Risk Factors for Central Neck Lymph Node Metastases in Micro- Versus Macro- Clinically Node Negative Papillary Thyroid Carcinoma

Impact of nodal status evaluation on therapeutic strategy for clinically unifocal T1b/small T2 node negative papillary thyroid carcinoma

PURPOSE

In absence of nodal metastases or aggressive features, thyroid lobectomy (TL) should be preferred over total thyroidectomy (TT) for 1-4 cm unifocal, papillary thyroid carcinoma (PTC). However, occult, despite non-microscopic (≥2 mm), nodal metastases may be present in clinically node-negative (cN0) PTC.

METHODS

Among 4216 thyroidectomies for malignancy (2014-2023), 110 TL plus ipsilateral central neck dissection (I-CND) were scheduled for unifocal cT1b/small cT2 (≤3 cm) cN0 PTCs. Frozen section examination (FSE) of removed nodes was performed: when positive, completion thyroidectomy (CT) was accomplished during the same procedure. In presence of aggressive pathologic features, CT was suggested within 6 months from index operation.

RESULTS

FSE was positive for occult not-microscopic nodal metastases in 33 cases (30%), underwent synchronous CT. Among the remaining 77 patients, 24 (31.2%) were scheduled for CT, after multidisciplinary tumor board discussion, due to at least 2 high-risk factors. The median number of removed and metastatic nodes was 8 (5-11) and 2 (1-5), respectively, at definitive histopathology. Furthermore, multifocality was present in 53 (48.2%) cases, lymphovascular invasion in 66 (60%) cases, aggressive subtypes in 20 (18.2%) cases and extracapsular invasion in 5 (4.5%) cases. Overall, 57 (51.8%) patients underwent immediate or delayed CT.

CONCLUSION

More than 50% of patients with unifocal cT1b/small cT2 cN0 PTC scheduled for TL may be eligible for CT because of aggressive tumor features. An intraoperative decision-making approach based on I-CND and nodes FSE may ensure accurate staging and risk stratification, thus reducing the risk of recurrence and the need for reoperation.

The value of total tumor diameter in unilateral multifocal papillary thyroid carcinoma: a propensity score matching analysis

Background

Tumor multifocality is frequently observed in papillary thyroid carcinoma (PTC). However, the maximum tumor diameter (MTD), currently utilized in various staging schemes, might not accurately indicate the level of aggressiveness exhibited by multifocal tumors. We aimed to investigate the relationship between total tumor diameter (TTD) and clinicopathological features of papillary thyroid carcinoma.

Methods

Retrospective data analysis was done on 1936 individuals who underwent complete thyroidectomy for PTC. Patients were classified into subgroups according to unilateral multifocality, central lymph node metastasis (CLNM) and lateral lymph node metastasis (LLNM). The relationships of clinicopathological features among these groups were analyzed.

Results

Unilateral multifocality was observed in 117 patients. The clinicopathological features of the unilateral multifocal PTC were similar to the unifocal PTC with approximate TTD. The unilateral multifocality played no independent role in CLNM and LLNM. Moreover, the efficiency of TTD in predicting CLNM and LLNM was significantly higher than that of MTD.

Conclusion

In the case of unilateral multifocal PTC, TTD is a more accurate indicator of the biological characteristics of the tumor than MTD.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSION

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

Role of prophylactic central neck lymph node dissection for papillary thyroid carcinoma in the era of de-escalation

Thyroid cancer is the most common endocrine malignancy. While there has been no appreciable increase in the observed mortality of well-differentiated thyroid cancer, there has been an overall rise in its incidence worldwide over the last few decades. Patients with papillary thyroid carcinoma (PTC) and clinical evidence of central (cN1) and/or lateral lymph node metastases require total thyroidectomy plus central and/or lateral neck dissection as the initial surgical treatment. Nodal status in PTC patients plays a crucial role in the prognostic evaluation of the recurrence risk. The 2015 guidelines of the American Thyroid Association (ATA) have more accurately determined the indications for therapeutic central and lateral lymph node dissection. However, prophylactic central neck lymph node dissection (pCND) in negative lymph node (cN0) PTC patients is controversial, as the 2009 ATA guidelines recommended that CND "should be considered" routinely in patients who underwent total thyroidectomy for PTC. Although the current guidelines show clear indications for therapeutic CND, the role of pCND in cN0 patients with PTC is still debated. In small solitary papillary carcinoma (T1, T2), pCND is not recommended unless there are high-risk prediction factors for recurrence and diffuse nodal spread (extrathyroid extension, mutation in the BRAF gene). pCND can be considered in cN0 disease with advanced primary tumors (T3 or T4) or clinical lateral neck disease (cN1b) or for staging and treatment planning purposes. The role of the preoperative evaluation is fund-amental to minimizing the possible detrimental effect of overtreatment of the types of patients who are associated with low disease-related morbidity and mortality. On the other hand, it determines the choice of appropriate treatment and determines if close monitoring of patients at a higher risk is needed. Thus, pCND is currently recommended for T3 and T4 tumors but not for T1 and T2 tumors without high-risk prediction factors of recurrence.

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

BACKGROUND AND AIM

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

METHOD

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

RESULTS

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

CONCLUSION

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

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

Objective

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

Methods

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

Results

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

Conclusion

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

The Differences Between Multifocal and Unifocal Papillary Thyroid Carcinoma in Unilateral Lobe: A Meta-Analysis

Background

As many inconsistent reports on the clinical manifestations and prognosis between unilateral unifocal PTC (UUPTC) and unilateral multifocal PTC (UMPTC), identifying the difference should guide management. The purpose of this study was to investigate other additional differences between UUPTC and UMPTC in addition to their difference in the number of cancer foci.

Data Sources

A systematic literature search was conducted in the PubMed and Web of Science databases for relevant studies published before December 31, 2020. Their reference lists were also reviewed.

Review Methods

Two reviewers independently extracted data and assessed the quality of eligible studies. Studies on patients who underwent an open thyroidectomy with or without neck dissection were included. Data were analyzed using the RevMan 5.3 software.

Results

Fifteen studies comprising 9,665 patients were selected for the meta-analysis. UMPTC occurred in 10% to 36% of all PTC cases. There were no significant differences between UMPTC and UUPTC patients in age, gender, tumor size, and extrathyroidal extension (ETE). However, significant differences (P < 0.05) between UMPTC and UUPTC patients were observed in central lymph node metastasis (CLNM), lateral lymph node metastasis (LLNM), tumor-node-metastasis (TNM) stage I+II, TNM stage III+IV, the recurrence/persistence of the UMPTC group after total thyroidectomy and overall recurrence/persistence.

Conclusion

UMPTC patients are more likely to have CLNM, LLNM, more advanced TNM stage, and recurrence/persistence than UUPTC patients. Compared with UUPTC, UMPTC patients should undergo central lymph node dissection, and pay more attention to LLNM, TNM stage and recurrence/persistence during the follow-up.

The advantages of carbon nanoparticles in level VII lymph node dissection in patients with papillary thyroid cancer

Background

The characteristics of level VII lymph nodes were explored and the advantages of using carbon nanoparticles (CNs) in papillary thyroid cancer (PTC) surgeries were examined. This was a retrospective study investigating the clinical data of patients with PTC who underwent surgical treatment.

Methods

From September 2019 to December 2020, a total of 191 consecutive patients with PTC were retrospectively analyzed. The patients were randomly divided into the CNs group and the control group. CNs were used in the CNs group during the operation. There were 103 cases in the CNs group, including 25 males and 78 females, and 88 cases in the control group, including 21 males and 67 females. Parameters, including the characteristics of dissected lymph nodes in level VII, metastatic rate, postoperative complications, and other inpatient-related indicators, were compared between the two groups.

Results

The number of lymph nodes dissected in level VII in the CNs group was significantly greater than that in the control group, and the metastatic rate of black-stained lymph nodes was significantly higher than that of non-black-stained lymph nodes (P<0.05). The postoperative hypoparathyroidism rate in the CNs group was significantly lower than that in the control group (P<0.05). There were no differences in the operation duration, intraoperative blood loss, postoperative drainage duration, or hospitalization days between the two groups (P>0.05).

Conclusions

The application of CNs for patients with PTC significantly increased the number of lymph nodes dissected in level VII and helped to protect the parathyroid glands (PGs). Moreover, the use of CNs did not increase the rate of postoperative complications. Thus, CNs may be a simple and safe approach when performing surgery in PTC patients.

Modulating the extension of thyroidectomy in patients with papillary thyroid carcinoma pre-operatively eligible for lobectomy: reliability of ipsilateral central neck dissection

PURPOSE

Pre-operative work-up and macroscopic intraoperative inspection could overlook occult central neck nodal metastases in patients with papillary thyroid carcinoma (PTC). An occult N1a status is able to change the initial risk stratification in small, clinically unifocal PTC potentially scheduled for thyroid lobectomy (TL) making total thyroidectomy (TT) the preferable option. We aimed to verified the reliability of an intraoperative management protocol based on frozen section examination (FSE) of ipsilateral central neck nodes (IpsiCND) to identify, among patients scheduled for TL, those who could benefit of a more extensive surgical resection (TT plus bilateral central neck dissection -CND-).

METHODS

Thirty PTC patients preoperatively classified as T1N0 underwent TL plus IpsiCND-FSE (TL-group). In case of positive FSE, TT plus bilateral CND was accomplished during the same surgical procedure. A comparative analysis was performed between TL-group and a control group (C-group), who underwent TT plus IpsiCND-FSE, matched by a propensity score analysis.

RESULTS

Nodal metastases (>2 mm) were found at final histology in 5/30 patients in the TL-group and in 6/30 in the C-group (p = 1.00). Micrometastases (≤2 mm) were retrieved in 5/30 TL-group patients and in 4/30 C-group patients (p = 1.00). Final histology staged as pN1a 10 (33.3%) patients for each group. FSE correctly identified five patients with occult nodal metastases >2 mm (16.6%) in TL-group, who underwent TT plus bilateral CND during the same surgical procedure. No permanent complications occurred. At a mean follow-up of 22.2 months, no local and/or nodal recurrence were observed.

CONCLUSIONS

Intraoperative assessment of N status obtained with IpsiCND plus FSE allows for an accurate risk stratification. IpsiCND plus FSE real time modulated thyroidectomy seems a safe and effective surgical strategy reducing the need of a subsequent completion surgery and, theoretically, the risk of local recurrence.

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

BACKGROUND

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

METHOD

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

DISCUSSION

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

Is it possible to intraoperatively modulate the extent of thyroidectomy in small papillary thyroid carcinoma?

BACKGROUND

Thyroid lobectomy is the preferred option for small, unifocal papillary thyroid carcinoma. Involvement of the central neck lymph nodes is an indication for total thyroidectomy plus central neck dissection. We aimed to verify if frozen section examination of ipsilateral central neck nodes can identify the subgroup of patients scheduled for thyroid lobectomy intraoperatively who could benefit of more extensive initial operative treatment.

METHODS

Ninety-four consenting patients with clinically unifocal cN0 papillary thyroid carcinoma underwent thyroid lobectomy plus ipsilateral central neck dissection with frozen section examination. If the frozen section examination was positive for metastases, a completion thyroidectomy and a bilateral central neck dissection were accomplished during the same procedure.

RESULTS

Frozen section examination identified occult nodal metastases in 25 of the 94 patients who then underwent immediate completion thyroidectomy and bilateral central neck dissection. Overall, central neck node metastases were found at final histology in 35 cases: occult micrometastases were observed in additional 9 patients and nodal metastases ≥2 mm in additional 1 patient.

CONCLUSION

Intraoperative assessment of nodal status obtained with ipsilateral central neck dissection and frozen section examination is able to change the extent of thyroidectomy in about one-fourth of patients scheduled for thyroid lobectomy. Frozen section examination appears a safe and effective strategy to decrease the need of a second-step completion procedure and, theoretically, the risk of recurrence.

Select Group of Patients Might Benefit From Prophylactic Central Lymph Node Dissection in Clinically Node Negative Papillary Thyroid Microcarcinoma

Objective

The aim of this study was to identify predictive factors for pathologic central lymph node metastasis (CLNM) in patients with clinically negative CLNM (cN0) papillary thyroid microcarcinoma (PTMC) to suggest a specific group of cN0 PTMC patients who benefit from prophylactic central lymph node dissection (CLND).

Background

PTMC have excellent prognosis, however, 8% have recurrent disease. Recurrence is associated with regional lymph node metastasis. It has been reported that pathologic CLNM is found in 30 to 65% of cN0 PTMC patients. However, prophylactic CLND for cN0 PTMC remains controversial.

Methods

We reviewed the records of papillary thyroid carcinoma patients with a tumor size on preoperative ultrasonography (US) of ≤10 mm and negative CLNM on preoperative physical examination, US, and positron emission tomography/computed tomography (PET/CT), who underwent total thyroidectomy or thyroid lobectomy with prophylactic CLND between April 2010 and February 2013. In total, 163 patients were included. We evaluated the relationship between preoperatively assessable factors including age, gender, body mass index, preoperative metformin use, primary tumor size through preoperative US, the maximum standardized uptake value (SUVmax) of the primary tumor through preoperative PET/CT, and the bilaterality of the primary tumor and pathologic CLNM.

Results

A SUVmax of the primary tumor of &gt;3 was an independent preoperatively assessable factor predictive of pathologic CLNM in cN0 PTMC patients.

Conclusions

Prophylactic CLND might be considered in cN0 PTMC patients with a SUVmax of the primary tumor of &gt; 3 to reduce the risks of residual CLNM and recurrence.

Total thyroidectomy versus thyroid lobectomy in the treatment of papillary carcinoma

Extent of thyroidectomy for papillary thyroid carcinoma is still matter of debate. Indeed, recently, international guidelines endorsed thyroid lobectomy as initial surgical approach for low risk, small medium-sized (T1-T2), N0 papillary thyroid carcinoma in absence of extrathyroidal extension. When dealing with a conservative surgery for oncologic disease is of utmost importance to exclude effectively more advanced disease, which could benefit from a more aggressive initial operation. However, in the setting of surgery for papillary thyroid carcinoma, despite an accurate preoperative work up could led to identify some suspicious characteristics as macroscopic evidence of multifocality or extrathyroidal extension, and/or evidence of lateral neck lymph node metastases, it is difficult to reliably assess the central neck nodal status both pre- and intra-operatively. Frozen section examination of the central neck nodes ipsilateral to the side of the tumor has been proposed in patients scheduled for thyroid lobectomy, in order to modulate the extension of both thyroidectomy and central neck dissection. Future molecular and genetic evidences are needed to establish high-risk patients with small papillary thyroid carcinoma in which thyroid lobectomy could be not and adequate surgical treatment.

IL-17A increases MHC class I expression and promotes T cell activation in papillary thyroid cancer patients with coexistent Hashimoto's thyroiditis

Background

The incidence of coexisting papillary thyroid cancer (PTC) and Hashimoto’s thyroiditis (HT) is increasing. The impact of HT on PTC prognosis and its possible mechanism remains controversial. Interleukin-17A (IL-17A) has been reported to participate in the pathogenesis of multiple autoimmune diseases and cancers. The aim of this study is to investigate the role of IL-17A in PTC with coexistent HT and evaluate the changes in tumor antigenicity.

Methods

Expression of IL-17A and major histocompatibility complex (MHC) class I molecules were compared on PTC tissue samples with or without HT. PTC cell lines K1 and TPC-1 were stimulated with IL-17A and analyzed for MHC class I expression afterwards. Cluster of differentiation (CD) 8⁺T cell activation, production of Interleukin-2 (IL-2) and Interferon-gamma (IFN-γ) as well as the programmed death-1 (PD-1) expression on lymphocytes were assessed by coculture of donor peripheral blood lymphocytes (PBLs) with IL-17A pretreated PTC cells.

Results

Elevated IL-17A and MHC class I expression were observed in PTC tissue samples with coexistent HT. Stimulation of PTC cells with IL-17A effectively increased MHC class I expression in vitro. Coculture of PBLs with IL-17A pretreated PTC cells resulted in enhanced T cell activation (%CD25⁺ of CD3⁺T cells) and increased IL-2 production along with decreased IFN-γ secretion and PD-1 expression of the lymphocytes.

Conclusions

Papillary thyroid cancer with coexisting Hashimoto’s thyroiditis presents elevated MHC class I expression, which may be the result of IL-17A secretion. T cell activation is enhanced in vitro by IL-17A and may provide future utility in PTC immunotherapy.

Electronic supplementary material

The online version of this article (10.1186/s13000-019-0832-2) contains supplementary material, which is available to authorized users.