic cCLND; however, prophylactic cCLND is necessary in cases which display high-risk factors for cCLNM, including primary diameter >2 cm, iCLNM, and number of LLNM >3.

Role of computed tomography in the evaluation of regional metastasis in well-differentiated thyroid cancer

Background

Accurate neck staging is essential for performing appropriate surgery and avoiding undue morbidity in thyroid cancer. The modality of choice for evaluation is ultrasonography (US), which has limitations, particularly in the central compartment, that can be overcome by adding a computed tomography (CT).

Methods

A total of 314 nodal levels were analyzed in 43 patients with CT, and US; evaluations were done between January 2013 and November 2015. The images were reviewed by two radiologists independently who were blinded to histopathological outcomes. The sensitivity, specificity, negative predictive value (NPV), positive predictive value (PPV), and accuracy of US, CT, and US + CT were calculated using histology as the gold standard.

Results

The overall sensitivity, specificity, PPV, and NPV for US, CT, and US + CT were 53.9%, 88.8%, 74.1%, and 76.4%; 81.2%, 68.0%, 60.1%, and 85.9%; and 84.6%, 66.0%, 59.6%, and 87.8%, respectively. The overall accuracy of the US was 75.80%, the CT scan was 72.93%, and the US + CT scan was 72.93%. For the lateral compartment, the sensitivity, specificity, PPV, and NPV for the US, CT, and US + CT were 56.6%, 91.4%, 77.1%, and 80.5%; 80.7%, 70.6%, 58.3%, and 87.8%; and 84.3%, 68.7%, 57.9%, and 89.6%, respectively. The accuracy of the US was 79.67%, the CT scan was 73.98%, and the US + CT scan was 73.98% for the lateral compartment. For the central compartment, the sensitivity, specificity, PPV, and NPV for the US, CT, and US + CT were 47.1%, 76.5%, 66.7%, and 59.1%; 82.4%, 55.9%, 65.1%, and 76.0%; and 85.3%, 52.9%, 64.4%, and 78.3%, respectively. The accuracy of the US was 61.76%, the CT scan was 69.12%, and the US + CT scan was 69.12% for the central compartment.

Conclusions

This study demonstrated that CT has higher sensitivity in detecting nodal metastasis; however, its role is complementary to US due to low specificity.

Evolving variation in the extent of surgery for low-risk papillary thyroid cancer in the United States

BACKGROUND

The continued debate over total thyroidectomy versus lobectomy and declining favor for prophylactic central neck dissection for patients with clinically node-negative papillary thyroid cancer ≤4 cm is ongoing after the 2015 guideline updates from the American Thyroid Association. This study aimed to evaluate contemporary trends in the extent of surgery in this low-risk cohort.

METHODS

Retrospective data from the National Cancer Database were used to identify adult patients with clinically node-negative papillary thyroid cancer ≤4 cm who underwent resection from 2012 to 2020. The primary outcome was the extent of surgery (lobectomy or total thyroidectomy, with or without prophylactic central neck dissection). Multivariable regression was performed to identify characteristics associated with variation in the extent of surgery.

RESULTS

Of 83,464 included patients, 79.3% were female patients with a median age of 51 years. The majority underwent total thyroidectomy either with prophylactic central neck dissection (39.1%) or without (37.5%) versus lobectomy with prophylactic central neck dissection (7.2%) or without (16.2%). Lobectomy rates increased from 18.3% in 2012 to 29.9% in 2020. Prophylactic central neck dissection rates also increased (42.9% to 52.1%). Patients who were male sex, Asian American, had smaller tumors or were treated at community cancer programs had a decreased likelihood of total thyroidectomy. Patients who were older, male sex, Black race, with smaller tumors, or were treated at community cancer programs or mid- or low-volume facilities had decreased likelihood of prophylactic central neck dissection.

CONCLUSION

Proportional use rates of operative approaches for low-risk, clinically node-negative papillary thyroid cancer have changed in recent years after the American Thyroid Association guideline changes, including increasing overall rates of lobectomy as well as prophylactic central neck dissection, with differences noted based on patient- and facility-level factors.

Prophylactic Central Neck Dissection Based on Preoperative Imaging and Intraoperative Surgeon's Palpation Versus Total Thyroidectomy Alone for Papillary Thyroid Cancer

INTRODUCTION

To compare the overall morbidity and recurrence of papillary thyroid cancer (PTC) after total thyroidectomy (TT) with or without prophylactic central compartment neck dissection (CCND) in cases of both preoperative and intraoperative nonsuspicious central lymph nodes (CLNs).

METHODS

A total of 570 PTC patients who harbored no preoperative and intraoperative suspicious CLNs at two institutions were enrolled. They were randomly assigned to TT alone or TT with prophylactic CCND (pCCND) after intraoperative assessment of CLNs during the surgery. Lymph nodes that were hard or large enough to be palpated were regarded as suspicious metastatic lymph nodes during the surgery. The characteristics, postoperative complications, and locoregional recurrence of the two groups were recorded and compared.

RESULTS

With a median follow-up of 5 y, the rates of lymph node recurrence in the TT alone and TT with pCCND groups were similar (7.3% versus 4.6%, P = 0.247), but there were significantly higher rates of overall morbidity (6.6% versus 19.1%, P < 0.001) when pCCND was performed.

CONCLUSIONS

pCCND is not recommended for patients with clinically node-negative PTC preoperatively and intraoperatively because of the high complication rate and lack of benefit of reducing recurrence.

Lymph node metastasis in cancer progression: molecular mechanisms, clinical significance and therapeutic interventions

Lymph nodes (LNs) are important hubs for metastatic cell arrest and growth, immune modulation, and secondary dissemination to distant sites through a series of mechanisms, and it has been proved that lymph node metastasis (LNM) is an essential prognostic indicator in many different types of cancer. Therefore, it is important for oncologists to understand the mechanisms of tumor cells to metastasize to LNs, as well as how LNM affects the prognosis and therapy of patients with cancer in order to provide patients with accurate disease assessment and effective treatment strategies. In recent years, with the updates in both basic and clinical studies on LNM and the application of advanced medical technologies, much progress has been made in the understanding of the mechanisms of LNM and the strategies for diagnosis and treatment of LNM. In this review, current knowledge of the anatomical and physiological characteristics of LNs, as well as the molecular mechanisms of LNM, are described. The clinical significance of LNM in different anatomical sites is summarized, including the roles of LNM playing in staging, prognostic prediction, and treatment selection for patients with various types of cancers. And the novel exploration and academic disputes of strategies for recognition, diagnosis, and therapeutic interventions of metastatic LNs are also discussed.

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.

Prediction of Cervical Lymph Node Metastasis in Clinically Node-Negative T1 and T2 Papillary Thyroid Carcinoma Using Supervised Machine Learning Approach

Papillary thyroid carcinoma (PTC) is generally considered an indolent cancer. However, patients with cervical lymph node metastasis (LNM) have a higher risk of local recurrence. This study evaluated and compared four machine learning (ML)-based classifiers to predict the presence of cervical LNM in clinically node-negative (cN0) T1 and T2 PTC patients. The algorithm was developed using clinicopathological data from 288 patients who underwent total thyroidectomy and prophylactic central neck dissection, with sentinel lymph node biopsy performed to identify lateral LNM. The final ML classifier was selected based on the highest specificity and the lowest degree of overfitting while maintaining a sensitivity of 95%. Among the models evaluated, the k-Nearest Neighbor (k-NN) classifier was found to be the best fit, with an area under the receiver operating characteristic curve of 0.72, and sensitivity, specificity, positive and negative predictive values, F1 and F2 scores of 98%, 27%, 56%, 93%, 72%, and 85%, respectively. A web application based on a sensitivity-optimized kNN classifier was also created to predict the potential of cervical LNM, allowing users to explore and potentially build upon the model. These findings suggest that ML can improve the prediction of LNM in cN0 T1 and T2 PTC patients, thereby aiding in individual treatment planning.

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.

Comparative Study of Initial Post-Therapeutic 131I Single-Photon Emission Computed Tomography/Computed Tomography and Reoperation for the Detection of Residual Lymph Node Metastasis in Patients With Papillary Thyroid Cancer

OBJECTIVE

To assess the diagnostic performance of initial post-therapeutic ¹³¹I single-photon emission computed tomography/computed tomography (SPECT/CT) compared with that of reoperation in detecting residual lymph node metastasis (LNM).

METHODS

Patients with iodine-avid LNM detected on the initial post-therapeutic ¹³¹I SPECT/CT and who underwent reoperative dissection within 6 months were included. LNMs (numbers and locations) detected via both methods were compared. The American Thyroid Association dynamic risk stratification was performed for patients receiving second radioactive iodine therapy after reoperation.

RESULTS

Fifty-three patients with 95 iodine-avid LNMs detected by ¹³¹I SPECT/CT were enrolled. Fifty-one (96.2%) patients had 212 LNMs confirmed by reoperation (P = .004). The sensitivity and specificity of ¹³¹I SPECT/CT in detecting LNM were 44.8% (95/212) and 91.6% (87/95), respectively. The location frequency of residual LNMs found by ¹³¹I SPECT/CT was similar to that of reoperation (P = .057). Thirty-two patients received a second radioactive iodine treatment, and 6 (18.8%) patients still had residual iodine-avid LNM on SPECT/CT. Therapeutic response was evaluated by American Thyroid Association dynamic risk stratification in 16 patients. The number of patients with structural incomplete response, biochemical incomplete response, indeterminate response, and excellent response was 4 (23.5%), 4 (23.5%), 5 (29.4%), and 3 (17.6%), respectively.

CONCLUSION

¹³¹I SPECT/CT has high specificity but relatively low sensitivity in detecting all residual LNMs. Approximately 80% of patients were rendered structurally disease free after reoperation.

En bloc resection of total thyroid and bilateral central compartment lymph nodes via a gasless transoral approach in papillary thyroid carcinoma

INTRODUCTION

The current study presents a preliminary exploration of en bloc resection via a gasless transoral approach in papillary thyroid carcinoma.

OBJECTIVE

This study aimed to summarize and explore the efficacy and safety of en bloc resection of total thyroid and bilateral central compartment lymph nodes via a gasless transoral approach in patients with papillary thyroid carcinoma.

METHODS

This study was conducted between January 2021 and December 2021. It involved 30 patients with bilateral papillary thyroid carcinoma who had undergone en bloc resection of the total thyroid and bilateral central compartment lymph nodes via a gasless transoral approach using a three-trocar and four-instrument technique at The First Affiliated Hospital of the University of Science and Technology of China. The key steps and difficulties of the operation were summarized, and the clinicopathological characteristics and surgical complications of patients were analyzed.

RESULTS

All operations were successful without conversion to open surgery. The pathological diagnosis was bilateral papillary thyroid carcinoma. The mean maximum tumor diameter was 0.85 ± 0.51 cm (range 0.3-2.5 cm). There was no case of gross capsular invasion. The mean number of harvested central compartment lymph nodes was 11.36 ± 5.36. Central compartment lymph node metastases were found in 16 patients (53.3%) with a mean of 1.53 ± 2.39. On the other hand, lymphocytic thyroiditis was observed in 12 cases (40%), and microscopic capsular invasion was observed in five cases (16.6%). All patients had normal parathyroid hormone levels after the operation. However, one patient developed hoarseness after the operation due to injury of the recurrent laryngeal nerve branch, but there was no numbness of the mandible and lower lip or infection of the oral incision.

CONCLUSION

The study revealed that the three-trocar and four-instrument technique can be used in the en bloc resection of total thyroid and bilateral central compartment lymph nodes via a gasless transoral approach without disconnecting the thyroid isthmus. As a result, the operation is considered effective and safe. Therefore, this technique may be a better surgical method for patients with bilateral thyroid cancer and cosmetic needs.

Dual-modal radiomics for predicting cervical lymph node metastasis in papillary thyroid carcinoma

BACKGROUND

Preoperative prediction of cervical lymph node metastasis (CLNM) in patients with papillary thyroid carcinoma (PTC) is significant for surgical decision-making.

OBJECTIVE

This study aims to develop a dual-modal radiomics (DMR) model based on grayscale ultrasound (GSUS) and dual-energy computed tomography (DECT) for non-invasive CLNM in PTC.

METHODS

In this study, 348 patients with pathologically confirmed PTC at Jiangsu University Affiliated People's Hospital who completed preoperative ultrasound (US) and DECT examinations were enrolled and randomly assigned to training (n = 261) and test (n = 87) cohorts. The enrolled patients were divided into two groups based on pathology findings namely, CLNM (n = 179) and CLNM-Free (n = 169). Radiomics features were extracted from GSUS images (464 features) and DECT images (960 features), respectively. Pearson correlation coefficient (PCC) and the least absolute shrinkage and selection operator (LASSO) regression with 10-fold cross-validation were then used to select CLNM-related features. Based on the selected features, GSUS, DECT, and GSUS combined DECT radiomics models were constructed by using a Support Vector Machine (SVM) classifier.

RESULTS

Three predictive models based on GSUS, DECT, and a combination of GSUS and DECT, yielded performance of areas under the curve (AUC) = 0.700 [95% confidence interval (CI), 0.662-0.706], 0.721 [95% CI, 0.683-0.727], and 0.760 [95% CI, 0.728-0.762] in the training dataset, and AUC = 0.643 [95% CI, 0.582-0.734], 0.680 [95% CI, 0.623-0.772], and 0.744 [95% CI, 0.686-0.784] in the test dataset, respectively. It shows that the predictive model combined GSUS and DECT outperforms both models using GSUS and DECT only.

CONCLUSIONS

The newly developed combined radiomics model could more accurately predict CLNM in PTC patients and aid in better surgical planning.

Log odds of negative lymph nodes/T stage ratio (LONT): A new prognostic tool for differentiated thyroid cancer without metastases in patients aged 55 and older

BACKGROUND

The optimal approach to assess the postoperative status of lymph nodes in differentiated thyroid cancer (DTC) remains controversial. Our aim was to determine if the log odds of negative lymph nodes/T stage ratio (LONT) could serve as a new prognostic and predictive tool for DTC without metastases in patients aged ≥ 55 years.

METHODS

The Surveillance, Epidemiology, and End Results (SEER) database was used to study the role of LONT in patients aged ≥55 years diagnosed with DTC without metastases. The primary outcome was overall survival (OS). The Kaplan-Meier method and the Cox proportional hazard regression model were used to calculate the outcome. Moreover, the robustness of research findings was evaluated using sensitivity analyses.

RESULTS

A total of 21,172 DTC patients aged ≥55 years without distant metastasis were enrolled. Multivariate Cox regression analyses and a "floating absolute risk" analysis showed that a LONT ≥0.920 (vs. -0.56 to 0.92) was a protective factor for OS in DTC patients. Sensitivity analyses revealed an E-value of 1.98 for the obtained LONT value. In subgroup analyses, LONT was correlated significantly with OS in different subgroups of negative lymph nodes, stage-I-II subgroups and the N0 subgroup. The conditional probability of survival of DTC improved with prolonged survival time in the LONT ≥0.920 group.

CONCLUSION

A high LONT was associated with longer OS compared with low LONT in patients aged ≥55 years with non-metastatic DTC. LONT could provide valuable information for undertaking postoperative evaluations.

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.

Advances in Endocrine Surgery

Recent changes in the landscape of endocrine surgery include a shift from total thyroidectomy for almost all patients with papillary thyroid cancer to the incorporation of thyroid lobectomy for well-selected patients with low-risk disease; minimally invasive parathyroidectomy with, and potentially without, intraoperative parathyroid hormone monitoring for patients with well-localized primary hyperparathyroidism; improvement in the management of parathyroid cancer with the incorporation of immune checkpoint blockade and/or targeted therapies; and the incorporation of minimally invasive techniques in the management of patients with benign tumors and selected secondary malignancies of the adrenal gland.

Bilateral and Ipsilateral Central Neck Dissection in Total Thyroidectomy: a Long Term Comparison of Complications

The role of prophylactic central compartment neck dissection (CCND) in total thyroidectomy (TT) is controversial in patients without clinically evident lymph nodes metastasis (cN0) because of association with transient and permanent hypoparathyroidism (HPT) as well as transient and permanent recurrent laryngeal nerve (RLN) injury. Instead of bilateral central neck dissection (bCCND), ipsilateral central compartment neck dissection (iCCND) has recently been proposed as a safer, alternative treatment for selected patients. The aim of this study is to characterize the morbidity that CCND (ipsilateral and bilateral) adds to TT. We enrolled 453 patients: Group A (316 patients) underwent TT alone, Group B (86 patients) underwent TT + iCCND, Group C (51 patients) underwent TT + bCCND. We compared the rates of RLN injury and HPT in three groups and data analysis showed that iCCND was associated with increased rate of transient HPT but not permanent HPT and bCCND was associated with increased rate of transient and permanent HPT, when compared with TT alone. Further studies are needed to evaluate the clear advantages of CCND (both ipsilateral and bilateral), but this should be considered in the context of an higher risk of surgical complications (especially transient and permanent hypoparathyroidism), in comparison with TT alone.

Evaluation of recurrence risk in patients with papillary thyroid cancer through tumor-node-metastasis staging: A single-center observational study in Taiwan

BACKGROUND

Many patients with papillary thyroid cancer (PTC) demonstrate satisfactory outcomes. However, 8%-28% of patients with PTC show tumor recurrence, which may affect prognosis. Therefore, identifying factors associated with tumor recurrence in patients with PTC may be helpful to refine therapeutic strategies.

METHODS

To identify factors associated with PTC recurrence, we retrospectively reviewed demographic features (sex and age), operation method, image character, serum thyroglobulin (Tg), accumulated radioactive iodine (I-131) therapeutic dose, I-131 uptake, and metastases at diagnosis in 829 patients with PTC. Patients were grouped into early (stage I and II; n = 698) and advanced (stage III and IV; n = 131) tumor-node-metastasis (TNM) stages. Recurrence rate, mortality rate, risk factors of recurrence, recurrent free survival and overall survival curve were compared between two groups.

RESULTS

Patients in the early stage demonstrated a lower recurrence rate (7.2%) than did those in the advanced stage (28.2%, p < 0.05). The mortality rate of patients with recurrence in the advanced stage was higher than that of those in the early stage (51.4% vs. 12.0%). The major impact factors on tumor recurrence in early TNM stage were distant metastasis and lymph node metastasis, while in advanced TNM stage were distant metastasis, male gender, total thyroidectomy with limited lymph node dissection, and a high serum Tg level.

CONCLUSIONS

Strategies to monitor tumor recurrence might be refined according to the TNM stages of PTC patients.

Prophylactic Central Neck Dissection to Improve Disease-Free Survival in Pediatric Papillary Thyroid Cancer

Background

Pediatric PTC is a rare disease. Although, the prognosis is excellent and the mortality rate is low, the role of prophylactic central neck dissection is still the subject of debate. The aim was to evaluate both the role and safety of prophylactic central neck dissection (CND) in managing pediatric papillary thyroid cancer (PTC), especially in respect of disease-free survival (DFS).

Patients and Methods

In this retrospective study, we collected 54 pediatric cN0 PTC patients (≤ 18 years of age) who were treated from January 2014 to January 2021 at a high-volume thyroid surgery center. Patients were divided into two groups based on the status of prophylactic CND. We analyzed the factors related to the clinicopathological features and recurrence of PTC in children.

Results

Of the 54 cN0 patients, 35 underwent prophylactic CND and 19 patients did not undergo prophylactic CND. The two groups were similar in clinical and pathologic features, such as age, gender, tumor size, multifocal status, and follow-up time. The average DFS was 84.4 ± 2.7 months. Log-rank tests on Kaplan-Meier curves revealed that age, gender, tumor size, multifocality, and extrathyroid extension did not relate to DFS time. Furthermore, DFS time was not affected by the extent of thyroidectomy (p=0.07) or RAI treatment (p=0.21). Prophylactic CND was found to increase DFS time for pediatric patients with cN0 PTC (p = 0.003). There was no statistically significant difference in complications such as transient hypocalcemia (p=0.15) and transient recurrent laryngeal nerve injury (p=0.37) between the prophylactic CND group and the no-prophylactic CND group.

Conclusion

Prophylactic CND was found to be associated with increased DFS and not with increased rates of complications after surgery.

Quantification and Pattern of Central Compartment Lymph Nodes in pN1a Papillary Thyroid Cancer Patients

Background: The background is to investigate the results of central compartment lymphadenectomy for pN1a papillary thyroid carcinoma (PTC) with regard to quantification and pattern of resected lymph nodes thereby providing basis for future compartment VI surgical intervention. Methods: The study comprised 443 pN1a PTC patients whose clinicopathological characteristics and central compartment lymphadenectomy results were compared and correlated with the primary thyroid cancer and lymph node metastasis (LNM) features. Ultimately, multivariate analysis was conducted to identify statistically significant impact factors for a high metastatic ratio (MR). Results: Dissected lymph nodes (DLNs) were more frequently identified in right level VI than left (P < .05) although there was no difference in in the number of resected metastatic lymph nodes (MLNs). Male sex, multifocality, extrathyroidal extension (ETE), and fewer DLNs were related to a high MR. There was a positive correlation between DLN and MLN, and a negative correlation between DLN and MR. Disease multifocality and ETE were identified more frequently in the left than the right thyroid lobe. Conclusion: The outcome of central compartment lymphadenectomy in pN1a PTC patients is associated with several factors, and a thorough dissection of lymph nodes improves the rate of metastatic lymph node resection.

Clinical Factors Predictive of Lymph Node Metastasis in Thyroid Cancer Patients: A Multivariate Analysis

BACKGROUND

Early-stage thyroid cancers have excellent survival. However, lymph node metastases (LNM) confer a worse prognosis and are not always known preoperatively. Therefore, investigation on the clinical and histological factors predictive of LNM in thyroid cancers was conducted to tailor the extent of surgery and radioactive iodine therapy.

STUDY DESIGN

Multivariate logistic regressions were performed based on retrospective data from thyroid cancer patients seen between 2013 and 2020 at a single institution.

RESULTS

Among 913 patients, mean age was 49.4 years, 76.5% were female, 58.3% were White, 21.2% were Black, and 27.9% had LNM. In the multivariate analyses in which the outcome was LNM, White (odds ratio [OR] 1.74, 95% CI 0.98 to 3.15, p = 0.064) and Hispanic patients (OR 2.36, 95% CI 0.97 to 5.77, p = 0.059) trended toward higher risk of LNM compared to Black patients, whereas age (OR 0.98, 95% CI 0.97 to 1.00, p = 0.008) showed protective effect. Tumor size (OR 1.04, 95% CI 1.01 to 1.07, p = 0.007), extrathyroidal extension (OR 2.46, 95% CI 1.53 to 3.97, p < 0.001), lymphovascular invasion (OR 6.30, 95% CI 3.68 to 11.14, p < 0.001), and multifocality (OR 1.47, 95% CI 1.01 to 2.12, p = 0.042) were associated with higher risk of LNM. In another model with outcome as >5 LNM, tumor size (OR 1.07, 95% CI 1.03 to 1.11, p = 0.001), age (OR 0.95, 95% CI 0.93 to 0.97, p < 0.001), extrathyroidal extension (OR 3.20, 95% CI 1.83 to 5.61, p < 0.001), and lymphovascular invasion (OR 6.82, 95% CI 3.87 to 12.17, p < 0.001) remained significant predictors.

CONCLUSION

Our analyses demonstrated and confirmed that age, tumor size, extrathyroidal extension, and lymphovascular invasion are independent predictors of significant LNM, thereby conferring higher risk of recurrence. Risk of LNM based on these patient characteristics should be considered when planning an operative approach.

Clinical advantages and neuroprotective effects of monitor guided fang's capillary fascia preservation right RLN dissection technique

OBJECTIVE

To investigate the feasibility and advantages of Fang's capillary fascia preservation right recurrent laryngeal nerve (RLN) dissection technique (F-R-RLN dissection) with preservation of the capillary network and fascia between the RLN and common carotid artery for greater neuroprotective efficiency compared with traditional techniques.

METHODS

We retrospectively analyzed 102 patients with papillary thyroid carcinoma undergoing right level VI lymph node dissection in our department from March 2021 to January 2022. Sixty patients underwent F-R-RLN dissection (the experimental group) and 42 patients underwent standard dissection (the control group). The intraoperative electrical signal amplitude ratios of the RLN, the number of dissected lymph nodes, and the preservation rates of the parathyroid glands were recorded and compared between the two groups.

RESULTS

The electrical signal amplitude ratio of the lower neck part point of the RLN to the upper laryngeal inlet point in the experimental group was significantly lower than the ratio in the control group (p = 0.006, Z-score = -2.726). One patient suffered transient RLN paralysis in both groups, but this resolved within 1 month after operation. There were no significant differences between the two groups in terms of the number of level VIa or level VIb lymph nodes dissected, nor in the rate of preservation of the parathyroid glands.

CONCLUSIONS

F-R-RLN dissection is a thorough dissection technique that is effective at preventing an electrical signal amplitude decrease in the RLN, and at preventing RLN paralysis by preserving its blood supply.

Prophylactic central neck dissection for well-differentiated thyroid carcinoma: results and methodological assessment of systematic reviews

OBJECTIVE

The aim was to assess the methodological quality of systematic reviews evaluating the effectivness of prophylactic central neck dissection plus thyroidectomy to decrease locoregional recurrence in patients with thyroid carcinoma.

INTRODUCTION

Many systematic reviews have been published concerning prophylactic central neck dissection in well-differentiated thyroid carcinoma, finding inconsistent results regarding the risk of locoregional recurrence. Because systematic reviews are considered the best source on which to base clinical decisions, the assessment of methodological quality is important.

INCLUSION CRITERIA

This paper included studies that mentioned that a systematic review was performed in adult patients with confirmed diagnosis of well-differentiated thyroid carcinoma without evidence of nodal metastatic disease who underwent total thyroidectomy. Reviews evaluated prophylactic central neck dissection compared with no neck diessection for decreasing locoregional recurrence.

METHODS

A systematic search was performed using MEDLINE, Embase, the Cochrane Database of Systematic Reviews, LILACS, Web of Science, CNKI, and Google Scholar. PROSPERO was searched for unpublished studies and gray literature. Data regarding the study characteristics, patient types, numbers of patients, and locoregional recurrence by group were extracted. Methodological characteristics, type of statistical analysis and summary estimator, heterogeneity, and publication bias were recorded. The methodological quality was measured using the AMSTAR 2 tool.

RESULTS

The search identified 12 systematic reviews. Only four systematic reviews reported adherence to methodological guidelines. The AMSTAR 2 critical criteria classified all the studies as critically low quality. The pooled risk difference for locoregional recurrence varied among studies from -5% to 0%. Most of the studies were published in high-impact journals.

CONCLUSIONS

The published systematic reviews that assessed prophylactic central neck dissection as an intervention to decrease the rate of locoregional recurrence have a critically low methodological quality. The results and recommendations based on these studies should be used with caution. The evaluation of methodological quality by peer reviewers must be improved.

Effects of Central Neck Dissection on Complications in Differentiated Thyroid Cancer

Objective

It is still controversial whether performing central neck dissection (CND) in addition to total thyroidectomy (TT) increases the risk of complications. In the present study, we aimed to evaluate the effect of CND on the development of complications in differentiated thyroid cancer (DTC) compared to TT.

Material and Methods

The data of 186 patients (136 females and 50 males) with a mean age of 48.73±14.78 (range, 17-82) whom were operated for DTC were evaluated retrospectively. The patients were divided into two groups; TT (Group 1) and CND±TT/Completion thyroidectomy±lateral neck dissection (Group 2).

Results

There were 117 (91 F, 26 M) patients in Group 1 and 69 (45 F, 24 M) patients in Group 2. Parathyroid auto transplantation (PA) was significantly higher in Group 2 compared to Group 1 (42% vs. 6%) (p=0.000). Total (58% vs. 21.4%, respectively; p=0.000) and transient hypoparathyroidism (52.2% vs. 20.5%, respectively; p=0.000) were significantly higher in Group 2 than in Group 1, but permanent hypoparathyroidism rates were statistically not significant (5.8% vs. 0.9%, respectively; p=0.064). In the multinomial logistic regression analysis, CND alone was determined as an independent risk factor for increased both total and transient hypoparathyroidism. The relative risk (RR) of CND for total hypoparathyroidism was 5.2 times increased (odds ratio [OR]: 0.192) (p=0.007), while the RR for transient hypoparathyroidism was 3.5 times increased (OR: 0.285) (p=0.036). According to the number of nerves at risk, CND was performed in 119 neck side and only thyroidectomy was performed in 253 neck side. Total vocal cord paralysis (VCP) rate (9 [7.6%] vs. 6 [2.4%], respectively) (p=0.017) and transient VCP rate (7 [6%] vs. 4 [1.6%], respectively) (p=0.021) in patients who underwent CND were significantly higher compared to those who underwent only thyroidectomy. In multinomial logistic regression analysis performing only CND was an independent risk factor for total VCP, and increased the total VCP RR approximately 5.34 times (OR:0.184; p=0.007).

Conclusion

Although CND can be applied without increasing the rates of permanent hypoparathyroidism and VCP compared to TT, it increases the risk of total and transient hypoparathyroidism, total, and transient VCP. Patients undergoing CND should be followed carefully in terms of transient hypoparathyroidism.

Prophylactic Central Neck Dissection for Clinically Node-Negative Papillary Thyroid Carcinoma

OBJECTIVE

We performed a systematic review and meta-analysis of randomized controlled trials (RCTs) that scrutinized the oncological benefits and postsurgical complications of total thyroidectomy (TT) plus prophylactic central neck dissection (pCND) versus TT alone among clinically node-negative (cN0) papillary thyroid cancer (PTC) patients.

METHODS

We screened five databases from inception to September 4, 2021 and evaluated the risk of bias of the eligible studies. We pooled dichotomous outcomes using the risk ratio (RR) with 95% confidence interval (CI).

RESULTS

Overall, we included 5 RCTs with low risk of bias comprising 795 patients (TT plus pCND = 410 and TT alone = 385). With regard to efficacy endpoint, the rate of structural loco-regional recurrence did not significantly differ between both groups (n = 4 RCTs, RR = 0.49, 95% CI [0.19, 1.27], P = .14). With regard to safety endpoints, the rates of hypoparathyroidism (n = 5 RCTs, RR = 1.48, 95% CI [0.73, 2.97], P = .27), recurrent laryngeal nerve injury (n = 5 RCTs, RR = 1.34, 95% CI [0.59, 3.03], P = .48), and bleeding (n = 3 RCTs, RR = 1.75, 95% CI [0.42, 7.26], P = .44) did not significantly differ between both groups.

CONCLUSION

For cN0 PTC patients, there was no significant difference between TT plus pCND and TT alone with regard to the rate of structural loco-regional recurrence or frequency of postsurgical complications. Adaptation of pCND in cN0 PTC patients should be contemplated by taking into consideration the clinical oncological benefits and rate of postsurgical adverse events.

LEVEL OF EVIDENCE

1 Laryngoscope, 2021.

Development and validation of a population-based model for predicting the regional lymph node metastasis in adolescent differentiated thyroid carcinoma

BACKGROUND

Adolescent differentiated thyroid carcinoma (DTC) is a rare type of thyroid cancer that represents a special entity of all endocrine-related cancer. This study aims to establish the first nomogram for predicting the regional (central and lateral) lymph node metastasis (LNM) in the adolescent population for better surgical management.

METHOD

We retrospectively reviewed the clinicopathology characteristics of adolescent patients with DTC in the Surveillance, Epidemiology, and End Results database between 2010 and 2015.

RESULTS

A total of 1,930 adolescent patients between the ages of 10 and 24 years from the SEER database were enrolled in this study. Six predictive factors including age, race, histology, multifocality, extrathyroidal invasion (EI) and tumor size were identified to be significantly associated with the regional LNM via univariate and multivariate logistic regression analyses. These indicators were used to construct a nomogram for predicting the regional LNM in adolescent patients with DTC. Moreover, a satisfied predictive ability of the model was determined with a C-index of 0.794, supported by an internal validation group with a C-index of 0.776. The Decision Curve Analysis and calibration curve further conducted a great agreement in our model.

CONCLUSION

The first predictive model containing multiple factors has been successfully established with good discrimination for predicting the regional LNM in adolescent patients with DTC. This nomogram could effectively help surgeons to make better individualized surgical decision intraoperatively, especially in terms of whether cervical lymph node dissection (LND) is warranted.

A prospective randomized controlled trial to assess the efficacy and safety of prophylactic central compartment lymph node dissection in papillary thyroid carcinoma

BACKGROUND

The efficacy of prophylactic central compartment lymph node dissection for papillary thyroid carcinoma remains controversial. We performed a randomized controlled trial to evaluate the efficacy and safety of prophylactic central compartment lymph node dissection in patients with papillary thyroid carcinoma.

METHODS

In this parallel-group randomized controlled trial, we assessed 101 patients aged 20 to 70 years with small/noninvasive papillary thyroid carcinoma and no clinical metastases or history of cervical surgery/radiation exposure. Randomization ran from April 2015 to November 2017. Data were collected between April 2015 and October 2020. Of the 101 enrolled patients, 50 underwent total thyroidectomy (TTx group) and 51 underwent total thyroidectomy as well as prophylactic central compartment lymph node dissection (TTx+pCND group). Surgical completeness, local recurrence, successful ablation, postoperative complication, and papillary thyroid carcinoma upstaging were compared between the 2 groups.

RESULTS

No patient showed structural recurrence after 46.6 ± 9.1 months of follow-up. Both groups had similar rates of surgical completeness and successful ablation. There was no difference in the incidence of complications. More patients were upstaged to pN1a in the TTx+pCND group compared to those in the TTx group (P < .05).

CONCLUSIONS

Prophylactic central compartment lymph node dissection detected more lymph node metastases but did not affect recurrence. The 2 groups showed similar outcomes with regard to surgical completeness, successful ablation, and complications. In conclusion, for small/noninvasive papillary thyroid carcinoma without clinical evidence of lymph node metastases, prophylactic central compartment lymph node dissection may not be required if total thyroidectomy is planned.

Can Cytologic and Sonographic Features Help Prevent Overtreatment of Bethesda V Thyroid Nodules?

BACKGROUND

Although nearly half of thyroid nodules with Bethesda V cytology (suspicious for malignancy) may be benign or harbor low-grade neoplasms that can be sufficiently treated with lobectomy, many patients with Bethesda V cytology continue to be treated with total thyroidectomy. The objectives of this study were to establish whether cytomorphologic and ultrasonographic features can determine appropriate surgery for thyroid nodules with Bethesda V cytology and how often patients are overtreated with total instead of partial thyroidectomy.

METHODS

Utilizing a 10-y prospective database starting January 1, 2004, cytomorphologic and ultrasonographic features of thyroid nodules with Bethesda V cytology were reviewed. Overtreatment was defined as total thyroidectomy when histopathology revealed benign nodule, noninvasive follicular thyroid neoplasm with papillary-like nuclear features (NIFTP) or a unilateral < 4 cm low risk cancer.

RESULTS

Sixty-three patients were included in the study. Seventeen (27%) had benign, 14 (22%) NIFTP, and 32 (51%) malignant nodules. On cytology, nuclear pseudoinclusions, and on ultrasound, taller-than-wide configuration, were more common in malignant than benign or NIFTP nodules. Among 56 patients who underwent total thyroidectomy, 14 and 11 had a benign or NIFTP nodule, respectively, and 13 had a unilateral < 4 cm low risk cancer, suggesting that 68% (38/56) were overtreated.

CONCLUSIONS

Total thyroidectomy for Bethesda V thyroid nodules may result in overtreatment in more than half of the patients. Although certain cytomorphologic and ultarsonographic features may be helpful in determining appropriate surgery for Bethesda V thyroid nodules, additional characteristics are needed to reduce overtreatment of these nodules.

Magnetic resonance imaging (MRI) radiomics of papillary thyroid cancer (PTC): a comparison of predictive performance of multiple classifiers modeling to identify cervical lymph node metastases before surgery

PURPOSE

To compare predictive efficiency of multiple classifiers modeling and establish a combined magnetic resonance imaging (MRI) radiomics model for identifying lymph node (LN) metastases of papillary thyroid cancer (PTC) preoperatively.

MATERIALS AND METHODS

A retrospective analysis based on the preoperative MRI scans of 109 PTC patients including 77 patients with LN metastases and 32 patients without metastases was conducted, and we divided enroll cases into trained group and validation group. Radiomics signatures were selected from fat-suppressed T2-weighted MRI images, and the optimal characteristics were confirmed by spearman correlation test, hypothesis testing and random forest methods, and then, eight predictive models were constructed by eight classifiers. The receiver operating characteristic (ROC) curves analysis were performed to demonstrate the effectiveness of the models.

RESULTS

The area under the curve (AUC) of ROC based on MRI texture diagnosed LN status by naked eye was 0.739 (sensitivity = 0.571, specificity = 0.906). Based on the 5 optimal signatures, the best AUC of MRI radiomics model by logistics regression classifier had a considerable prediction performance with AUCs 0.805 in trained group and 0.760 in validation group, respectively, and a combination of best radiomics model with visual diagnosis of MRI texture had a high AUC as 0.969 (sensitivity = 0.938, specificity = 1.000), suggesting combined model had a preferable diagnostic efficiency in evaluating LN metastases of PTC.

CONCLUSION

Our combined radiomics model with visual diagnosis could be a potentially effective strategy to preoperatively predict LN metastases in PTC patients before clinical intervention.

Application of Machine Learning Algorithms to Predict Central Lymph Node Metastasis in T1-T2, Non-invasive, and Clinically Node Negative Papillary Thyroid Carcinoma

Purpose: While there are no clear indications of whether central lymph node dissection is necessary in patients with T1-T2, non-invasive, clinically uninvolved central neck lymph nodes papillary thyroid carcinoma (PTC), this study seeks to develop and validate models for predicting the risk of central lymph node metastasis (CLNM) in these patients based on machine learning algorithms.

Methods: This is a retrospective study comprising 1,271 patients with T1-T2 stage, non-invasive, and clinically node negative (cN0) PTC who underwent surgery at the Department of Endocrine and Breast Surgery of The First Affiliated Hospital of Chongqing Medical University from February 1, 2016, to December 31, 2018. We applied six machine learning (ML) algorithms, including Logistic Regression (LR), Gradient Boosting Machine (GBM), Extreme Gradient Boosting (XGBoost), Random Forest (RF), Decision Tree (DT), and Neural Network (NNET), coupled with preoperative clinical characteristics and intraoperative information to develop prediction models for CLNM. Among all the samples, 70% were randomly selected to train the models while the remaining 30% were used for validation. Indices like the area under the receiver operating characteristic (AUROC), sensitivity, specificity, and accuracy were calculated to test the models' performance.

Results: The results showed that ~51.3% (652 out of 1,271) of the patients had pN1 disease. In multivariate logistic regression analyses, gender, tumor size and location, multifocality, age, and Delphian lymph node status were all independent predictors of CLNM. In predicting CLNM, six ML algorithms posted AUROC of 0.70–0.75, with the extreme gradient boosting (XGBoost) model standing out, registering 0.75. Thus, we employed the best-performing ML algorithm model and uploaded the results to a self-made online risk calculator to estimate an individual's probability of CLNM (https://jin63.shinyapps.io/ML_CLNM/).

Conclusions: With the incorporation of preoperative and intraoperative risk factors, ML algorithms can achieve acceptable prediction of CLNM with Xgboost model performing the best. Our online risk calculator based on ML algorithm may help determine the optimal extent of initial surgical treatment for patients with T1-T2 stage, non-invasive, and clinically node negative PTC.

The Diagnostic Accuracy of One-Step Nucleic Acid Amplification for Lymph Node Metastases of Papillary Thyroid Carcinoma： A Systematic Review and Meta-Analysis

BACKGROUND

One-step nucleic acid amplification (OSNA) analysis is a molecular diagnostic technique for lymph node metastases (LNMs) by quantifying cytokeratin 19(CK 19) mRNA. We aim to evaluate the intraoperative diagnostic accuracy of OSNA assay for LNMs of papillary thyroid carcinoma (PTC).

METHODS

PubMed, Embase, Cochrane Library, and Web of Science databases were searched to retrieve related literature. A meta-analysis was performed using STATA11.0, Meta-Disc 1.4 and RevMan 5.3.

RESULTS

This meta-analysis included six studies involving 987 lymph nodes from 194 patients. The pooled sensitivity, specificity, and area under the summary receiver-operating characteristic curve (AUC) of OSNA for detecting LNM were 0.88, 0.90, and 0.95, respectively.

CONCLUSION

OSNA assay is an accurate molecular diagnosis for intraoperative detection of lymph node metastasis in PTC.

Surgical Extent of Central Lymph Node Dissection for Papillary Thyroid Carcinoma Located in the Isthmus: A Propensity Scoring Matched Study

INTRODUCTION

To assess the risk factor for the central lymph node (CLN) metastasis and investigated the surgery extent of lymph node dissection for patients with isthmic PTC (papillary thyroid carcinoma).

MATERIALS AND METHODS

A total of 669 patients with a single nodule of isthmic PTC were retrospectively reviewed. The propensity score matching was performed twice separately. 176 patients respectively from patients who underwent thyroidectomy plus bilateral central lymph node dissection (BCLND) and who underwent thyroidectomy plus unilateral central lymph node dissection (UCLND) were matched. 77 patients were respectively selected from patients who underwent thyroidectomy plus BCLND and who underwent thyroidectomy with no central lymph node dissection (NCLND) were matched.

RESULTS

Among all the patients who underwent BCLND, 81/177 (45.76%) was confirmed with histologically positive CLN metastasis, and the occult lymph node metastasis is 25.42%. A tumor size of 1.05 cm was calculated as the cutoff point for predicting CLN metastasis by ROC curve analysis with 177 patients who underwent BCLND. The 5-year recurrence-free survival (RFS) rates were 92.9% in the NCLND group and 100% in the BCLND group with P<0.05, while there was no statistical difference in 5-year RFS between the BCLND group and UCLND group (P=0.11). The multivariate logistic regression analysis identified that age<55, tumor size>1cm, capsule invasion and lymphovascular invasion were significantly associated with CLN metastasis, while only age and lymphovascular invasion were proved to be independent risk factors related to contralateral CLN metastasis.

CONCLUSIONS

The thyroidectomy with NCLND could be insufficient for patients with isthmic PTC especially for those patients with high risk of central lymph node metastasis, considering that the rate of occult lymph node metastasis could not be ignored.

Clinical implications of Delphian lymph node metastasis in papillary thyroid carcinoma

Background

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

Methods

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

Results

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

Conclusions

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

Effect of Prophylactic Central Lymph Node Dissection on Locoregional Recurrence in Patients with Papillary Thyroid Microcarcinoma

There is a consensus that central compartment lymph node dissection or modified radical lateral neck dissection should be performed in papillary thyroid microcarcinoma (PTMC) patients with lymph node metastases. Prophylactic central lymph node dissection (PCLND) in patients with clinically node-negative (cN0) PTMC to reduce locoregional recurrence (LRR) rate and improve prognosis remains controversial. The present study aimed to analyze the effect of PCLND on LRR and postoperative complications of PTMC in cN0 patients. We reviewed a cohort of patients with cN0 PTMC who underwent surgery between January 1997 and October 2019. The patients were divided into the PCLND and no lymph node dissection (NLND) groups. Kaplan-Meier curves were constructed to estimate 15-year locoregional recurrence-free survival rate of the two groups, and the difference was compared by the log-rank test. Three Cox regression models were performed to evaluate the correlation between PCLND and LRR. All patients underwent thyroidectomy, and 25 patients developed LRR; of whom, 23 underwent PCLND at initial surgery and 2 went without lymph node dissection. Cox regression analysis showed that PCLND had no effect on LRR. Postoperative hematoma and permanent recurrent laryngeal nerve injury did not occur in the NLND group, and their incidences were 0.5% and 0.3% in the PCLND group, respectively. PCLND had no significant correlation with LRR in patients with cN0 PTMC, and the absolute benefit for PTMC was small.

Personalized treatment for differentiated thyroid cancer: current data and new perspectives

More conservative and personalized treatment options have been developed in recent years to face the rising diagnosis of low-risk differentiated thyroid carcinoma (DTC). The present review describes the change towards a more risk-adapted management either in the treatment or in the follow-up of DTC. Particular attention is given to the innovations introduced by the latest guidelines for low-risk tumors, starting from the most appropriate extension of surgery up to the postoperative management. The emerging role of active surveillance for low-risk microcarcinoma is discussed, as well as the development of percutaneous strategies in the setting of malignant thyroid disease. The recent use of approved new systemic target therapies for advanced radioiodine refractory thyroid cancer is reported, together with the description of new compounds in trial. Finally, we provide some considerations to improve the risk evaluation in a presurgical setting, especially related to the rising role of genetics, to enable better risk-based cancer management and personalized treatment choices.

Prophylactic central node dissection in differentiated thyroid cancer: A prospective tertiary care center experience

BACKGROUND

With increasing incidence of thyroid carcinoma, the optimal management of central lymph nodes remains an unanswered question although central neck nodes represent the most common site of recurrence. The aim of this study was to determine the morbidity of prophylactic central neck dissection in differentiated thyroid cancer and to evaluate histopathological correlation between nodal metastases and histological features.

METHOD

This was a prospective, observational study of 2 years duration (May 2017 to May 2019) involving 30 patients with proven differentiated thyroid cancers and clinicoradiologically negative lymph node with no history of neck surgeries. They all underwent total thyroidectomy with bilateral central neck dissection. Surgical outcomes in the form of transient or permanent hypoparathyroidism, transient and permanent recurrent nerve palsy were assessed along with histopathological correlation of primary tumor with central node positivity.

DISCUSSION

Classical histology (p = 0.05), >4 cm tumor size (p = 0.04), lymphovascular invasion (p = 0.04) and multifocality (p = 0.04) were all significantly associated with increased risk of central lymph nodal metastasis. The incidence of transient and permanent hypoparathyroidism was 36.3% and 10% respectively. Metastatic lymph node ratio of >60% is significantly associated with increased preablative serum thyroglobulin levels. Around 35% of the pT1 or T2 lesions were upstaged for postoperative radioiodine ablation CONCLUSION: An important role of prophylactic central neck dissection may lie in male patients, age > 45years, tumor size >4 cm, extrathyroidal extension, lymphovascular invasion and multifocality in accurate staging and can be performed with minimal morbidity at a high volume center.

Lymph node metastasis in suprasternal space and intra-infrahyoid strap muscle space from papillary thyroid carcinoma

Background

This study was performed to evaluate the clinicopathologic characteristics of Lymph Node metastasis between investing layer of Cervical fascia and deep fascia of infrahyoid strap Muscles (LNCM) in papillary thyroid carcinoma (PTC).

Methods

Retrospective review of patients with PTC who underwent thyroidectomy and central compartment neck dissection (CND) from January 2016 to January 2018 was performed in two tertiary referral academic medical centers. A total of 2104 consecutive patients with PTC who underwent thyroidectomy and CND were included in the retrospective review. The LNCM was resected as a separate specimen by the surgeon and the clinicopathologic characteristics of the patients were recorded. Multivariate logistic regression analysis was performed to identify risk factors for LNCM metastasis.

Results

Of 2104 PTC patients, 451 patients (21.4%) had lymph nodes in the LNCM. Among them, 68 (15.1%) cases were confirmed to be positive in the LNCM. In total, the metastasis rate of LNCM in PTC patients was 3.2% (68/2104). Univariate analysis revealed that the metastasis of LNCM were more likely to have a primary site in the inferior pole, extrathyroidal extension (ETE), central cervical metastasis, level III and level IV metastasis. Multivariate analysis further showed tumor location in the inferior pole, ETE, level III and level IV metastasis conferred a significantly increased odds ratio for LNCM metastasis.

Conclusion

Attention should be paid to the lymph tissue in the LNCM for PTC patients, especially in presence of a primary site in the inferior pole, ETE, level III and level IV metastasis.

Prophylactic central lymph node dissection informs the decision of radioactive iodine ablation in papillary thyroid cancer

BACKGROUND

Prophylactic central lymph node dissection (CLND) in papillary thyroid cancer (PTC) is controversial. We aimed to investigate if prophylactic CLND aids risk stratification and contributes to the decision for postoperative RAI ablation.

METHODS

Patients undergoing thyroidectomy for PTC and prophylactic CLND were identified from an endocrine surgical unit database. Pathology reports where reviewed for number and size of lymph nodes and patients stratified by risk according to the ATA guidelines.

RESULTS

426 patients were identified with PTC ≤4 cm and prophylactic CLND. 96 patients (23%) had central lymph node metastasis (CLNM) that qualified them for the intermediate risk group. In 17 patients (4%), the CLNM data led to upgrading independently of other histopathological characteristics. Correcting for multiple variables, CLNM was an independent factor contributing to RAI treatment.

CONCLUSION

Prophylactic CLND provides information to aid the selection of RAI ablation independent of primary cancer histology for risk stratification in 4% of patients. This benefit should be carefully balanced with the risk of CLND and patient treatment choice when deciding on management of PTC ≤4 cm.

Prophylactic lymph node dissection in clinically N0 differentiated thyroid carcinoma: example of personalized treatment

Considering the 'differentiated thyroid carcinoma (DTC) epidemic', the indolent nature of DTC imposes a treatment paradigm shift toward elimination of recurrence. Lymph node metastases in cervical compartments, encountered in 20-90% of DTC, are the main culprit of recurrent disease, affecting 5-30% of patients. Personalized risk-stratified cervical prophylactic lymph node dissection (PLND) at initial thyroidectomy in DTC with no clinical, sonographic or intraoperative evidence of lymph node metastases (clinically N0) has been advocated, though not unanimously. The present review dissects the controversy over PLND. Weighing the benefit yielded from PLND up against the PLND-related morbidity is so far hampered by the inconsistent profit yielded by PLND and the challenging patient selection. Advances in tailoring PLND are anticipated to empower optimal patient care.

Elective Central Compartment Lymph Node Dissection Does not Increase the Risk of Postoperative Hypoparathyroidism in Patients Treated for Differentiated Thyroid Cancer

Aim

The aim of this study was to compare the incidence of postoperative hypoparathyroidism in two groups of patients who were treated for differentiated thyroid cancer.

Methods

A retrospective analysis of 179 patients who were treated for differentiated thyroid cancer in our institution from January 2011 until December 2018 was performed. Only patients initially treated with total thyroidectomy and those who did not have preoperatively confirmed central compartment and lateral neck lymph node metastases were included in this study. Two main groups of patients were analysed. The patients who were treated with total thyroidectomy and elective central compartment lymph node dissection simultaneously were included in the first group. The patients who were treated only with total thyroidectomy were included in the second group. The rate of transitory and persistent postoperative hypoparathyroidism was compared between the two groups.

Results

A total of 117 patients (65.4%) underwent total thyroidectomy and elective central compartment lymph node dissection simultaneously (TT + CCLNd group). The remaining 62 patients (34.6%) underwent total thyroidectomy only (TT group). A total of 22.6% patients in the TT group developed postoperative hypoparathyroidism compared with 25.6% in the TT + CCLNd group. The rate of persistent hypoparathyroidism in the TT and TT + CCLNd groups was 3.2% and 6.0%, respectively. The difference in the rate of transient and persistent postoperative hypoparathyroidism was not statistically significant between the two groups. Within the TT + CCLNd group, 82.9% of patients underwent ipsilateral paratracheal lymph node dissection and 17.1% underwent bilateral paratracheal lymph node dissection. The rate of postoperative hypoparathyroidism was analysed in those two subgroups of patients and did not prove to be statistically significant.

Discussion

While its impact on the local recurrence rate is still controversial, elective central compartment lymph node dissection could be a great tool for selection of patients who could profit from adjuvant radioiodine treatment. On the other hand, central compartment lymph node dissection could potentially increase the risk of hypoparathyroidism due to involuntary injury to parathyroid glands and/or their blood supply. Our study did not find a statistically significant difference regarding postoperative hypoparathyroidism between patients who underwent central compartment lymph node dissection compared with patients who underwent total thyroidectomy only. Our data are not in accordance with some of the previously published studies.

Conclusion

Our results demonstrated that elective central compartment lymph node dissection is a safe procedure and does not significantly increase the risk of postoperative hypoparathyroidism when it is performed simultaneously with total thyroidectomy.

Quality Indicators of Central Compartment Neck Dissection in Thyroid Surgery

OBJECTIVES

Quality metrics are an increasingly important means of improving patient care. Variability in the number of lymph nodes removed during central compartment lymph node dissection (CCLND) at the time of thyroidectomy has not been studied.

STUDY DESIGN

A retrospective cohort study was performed using American College of Surgeons National Quality Improvement Program (ACS-NSQIP) data.

SETTING

Centers in North America and worldwide contributing data to ACS-NSQIP and performing thyroidectomy on adults in inpatient and outpatient settings were included.

SUBJECTS AND METHODS

Adult patients undergoing thyroidectomy with or without CCLND were included. Outcomes of interest were number of nodes removed during CCLND and risks of postoperative hypocalcemia.

RESULTS

In total, 6108 patients met inclusion criteria (1565 with CCLND). The median number of lymph nodes removed during CCLND was 2. There was no statistically significant association between postoperative hypocalcemia and CCNLD, regardless of number of nodes removed. However, we were underpowered to detect this association based on the overall low nodal yield of many CCLNDs performed.

CONCLUSION

In many cases where CCLND is documented as part of thyroidectomy, very few lymph nodes are removed. Our ability to draw conclusions regarding the effect of CCLND on postoperative hypocalcemia is restricted due to the limited nature of many CCLNDs performed.

The American Association of Endocrine Surgeons Guidelines for the Definitive Surgical Management of Thyroid Disease in Adults

OBJECTIVE

To develop evidence-based recommendations for safe, effective, and appropriate thyroidectomy.

BACKGROUND

Surgical management of thyroid disease has evolved considerably over several decades leading to variability in rendered care. Over 100,000 thyroid operations are performed annually in the US.

METHODS

The medical literature from 1/1/1985 to 11/9/2018 was reviewed by a panel of 19 experts in thyroid disorders representing multiple disciplines. The authors used the best available evidence to construct surgical management recommendations. Levels of evidence were determined using the American College of Physicians grading system, and management recommendations were discussed to consensus. Members of the American Association of Endocrine Surgeons reviewed and commented on preliminary drafts of the content.

RESULTS

These clinical guidelines analyze the indications for thyroidectomy as well as its definitions, technique, morbidity, and outcomes. Specific topics include Pathogenesis and Epidemiology, Initial Evaluation, Imaging, Fine Needle Aspiration Biopsy Diagnosis, Molecular Testing, Indications, Extent and Outcomes of Surgery, Preoperative Care, Initial Thyroidectomy, Perioperative Tissue Diagnosis, Nodal Dissection, Concurrent Parathyroidectomy, Hyperthyroid Conditions, Goiter, Adjuncts and Approaches to Thyroidectomy, Laryngology, Familial Thyroid Cancer, Postoperative Care and Complications, Cancer Management, and Reoperation.

CONCLUSIONS

Evidence-based guidelines were created to assist clinicians in the optimal surgical management of thyroid disease.

The Effect of Prophylactic Central Neck Dissection During Hemithyroidectomy on Locoregional Recurrence in Patients With Papillary Thyroid Carcinoma: A Meta-Analysis

Objectives.

Hemithyroidectomy is commonly performed in patients with low- to intermediate-risk papillary thyroid carcinoma. The purpose of this meta-analysis was to evaluate the effect of prophylactic central neck dissection on locoregional recurrence in patients undergoing hemithyroidectomy.

Methods.

A meta-analysis was performed of full-text publications published in English retrieved from the Embase database.

Results.

The rate of regional recurrence in the central compartment after hemithyroidectomy, with or without prophylactic central neck dissection, was 0.17% and 1.78%, respectively. This difference was statistically significant. Recurrence in the lateral compartment or contralateral thyroid was not affected by prophylactic central neck dissection; the overall rate of recurrence was 1.3% and 5.4%, respectively.

Conclusion.

Prophylactic central neck dissection significantly reduced the risk of recurrence in the central compartment in patients undergoing hemithyroidectomy.