Predictors of lateral lymph node metastasis and skip metastasis in patients with papillary thyroid microcarcinoma.

Papillary thyroid microcarcinoma (PTMC) is characterized by its favorable prognosis and potential for active surveillance (AS) as a management option. However, the presence of cervical lymph node (LN) metastasis, especially lateral LN metastasis, significantly impacts management and prognosis. Previous studies have focused on post-surgery risk factors for cervical LN metastasis. This study aims to identify predictors of lateral LN metastasis by analyzing pre-operative ultrasonographic findings alongside clinicopathological factors. A retrospective review of medical records was conducted for patients with PTMC who underwent surgery at Chonnam National University Hwasun Hospital between 2004 and 2013. This is a case-control study that compares patients with lateral LN metastasis (N1b) to age- and sex-matched patients without LN metastasis (N0). Subgroup analysis was performed to evaluate risk factors of skip metastasis. The study included 90 patients with PTMC with lateral LN metastasis (N1b) and 268 age- and sex-matched patients without LN metastasis (N0). The mean age was 49.3 years, and female patients were dominant in both groups. Structural recurrences of 4.4% (4/90) were observed only in the N1b group. The N1b group exhibited a higher frequency of upper lobe tumor location compared to the N0 group (38.9% vs. 16.0%, p < 0.001). There was no significant difference in the locations with the presence of invasion to adjacent organs. A higher proportion of non-parallel shape was observed in the N1b group than the N0 group (80.0% vs. 66.0%, p = 0.013). There were no differences in echogenicity, sonographic feature, margin, and AP diameter of the thyroid gland between the two groups. In multivariate analysis, independent risk factors for lateral LN metastasis included extrathyroidal extension, multiplicity, upper lobe tumor location, and non-parallel shape. Skip metastasis in patients with PTMC was associated with upper lobe tumor location. Detailed ultrasound examinations, evaluating tumor location, number, orientation, and the presence of ETE, are crucial in accurately predicting lateral LN metastasis especially when primary tumor was in the upper lobe to avoid missing skip metastasis. These evaluations can help guide the decision between AS and immediate surgery in patients with PTMC.

Yoon JH ，Park JY ，Hong AR ，Kim HK ，Kang HC ... -  《Frontiers in Endocrinology》

Lateral lymph node metastasis in papillary thyroid carcinoma: results of therapeutic lymph node dissection.

Chung YS ，Kim JY ，Bae JS ，Song BJ ，Kim JS ，Jeon HM ，Jeong SS ，Kim EK ，Park WC ... -  《-》

Predictive factors of lateral lymph node metastasis in solitary papillary thyroid microcarcinoma without gross extrathyroidal extension.

Solitary papillary thyroid microcarcinoma (PTMC) without gross extrathyroidal extension (ETE) were the main candidates for active surveillance (AS). Predictive factors of lateral lymph node metastasis (LLNM) in solitary PTMC without gross ETE were essential but still unknown. Altogether, 171 patients of solitary PTMC without gross ETE were enrolled in our study and divided into two groups. Group A: 123 patients without lateral lymph node dissection (LLND) were considered to be LLNM negative because there was no lateral recurrence by at least 8-year follow up for all patients. Group B: 48 patients with LLND were considered to be LLNM positive which confirmed by postoperative pathology. Multivariate logistic regression showed male gender, upper location of tumor and diameter of tumor ≥7 mm to be predictive factors (odds ratio = 4.237 [confidence interval (CI) 1.365-13.149, p = 0.012; odds ratio = 2.933 [CI 1.117-7.700, p = 0.029; odds ratio = 4.557 [CI 1383-15.016, p = 0.013) for LLNM in solitary PTMC patients without gross ETE. Multiple level metastasis happened in 29 (60.42%) cases while single level metastasis in 19 (39.58%). Within the lateral cervical lymph node chain, level Ⅲ nodes were consistently the most frequently involved (38/48, 79%), following by level Ⅳ (27/48, 56%), level Ⅱ (25/48, 52%) and level V (5/48, 10%). Most interesting, there are 12 (12/48, 25%) skip metastatic (positive in lateral neck and negative in central neck) patients among LLNM positive group. Male gender, upper location of tumor and diameter of tumor ≥0.7 cm to be predictive factors of LLNM in solitary PTMC without gross ETE.

Zhang X ，Zhang L ，Xue S ，Wang P ，Chen G ... -  《-》

Features of papillary thyroid microcarcinoma associated with lateral cervical lymph node metastasis.

Papillary thyroid microcarcinoma (PTMC) has an excellent prognosis with an indolent disease course. However, some PTMCs have an aggressive course with lateral cervical lymph node (LCLN) metastasis or distant metastasis. This study aimed to evaluate the pre-operative features of PTMC associated with LCLN metastasis. This retrospective cohort study with a nested, matched case-control design included 199 PTMC patients with LCLN metastasis at initial surgery (N1b group) and 196 PTMC patients without any LN metastasis or persistent disease (N0 NED group) as controls; primary tumour sizes were matched. Compared with the N0 NED group, the N1b group was younger (<50 years) and more likely to be male (P = 0·002 and P = 0·003, respectively). On pre-operative neck ultrasonography (US), N1b group PTMCs were more commonly associated with a location in the upper lobes of the thyroid, or in the subcapsular area and microcalcifications than N0 NED group PTMCs (all P < 0·001). An increase in the number of these features was significantly associated with a higher risk of LCLN metastasis (P < 0·001). Evaluation of the clinical and pre-operative US characteristics of 26 patients with confirmed LCLN recurrence after initial treatment of clinical N0 PTMCs revealed that the distribution of the number of suspicious features in these patients was similar to that of the N1b group. Papillary thyroid microcarcinomas in young (<50 years) or male patients, with an upper lobe or subcapsular location, and with microcalcification have a higher risk of LCLN metastasis. Individualized management according to the number of these suspicious features may be needed for small thyroid nodules.

Jeon MJ ，Chung MS ，Kwon H ，Kim M ，Park S ，Baek JH ，Song DE ，Sung TY ，Hong SJ ，Kim TY ，Kim WB ，Shong YK ，Lee JH ，Kim WG ... -  《-》

Central lymph node metastasis is an important prognostic factor in patients with papillary thyroid microcarcinoma.

Lee J ，Song Y ，Soh EY 《-》