Nodal status of central lymph nodes as a negative prognostic factor for papillary thyroid carcinoma: Specific Status of Central Lymph Nodes

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.

Predictive Risk-scoring Model For Central Lymph Node Metastasis and Predictors of Recurrence in Papillary Thyroid Carcinoma

There are about half of papillary thyroid carcinoma (PTC) patients with the experience of central lymph node metastasis (CLNM), while the model to predict high-risk groups of CLNM from PTC patients is uncertain. The aim of this study was to evaluate candidate risk factors of CLNM and identify risk factors of recurrence to guide the postoperative therapeutic decision and follow-up for physicians and patients.A total of 4107 patients(4884 lesions) who underwent lymph node dissection in two hospitals from 2005 to 2014 were evaluated. CLNM risk was stratified and a risk-scoring model was developed on the basis of the identified independent risk factors for CLNM. Cox's proportional hazards regression model was used to investigate the risk factors for recurrence.CLNM was proved in 37.96% (1559/4107) of patients and 33.96% (1659/4884) of lesions. In the multivariate analysis, Male, Age ≤35 years, Tumor size >0.5 cm,Lobe dissemination (+), Psammoma body (+), Multifocality and Capsule invasion (+) were independent risk predictors of CLNM (P  < 0.01). A 14-point risk-scoring model was built to predict the stratified CLNM in PTC patients and the area under receiver operating characteristic curve of the model for the prediction of CLNM was 0.672 (95% CI: 0.656-0.688) (P < 0.01). COX regression model showed that Tumor size >0.5 cm, Lobe dissemination (+), Multifocality and CLNM were significant risk factors associated with poor outcomes. The research suggested that prophylactic CLN dissection could be performed in patients with total score ≥4 according to the risk-scoring model, and more aggressive treatment and more frequent follow-up should be considered for patients with Tumor size >0.5 cm, Lobe dissemination (+), Multifocality and CLNM.

Current trends of practical issues concerning micropapillary thyroid carcinoma: The Korean Society of Thyroid-Head and Neck Surgery

Although several thyroid associations have published various guidelines, controversies especially in cases of micropapillary thyroid cancer (MPTC) still exist. This survey was designed to collect information about diagnostic tests and treatments performed on patients with MPTC and help identify current trends in thyroid surgery.We developed questionnaires about the management methods for MPTC, which were used to identify factors related to indications of fine needle aspiration (FNA), type of surgery, and central lymph node dissection (CLND). Active 60 members of the Korean Society of Thyroid-Head and Neck Surgery participated in the study in September 2016.Ultrasound-guided FNA was usually initiated when the tumor was at least 5 mm (60%). All respondents preferred ultrasound-guided FNA and surgery for nodules with extrathyroidal extension (ETE). The preferred treatment option for intraglandular MPTC was lobectomy (92%) rather than active surveillance (8%). Posterolateral ETE increased the respondents' preference for total thyroidectomy (61.7%). Active surveillance was preferred for tumors <5 mm, which was decreased by the presence of ETE. The presence of ETE (73.3%) and its proximity to critical organs (46.7%) were the main determining factors for prophylactic CLND. For multiple metastatic lymph nodes at level III, selective neck dissection including levels IIb (23.3%) and V (78.3%) was preferred in addition to levels IIa, III, VI, and V.Korean head and neck surgeons favored total thyroidectomy and CLND in cases wherein ETE, central lymph node metastasis, or critical organ involvement was suspected.

Persistent and recurrent disease in patients with papillary thyroid carcinoma with clinically apparent (cN1), but not extensive, lymph node involvement and without other factors for poor prognosis

OBJECTIVE

Lymph node metastases (LNM) are frequent in patients with papillary thyroid cancer (PTC). The risk of persistent disease (PD) and tumor recurrence (TR) is increased when factors for poor prognosis other than LNM exist, when LNM are numerous, large, detected by preoperative ultrasonography (US), or exhibit extranodal extension. This study evaluated the risk of PD and TR in patients with LNM not exhibiting these characteristics.

SUBJECTS AND METHODS

Eighty-six patients with 5 or fewer LNM detected during intraoperative inspection, but not by preoperative US, who had no other factors for poor prognosis [tumors > 4 cm, extensive extrathyroid invasion, vascular invasion, aggressive histological subtype, distant metastases, incomplete tumor resection], were studied. All patients underwent total thyroidectomy followed by radioiodine ablation. PD was defined as metastases on initial post-therapy whole-body scans (RxWBS) or detected by imaging methods up to 12 months after ablation. TR was defined as structural disease diagnosed more than one year after ablation in patients without PD.

RESULTS

PD was diagnosed in 3/86 patients (3.5%). TR was observed in 2/83 patients (2.5%) after 62 months of follow-up. There was no case of death due to the disease. A correlation was observed between pre-ablation Tg and PD or TR [1/48 (2%) with Tg ≤ 2 ng/mL versus 2/22 (9%) with Tg > 2 ≤ 10 ng/mL versus 2/7 (28.5%) with Tg ≥ 10 ng/ml)]. It is noteworthy that 38 patients had up to 3 positive LN and pre-ablation Tg ≤ 2 ng/ml, and none of them had PD or TR.

CONCLUSIONS

The frequency of PD and TR was low in patients with PTC with 5 or fewer LNM and without other factors for poor prognosis. Low postoperative stimulated Tg was predictive of the absence of PD and TR in these patients.

Prognostic Value of Extranodal Extension in Thyroid Cancer: A Meta-Analysis

PURPOSE

Thyroid cancer is the most common endocrine cancer and its incidence has continuously increased in the last three decades all over the world. We aimed to evaluate the prognostic value of extranodal extension (ENE) of thyroid cancer.

MATERIALS AND METHODS

We performed a systematic search of MEDLINE (from inception to June 2014) and EMBASE (from inception to June 2014) for English-language publication. The inclusion criteria were studies of thyroid cancer that reported the prognostic value of ENE in thyroid cancer. Reviews, abstracts, and editorial materials were excluded, and duplicate data were removed. Two authors performed the data extraction independently.

RESULTS

6 studies including 1830 patients were eligible for inclusion in the study. All patients included in the meta-analysis had papillary thyroid cancer (PTC). Recurrence-free survival was analyzed based on 3 studies. The pooled hazard ratio for recurrence was 2.01 [95% confidence interval (CI) 1.19-3.40, p=0.009]. Disease-specific survival was analyzed based on 3 studies with 973 patients. Patients of PTC with ENE showed 3.37-fold higher risk of death from the disease (95% CI 1.55-7.32, p=0.002).

CONCLUSION

ENE should be considered to be a poor prognostic marker in thyroid cancer; such knowledge might improve the management of individual patients. This might facilitate the planning of appropriate ablation therapy and tailored patient follow-up from the beginning of treatment.

The Impact of Metastatic Lymph Nodes on Risk Stratification in Differentiated Thyroid Cancer: Have We Reached a Higher Level of Understanding?

BACKGROUND

The revised American Thyroid Association (ATA) management guidelines for differentiated thyroid cancer emphasize a variety of clinicopathologic features of metastatic lymph nodes in determining the risk of recurrence. The mere presence of a positive node is not sufficient to confer reliable prognostic significance. The number and size of lymph nodes, as well as the presence of extranodal extension (ENE), impact risk stratification. Moreover, the presence of clinically evident lymph nodes is important for determining risk of recurrence. A patient's place on the risk spectrum has ramifications for the management of differentiated thyroid cancer. However, there are inherent inconsistencies in the identification and characterization of metastatic lymph nodes. Moreover, the significance of ENE must be clarified.

SUMMARY

There are many obstacles to the consistent reporting of metastatic lymph nodes. What constitutes a "clinically evident" lymph node has not been well defined, lacks precision, and varies depending on clinical context, as well as the experience of the surgeon and the ultrasonographer. The number of lymph nodes sampled by surgeons and reported by pathologists may vary from institution to institution. The literature on ENE has been limited by the fact that the definition of ENE has not been standardized. Nevertheless, 17/19 manuscripts reviewed herein suggest that ENE confers a worse prognosis. The ATA risk stratification for metastatic lymph nodes published in the 2015 guidelines combines clinicopathological features that are variably identified and reported across institutions. This review brings into question the significance of the number of nodes with ENE, a factor that is used as an important stratifying variable in the latest guidelines.

CONCLUSIONS

Metastatic lymph nodes do not all carry the same prognostic significance, but a risk assignment based on the ATA guidelines is limited by a lack of standardization in clinical and pathologic definitions, lymph node sampling, and reporting. This study reviews the limitations of prior studies on ENE and concludes that the body of the evidence reported in those studies suggests that ENE increases the risk of recurrence. The impact of ENE in lymph nodes in thyroid cancer risk stratification should be reconsidered.

Pathologic features of metastatic lymph nodes identified from prophylactic central neck dissection in patients with papillary thyroid carcinoma

The importance of pathologic features of metastatic lymph nodes (LNs), such as size, number, and extranodal extension, has been recently emphasized in patients with papillary thyroid carcinoma (PTC). We evaluated the characteristics of metastatic LNs identified after prophylactic central neck dissection (CND) in patients with PTC. We performed a retrospective review of 1,046 patients who underwent unilateral or bilateral thyroidectomy with ipsilateral prophylactic CND. We reviewed the characteristics of the metastatic LNs and analyzed their correlation to the clinicopathologic characteristics of the primary tumor. Cervical LN metastasis after prophylactic CND was identified in 280 out of 1046 patients (26.8 %). The size of metastatic foci (≥2 mm) was independently correlated with primary tumor size (≥1 cm) (p = 0.016, OR = 1.88). Primary tumor size (≥1 cm) was also correlated to the number of metastatic LNs (≥5) (p = 0.004, OR = 3.14) and extranodal extension (p = 0.021, OR = 2.41) in univariate analysis. The size of the primary tumor affects pathologic features of subclinical LN metastasis in patients with PTC. Patients with primary tumors ≥1 cm have an increased risk of larger LN metastases (≥2 mm), an increased number of LN metastases (≥5), and a higher incidence of ENE, which should be considered in decision for prophylactic CND.

Significance of the Extracapsular Spread of Metastatic Lymph Nodes in Papillary Thyroid Carcinoma

OBJECTIVES

The extracapsular spread (ECS) of metastatic lymph nodes is associated with aggressive tumor behavior, and is regarded as a major risk factor for local recurrence in patients with head and neck squamous cell carcinoma. However, the significance of ECS of metastatic lymph nodes has not been well established in well-differentiated thyroid carcinoma. The purpose of this study was to examine this question.

METHODS

A retrospective review was performed of 335 patients with papillary thyroid carcinoma who underwent total thyroidectomy with lymph node dissection from April 2001 to December 2009. We analyzed various clinical characteristics, pathologic factors, and the size, number, and ECS of foci in metastatic lymph nodes.

RESULTS

On pathologic review, 201 of the patients (56.6%) had lymph node metastasis. This was significantly related to age and tumor size. ECS was noted in 64 of these 201 patients (31.8%), and was significantly related to male gender, tumor size, presence of extrathyroidal extension, metastatic lymph node size, and focus size. Recurrence occurred in 13 patients (3.9%), and the presence of ECS was significantly related to recurrence.

CONCLUSION

ECS of metastatic lymph nodes is an important prognostic factor for loco-regional recurrence in papillary thyroid carcinoma.

Characteristics of neck level VI lymph nodes in papillary thyroid carcinoma: correlation between nodal characteristics and primary tumor

Little is known about the pathological characteristics of metastatic and nonmetastatic lymph nodes (LNs) in papillary thyroid carcinoma (PTC). The aim of this study was to elucidate the pathological characteristics of neck level VI nodes and correlations with clinicopathological parameters. We investigated the clinicopathological features of 124 classical PTCs and characteristics of 850 dissected neck level VI LNs. Immunohistochemistry for nuclear factor-κB (NF-κB) and Ki-67 was performed on primary tumors, and correlations with nodal characteristics were investigated. Nodal metastasis at neck level VI was identified in 68 of 124 PTCs (54.8 %) and was significantly correlated with tumor size, tumor multifocality, extrathyroidal extension, and tumor stage. LN metastasis was significantly correlated with larger mean LN size (P < 0.001), larger size of the largest LN (P < 0.001), and more LNs (P < 0.001). The mean size of metastatic LNs (n = 233) was significantly larger than nonmetastatic LNs (n = 617) (P < 0.001). Primary tumor diameter significantly correlated with the largest LN size (P = 0.014, R (2) = 0.049), but not mean size or number of LNs by linear regression analysis. NF-κB and Ki-67 proliferation indexes were not significantly correlated with larger nodal size. These results suggested that characteristics of nodes and primary tumor would be useful criteria for making decisions about preoperative surveillance of nodal metastasis.

Lateral Neck Lymph Node Characteristics Prognostic of Outcome in Patients with Clinically Evident N1b Papillary Thyroid Cancer

PURPOSE

To identify lateral lymph node (LN) characteristics predictive of outcome in papillary thyroid cancer patients with clinically evident nodal disease.

METHODS

A total of 438 patients with lateral neck metastases from papillary thyroid cancer were identified from an institutional database of 3,664 differentiated thyroid cancers. The number of positive LNs, size of the largest LN, number of positive LNs to total number of LNs removed (LN burden), and presence of extranodal spread (ENS) were recorded. Cutoffs for continuous variables were determined by receiver operating characteristic curves. LN variables predictive of recurrence free survival and disease-specific survival (DSS) were identified by the Kaplan-Meier method and the Cox proportional hazard model.

RESULTS

The median age was 41 years (range 5-86 years). The median follow-up was 65 months (range 1-332 months). Fifty-nine patients developed disease recurrence; these were local in five, regional in 40, and distant in 30 patients. Fifteen patients died of disease. Receiver operating characteristic cutoffs were >10 positive LNs and a LN burden >17 %. No lateral LN characteristics were predictive of DSS. In patients <45 years old, univariate predictors of recurrence were >10 positive nodes (p = 0.049) and LN burden >17 % (p < 0.001). In patients ≥45 years old, >10 positive nodes, LN burden >17 %, and presence of ENS were predictive of recurrence (p = 0.019, p = 0.019, and p = 0.029, respectively).

CONCLUSIONS

LN burden >17 % (1 positive LN in 6 LNs removed) in the lateral neck is predictive for recurrence in patients of all ages, whereas ENS is also prognostic for recurrence in older patients.

Long-term outcomes of observation for clinically negative central compartment lymph nodes in papillary thyroid carcinoma

The treatment strategy for clinically negative lymph nodes of papillary thyroid carcinoma is controversial. We report the long-term outcomes of a series of cases treated with thyroidectomy without prophylactic central neck dissection. We reviewed 1,397 cases with papillary thyroid carcinoma treated at our institution between 1991 and 2000. One hundred and seventy-two newly diagnosed cases underwent observation for cN0 central neck lymph nodes. Regional recurrence of the ipsilateral side including central compartment and the lateral neck which needs reoperation was considered as key point for analysis. With a mean follow-up of 96.4 months (34-204 months), the overall 10-year disease-specific and recurrence-free survival rates were 99 and 86 %, respectively. The recurrence and reoperation rates of the central compartment were 3 % (5/172) and 4 % (7/172), respectively. Univariate analysis showed that extrathyroidal extension was associated with regional recurrence (99 vs. 82 %; p = 0.002). Central compartment observation is safe in cN0 cases with papillary thyroid carcinoma, particularly in those without extrathyroidal extension.

Central lymph node characteristics predictive of outcome in patients with differentiated thyroid cancer

BACKGROUND

The aim of our study was to determine central compartment lymph node (LN) characteristics predictive of outcomes in patients with differentiated thyroid cancer (DTC) and pathologically confirmed positive central LNs, in the absence of lateral neck disease or distant metastases at presentation.

METHODS

An institutional database of 3664 previously untreated patients with DTC operated between 1986 and 2010 was reviewed. Six hundred patients with central compartment nodal disease on histopathology were identified. Patient demographics, number of positive LNs, size of largest LN, and presence of extranodal spread (ENS) were recorded for each patient. Variables predictive of recurrence-free survival (RFS) were identified using the Kaplan-Meier method. Univariate analysis was carried out by the log-rank test and multivariable analysis was carried out using cox proportional hazard model.

RESULTS

The median age of the cohort was 41 years (range 12-91 years). The median follow-up was 61 months (range 1-330 months). Neck recurrence occurred in 43 patients. Recurrence occurred in the central neck in 11 patients, lateral neck in 27 patients, and both compartments in five patients. Factors predictive of neck RFS on univariate analysis were higher T stage (p=0.007), increased number of positive LNs, increased LN diameter, and presence of ENS (p=0.001). Multivariable analysis of LN characteristics showed that the only statistically significant predictor of neck recurrence was the presence of ENS. Neck RFS at five years for patients with and without ENS was 84.7% and 94.5% respectively (p=0.001).

CONCLUSION

The LN feature most predictive of neck recurrence appears to be the presence of ENS in the positive central neck.

Ultrasonographic findings relating to lymph node metastasis in single micropapillary thyroid cancer

Background

In thyroid cancer, preoperative ultrasonography (US) is performed to detect the primary tumor and lymph node metastasis (LNM), which are related to prognosis. This study examined the relationships between specific US findings and LNM in micropapillary thyroid cancer (MPTC).

Methods

Data on 220 patients with solitary MPTC who underwent total thyroidectomy and neck dissection between 2008 and 2009 were evaluated retrospectively. We classified the US findings according to the nature, shape, echogenicity, extent, margin, and calcification of the primary tumor and evaluated the correlations between these findings and those of LNM.

Results

Hypoechogenicity (odds ratio = 2.331, P = 0.025) and marked hypoechogenicity (OR = 4.032, P = 0.016) of MPTC were risk factors for central LNM. All of the patients with lateral cervical LNM showed hypoechogenicity or marked hypoechogenicity. Hypoechogenicity (odds ratio = 5.349, P = 0.047) and other types of calcification (odds ratio = 2.495, P = 0.010) were significant risk factors for lateral cervical LNM.

Conclusions

Specific sonographic findings (hypoechogenicity or marked hypoechogenicity, and calcification) suggest LNM.

Prediction of thyroid extracapsular extension with cervical lymph node metastases (ECE-LN) by CEUS and BRAF expression in papillary thyroid carcinoma

The aim of our study was to find a specific imaging (contrast-enhanced ultrasound, CEUS) to detect extracapsular extension and cervical lymph node metastases (ECE-LNM) that associated with BRAF protein expression in papillary thyroid carcinoma (PTC). Preoperative utrasonography (US) or CEUS was performed in the diagnosis of extracapsular extension (ECE) in 317 patients with 369 PTC. BRAF protein status was tested on the primary tumor and lymph node involvement. The diagnostic accuracy of CEUS and US was evaluated after thyroid surgery. The association between CEUS and BRAF expression were then analyzed to investigate the diagnostic value of ECE-LNM in PTC. The sensitivity and specificity of CEUS were higher than those in US in the diagnosis of ECE in patients with PTC (91.1, 86.5 vs 49, 55 %). BRAF protein overexpression were significantly associated with ECE (P = 0.0003) and lymph node metastasis (LNM) positive cases (P = 0.0014). The results of CEUS, not US, have a significant correlation with BRAF expression status in PTC samples (P < 0.0001). Associated with BRAF protein expression status, the routine preoperative CEUS could have a good value in the diagnosis of ECE-LNM in PTC and facilitate a surgeon to improve further clinical management.