Skip Metastases in Papillary Thyroid Carcinoma - Prevalence, Predictive and Clinicopathological Factors

Predictive Factors Affecting the Development of Lateral Lymph Node Metastasis in Papillary Thyroid Cancer

Objectives

Lateral lymph node metastasis (LLNM) in papillary thyroid cancer (PTC) determines the extent of surgery to be performed and the prognosis of the disease. In this study, we aimed to evaluate the clinicopathological risk factors affecting the development of LLNM.

Methods

We retrospectively evaluated the demographic and clinicopathological data of 346 cases with PTC who were operated in our clinic between May 2012 and September 2020. The patients were divided into 2 groups as patients with LLNM (Group 1) and without LLNM (Group 2).

Results

Thirty-six (10.4%) patients out of 346 patients with PTC had LLNM. A statistically significant difference was found between Group 1 and Group 2 regarding the male gender (M/F: 38.9% vs. 21.6%; p=0.020), tumor size (2.30±1.99 cm vs. 1.31±1.40 cm; p=0.000), lymphovascular invasion (69.4 vs. 20.6%; p=0.000), multicentricity (69.4% vs. 35.5%; p=0.000), multifocality (p=0.000), aggressive variant (22.2% vs. 9.4%; p=0.000), extrathyroidal extension (50% vs. 16.1% p=0.000), central lymph node metastasis (CLNM) rates (75% vs. 6.5%; p=0.000), and ≥3 cm lymph node metastasis (48.5% vs. 0%, p=0.000), distant metastasis (2.1% vs. 0%, p=0.000), respectively. Multivariance analysis determined the presence of CLNM as an independent risk factor for the development of LLNM.

Conclusion

The presence of CLNM in patients with PTC was determined as an independent risk factor for the development of LLNM. Although there has been increasing debate about prophylactic central neck dissection (pCND) in LLNM, pCND should still be considered in these patients as the rate of CLNM is high in patients with LLNM. CLNM might be a reference for surgeons to determine the extent of surgery. In addition, the presence of CLNM is important for close follow-up for the early detection of LLNM recurrence.

Analysis of factors influencing cervical lymph node metastasis of papillary thyroid carcinoma at each lateral level

Objective

To analyze the clinicopathological characteristics of patients with papillary thyroid carcinoma (PTC) and its influence on the distribution of lymph node metastasis at each lateral level of the neck to guide precise treatment of the lateral area.

Methods

The clinicopathological data of patients with PTC initially diagnosed and treated at our hospital from February 2014 to September 2021 were collected; the metastatic status of each lateral level was recorded, and correlations were analyzed.

Results

A total of 203 patients were enrolled in this study. There were 67 males and 136 females, with an average age of 41.1 years. In the lateral cervical area, lymph node metastasis was found at level IIa in 81 patients (39.9%); level III, 171 patients (84.2%); level IV, 122 patients (60%); and level Vb, 18 patients (8.9%). Correlation analysis showed that age (r = 0.198, P < 0.01) and sex (r = 0.196, P < 0.01) were weakly correlated with the number of positive lymph nodes in the central region. The tumor size (r = 0.164, P < 0.05) was weakly correlated with lymph node metastasis at level IV. The presence of multiple tumor foci was weakly correlated with lymph node metastasis at level IIa (r = 0.163, P < 0.05) and Vb (r = 0.143, P < 0.05). The tumor location (r = − 0.168, P < 0.05) was weakly correlated with lymph node metastasis at level III. The number of positive lymph nodes in the central region (r = 0.189, P < 0.01) was weakly correlated with lymph node metastasis at level IV. Binary logistic regression analysis showed that the risk of metastasis of multifocal tumors was higher than that of unifocal tumors by 1.958 times at level IIa (P = 0.021, OR = 1.958) and 2.929 times at level Vb (P = 0.049, OR = 2.929). The higher the tumor was located, the higher the risk of metastasis at level III (P = 0.014, OR = 0.563). Every additional positive lymph node in the central region increased the risk of metastasis at level IV by 1.126 times (P = 0.009, OR = 1.126).

Conclusions

For patients with pathological evidence of lateral metastasis, standard dissection of level IIa through Vb is recommended; selective dissection requires careful consideration. Patients with multifocal tumors have a high risk of metastasis at levels IIa and Vb, which requires special attention during the operation.

Related factor analysis for predicting large-volume central cervical lymph node metastasis in papillary thyroid carcinoma

The aim of this study was to investigate the factors related to large-volume central cervical lymph node metastasis (LNM) in papillary thyroid carcinoma. A retrospective study of 340 patients with 642 papillary thyroid carcinoma nodules who underwent thyroidectomy in Peking Union Medical College Hospital between 2011 and 2015 was conducted. These nodules were divided into two groups by the number of central cervical lymph node metastases: large-volume central cervical LNM (>5 metastatic lymph nodes, n = 129) and no central cervical LNM (n = 211). We evaluated the correlations between gender, age, chronic lymphocytic thyroiditis, thyroid ultrasonographic features, and large-volume central cervical LNM. We found that younger age (≤40 years) (OR = 3.796, 95% CI = 2.842, 5.070), male gender (OR = 4.005, 95% CI = 2.858, 5.61), and ultrasonographic features such as tumor macroaxis size (OR = 2.985, 95% CI = 1.581, 5.633), tumor located in the isthmus (OR = 7.578, 95% CI = 4.863, 11.810), ill-defined margin (OR = 3.008, 95% CI = 1.986, 4.556), microcalcification (OR = 2.155, 95% CI = 1.585, 2.929), and abnormal cervical lymph nodes (OR = 13.753, 95% CI = 9.278, 20.385) were independent risk factors for large-volume central cervical LNM in papillary thyroid carcinoma, while chronic lymphocytic thyroiditis (OR = 0.248, 95% CI = 0.172, 0.358) was a protective factor. Younger age (≤40 years), male sex, and ultrasonographic features such as tumor macroaxis size, tumor located in the isthmus, ill-defined margin, microcalcification, and abnormal cervical lymph nodes were independent risk factors for large-volume central cervical LNM in papillary thyroid carcinoma, while chronic lymphocytic thyroiditis can be considered a protective factor. Our results provide a reference for adjusting clinical treatment approaches.