Predictive Factors of Central-Compartment Lymph Node Metastasis for Clinical N0 Papillary Thyroid Carcinoma With Strap Muscle Invasion.

Meishan Jin,Li Zhang,Bingfei Dong,Guang Chen,Liang Guo,Shuai Xue,Peisong Wang,Yuhua Zhou,Renzhu Pang

doi:10.3389/fendo.2020.00511

Abstract

Background: Papillary thyroid carcinoma (PTC) patients with anterior extrathyroidal extension (ETE) involving the strap muscle have a relatively better prognosis than those with posterior gross ETE involving the recurrent laryngeal nerve. Whether prophylactic central-compartment lymph node dissection (CLND) should be performed in PTCs with only strap muscle invasion (SMI) is still unclear.Methods: A retrospective cohort study was conducted in clinical N0 (cN0) PTC patients with SMI who underwent thyroid surgery from 2009 to 2017. A total of 152 patients were included, and predictive factors of central-compartment lymph node metastasis (CLNM) were determined.Results: Among the 281 PTCs patients with SMI, 152 (51.1%) did not clinically present with lymph node metastasis. Microscopic CLNM was identified in 77 (50.7%) cN0 PTC patients with SMI. According to the univariate and multivariate analyses, male patients and those aged <40 years were more likely to be diagnosed with CLNM than female patients and those aged >40 years (odds ratio [OR] = 6.22 [95% confidence interval (CI), 1.43–27.10], p = 0.02 vs. OR = 9.94 [95% CI, 2.79–35.44], p = 0.00). The CLNM positive rate of male patients aged <40 years was 87.5%, while that for female patients aged ≥55 years was 23.8%. However, risk factors associated with large-volume CLNM were not identified because of the small number of patients.Conclusions: Taken together, nearly half of PTC patients with SMI did not clinically present with lymph node metastasis. Male sex and patients aged <40 years were identified as the predictive factors of CLNM in cN0 PTCs with SMI. Hence, the results of this single-center study raise the possibility that prophylactic CLND may be more often considered for younger male PTC patients with SMI.

Highlights

The incidence of papillary thyroid carcinoma (PTC) has significantly increased worldwide during the past decades [1, 2]
This study aimed to evaluate compartment lymph node metastasis (CLNM) in clinical N0 PTC with only strap muscle invasion (SMI) by performing a retrospective analysis of our clinical PTC cohort and identifying the clinicopathological features to predict CLNM, which may guide physicians in planning further treatment strategies
The inclusion criteria for patient selection were as follows: [1] patient information found in a hospital database; [2] postoperative pathological diagnosis of conventional PTC with SMI; and [3] absence of suspicious cervical lymph nodes observed during US, computed tomography (CT), and/or fine-needle aspiration

Summary

Introduction

The incidence of papillary thyroid carcinoma (PTC) has significantly increased worldwide during the past decades [1, 2]. Central-compartment lymph node metastasis (CLNM), considered a poor clinical feature, is associated with the prognosis of PTC [3, 4]. Patients with >5 lymph node metastasis (LNM), are associated with structural recurrence, distant metastasis, and mortality [4, 5], even despite being micrometastases. Prophylactic central-compartment lymph node dissection (CLND) was recommended for T3 or T4 primary tumors, or if the information of LNM would be used to plan further treatment strategies, like completion thyroidectomy or radioiodine ablation [5]. Papillary thyroid carcinoma (PTC) patients with anterior extrathyroidal extension (ETE) involving the strap muscle have a relatively better prognosis than those with posterior gross ETE involving the recurrent laryngeal nerve. Whether prophylactic central-compartment lymph node dissection (CLND) should be performed in PTCs with only strap muscle invasion (SMI) is still unclear

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