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

Characteristics and risk factors of cervical lymph node metastasis in cN0 papillary thyroid microcarcinoma of the isthmus

The surgical resection range of papillary thyroid microcarcinoma of the isthmus (PTMCI) is controversial, and the guidelines do not fully guide the central lymph node dissection (CLND).We retrospectively studied the comparison of PTMCI (Group A, n = 65 cases) and non-PTMCI (Group B, n = 80 cases). Based on whether central lymph node metastasis (CLNM) was further detected, they were further divided into the PTMCI with CLNM (group C, n = 42 cases), the PTMCI without CLNM (group D, n = 23 cases), the non-PTMCI with CLNM (group E, n = 45 cases), the non-PTMCI without CLNM (group F, n = 35 cases). All patients underwent total thyroidectomy and CLND. The CLNM pathological examination was divided into right recurrent laryngeal nerve superficial lymph nodes (Right VI a), right recurrent laryngeal nerve deep lymph nodes (Right VI b), left VI area lymph nodes (Left VI), prelaryngeal lymph node, and pretracheal lymph node. The extent of lymph node metastasis and risk factors of PTMCI were analyzed by univariate and multivariate analysis. The ROC curve was used to calculate the maximum diameter of the tumor and the Youden index was calculated to analyze the impact of diameter on the risk factors for CLNM in PTMCI. To construct a prediction model of transfer risk of high risk factors by Nomogram, there were significant differences in prelaryngeal lymph nodes (p = 0.034) and pretracheal lymph nodes ( n = 0.035) between group A and group B, and the risk factors of lymph node metastasis were tumor invasion (p = 0.003), multifocality (p = 0.001), and the maximum tumor diameter≧6.5 mm. PTMCI is more prone to metastasis of pretracheal lymph nodes and prelaryngeal lymph nodes, and the presence of tumor invasion, multifocality, and tumor diameter≧6.5 mm are high risk factors for metastasis in PTMCI. According to the prediction model, with all risk factors the risk of cervical lymph node metastasis is up to 90%.

Bilateral papillary thyroid cancer: pitfalls of ACR TI-RADS and evaluation of modified parameters

PURPOSE

To explore modified parameters of the American College of Radiology Thyroid Imaging Reporting and Data System (TI-RADS) for evaluating contralateral nodules based on preoperative ultrasound features of papillary thyroid carcinoma (PTC) in the suspected lobe, thus guiding the management of bilateral PTC.

METHODS

We retrospectively analyzed 389 consecutive patients with PTC (272 in training set, 117 in validation set) who underwent total thyroidectomy from March 2020 to March 2022. According to their postoperative pathological data, the patients were divided into unilateral and bilateral PTC groups. The clinicopathological features and sonographic characteristics of suspected nodules were compared between the groups, and further ultrasonic characteristics of TI-RADS grade (TR grade)-underestimated nodules were analyzed.

RESULTS

Patients with a body mass index of ≥25 kg/m2 (P < 0.001), multifocality in the suspected lobe (P < 0.001), and TR > 3 isthmus nodules (P = 0.003) tended to have bilateral PTC. After modifying the TI-RADS classification for contralateral nodules using these three parameters, the area under the curve for diagnosing contralateral lesions increased from 0.79 (95% confidence interval, 0.74-0.84) to 0.83 (0.78-0.87) in the training set. The missed diagnosis rate of contralateral PTC decreased in both the training set [21.1% (28/133) to 4.5% (6/133)] and validation set [11.4% (8/70) to 2.9% (2/70)]. Preoperative ultrasound tended to underestimate the contralateral nodules with the presence of cystic components [100% (6/6)] and halo sign [73.3% (11/15)].

CONCLUSION

The modified TI-RADS classification based on the suspected lobe may facilitate effective preoperative malignant risk stratification of contralateral nodules in bilateral PTC.

The use of thyroid isthmusectomy for management of well differentiated thyroid carcinoma - A systematic review and meta-analysis

OBJECTIVE

With the growing global incidence of thyroid carcinomas, there is an increasing need for distinct guidelines for isthmus-confined carcinomas. Here, we performed the first systematic review on the topic to date, aiming to provide understanding to isthmusectomy as surgical management for well-differentiated thyroid carcinoma of the isthmus.

METHODS

We conducted a systematic review following the PRISMA guidelines, analyzing English-language studies from the past decade that report on thyroid isthmusectomy. Exclusion criteria included isthmusectomy performed alongside full thyroidectomy or partial thyroid lobectomy, lack of data on tumor characteristics or survival outcomes, and non-English publications where a translation was unavailable. Our review identified a total of 227 patients from seven studies.

RESULTS

The average 5-year overall survival and disease-free survival rates for patients with isthmus-confined PTC who underwent isthmusectomy were 100 % and 93.1 %, respectively. Similar to that of total thyroidectomy. 3.1 % of patients required completion thyroidectomy. Furthermore, isthmusectomy resulted in fewer surgical complications than total thyroidectomy.

CONCLUSIONS

The scarcity of studies providing detailed tumor characteristics and patient outcomes limits our ability to fully evaluate the safety and efficacy of isthmusectomy for isthmus-confined PTC. Additionally, the variable sample sizes and restricted geographic distribution of the included studies calls into questions the generalizability of their findings. Despite these limitations, the data suggest that isthmusectomy may be a viable surgical option for select patients with small, isthmus-confined PTC. In the absence of a randomized controlled trial on the noninferiority of isthmusectomy, significantly more publications are needed before strong conclusions can be drawn.

Isthmusectomy for papillarythyroid carcinoma in the isthmus: The less the better

BACKGROUND

Appropriate surgical treatments of papillary thyroid carcinoma (PTC) located in the isthmus (PTCI) remains controversial. This study evaluated the outcomes from isthmusectomy in single PTCI and compared it with those for patients who underwent total thyroidectomy.

MATERIAL AND METHODS

This study enrolled 89 PTCI patients who underwent total thyroidectomy or isthmusectomy plus bilateral central lymph node dissection (BCLND). Patients were divided into Group A (n = 48) with total thyroidectomy plus BCLND and Group B (n = 41) with isthmusectomy plus BCLND. We compared the effects of different surgical modalities and clinicopathological characteristics on the prognosis of PTCI, and conducted a multivariate analysis to assess risk factors for bilateral central node metastasis for PTCI.

RESULTS

There was no significant difference in postoperative recurrence-free survival (RFS) between Group A and Group B (P = 0.574). Temporary hypocalcemia occurred more in Group A than Group B (χ2 = 4.608, P = 0.032). There was no significant difference in metastatic lymph nodes between the 2 groups. However, there are 8 patients occurred bilateral central node metastasis in group A, and 6 in Group B (16.7% vs. 14.6%, respectively, P = 0.793). Multiple logistic analysis suggested that tumor size greater than 1.0 cm (OR = 9.72, 95% CI: 2.06-56.59, P < 0.001), and tumor located in the center of isthmus (OR = 5.19, 95% CI: 1.04-2.58,P < 0.001) were risk factors for bilateral central node metastasis.

CONCLUSIONS

Our results reveal that isthmusectomy plus BCLND may be a simple but feasible approach for selected PTCI patients, resulting in a better quality of life than total thyroidectomy plus BCLND.

Total thyroidectomy versus less-than-total thyroidectomy for papillary thyroid carcinoma of isthmus: a systematic review and meta-analysis

Background

Papillary thyroid carcinoma of isthmus (PTCI) has a more aggressive nature, a higher rate of lymph node metastasis and tumor recurrence. Clinicians have different preferences for the surgical approach to PTCI, but there are no definitive guidelines. The purpose of this article is to compare the oncologic outcomes and complications of total thyroidectomy and less-than-total thyroidectomy for PTCI using meta-analysis.

Methods

We searched PubMed, Embase, Cochrane Library, and Web of Science databases for articles that met the inclusion criteria, with an unlimited start date and an end date of February 19, 2023. Exclusion criteria were applied to filter out articles for further analysis. Ultimately, seven articles were used for analysis, all of which were retrospective studies. The MINORS scale was adopted to evaluate the quality of the included literature, and Review Manager 5.4 was used for data analysis.

Results

A total of 814 patients were included in the seven articles, including 401 in the less-than-total thyroidectomy group (trial group) and 413 in the total thyroidectomy group (control group). The results of the meta-analysis showed that there was no significant difference in the tumor recurrence rate between the two groups after total thyroidectomy or less-than-thyroidectomy for PTCI (odds ratio, 1.51; 95% confidence interval: 0.49, 4.65; P=0.47), and there was no statistical difference in the incidence of all postoperative complications between the two groups.

Conclusions

There may be some limitations in this analysis, such as publication bias and the fact that the included articles were all retrospective studies with a certain degree of heterogeneity. PTCI patients with early staging and no significant lymph node metastases may be able to choose a more conservative surgical approach, which is less-than-total thyroidectomy. Patients with relatively late staging and significant preoperative lymph node metastases or extra thyroidal extension may opt for total thyroidectomy plus lymph node dissection in the central region and, if necessary, lymph node dissection in the lateral cervical region.

Robotic thyroidectomy using gas-insufflation one-step single-port transaxillary (GOSTA) approach

BACKGROUND

We conducted this study to report our novel robotic thyroidectomy using gas-insufflation one-step single-port transaxillary (GOSTA) approach and compare it with a conventional transaxillary (CTA) approach using a retraction method for intraoperative and postoperative outcomes.

METHODS

We retrospectively analyzed 354 patients who underwent robotic thyroidectomy between January 2019 and April 2023. Of these patients, 143 underwent the procedure through the GOSTA approach, which involves a small incision of 3 cm along the axillary folds with both arms down and a gas-insufflation, from skin flap creation to the completion of thyroidectomy as a one-step single-port procedure without the need for a retractor. The remaining 211 patients underwent the CTA approach. We analyzed the GOSTA approach and compared the surgical outcomes of the GOSTA (n = 100) and CTA (n = 167) approaches in patients with differentiated thyroid cancer who underwent thyroid lobectomy.

RESULTS

Out of the 143 patients who underwent the GOSTA approach, 12 underwent total thyroidectomy and 9 underwent lateral neck lymph node dissection with total thyroidectomy. GOSTA-thyroid lobectomy was performed on 122 patients; of these, 100 were diagnosed with differentiated thyroid carcinoma. A comparative study with the CTA approach was only conducted in patients who underwent thyroid lobectomy. No significant differences were found in operative time, hospital stay, or complications between the two groups.

CONCLUSIONS

Despite proceeding in one-step with a single smaller incision, from skin flap creation to the completion of thyroidectomy, the GOSTA approach is as feasible and safe as the CTA approach. Additionally, the GOSTA approach allows for thyroidectomy without using a retractor and reduces the workload for the surgeon and assistants.

Implications of isthmic location as a risk factor in papillary thyroid carcinoma

Background

Papillary thyroid carcinoma (PTC) located in the isthmus generally has been known to have more extrathyroidal extension (ETE), lymph node involvement, and multifocality. The purpose of this study was to determine the clinical significance of an isthmic location of PTC.

Methods

The records of 160 patients who underwent a total thyroidectomy due to a single, dominant isthmic PTC were retrospectively reviewed. The characteristics of isthmic cancer were compared with those of unilateral-lobar cancer in a PTC cohort at Seoul St. Mary's hospital. After propensity score matching for age, sex, and tumor size, 160 isthmic PTCs and 800 unilateral-lobar PTCs were compared. The clinicopathologic characteristics were analyzed to evaluate the prognostic significance of an isthmic tumor location.

Results

The isthmic group was significantly older (49.6 vs. 46.8 years, P=0.007) and had a smaller mean tumor size (0.8±0.4 vs. 1.0±0.7 cm, P<0.001) than the unilateral-lobar group. After propensity score matching, tumor size categories, ETE, multifocality, nodal metastasis and proportion of patients with more than five metastatic lymph nodes were similar in both groups. However, N1b cases were more frequent in the unilateral-lobar group both before and after propensity score matching. In multivariate analysis, isthmic location was not correlated with gross ETE, multifocality, and higher-risk N1 disease. Younger age and more than five metastatic nodes increased the risk of PTC recurrence. However, isthmic tumor location was not significantly correlated with recurrence-free survival.

Conclusions

Isthmic location is not an independent risk factor for aggressive clinicopathologic features and is not related to PTC recurrence.

Clinical and Ultrasonographic Features of Papillary Thyroid Carcinoma Located in the Isthmus

ABSTRACT

The aim of this research was to investigate the clinical and ultrasonographic features of papillary thyroid carcinoma (PTC) in the isthmus. A total of 823 patients with 823 PTCs including 133 in the isthmus and 690 in the lateral lobe were included in our study. All patients were confirmed by postoperative pathology. The clinical and ultrasonographic characteristics were retrospectively analyzed and compared. Univariate analysis and multivariate logistic regression analysis were performed. Multifactor analyses showed that PTC in the isthmus was significantly different from PTC originating from the lateral lobe in aspect ratio, microcalcification, extrathyroid extension, lymph node metastases, and lymph node density ( P < 0.05, for all). There were no significant differences in age, sex, tumor size, margin, halo, echogenicity, and homogeneity ( P > 0.05, for all). The results indicated that the sonographic appearances of PTC in the isthmus were relatively atypical; however, it had a higher incidence of extrathyroidal extension, central lymph node metastasis, and a tendency of higher lymph node density. Therefore, more careful ultrasound evaluation should be performed for these nodules.

Prophylactic bilateral central neck dissection should be evaluated based on prospective randomized study of 581 PTC patients

BACKGROUND

Prophylactic central lymph node dissection (PCND) was a basic consensus for patients with papillary thyroid carcinoma (PTC) in China. However, unilateral or bilateral central lymph node dissection (CND) was still controversial. This study aimed at investigating the safety and long-term benefit for the patients undergone with bilateral central lymph node dissection (BCCD).

METHODS

581 patients were enrolled and divided randomly into the test and control groups according to range of CND. 285 patients were prospectively assigned to undergo thyroid lobectomy plus BCND in the test group, other 296 patients were assigned to undergo thyroid lobectomy plus ipsilateral central lymph node dissection (ICND) in the control group.

RESULTS

We found that the numbers of total LN and pN1a in the test group were more than that of the control group (p = 0.002,0.004), but there was no difference in the number of metastasized lymph nodes (p = 0.857) and tumor recurrence (p = 0.308). Additionally, in the aspect of postoperative complication (1 day after surgery), the serum levels of parathyroid hormone in the BCND group were lower than that in the ICND group (P = 0.010), and the numbers of transient laryngeal nerve palsy were more than that(p = 0.033). Meanwhile, we further found that pathological tumor size larger than 1 cm and tumor side lymph node metastasis were independent risk factors for contralateral central lymph node metastasis(p = 0.002,0.001).

CONCLUSION

BCND may be an alternative for patients with tumor sizes larger than 1 cm, but it would significantly increase the rate of transient vocal cord palsy, parathyroid auto transplantation and decreased PTH, but the risk of permanent complications was similar to the ICND group.

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.

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.

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.

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.

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.

Comparison of Ultrasonography Features and K-TIRADS for Isthmic and Lobar Papillary Thyroid Carcinomas: A Single-Center Study

Objective: This study aimed to compare ultrasonography (US) features and the Korean-Thyroid Imaging Reporting and Data System (K-TIRADS) categories for diagnosing isthmic and lobar papillary thyroid carcinomas (PTC). Methods: From January 2009 to December 2012, 163 patients who underwent thyroid surgery and were confirmed with a post-operative histopathological diagnosis of isthmic PTC were retrospectively included. Fifty-nine patients were excluded because their tumor size was <0.5 cm or because of other reasons. The control group comprised of 145 patients who underwent thyroid surgery from January to April 2013 for a classic type of PTC, with the largest diameter being ≥ 0.5 cm and located in the thyroid lobe. A single radiologist retrospectively reviewed the US features and K-TIRADS categories of each nodule using a picture archiving and communication system. Results: Among 104 patients with isthmic PTC, 95 and 9 had primary and secondary cancers, respectively. On the other hand, all 145 patients with lobar PTC had primary cancers. Isthmic PTC showed a lower prevalence of non-parallel orientation than lobar PTC (23.1 and 71%). Nodule orientation was the only US feature statistically different between the two groups (p < 0.0001). However, there was no significant difference in patient age, sex, nodule size, composition, echogenicity, microcalcification, spiculated/microlobulated margin, and K-TIRADS category between the two groups (p > 0.05). Conclusions: K-TIRADS may be useful in the diagnosis of both isthmic and lobar PTC.

Correlation of Primary Tumour Size and Central Compartment Lymph Nodes Metastasis in Well Differentiated Thyroid Malignancies in a Tertiary Care Centre

Central compartment lymph nodes are the first to be involved in thyroid carcinoma and associated with higher chances of recurrence. (1) Recurrence and revision surgery can be associated with a high risk of vocal cord paralysis and hypocalcemia. (2) However, the need for central compartment lymph nodes dissection routinely in all cases of thyroid malignancies is controversial considering the risk to recurrent laryngeal nerve and parathyroids. (3) The aim of the study was to evaluate the incidence of central compartment lymph nodes metastasis in well differentiated thyroid malignancy and their correlation with size of the primary tumour along with incidence of postoperative hypocalcemia and recurrent laryngeal nerve injury after central compartment lymph node dissection. Observational study 30 patients diagnosed as well-differentiated thyroid carcinoma after fine needle aspiration cytology and planned for total thyroidectomy and central compartment lymph node dissection in the Department of ENT at a tertiary care hospital in Mysuru were studied. After surgery, histopathological examination (HPE) of thyroid and lymph node specimen was done. Postoperatively, all patients were evaluated for hypocalcemia and recurrent laryngeal nerve injury. The incidence of central compartment lymph node metastasis after HPE was 66.6%. 80% cases with tumor size ≤ 1 cm and 64% cases having tumor size > 1 cm showed central compartment lymph node involvement. Overall Incidence of transient Hypocalcaemia was 40%. No case of recurrent laryngeal nerve palsy was observed. In well-differentiated thyroid malignancies we found a high incidence of central compartment lymph node involvement which was even higher with primary tumour of smaller size (≤ 1 cm). We did not find any incidence of permanent hypocalcemia and recurrent laryngeal nerve injury. So based on our study we emphasize on elective central compartment lymph node clearance to avoid recurrence.