Management of Lateral Multiple-Level Metastasis in N1b Papillary Thyroid Microcarcinoma

Abstract

Background: The optimal extent of therapeutic lateral neck dissection (LND) in the management of N1b papillary thyroid microcarcinoma (PTMC) is still under debate in clinical practice. In this light, our study aims to explore the incidence, patterns, and predictive factors of the lateral multiple-level metastasis in N1b PTMC patients. Methods: The clinical records of 142 patients diagnosed with N1b PTMC who underwent therapeutic LND from July 2015 to November 2018 at our institution were retrospectively reviewed. Univariate and multivariate analyses were conducted to examine the predictive factors associated with lateral multiple-level metastasis. The recurrence-free survival was analyzed and confirmed by Kaplan–Meier plots and log-rank test. Results: The overall frequency of lateral multiple-level metastasis was 50.7% in N1b PTMC patients, and two-level to four-level simultaneous metastasis were present in 26.8, 17.6, and 6.3% patients, respectively. Extrathyroidal extension (ETE) (OR = 5.79, 95% CI, 1.36–24.59; P = 0.017) and the central metastatic lymph node ratio (CLNR) with values equal or higher than 0.61 (OR = 6.18, 95% CI, 2.53–15.09; P < 0.001) served as independent predictors of multiple-level metastasis in N1b PTMC patients. Moreover, locoregional recurrence was significantly higher in the selective neck dissection (SND) group compared to the modified radical neck dissection (MRND) one (HR = 3.65, 95% CI, 1.11–12.00; P = 0.03). Conclusion: Our results show that the lateral multiple-level metastasis was relatively common, and we suggest MRND to be considered for N1b PTMC patients with ETE or CLNR equal or higher than 0.61.

The optimal extent of lymph node dissection in N1b papillary thyroid microcarcinoma based on clinicopathological factors and preoperative ultrasonography

“…SND refers to dissection of the lateral LNs, sparing ≥1 of the lateral neck levels. SND may be accompanied by a high local recurrence rate (9,10), and MRND can result in a certain degree of shoulder dysfunction and sensory changes (6,11), caused by dissection, traction, or transection of the nerve, which impairs the patient's quality of life (12). The main goal of the clinical management of PTMC is to prevent disease recurrence, reduce patient deaths, and minimize treatmentrelated adverse events.…”

Clinical and prognosis value of the number of metastatic lymph nodes in patients with papillary thyroid carcinoma

“…However, the incidence and recurrence rate of PTC is gradually increasing throughout the world [ 2 , 3 ]. Further, it has been reported that 66.7% of recurrence incidences of PTC occurred between 5 and 10 years after operation [ 4 , 5 ]. Notably, when recurrence and distant metastasis occur, the treatment of PTC is usually more compliable and difficult.…”

Can Cervical Lymph Node Metastasis Increase the Risk of Distant Metastasis in Papillary Thyroid Carcinoma?

“…Papillary thyroid carcinoma (PTC) was the most frequent histological subtype of thyroid malignancy which has a rapidly rising incidence worldwide in the last few decades (1,2). In total, 20.7-62% of patients with PTC present cervical lymph node metastasis (LNM) at initial diagnosis, which was associated with a poor prognosis (3,4), yet the recently updated 8th edition of the TNM staging system eliminates the difference between central (N1a) and lateral (N1b) LNM, and N1b disease is not adopted for the final staging classification (5)(6)(7). These changes have been questioned, and concern arises in such a way that ignoring the metastatic lymph node sites may underestimate recurrence and mortality in patients with PTC.…”