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

Abstract

ObjectivesThe 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.MethodsA 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.ResultsOn 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.ConclusionECS of metastatic lymph nodes is an important prognostic factor for loco-regional recurrence in papillary thyroid carcinoma.

Lymph node metastasis around the entrance point to recurrent laryngeal nerve in papillary thyroid carcinoma

“…Therefore, it's important to improve the thoroughness of CLND. Our results mirror the data from literature: Reoperative CLND has been shown to have rates of RLN injury 21% transiently and postoperative hypocalcemia with a large range of 0-24% [23][24][25][26][27][28][29][30] . However, the incidence of complications varies according to the skill and experience of the surgeon [7,31] .…”

Extranodal extension of lymph node metastasis as a prognostic indicator of recurrence and survival in papillary thyroid carcinoma

“…Yamashita et al first identified the prognostic importance of ENE as an indicator of distant metastasis in a case‐control study including 100 PTC patients . The close relationship between ENE and distant metastasis was also identified by Sugitani et al Thereafter, several studies have reported that ENE predicts high risk of recurrence and impaired cancer‐specific survival . Lango et al found that, after treatment, patients with ENE are less likely to have a complete biochemical response (a stimulated serum Tg of <1 ng/mL) and have an increased probability of tumor persistence after thyroidectomy, indicating eventual systemic disease progression .…”

“…10 The close relationship between ENE and distant metastasis was also identified by Sugitani et al 22 Thereafter, several studies have reported that ENE predicts high risk of recurrence and impaired cancer-specific survival. 7,9,11,14,23 They found that minimally invasive ETE was associated with a 13-fold increased incidence of ENE compared to tumors without ETE, and that tumors associated with ENE as well as ETE were larger, compared with those without either ETE or ENE (mean 2.3 vs 1.4 cm, P = 0.004). 23 However, small metastatic LNs have been shown to have ENE: 59% of the metastatic LNs with ENE were smaller than 1.5 cm, 26 the threshold size for recurrence previously reported by Ito et al 27 Our study also highlighted the close relationship between macroscopic ETE with ENE or macroscopic ENE, and showed that a higher number of metastatic LNs (>5) was also associated with ENE.…”

“…Therefore, the size and number of metastatic LNs has been included in the risk stratification system of structural disease recurrence recently proposed by the American Thyroid Association (ATA) . Furthermore, extranodal extension (ENE) of metastatic LNs is recognized as an important prognosticator of increased nodal persistence, distant metastasis, and cancer‐related death . However, the tumor‐node‐metastasis (TNM) staging system proposed by the American Joint Committee on Cancer (AJCC) does not include ENE …”

“…8 Furthermore, extranodal extension (ENE) of metastatic LNs is recognized as an important prognosticator of increased nodal persistence, distant metastasis, and cancer-related death. [9][10][11][12] However, the tumornode-metastasis (TNM) staging system proposed by the American Joint Committee on Cancer (AJCC) does not include ENE. 13 The presence of microscopic ENE is indicative of a higher risk of PTC recurrence, 14 and macroscopic ENE increases the risk of recurrence to 14.5% compared to 2.4% with no metastatic LNs or ENE.…”