Frequency and pattern of central lymph node metastasis in papillary carcinoma of the thyroid isthmus

Should there be a paradigm shift for the evaluation of isthmic thyroid nodules?

PURPOSE

Although the thyroid isthmus seems like a rudimentary structure that connects bilateral lobes, it is an undiscovered area that needs to be explored. Currently, the data is evolving that the increase in the risk of malignancy is higher in the isthmic nodules, and extrathyroidal extensions and lymph node metastases are more common in isthmic-derived malignant thyroid nodules. Therefore, we aimed to compare the malignancy rate of isthmic and lobar nodules, the ultrasonographic features of isthmic and lobar nodules, and presence of lymph node metastases, distant metastases, and extrathyroidal invasions in malignant isthmic nodules.

METHODS

In this retrospective study, we enrolled patients between the ages of 18-80 years, who had thyroid nodule/nodules cytology and/or pathology results from January 2009 to November 2022. 9504 nodules were selected for the analysis of US findings, cytopathology results, and malignancy rates.

RESULTS

A mean ± SD age of 55.3 ± 13.0 years with a female to male ratio of [7618 (80.2%)/1886(19.8%)] were included in the study. 962 of the nodules were at isthmic localization; whereas 8542 nodules were at lobar localization. 1188 nodules were resulted as malignant from histopathological evaluation. Of the 1188 malignant nodules, 986 nodules were (83.0%) PTC, 114 nodules (9.6%) were FTC, 55 nodules were (4.6%) MTC, 16 nodules 1.3% were Hurtle cell carcinoma, 8 nodules (0.7%) were anaplastic thyroid carcinoma, and 9 nodules (0.8%) were thyroid tumors of uncertain malignant potential (TT-UMP). 156 of the malignant nodules (13.1%) were located in the isthmus, whereas the majority of the malignant nodules (n = 1032, 86.9%) were located at the lobar parts (right or left) of the thyroid. When the metastasis patterns of isthmic and lobar thyroid cancers were examined, no significant relationship was found between isthmic and lobar cancers in terms of capsule invasion (p = 0.435), muscle invasion (p = 0.294), and lymph node metastasis (p = 0.633). A significant relation was found between nodule localization (isthmus-upper-middle and lower lobes) and malignancy (p < 0.001). In our logistic regression analysis, isthmic and upper pole nodule localizations, age and TI-RADS were evaluated as independent risk factors for malignancy (p < 0.001 for all factors).

CONCLUSION

We recommend nodule localization has to be considered an additional risk factor when performing a Fine Needle Aspiration Biopsy for the increased malignancy risk in this localization.

Comparison of prophylactic ipsilateral and bilateral central lymph node dissection in papillary thyroid carcinoma: a meta-analysis

OBJECTIVE

The scope of surgical resection for paratracheal (level VI) lymph nodes in patients with Papillary Thyroid Carcinoma (PTC) remains debatable. The aim of our study was to evaluate the effectiveness and safety of prophylactic ipsilateral Central Neck lymph node Dissection (CND) versus bilateral CND at the time of total thyroidectomy for Clinically Node-negative (cN0) unilateral PTC.

METHODS

A systematic retrieval of electronic databases, including Pubmed, Web of Science, and the China Journal Net, was conducted from January 1990 to September 2021. Outcome data of interest included transient hypoparathyroidism, permanent hypoparathyroidism, transient Recurrent Laryngeal Nerve (RLN) injury, permanent RLN injury and local recurrence. We constructed the summary Odds Ratios (ORs) and 95% Confidence Intervals (CIs) for every study with either fixed or random effect models.

RESULTS

A full total of 1792 patients from 6 studies were enrolled. Our meta-analysis showed that transient hypoparathyroidism was significantly more frequent in bilateral CND group (OR=0.58; 95% CI 0.44-0.76). The prevalence of permanent hypoparathyroidism was significantly higher in bilateral CND group patients compared to those in ipsilateral CND group (OR=0.26; 95% CI 0.15-0.45). On the other hand, our meta-analysis indicated that there were no significant differences in the incidence of transient RLN injury, permanent RLN injury and local recurrence.

CONCLUSIONS

Compared with bilateral CND, the rate of temporary and permanent hypoparathyroidism in ipsilateral CND is lower, but the local recurrence is similar. It may be presumptuous to suggest that ipsilateral CND is an adequate treatment for cN0 unilateral PTC.

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.

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.

Nomogram to differentiate benign and malignant thyroid nodules in the American College of Radiology Thyroid Imaging Reporting and Data System level 5

OBJECTIVES

To develop and validate a nomogram for differentiating benign and malignant thyroid nodules of American College of Radiology (ACR) Thyroid Imaging Reporting and Data System (TI-RADS) level 5 (TR5) and improving the performance of the guideline.

METHODS

From May 2018 to December 2019, 640 patients with TR5 nodules were retrospectively included in the primary cohort. Univariate and multivariable analyses were performed to determine the risk factors for thyroid cancer. A nomogram was established on the basis of multivariable analyses; the performance of the nomogram was evaluated with respect to discrimination, calibration, and clinical usefulness. The nomogram model was also compared to the ACR score model. External validation was performed and the independent validation cohort contained 201 patients from April 2021 to January 2022.

RESULTS

Multivariable analyses showed that age, tumour location, multifocality, concomitant Hashimoto's disease, neck lymph node status reported by ultrasound (US) and ACR score were the independent risk factors for thyroid cancer (all p < .05). The nomogram showed good discrimination, with an area under the curve (AUC) of 0.786 (95% confidence interval [CI]: 0.742-0.830) and 0.712 (95% CI: 0.615-0.809) in the primary cohort and external validation cohort, respectively. Decision curve analysis demonstrated the clinical usefulness of the model. Compared to the ACR score model, the nomogram showed higher AUC (0.786 vs. 0.626, p < .001) and specificity (0.783 vs. 0.391).

CONCLUSIONS

The presented nomogram model, based on age, tumour features and ACR score, can differentiate benign and malignant thyroid nodules in TR5 and had a high specificity.

Preoperative prediction of central neck metastasis in patients with clinical T1-2N0 papillary thyroid carcinoma

BACKGROUND

Central neck metastasis (CNM) is common in patients with papillary thyroid carcinoma (PTC). However, the prediction of CNM risk remains poorly defined, especially for patients with clinically negative lymph nodes. We developed a preoperative clinical nomogram to predict CNM risk in patients with clinical T1-2N0 (cT1-2N0) PTC.

METHODS

Data from 436 patients with unifocal cT1-2N0 PTC were available. We analyzed the association between preoperative variables and CNM using univariate and multivariate logistic regression and developed a clinical nomogram based on the multivariate regression model. The nomogram was validated externally using an independent dataset.

RESULTS

The CNM rate was 25.5%. Three clinical variables were associated with CNM, including age, gender, and tumor size. We built a CNM nomogram integrating these three variables. It had a poor index of internal discrimination (C-index, 0.655; 95% CI 0.596-0.715) and a poor index of external discrimination (C-index, 0.690; 95% CI 0.611-0.769).

CONCLUSIONS

We developed a preoperative nomogram to quantify the risk of CNM in unifocal cT1-2N0 PTC patients. However, our data showed that preoperative clinical parameters were not able to accurately predict the likelihood of CNM. Other variables need to be investigated to improve the prediction capability of this nomogram.

Differences in the clinical characteristics of papillary thyroid microcarcinoma located in the isthmus ≤5 mm and >5mm in diameter

Background

The optimal treatment of papillary thyroid microcarcinomas (PTMCs) located in the isthmus (iPTMCs) is still controversial. The purpose of this study was to compare the clinicopathologic features of patients with iPTMCs ≤5 mm and >5 mm in diameter after total thyroidectomy, and to identify the risk factors for recurrence in patients with iPTMCs.

Methods

A total of 102 iPTMC patients who underwent total thyroidectomy were reviewed retrospectively. The clinicopathologic characteristics of iPTMCs ≤5 mm group (n = 29) have been compared with a group >5 mm (n = 73). Univariate and multivariate Cox proportional hazard models served to identify risk factors associated with recurrence-free survival (RFS).

Results

Gender (p = 0.033), multifocality (p = 0.041), and central lymph node metastasis (CLNM) (p = 0.009) of patients in the ≤5 mm and >5 mm groups differed significantly. iPTMC patients with age <55 years, male, multiple tumor, and extrathyroidal extension showed comparatively more frequent of CLNM in >5 mm groups. Of the 102 patients, nine (8.8%) developed recurrence during follow-up (median: 49.5 months). The patients with recurrences had comparatively high rates of CLNM (p = 0.038), extranodal invasion (p = 0.018), and more MNCND (Metastasis Nodes for Central Neck dissection) (p = 0.020). A cutoff of MNCND >2.46 was established as the most sensitive and specific level for the prediction of recurrence based on receiver operating characteristic (ROC) curve analyses. Multivariate analysis showed that the number of MNCND ≥3 was an independent predictor of poor RFS (p = 0.028).

Conclusion

We have found that the recurrence rates are similar in patients with iPTMCs ≤5 mm and >5 mm. The iPTMCs >5 mm were more likely to be associated with pathological features such as multifocality and CLNM. The male gender, extrathyroidal extension, and CLNM were associated with recurrence of iPTMCs except for tumor size and multifocality. Higher risk of CLNM should be considered in iPTMC >5 mm when it reaches some risk factors. The numbers of MNCND ≥3 may be an independent predictor for recurrence, which could help clinicians for the decision of radioiodine administration and the modulation of follow-up modalities.

The localization of thyroid cancers on the thyroid gland is a new risk factor for metastases of perithyroidal, peritracheal and central lymph nodes

OBJECTIVE

Lymph node metastasis is frequently detected in differentiated thyroid cancers. Central dissection is performed to the lymph nodes in patients with microscopic metastases in the intraoperative evaluation. Other indications for central dissections are tumor size and cervical lateral lymph node metastasis. We consider that the localization of thyroid cancer in the thyroid lodge may be another risk factor for central lymph node metastasis. For this reason, the purpose of the present study was to investigate the relations between thyroid cancer localization and lymph node metastasis in differentiated thyroid cancer patients who had no preoperative cervical metastases and who underwent total thyroidectomy, and peritracheal, perithyroidal, and central lymph node dissection.

METHOD

A total of 213 differentiated thyroid cancer cases followed in our general surgery and endocrinology clinic between September 2016 and May 2020 were evaluated retrospectively. Based on the data in the files, the patients who underwent total thyroidectomy, and central, perithyroidal, and peritracheal lymph node dissection were included in the study. The patients were divided into four Groups according to tumor localizations, those with tumors adjacent to the trachea (Group 1), upper thyroid pole (Group 2), thyroid middle part (Group 3), thyroid inferior (Group 4). The demographic characteristics, laboratory parameters, cancer types, and lymph node metastasis rates of the Groups were evaluated.

RESULTS

A total of 84% (179) of the cases had thyroid papillary cancer, 11.73% (25) had thyroid follicular cancer, and 4.2% (9) had poorly differentiated thyroid cancer. The mean age of all patients was found to be 49 ± 8.3 years, and the female/male ratio was 2.4. It was found that the differentiated thyroid cancers metastasized to the perithyroidal, peritracheal, and central lymph nodes at a rate of 57.74%. The distribution of these metastases according to the Groups was; 62.85% in Group 1, 11.53% in Group 2, 43.9% in Group 3, and 88.57% in Group 4. It was also found that 80.32% of the papillary cancer cases and 57.14% of the follicular cancer cases metastasized to central (level VI) lymph nodes in Group 4.

CONCLUSION

The localization of differentiated thyroid cancers is a new risk factor for perithyroidal metastases.

Isthmectomy is effective and sufficient for selected patients with solitary papillary thyroid carcinoma confined to the isthmus

BACKGROUND

To retrospectively analyze the outcomes of patients treated with isthmusectomy for a solitary papillary thyroid carcinoma (PTC) confined to the isthmus, and re-assess the role of isthmusectomy in these patients.

METHODS

The medical records of 65 patients who underwent isthmusectomy for a solitary PTC confined to the isthmus at the National Cancer Center/Cancer Hospital, Chinese Academy of Medical Sciences, Peking Union Medical College between 1985 and 2015 were retrospectively reviewed. Demographic data, surgical procedures, pathological characteristics, stages, and outcomes were analyzed.

RESULTS

Patients' median age was 39 years (range, 19-63), and the majority were female (86.2% female, 13.8% male). All patients had a solitary PTC confined to the isthmus and were treated with isthmusectomy. Pretracheal lymph node dissection was performed in 34 patients, in which unilateral central neck dissection was performed in 4 patients and bilateral central neck dissection in 2 patients. Microscopic extrathyroidal extension (ETE) was observed in 23 (35.4%) patients, and macroscopic ETE was observed in 3 (4.6%) patients. Thirty-eight (58.5%) patients were stage pT1a, 19 (29.2%) patients were stage pT1b, 5 (7.7%) patients were stage pT2, and 3 (4.6%) patients were stage p3b. Fifteen (23.1%) patients were stage pN1a. Median follow-up time was 78 months (range, 12-274). Two patients experienced a recurrence and both achieved remission after re-operation. The 10-year recurrence-free survival was 92.1%. The 10-year overall survival and disease specific survival were 98.3% and 100%, respectively.

CONCLUSIONS

Isthmusectomy is effective and sufficient for select patients with a solitary PTC confined to the isthmus.

Thermal ablation for papillary thyroid microcarcinoma located in the isthmus: a study with 3 years of follow-up

Aims: To analyze the outcomes of thermal ablation for isthmic papillary thyroid microcarcinoma (PTMC). Patients & methods: Data for 21 isthmic-PTMC patients who underwent microwave ablation under ultrasound guidance were retrospectively collected. General information on patients and characteristics of tumors were collected. The technical effectiveness, tumor recurrence and volume changes and postoperative complications were recorded during the follow-up. Comparisons with 105 nonisthmic-PTMCs were done. Results: The technical effectiveness was 100%. No recurrence or lymph node metastases were detected. Tumor volume decreased significantly with a volume reduction rate of 1.00 ± 0.01 (range: 0.99 to 1.0) at the final evaluation and seven cases (31.8%) were completely resolved. No complication was encountered. No statistical differences were observed in terms of complications, recurrence or the volume reduction rate compared with the nonisthmic group (all p > 0.05). Conclusions: Percutaneous microwave ablation is an effective treatment strategy for isthmic-PTMC.

Risk prediction for central lymph node metastasis in isolated isthmic papillary thyroid carcinoma by nomogram: A retrospective study from 2010 to 2021

BACKGROUND

Isthmic papillary thyroid carcinoma (IPTC) is an aggressive thyroid cancer associated with a poor prognosis. Guidelines elaborating on the extent of surgery for IPTC are yet to be developed. This study aims to construct and validate a model to predict central lymph node metastasis (CLNM) in patients with IPTC, which could be used as a risk stratification tool to determine the best surgical approach for patients.

METHODS

Electronic medical records for patients diagnosed with isolated papillary thyroid carcinoma who underwent surgery at Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, from January 2010 to December 2021 were reviewed. All patients who underwent thyroidectomy with central neck dissection (CND) for isolated IPTC were included. We conducted univariate and multivariate logistic regression analyses to assess risk factors for ipsilateral and contralateral CLNM and the number of CLNM in IPTC patients. Based on the analysis, the nomogram construction and internal validations were performed.

RESULTS

A total of 147 patients with isolated IPTC were included. The occurrence of CLNM was 53.7% in the patients. We identified three predictors of ipsilateral CLNM, including age, gender, and size. For contralateral CLNM, three identified predictors were age, gender, and capsular invasion. Predictors for the number of CLNM included age, gender, capsular invasion, tumor size, and chronic lymphocytic thyroiditis (CLT). The concordance index(C-index) of the models predicting ipsilateral CLNM, contralateral CLNM, 1-4 CLNM, and ≥5 CLNM was 0.779 (95%CI, 0.704, to 0.854), 0.779 (95%CI, 0.703 to 0.855), 0.724 (95%CI, 0.629 to 0.818), and 0.932 (95%CI, 0.884 to 0.980), respectively. The corresponding indices for the internal validation were 0.756 (95%CI, 0.753 to 0.758), 0.753 (95%CI, 0.750 to 0.756), 0.706 (95%CI, 0.702 to 0.708), and 0.920 (95%CI, 0.918 to 0.922). Receiver operating characteristic (ROC) curves, calibration, and decision curve analysis (DCA) results confirmed that the three nomograms could precisely predict CLNM in patients with isolated IPTC.

CONCLUSION

We constructed predictive nomograms for CLNM in IPTC patients. A risk stratification scheme and corresponding surgical treatment recommendations were provided accordingly. Our predictive models can be used as a risk stratification tool to help clinicians make individualized surgical plans for their patients.

Clinicopathological characteristics of papillary thyroid cancer located in the isthmus with Delphian lymph node metastasis

Papillary thyroid carcinomas (PTC) arising from the isthmus have aggressive clinical and pathological features, especially regarding the Delphian lymph node (DLN), which are associated with poor overall and disease-specific survival of patients with head and neck cancer. In the present study, we evaluated clinicopathological characteristics in 195 DLN-positive isthmus PTCs (14.9%) and their lymph node metastatic pattern in 1305 isthmus PTC patients in our hospital between January 2016 and July 2019. Furthermore, a multivariate analysis was conducted to investigate independent risk factors for isthmus PTC with a positive DLN. The results showed that a positive DLN was significantly related to tumour size, extrathyroid extension, median number of DLN, and metastasis to the central, bilateral central, lateral, and pretracheal lymph nodes. Meanwhile, patients with DLN-positive PTC had a significantly increased incidence of suspected preoperative lymph node status than patients with DLN-negative PTC. Multivariate logistic regression of DLN metastasis in PTC located in the isthmus showed that tumour size, extrathyroid extension, and metastasis to the central, bilateral central, lateral, and pretracheal lymph nodes, were independent risk factors.

Pathological analysis and surgical modalities selection of cT1N0M0 solitary papillary thyroid carcinoma in the isthmus

Background

prognosis, identify clinicopathological characteristics, and determine optimal modalities for cT1N0M0 solitary papillary thyroid carcinoma in the isthmus (PTCI).

Methods

The clinical data of 124 patients with cT1N0M0 solitary PTCI from 3 medical centers were analyzed retrospectively. Of these, 32 participants had undergone total thyroidectomy plus unilateral central neck dissection, 36 had received total thyroidectomy plus bilateral central neck dissection, 24 had less-than-total thyroidectomy plus unilateral central neck dissection, and 32 had less-than-total thyroidectomy plus bilateral central neck dissection. We compared the effects of different surgical modalities and clinicopathological characteristics on the prognosis of cT1N0M0 solitary PTCI.

Results

There was no significant difference in postoperative recurrence-free survival between participants who received different extents of central region lymph node dissection and thyroidectomies (P>0.05). Temporary hypocalcemia occurred in participants who underwent total thyroidectomy plus bilateral central neck dissection [chi-square (χ²) =7.87, P=0.005]. Tumors with primary lesions ≥0.55 cm were prone to have central lymph node metastasis [95% confidence interval (CI): 0.51 to 0.71, P=0.047]. Multiple logistic analysis suggested that age over 55 years [odds ratio (OR) =11.90, 95% CI: 1.36 to 104.03, P=0.025], tumor size greater than 0.55 cm (OR =4.16, 95% CI: 1.28 to 13.52, P=0.018), and absence of nodular goiter (OR =2.57, 95% CI: 1.05 to 6.32, P=0.04) were risk factors for central lymph node metastasis of patients with cT1N0M0 solitary PTCI.

Conclusions

Less-than-total thyroidectomy is recommended for patients with cT1N0M0 solitary PTCI. Central lymph node dissection is recommended for patients who are prone to have central occult lymph node metastases with tumor size ≥55 cm, older than 55 years, and without nodular goiter.

Effect of Tumor Location on the Risk of Bilateral Central Lymph Node Metastasis in Unilateral 1-4 cm Papillary Thyroid Carcinoma

Purpose

Papillary thyroid carcinoma (PTC) has a high incidence of lymph node metastasis (LNM). Our aim was to determine whether tumor location is a useful feature to predict bilateral central lymph node metastasis (CLNM) in unilateral 1–4 cm PTC.

Patients and Methods

Data on unilateral 1–4 cm PTC patients from 2016 to 2019 were collected retrospectively. The clinical and pathological characteristics of the tumors and lymph nodes were analyzed statistically.

Results

The mean patient age was 49.1±12.3 (23–73) years, and the majority were women (n=1334, 75.4%). A total of 1767 patients were analyzed, and 256 (14.5%) had bilateral CLNM. Tumor location was an independent risk factor in predicting bilateral CLNM (p<0.001). The odds of bilateral CLNM were the highest in the near isthmus (OR 6.452, 95% CI: 3.658–11.379, p<0.001). In a multivariate regression model adjusting for other risk factors, near-isthmus tumors had the highest risk of bilateral CLNM (OR 7.319, 95% CI: 3.844–13.933, p<0.001), followed by lower lobe tumors (OR 2.338, 95% CI: 1.315–4.155, p=0.004) and middle lobe tumors (OR 1.845, 95% CI: 1.035–3.291, p=0.038), compared to upper lobe tumors.

Conclusion

Tumor location is an independent risk factor in predicting the risk of bilateral CLNM. Near-isthmus tumors carry the highest risk of bilateral CLNM.

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.

Clinicopathological Significance of Papillary Thyroid Carcinoma Located in the Isthmus: A Meta-Analysis

BACKGROUND

The thyroid isthmus is located directly anterior to the trachea and is covered by the strap muscles. Several studies have suggested that papillary thyroid carcinoma (PTC) in the isthmus is more aggressive and is associated with a poor prognosis. The purpose of this meta-analysis was to assess the clinicopathological characteristics and recurrence rates of PTC in the isthmus compared to PTC at other sites.

METHODS

Relevant articles were obtained by searching the PubMed database. A meta-analysis was performed using 11 eligible studies.

RESULTS

The rate of extrathyroidal extension was 0.502 (95% confidence interval [CI]: 0.239-0.764) and 0.454 (95% CI: 0.331-0.582) for isthmus PTC and PTC at other site, respectively; however, the difference in the rates was not statistically significant. Lymphovascular invasion did not significantly differ between isthmus PTC (0.179 [95% CI: 0.102-0.297]) and PTC at other sites (0.114 [95% CI: 0.066-0.188]). The rate of central lymph node (LN) metastasis was significantly higher in isthmus PTC (0.527 [95% CI: 0.435-0.617]) than in PTC at other sites (0.352 [95% CI: 0.280-0.432]). No significant difference was observed between the two groups in terms of lateral cervical LN metastasis rate. Isthmus PTC was more likely to have a prominent recurrence rate (0.046 [95% CI: 0.022-0.094]) than PTC at other sites (0.010 [95% CI: 0.001-0.070]); however, the difference was not statistically significant (because of the small number of included studies).

CONCLUSIONS

The results of this meta-analysis indicated that isthmus PTC was associated with an increased risk of central LN metastasis. Isthmus PTC seems to have a slightly higher recurrence rate than PTC at other sites. Therefore, considering the potential of the isthmus location as an unfavorable factor, more attention should be focused on isthmus PTC, and a more aggressive approach such as prophylactic central LN dissection might provide better outcomes in PTC management.

Are clinicopathological features of the isthmic thyroid nodule different from nodules in thyroid lobes? A single center experience

Objective

Thyroid nodules located in isthmus were found less prevalent, although papillary thyroid cancer in this location was reported to be more aggressive behaviour in some studies. Our aim was to evaluate hormonal, ultrasonographic, and cytopathologic features of nodules located in isthmus (isthmic nodules).

Methods

Patients who underwent thyroidectomy between 2006-2014 reviewed retrospectively. Hormonal, ultrasonographic, and cytopathologic features compared between patients with isthmic (Group-1) and with lober (non-isthmic, Group-2) nodules.

Results

Group-1 and Group-2 consisted of 251 and 2076 patients, respectively. 260 isthmic (5.5%) and 4433 non-isthmic (94.5%) nodules were compared. However, most ultrasonographical features such as presence of microcalcification and halo, diameters, echogenicity, texture, margin, and vascularity were similar between groups, macrocalcification rate was lower in isthmic nodules (18.8%, 25.9%; p = 0.012). Cytologic results were also similar. Although malignancy rate was lower in isthmic nodules (6.2%, 12.5%; p = 0.002), type of thyroid cancer was similar in isthmic and non-isthmic nodules. When malignant isthmic (n = 16,2.8%) and malignant non-isthmic nodules (n = 553, 97.2%) were compared, diameter and type of tumor, lymphovascular and capsular invasions, extrathyroidal extension and multifocality rates were not statistically significant. Malignant isthmic nodules (n = 16, 6.2%) had smaller size [10.1 (7.5-34.5) mm, 19.95 (8.4-74.1) mm; p = 0.002], and higher hypoechogenicity rate (31.3%, 5.7%, p = 0.003) compared to benign isthmic nodules (n = 244, 93.8%). Negative predictive value was higher and positive predictive value was lower in isthmic nodules compared to non-isthmic nodules (p = 0.033, p = 0.047, respectively).

Conclusion

Isthmic nodules appear to be indolent because of having lower malignancy rate. FNAB might be required in isthmic nodules even if it has relatively small size. The surgery with limited extent or follow-up might seem to be reliable in the management of patients having isthmic nodules especially with indeterminate cytology.

Thyroid Isthmusectomy with Prophylactic Central Compartment Neck Dissection is a Feasible Approach for Papillary Thyroid Cancer on the Isthmus

BACKGROUND

The treatment for papillary thyroid cancer (PTC) has become more conservative, but still no specific guidelines exist for managing isthmic PTC. This study analyzed the outcomes from isthmusectomy in single isthmic PTC and compared it with those for patients who previously had undergone a total thyroidectomy.

METHODS

An isthmusectomy with prophylactic central compartment neck dissection (pCCND) was planned for a single isthmic PTC between 2014 and 2018 (isthmusectomy group). For cases with gross extrathyroidal extension (ETE) or multiple nodal metastasis, the procedure was converted to a total thyroidectomy. The study analyzed the characteristics and outcomes of the isthmusectomy group. Additionally, the results were compared with those of the isthmusectomy-feasible group who met the eligibility criteria for isthmusectomy among total thyroidectomies performed between 2009 and 2013.

RESULTS

Of the 90 patients in the isthmusectomy group, 81 received isthmusectomy and 9 had conversion to a total thyroidectomy. Microcarcinoma occurred in 72 cases and gross ETE in 3 cases. One patient showed occult satellite cancer, and seven patients showed more than five metastatic nodes. Transient hypocalcemia developed in five and patients and permanent hypocalcemia in one patient with total thyroidectomy. Of 46 patients who began hormone replacement postoperatively, 13 completely stopped taking medication during the follow-up period. Metachronous PTC was diagnosed for one patient 12 months after isthmusectomy. The isthmusectomy group and the isthmusectomy-feasible group showed similar clinicopathologic properties including multifocality, ETE, and nodal metastasis. However, the isthmusectomy group showed significantly less transient or permanent hypocalcemia and thyroid hormone dependency.

CONCLUSIONS

Isthmusectomy with pCCND may be a feasible alternative for properly selected isthmic PTC, resulting in a better quality of life than total thyroidectomy.

Analysis of risk factors for lateral lymph node metastasis in papillary thyroid carcinoma: a retrospective cohort study

Objective

To investigate the risk factors for lateral lymph node metastasis (LLNM) in papillary thyroid carcinoma (PTC).

Methods

A retrospective analysis of 209 patients with PTC who underwent primary surgery at the Beijing Friendship Hospital affiliated with Capital Medical University from November 2014 to November 2018 was performed. The patients were divided into the LLNM group and the non‐LLNM group. The clinical and pathological characteristics of the patients were analysed. The risk factors for LLNM were analysed by univariate and multivariate analyses.

Results

The incidence of LLNM was 13.4% in PTC patients. Univariate analysis showed that the maximum diameter of the primary tumour > 2 cm (P < 0.001), bilateral primary tumour (P = 0.020), extrathyroidal extension (ETE) (P < 0.001), central lymph node metastasis (CLNM) (P < 0.001), and CLNM number ≥ 5 (P < 0.001) were significantly associated with LLNM. Multivariate logistic regression analysis showed that the maximum diameter of the primary tumour > 2 cm, ETE, and CLNM were independent risk factors for LLNM (OR values were 3.880, 5.202, and 4.474, respectively). There were 6 patients with skip lateral cervical lymph node metastasis, accounting for 21% of all LLNM patients.

Conclusion

This study revealed several independent risk factors for predicting LLNM in PTC patients, such as the maximum diameter of the primary tumour > 2 cm, ETE and CLNM. Lateral neck dissection may be recommended in PTC patients with those risk factors. Paying attention to the occurrence of skip lateral cervical lymph node metastasis during the clinical diagnosis and treatment processes is necessary.

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.

Metastasis of cN0 Papillary Thyroid Carcinoma of the Isthmus to the Lymph Node Posterior to the Right Recurrent Laryngeal Nerve

OBJECTIVE

The association between metastasis to the lymph node posterior to the right recurrent laryngeal nerve (LN-prRLN) and cN0 papillary thyroid carcinoma (PTC) located in the thyroid isthmus remains unknown; therefore, our goal was to analyze the characteristics of LN-prRLN metastasis of cN0 PTCs of the thyroid isthmus and determine its potential predictors.

PATIENTS AND METHODS

This retrospective study included patients who underwent bilateral central neck dissection between January 2018 and January 2021. The specimen was divided into five groups of prelaryngeal lymph node (LN), pretracheal LN, left paratracheal LN, lymph node anterior to the right recurrent laryngeal nerve (LN-arRLN), and LN-prRLN. Univariate and multivariate analyses were used to assess the association between the clinical pathologic variables and LN-prRLN metastases. Surgical complications were presented descriptively.

RESULTS

A total of 357 patients were included, LN-prRLN metastasis occurred in 23 (6.4%) patients, and LN-prRLN was positive only when there were other LN metastases, especially LN-arRLN metastases. Other independent risk factors for LN-prRLN included foci numbers ≥2, tumor size ≥5.0 mm, and extrathyroidal extensions. The rates of permanent hypoparathyroidism and vocal cord paralysis were 1.1% and 2.0%, respectively.

CONCLUSION

LN-prRLN metastases should not be ignored in cN0 PTC located in the thyroid isthmus; however, its dissection is a safe procedure, and the status of LN-arRLN can be a reliable predictor for LN-prRLN metastases.

Comparison of Outcomes Following Thyroid Isthmusectomy, Unilateral Thyroid Lobectomy, and Total Thyroidectomy in Patients with Papillary Thyroid Microcarcinoma of the Thyroid Isthmus: A Retrospective Study at a Single Center

Background

Papillary thyroid microcarcinoma (PTMC) measures less than 10 mm in diameter, is more common in the thyroid lobes, but rarely presents in the thyroid isthmus. This retrospective study aimed to compare patient outcomes following various types of surgery in patients with PTMC of the thyroid isthmus, at a single center in China.

Material/Methods

We analyzed the clinical data of patients with isthmus thyroid cancer treated at the First Hospital of China Medical University. Patients were divided into 2 groups according to the tumor diameter-PTMC of the thyroid isthmus and papillary thyroid carcinoma >10 mm. The clinicopathological features between the 2 groups were compared, and the effects of various surgical methods on the prognosis of patients were analyzed.

Results

A total of 70 patients were included in this study: 29 with PTMC of the thyroid isthmus (41.4%) and 41 with papillary thyroid carcinoma >10 mm (58.6%). The rates of lymph node metastasis (10.3% vs. 34.1%) and extrathyroid extension (0% vs. 14.6%) in the PTMC of the thyroid isthmus were significantly lower than those in the papillary thyroid carcinoma >10 mm. The recurrence-free survival (RFS) rate was 97.1%. Survival analysis showed that there was no significant difference in RFS among patients with PTMC of the thyroid isthmus undergoing isthmusectomy, unilateral lobectomy, and total thyroidectomy.

Conclusions

These findings from a single center showed that for patients with PTMC of the thyroid isthmus, who had no comorbidities, there was no significant difference in outcome between the 3 types of thyroid surgery.

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.

Bethesda System Categories of Fine Needle Aspiration Cytology Are Not Associated with Thyroid Nodule Location: A Single Institution Experience

INTRODUCTION

Thyroid isthmus is defined as the thin band connecting thyroid tissue between both lateral thyroid lobes. Recently, a possible association between thyroid nodules located in the isthmus and malignancy was proposed. The aim of this study was to compare the frequency of The Bethesda System for Reporting Thyroid Cytopathology (TBSRTC) categories between nodules from the isthmus and nodules from both thyroid lobes.

METHODS

All fine needle aspiration cytology procedures performed between January 2016 and December 2019 at the Pathology Institute of Araçatuba, São Paulo, Brazil, were analyzed. For each nodule, at least 2 conventional slides were produced (1 stained by Giemsa and the other by hematoxylin and eosin). All cases were reported according to the TBSRTC. Clinical information (gender, age, and localization) and ultrasound data (size of nodules) were collected from medical requisition forms. To assess the association between the frequency of TBSRTC categories and nodule location, univariate analysis was performed using the χ2 test or Fisher's exact test, as appropriate. A p value <0.05 was considered statistically significant. Nodules located in transition between the isthmus and a right or left lobe were included in the isthmus group.

RESULTS

Considering the p value between the TBSRTC categories and thyroid nodule location, statistic association was not observed: nondiagnostic or unsatisfactory (p = 0.1442), atypia of undetermined significance or follicular lesion of undetermined significance (p = 0.3296), follicular neoplasm or suspicious for a follicular neoplasm (p = 0.0817), suspicious for malignancy (p = 0.8464), and malignant (p = 0.1082).

CONCLUSION

In the studied population, nodules located in the isthmus were not related to any Bethesda System category.

BRAFV600E mutation, BRAF-activated long non-coding RNA and miR-9 expression in papillary thyroid carcinoma, and their association with clinicopathological features

Background

The incidence of thyroid cancer is increasing worldwide. This study investigated the association of B-type RAF kinase (BRAF)^V600E mutation status, the expression of BRAF-activated long non-coding RNA (BANCR) and microRNA miR-9, and the clinicopathological features of papillary thyroid carcinoma (PTC).

Methods

Clinicopathological data for PTC patients (n = 51) diagnosed and treated between 2018 and 2019 were collected. Carcinoma and adjacent normal tissue samples were analyzed for the presence of the BRAF^V600E mutation and/or expression of BANCR and miR-9.

Results

Larger tumor, higher rate of bilateral tumors and multifocality, extracapsular invasion, and lateral lymph node metastasis (LNM) were observed in PTC patients with BRAF ^V600E mutation. Patients with higher BANCR expression had a higher rate of extracapsular invasion and lateral LNM in carcinoma tissue and a lower frequency of bilateral tumors and multifocality in normal adjacent tissue. Patients with higher miR-9 expression had a lower rate of central and lateral LNM in carcinoma tissue and higher rates of bilateral tumor location and multifocality in normal adjacent tissue. Patients with BRAF^V600E mutation have a higher rate of BANCR overexpression and tended to have a lower rate of miR-9 overexpression (P = 0.057), and a negative association was observed between BANCR and miR-9 expression in carcinoma tissue.

Conclusions

BRAF^V600E mutation and the BANCR and miR-9 expression were closely associated with the tumor size, bilateral tumor location, multifocality, extracapsular invasion, and lateral LNM. PTC patients with these clinicopathological characteristics, BRAFV600E mutation, and high BANCR expression and low miR-9 expression needed earlier surgical treatment and are recommended for total thyroidectomy in primary surgery for reducing the risk of recurrence. These findings provide new insight into the molecular basis for PTC and can inform strategies for the management of PTC.

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.

Isthmic Papillary Thyroid Carcinoma Presents a Unique Pattern of Central Lymph Node Metastasis

Purpose

Treatment protocols for occult central lymph node metastasis (LNM) associated with papillary thyroid cancer (PTC) located in the isthmus are debatable. We aimed to analyze the pattern of occult central LNM in isthmic PTC, including risk factors for bilateral paratracheal LNM.

Patients and Methods

Consecutive patients with PTC were recruited to this study. All patients underwent total thyroidectomy and prophylactic bilateral central neck dissection. The clinicopathologic features and distribution of central LNM were compared between the two groups, and risk factors for bilateral paratracheal LNM were analyzed.

Results

A total of 174 patients with PTC were enrolled in this study, of whom 87 patients had isthmic PTC (study group) and 87 patients had lobe-originating PTC (control group). The two groups had comparable demographics and tumor features. There were higher frequencies of pretracheal LNM (P =0.001) and bilateral paratracheal LNM (P = 0.002) in the isthmic PTC group. Bilateral paratracheal LNM was significantly associated with age <55 years (P = 0.037), capsular invasion (P = 0.034), tumor location (isthmus) (P < 0.001), BRAF gene mutation (P = 0.013), and pretracheal LNM (P < 0.001). Isthmus location (odds ratio [OR]: 4.116, 95% confidence interval [CI]: 1.264–13.433, P = 0.019) and pretracheal LNM (OR: 3.422, 95% CI: 1.214–9.642, P = 0.020) were independent risk factors for bilateral paratracheal LNM.

Conclusion

Because of its unique anatomic location, isthmic PTC differs from PTC in the lobe with respect to pretracheal and bilateral paratracheal LNM, even in patients of comparable age, sex, tumor size, extrathyroidal extension, BRAF mutation, and pathologic TNM staging. The isthmus location was found to be an independent risk factor for bilateral paratracheal LNM. This information may contribute to the development of an appropriate surgical protocol for isthmic PTC.

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.

Surgical Outcomes and Efficacy of Isthmusectomy in Single Isthmic Papillary Thyroid Carcinoma: A Preliminary Retrospective Study

BACKGROUND AND OBJECTIVES

The optimal extent of surgery needed for isthmic papillary thyroid carcinoma (PTC) is not well-defined, although total thyroidectomy is usually recommended. This study aimed to evaluate the efficacy of isthmusectomy in the surgical treatment of isthmic PTC. Materials and Methods: We retrospectively studied 121 patients who underwent thyroidectomy with or without central neck dissection (CND) for single isthmic PTC from January 2003 to June 2019. We excluded patients who were clinically suspected to have clinically positive cervical lymph node metastasis and gross extrathyroidal extension or to have cancers at sites other than the thyroid isthmus. Patients were divided into three groups according to the extent of thyroidectomy-total thyroidectomy, lobectomy with isthmusectomy (the lobectomy group), and isthmusectomy. Clinical and pathologic characteristics, surgical outcomes, recurrence rate, and survival were analyzed. Results: Of 121 isthmic PTC patients, 28 were men and 93 were women. Total thyroidectomy, lobectomy with isthmusectomy, and isthmusectomy were performed in 70 (57.8%), 40 (33.1%), and 11 (9.1%) patients, respectively. Prophylactic CND was performed in 104 (86%) patients. In a subgroup analysis, patients who underwent total thyroidectomy showed higher postoperative hypoparathyroidism (p < 0.001) than those who underwent lobectomy and isthmusectomy. However, there were no differences in the recurrence rate or survival between the three groups. Conclusion: Thyroid isthmusectomy may be effective in the surgical treatment of small single isthmic PTC. Further studies are necessary to verify this result.

Investigating the Effect of Thyroid Nodule Location on the Risk of Thyroid Cancer

Background: Thyroid nodules are routinely evaluated with ultrasound. Our aim was to determine if thyroid nodule location was a useful feature to predict thyroid cancer. Materials and Methods: Retrospective review of patients with thyroid nodules from six referral centers from 2006 to 2010. A total of 3313 adult patients with thyroid nodules and confirmed benign or malignant thyroid diagnoses were included. Results: Mean patient age was 54.2 (18-97) years, and the majority were women (n = 2635, 79.8%). A total of 3241 nodules were analyzed, 335 (10.3%) of which were malignant. Thyroid nodule location was an independent risk factor in predicting thyroid cancer (p = 0.005). Thyroid cancer odds were highest in the isthmus (odds ratio [OR] = 2.4, 95% confidence interval [CI] 1.6-3.6, p < 0.0001). In a multivariate regression model adjusting for age, sex, family history of thyroid cancer, radiation exposure, nodule size, and American College of Radiology (ACR) TI-RADS (Thyroid Imaging Reporting and Data System) score, the isthmus nodules had the highest risk of malignancy (OR = 2.4 [CI 1.5-3.9], p = 0.0007), followed by upper thyroid nodules (OR = 1.8 [CI 1.2-2.7], p = 0.005) and then middle thyroid nodules (OR = 1.5 [CI 1.1-2.0], p = 0.01) compared with lower thyroid nodules. Isthmus nodules were significantly smaller in size compared with middle (p < 0.0001) and lower (p = 0.0004), but not upper nodules (p = 0.25), with a mean size of 15.5 mm (±10.7). Conclusions: Thyroid nodule location is an independent risk factor in predicting the risk of thyroid cancer. Isthmic nodules carry the highest risk of cancer diagnosis and lower lobe nodules carry the lowest risk.

Papillary Thyroid Cancers of the Thyroid Isthmus: The Pattern of Nodal Metastasis and the Significance of Extrathyroidal Extension

BACKGROUND

Cancers of the thyroid isthmus are less frequent compared with the lobar cancers yet have their own unique clinicopathological characteristics. Herein, we sought to examine the isthmic papillary thyroid carcinomas (PTCs) for the pattern of and risk factors for nodal metastasis and the significance of extrathyroidal extension (ETE).

METHODS

The medical records of 3138 patients diagnosed with solitary PTC who had undergone surgery were retrospectively reviewed. Of these, 122 isthmic PTCs were matched to common lobar PTCs at a ratio of 1:3 for age, sex, and nodule size. Patient demographics, surgical findings, and pathology reports were analyzed.

RESULTS

Isthmic PTCs comprised 4.6% of all PTCs and had more lymphatic invasion (22.1% vs. 13.4%, p = 0.021), ETE (73.0% vs. 57.1%, p = 0.002), and perithyroidal and prelaryngeal node metastasis (18.0% vs. 9.0%, p = 0.006) compared with lobar PTCs. However, there were no significant differences in the rate of central and lateral node metastasis between the two groups. ETE was identified not to be a risk factor for isthmic PTCs for central and lateral node metastasis, in contrast to lobar PTCs in which ETE was a significant risk factor (odds ratio 3.18, 95% confidence interval [CI] 1.89-5.34; and 4.72, 95% CI 1.04-21.41).

CONCLUSION

The rates of central and lateral node metastasis of isthmic PTCs are comparable with that of lobar PTCs despite a higher rate of ETE in the isthmic counterpart. Although the extent of surgery for isthmic PTCs remains to be investigated, careful dissection of perithyroidal and prelaryngeal nodes may be necessary for isthmic PTCs.

Isthmusectomy in selected patients with well-differentiated thyroid carcinoma

BACKGROUND

Isthmusectomy in the treatment of well-differentiated thyroid carcinoma (WDTC) is controversial. In this study, we analyze the outcomes of WDTC managed by isthmusectomy alone.

METHODS

Forty-three patients treated with isthmusectomy alone were identified from an institutional database of 6259 surgically treated patients with WDTC. Patient and tumor characteristics were analyzed. Disease-specific survival (DSS) and recurrence-free survival (RFS) were calculated using the Kaplan-Meier method.

RESULTS

The pT classification was T1 for 41 and T2 for two patients. All were clinical N0, but 10 pts were pN1a. Using the American Thyroid Association risk stratification system, 9 patients were low-risk and 22 were intermediate-risk. One patient developed local recurrence, and two developed regional lymph node metastases; the 5- and 10-year DSS was 100.0%. The 5- and 10-year RFS was 93.1%.

CONCLUSIONS

Isthmusectomy alone is an acceptable procedure in selected patients with low- and intermediate-risk WDTC limited to the isthmus.

Extent of central lymph node dissection for papillary thyroid carcinoma in the isthmus

Purpose

The incidence of papillary thyroid carcinoma (PTC) arising from the isthmus is low; however, these tumors have aggressive clinical and pathological features. Moreover, the existing guidelines regarding the extent of surgery for this type of tumor are unclear.

Methods

This study enrolled 282 patients who underwent total thyroidectomy with bilateral central lymph node dissection. The patients were divided into 2 groups based on the location of the median line of the PTC. Group I included patients in whom the median line was located between the lateral margins of the trachea; group II included all others. We compared the 2 groups and conducted a multivariate analysis to assess risk factors for contralateral node metastasis from a PTC arising from the isthmus.

Results

Patients in group I had significantly higher frequencies of extrathyroidal extension and central lymph node metastasis. Group I also had a higher frequency of contralateral node metastasis, and a tumor size >1.0 cm was identified as an independent risk factor for contralateral node metastasis among patients in this group.

Conclusion

Bilateral central lymph node dissection could be considered for patients with isthmic PTCs >1.0 cm in size who have clinically suspicious node metastasis.

Independent predictors and lymph node metastasis characteristics of multifocal papillary thyroid cancer

The multifocal papillary thyroid cancer (PTC), with more aggressive and poorer prognosis, is not rare in papillary histotype. Few studies evaluated risk factors and lymph node metastasis in multifocal PTC. The aim of this present study focusing on risk factors and lymph node metastasis characteristics in multifocal PTC was excepted to assist clinical decisions regarding surgery.It was a retrospective study. The 1249 consecutive patients with PTC were reviewed. Of these, 570 patients who met the criteria were selected: 285 with solitary papillary thyroid cancer and 285 with multifocal PTC. The risk factors and lymph node metastasis in multifocal PTC were investigated by univariate and multivariate analysis.Multifocal PTC showed a higher positive rate of capsular invasion, extrathyroidal extension, tumor size >10 mm, pathological T classification, N+ stage, local recurrence, and radioactive iodine ablation (RAI). Capsular invasion (hazard ratio [HR], 1.589; 95% confidence interval [CI],1.352-1.984), advanced pathological T classification (HR, 3.582; 95% CI, 2.184-5.870), and pathological N+ stage (HR, 1.872; 95% CI, 1.278-2.742) were related to increased risk of multifocality and there was a significant increased HR for central neck compartment involvement in male sex (HR, 2.694; 95% CI, 1.740-4.169), advanced pathological T classification (HR, 2.403; 95% CI, 1.479-3.907) and multifocality (HR, 1.988; 95% CI, 1.361-2.906).There is a significant association between capsular invasion, advanced pathological T classification, N+ stage, and multifocal PTC. Total thyroidectomy plus prophylactic bilateral central lymph node dissection should be recommended during surgery due to a stronger predilection for level VI lymph node metastasis in multifocal PTC.

Is the Isthmus Location an Additional Risk Factor for Indeterminate Thyroid Nodules? Case Report and Review of the Literature

Background: The management of indeterminate thyroid lesions is controversial. The American Thyroid Association (ATA) guidelines suggest a conservative approach for low risk indeterminate thyroid lesions (TIR3A). Case Report: We report a clinical case of a young girl who had TIR3A in a thyroid nodule located in the isthmus. After considering clinical and ultrasound (US) risk factors, we assessed literature data and guidelines to plan the extension of surgery. We found several studies supporting that the isthmus malignant lesions were associated with a higher rate of multifocality, capsular invasion, extrathyroidal extension, and central lymph node (LN) metastases. These data could predict a more aggressive behavior and a poor prognosis of the isthmus thyroid cancer compared to differentiated thyroid cancer, originating in the thyroid lobes. On the basis of these literature data and considering the familial risk for thyroid cancer of our patient, we decided to perform a total thyroidectomy. The histological examination revealed a follicular variant of papillary carcinoma located in the isthmus with capsular invasion. Conclusion: The isthmus location could be an additional risk factor to consider for a correct surgical approach in indeterminate thyroid lesions and thyroid cancer at fine-needle aspiration (FNA). We suggest that a careful ultrasonography should be carried out in patients with isthmus nodules. Total thyroidectomy should be performed in aggressive nodular disease. Prospective studies are needed to establish the best treatment for these lesions.

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.

Feasibility of Charcoal Tattooing for Localization of Metastatic Lymph Nodes in Robotic Selective Neck Dissection for Papillary Thyroid Carcinoma

BACKGROUND

This study aimed to evaluate the feasibility and effectiveness of ultrasound-guided charcoal tattooing in locating metastatic lymph nodes in robotic selective neck dissection (SND) for papillary thyroid carcinoma (PTC).

METHODS

The overall study group comprised 21 patients with PTC who underwent robotic SND via a unilateral transaxillary approach for treatment of suspicious lymph node metastasis in the lateral compartment. Charcoal suspension was injected into 10 of the patients (total of 23 lesions) 1 day before robotic SND. The authors evaluated the location of the tattoos, the success rate of localization, the intraoperative detection rate, and the complications associated with the procedure. The perioperative results were compared with those in the control group of 11 patients who did not receive charcoal tattooing.

RESULTS

Charcoal suspension was successfully injected into 22 of the 23 suspicious lymph nodes (95.7 %). The remaining lesion was located posterior to the internal jugular vein. Therefore, the charcoal was injected into the soft tissue around the lymph node. Ultrasound-guided injections were well tolerated in all the patients, and no major complications occurred. All the charcoal-tattooed lesions were identified intraoperatively by the surgeon. The number of harvested and metastatic lymph nodes in the lateral compartment was greater in the patients with charcoal tattoo localization than in the control group. The two groups did not differ in terms of perioperative complications, operation time, or volume of drainage.

CONCLUSION

Ultrasound-guided charcoal tattooing for localization of metastatic lymph nodes is feasible and effective in robotic SND for the treatment of PTC with lateral compartment lymph node metastasis.