Correlation analysis and clinical significance of lymph node metastasis in right recurrent laryngeal nerve of papillary thyroid carcinoma

Objective To explore the correlation factors and clinical significance of lymph node metastasis in right recurrent laryngeal nerve of thyroid papillary carcinoma (PTC). Methods Ninty-eight consecutive patients with PTC who were underwent total thyroidectomy with routine central lymph node dissection in the Second People′s Hospital of Hefei from January 2015 to August 2017 were analyzed. The right paratracheal lymph nodes in the central compartment lymph nodes were divided into the level Ⅵ-A (anterior) and level Ⅵ-B (posterior, that was lymph node posterior to recurrent laryngeal nerve) compartments by recurrent laryngeal nerve. The lymph node metastasis of Ⅵ-B area during central compartment lymph node dissection was analyzed. We drew the receiver-operating characteristic curve (ROC) for right neck Ⅵ-A number of lymph node metastasis, and calculated the area under the curve (AUC) and Youden index. Results Among 98 cases, 16 cases occurred Ⅵ-B district lymph node metastasis (16.33%). Single factor analysis results showed that lymph node metastasis in Ⅵ-B area of PTC patients were related to the tumor size (χ2=12.864, P 0.05). Lymph node metastasis in Ⅵ-B area of PTC patients were related to the number of right neck Ⅵ-A area lymph node metastasis. When the number of right neck Ⅵ-A metastatic lymph nodes was 2.5, the sensitivity and specificity were 70.60% and 70.00% respectively, AUC was 0.754, and Youden index was 0.406. Conclusion For patients with PTC, primary tumor diameter >1 cm, tumor extracapsular invasion, Ⅵ-A area lymph node metastasis, multiple tumor and lateral cervical lymph node metastasis were the predictive factors for the lymph node metastasis in Ⅵ-B area. When the number of right neck Ⅵ-A area metastatic lymph nodes was greater than 3, we should dissect Ⅵ-B area. Key words: Thyroid neoplasms; Papilloma; Lymphatic metastasis; Lymph node posterior to right recurrent laryngeal nerve